Re: [Emc-users] Question to electrics gurus: Correct setup forrectifier + capacitor

[Thaddeus Waldner]

Here’s a reference design that includes a soft power up feature.


https://www.infineon.com/dgdl/Infineon-AN2018-35_EVAL-M1-IM818-A-UserManual-v01_04-EN.pdf?fileId=5546d462677d0f460167bb2df0121ab1
Infineon-AN2018-35_EVAL-M1-IM818-A-UserManual-v01_04-EN
PDF Document · 1.7 MB



> On Aug 7, 2024, at 7:30 AM, gene heskett  wrote:
> 
> On 8/7/24 03:41, Viesturs Lācis wrote:
>> trešd., 2024. g. 7. aug., plkst. 00:21 — lietotājs Chris Albertson
>> () rakstīja:
>>> 
>>> The capacitor is charged when the switch is closed.   A huge current will 
>>> flow into the capacitor until it is “full”.  The usual solutions are to (1) 
>>> use a slow-blow fuse that can withstand the surge current or place a low 
>>> value power resister in series with the AC to limit maximum current.   
>>> Inductors can do this better than resistors.
>>> 
>> Yes, the inrush current that charges the capacitor is what I am
>> thinking about now. I would prefer taking some ferrite ring and wrap
>> the wire around it and be happy but I have no idea if that is how it
>> works and I was not able to find any place to explain how to
>> calculate.
> 
> ferrite in such a circuit is generally wrong. If the ferrite see's too much 
> magnetisim it may saturate, at which point it looses its ability to resist 
> the change and max current will flow according to the ohmage of the wire. It 
> also has a magnetic curie point, a $5 word that says if this happens above 
> its curie point temperature, it become austenitic, aka non-magnetic, and can 
> only be repaired by returning the core to Arnold for a factory heat 
> treatment. You might want to remember that for some of the high performance 
> ferrite alloy's, this "curie" temperature is below the boiling point of water 
> at 100C. That's not hot enough to discolor the paint on it. Moral of the 
> story is use silicon steel cores for such.
> 
> Initial values are: DC voltage is 340 V, current limit -
>> hopefully around 10A, fuse is adjustable, originally set at 12 A (can
>> be increased to 16 A). capacitor is 4700 uF.
>> How do I calculate the time it takes to [almost] charge the capacitor?
> 
> T=RC will give an answer for (IIRC) a 67% charge. Where T is time in seconds, 
> R is ohms and C is farads. 5T will give essentially a full charge time.  Its 
> the low R from the powerline that is clearing your fuse/breaker. :o)
> 
>> That would determine that transient state for inductor and then I have
>> no idea how to calculate the inductor from here.
>> I would prefer inductor because then there is nothing that can break.
>> Input is 3 phase AC so I see following drawbacks with introducing resistors:
>> 1) putting them after rectifier bridge seems like a violation of "no
>> switches in DC bus" recommendation from 8i20 manual. Maybe except by
>> having a resistor permanently connected in line and then having a SSR
>> in parallel to resistor would be solution. But if SSR fails (I have
>> experienced that) how will I know that? All load will go through
>> resistor and burn it.
> One of the reasons to use a honking high wattage resistor.
>> 2) putting them in AC line requires 3 sets of that and the issue of
>> the relay that bypasses resistor remains or have I missed something?
>> It seems to me that 340V and approximately 10A would require 30-50 ohm
>> resistor as suggested by Gene but somehow I am not sure 100W is
>> enough. Or is it fine because it is very short period of time?
> 
> That's the theory. In the case of my go704, 3 seconds seems to be enough.  
> That does not heat a 100 watt R more than 20F.
>> Viesturs
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> 
> Cheers, Gene Heskett, CET.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
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Re: [Emc-users] Question to electrics gurus: Correct setup for rectifier + capacitor

[Thaddeus Waldner]

Some designs fill the capacitor through a small resistor, then turn on a relay 
once the voltage is up. Drive operation needs to be inhibited during the fill 
process. 

> On Aug 6, 2024, at 4:21 PM, Chris Albertson  wrote:
> 
> The capacitor is charged when the switch is closed.   A huge current will 
> flow into the capacitor until it is “full”.  The usual solutions are to (1) 
> use a slow-blow fuse that can withstand the surge current or place a low 
> value power resister in series with the AC to limit maximum current.   
> Inductors can do this better than resistors. 
> 
> Also it might just be luck.  When you switch high-current AC, it is best to 
> switch on the zero crossing when there is zero volts.  Unless there is a 
> circuit to make that happen it is just luck what the volts are when the 
> contacts close.  Most poweerful AC powered heaters are switched usung a solid 
> state relay and these are designed to switch on zero.  Domestic water heaters 
> and resistive building heat is all done this way.
> 
> 
>>> 
>>> 
>>> I do not understand why was everything fine in initial testing - I did
>>> turn machine on and off lots of times and capacitor was discharged
>>> (and recharged!!!) numerous times. I have swapped that fuse for
>>> identical unit from a machine that has yet to go through the retrofit
>>> process. And it is the same.
>>> 
>>> So my question to electronics gurus - could capacitor be damaged or
>>> was it just a beginners luck that everything worked and do I need to
>>> introduce some inductor between rectifier bridge and capacitor to
>>> limit the startup current that charges capacitor?
>>> 
>>> Viesturs
>>> 
>> 
>> Typically a NTC is used to limit the surge current, either in the AC line
>> or the DC between the bridge and the filter capacitor. Here is a NTC 
>> manufacturers page on this usage:
>> 
>> https://product.tdk.com/en/techlibrary/applicationnote/howto_ntc-limiter.html
>> 
>> 
>> 
>>> 
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>>> 
>> 
>> Peter Wallace
>> Mesa Electronics
>> 
>> 
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Re: [Emc-users] Mitsubishi VFD control

[Thaddeus Waldner]

I failed to mention that this configuration is for connection via RS485. The 
mitsub_vfd module does not use modbus; it uses the Mitsubishi Inverter 
Protocol. 

> On Mar 1, 2024, at 12:55 PM, Thaddeus Waldner  wrote:
> 
> I recently set up a Mitsubishi D700 to work with Mitsub_vfd
> 
> These inverters are highly flexible in how they are configured to respond to 
> control commands. I spent many hours of trial and error to get the correct 
> combination of parameters to even get it to respond to network commands. What 
> tripped me up initially was that the drive must be reset by cycling the power 
> to make any changes take effect.
> 
> It has a handy list of all the non-default parameters. I have attached them 
> below. Everything appears to work, though there is some inconsistency in how 
> manual seed control works in gmoccapy.
> 
> 
> The E500 could be a whole different animal but maybe this will help. 
> 
> 
> prnamevalue
> 1 Maximum frequency   300
> 2 
> Minimum frequency 
> 30
> 3 
> Base frequency 
> 300
> 7 Acceleration time   2.5
> 8 
> Deceleration time 
> 3
> 9 
> Electronic thermal O/L relay 
> 9
> 13Starting speed  20
> 18High speed maximum frequency300
> 19
> Base frequency voltage
> 200
> 20
> Acceleration/deceleration reference frequency
> 300
> 29
> Acceleration/deceleration pattern selection
> 2
> 41
> RUN key rotation direction selection 
> 5
> 72
> PWM frequency selection 
> 15
> 77Parameter write selection   2
> 82Motor excitation current80
> 84
> Rated motor frequency 
> 120
> 96
> Auto tuning setting/status 
> 21
> 117   
> PU communication station number 
> 96
> 120   
> PU communication parity check 
> 0
> 124   
> PU communication CR/LF selection 
> 0
> 160   Extended function display selection 0
> 298   
> Frequency search gain 
> 39
> 340   
> Communication startup mode selection 
> 1
> 551   
> PU mode operation command source selection
> 4
> 
> Hope this helps!,
> 
> Thaddeus
> 
> 
> 
>> On Mar 1, 2024, at 7:34 AM, lloyd wilson  wrote:
>> 
>> I'm using a Mitsubishi E500 VFD for spindle drive on the VMC I'm 
>> retrofitting & can't get variable speed to cooperate. The mitsub_vfd program 
>> operates properly (I think)- run/stop behaves as expected, speed commands 
>> are generated and accepted by the VFD, but the  motor speed stays the same. 
>> I hacked in a couple of debugging statements to show the dialogs (running in 
>> halcmd):
>> 
>> setp sp.motor-cmd 50
>> halcmd: 01ED11388EF   SENT: 0x5 0x30 0x31 0x45 0x44 0x31 0x31 0x33 0x38 0x38 
>> 0x45 0x46
>> 7!DEBUG:  ,0,1, 0x6 0x30 0x31
>> 
>> show pins
>> 
>> 
>> 
>>  4  float IN 50  sp.motor-cmd
>> 
>> ...
>> 
>>  then
>> 
>> setp sp.motor-cmd 80
>> halcmd: 01ED11F40F6   SENT: 0x5 0x30 0x31 0x45 0x44 0x31 0x31 0x46 0x34 0x30 
>> 0x46 0x36
>> 7!DEBUG:  ,0,1, 0x6 0x30 0x31
>> 
>> show pins
>> 
>> 
>> 
>>  4  float IN 80  sp.motor-cmd
>> 
>> ...
>> 
>> the messages are properly formatted per the Mitsub manual & replies show no 
>> errors
>> 
>> --but the test motor keeps running at the same speed.
>> 
>> Anyone have a clue where to look for the solution?
>> 
>> as always, thanks
>> 
>> -ldw
>> 
>> 
>> 
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Re: [Emc-users] Mitsubishi VFD control

[Thaddeus Waldner]

I recently set up a Mitsubishi D700 to work with Mitsub_vfd

These inverters are highly flexible in how they are configured to respond to 
control commands. I spent many hours of trial and error to get the correct 
combination of parameters to even get it to respond to network commands. What 
tripped me up initially was that the drive must be reset by cycling the power 
to make any changes take effect.

It has a handy list of all the non-default parameters. I have attached them 
below. Everything appears to work, though there is some inconsistency in how 
manual seed control works in gmoccapy.


The E500 could be a whole different animal but maybe this will help. 


pr  namevalue
1   Maximum frequency   300
2   
Minimum frequency 
30
3   
Base frequency 
300
7   Acceleration time   2.5
8   
Deceleration time 
3
9   
Electronic thermal O/L relay 
9
13  Starting speed  20
18  High speed maximum frequency300
19  
Base frequency voltage
200
20  
Acceleration/deceleration reference frequency
300
29  
Acceleration/deceleration pattern selection
2
41  
RUN key rotation direction selection 
5
72  
PWM frequency selection 
15
77  Parameter write selection   2
82  Motor excitation current80
84  
Rated motor frequency 
120
96  
Auto tuning setting/status 
21
117 
PU communication station number 
96
120 
PU communication parity check 
0
124 
PU communication CR/LF selection 
0
160 Extended function display selection 0
298 
Frequency search gain 
39
340 
Communication startup mode selection 
1
551 
PU mode operation command source selection
4

Hope this helps!,

Thaddeus



> On Mar 1, 2024, at 7:34 AM, lloyd wilson  wrote:
> 
> I'm using a Mitsubishi E500 VFD for spindle drive on the VMC I'm retrofitting 
> & can't get variable speed to cooperate. The mitsub_vfd program operates 
> properly (I think)- run/stop behaves as expected, speed commands are 
> generated and accepted by the VFD, but the  motor speed stays the same. I 
> hacked in a couple of debugging statements to show the dialogs (running in 
> halcmd):
> 
> setp sp.motor-cmd 50
> halcmd: 01ED11388EF   SENT: 0x5 0x30 0x31 0x45 0x44 0x31 0x31 0x33 0x38 0x38 
> 0x45 0x46
> 7!DEBUG:  ,0,1, 0x6 0x30 0x31
> 
> show pins
> 
> 
> 
>  4  float IN 50  sp.motor-cmd
> 
> ...
> 
>  then
> 
> setp sp.motor-cmd 80
> halcmd: 01ED11F40F6   SENT: 0x5 0x30 0x31 0x45 0x44 0x31 0x31 0x46 0x34 0x30 
> 0x46 0x36
> 7!DEBUG:  ,0,1, 0x6 0x30 0x31
> 
> show pins
> 
> 
> 
>  4  float IN 80  sp.motor-cmd
> 
> ...
> 
> the messages are properly formatted per the Mitsub manual & replies show no 
> errors
> 
> --but the test motor keeps running at the same speed.
> 
> Anyone have a clue where to look for the solution?
> 
> as always, thanks
> 
> -ldw
> 
> 
> 
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Re: [Emc-users] Ball Screw Driving Questions

[Thaddeus Waldner]

Machines often have both ends fixed and the assembly preloaded by applying 
tension to the screw.


> On Dec 25, 2023, at 7:03 PM, Leonardo Marsaglia  wrote:
> 
> Hello Linden,
> 
> For your first question. I would mount the motor on a fixed end just to be
> sure, so that would lead you to make both ends fixed. I guess you can mount
> your servo on a non fixed end if the machine is not going to be used for
> heavy cuts on hard materials but I would go the extra effort and make the
> assembly fully supported.
> 
> Second question. I don't know what's your max rpm for the spindle or what's
> the softer material you're planning to machine but with 3000 rpm of max
> speed on your servo you can easily do a 2 to 1 reduction (if you have the
> room for the pulleys). That would give you 7500 mm/min for rapids. I don't
> know what power and torque your servo can provide but I assume 2 Nm at
> least on continuous so with your 5 mm and the 2 to 1 on the pulleys you can
> have 4000 N of linear force on the carriage and I think that's more than
> enough.
> 
> Hope this helps!
> 
> 
> 
> 
> El lun, 25 de dic. de 2023 21:08, Linden via Emc-users <
> emc-users@lists.sourceforge.net> escribió:
> 
>> Hello All,
>> 
>> In the early stages of converting a 13 x 24 inch manual Chinese
>> lathe to run with Linux CNC.
>> 
>> I have 2 questions regarding replacing the Z axis lead screw with a 3205
>> ball screw:
>> 
>>  What I am thinking is mounting the fixed end in a pillow block at the
>> head stock end of the lathe and the floating end in a second pillow
>> block at the tail stock end of the bed. The question I have is there any
>> reason I shouldn't  drive the ball screw from the floating end? My logic
>> for driving at the floating (tali stock) end is  1 I have more room for
>> belt reduction at this end and 2  with the fixed end of the ball screw
>> at the head stock end is that the ball screw will be in tension when it
>> is pulling the carriage toward the head stock during cutting and less
>> likely to flex or bend.
>> 
>> The second question I have is what would be a realistic cutting speed
>> range for the ball screw in RPM?  The servo motor I am using has a top
>> speed of 3000rpm and I am trying to figure out reduction ratio that is
>> realistic.
>> 
>> Thanks in advance for any help or suggestions.
>> 
>> 
>> Linden
>> 
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Re: [Emc-users] Suggested enhancment to linuxcnc

[Thaddeus Waldner]

Okuma have something like an accelerometer or perhaps a mic in the spindle but 
they use it to optimize feeds and speeds to minimize tool chatter.

> On Dec 17, 2023, at 7:14 PM, gene heskett  wrote:
> 
> On 12/17/23 18:19, Chris Albertson wrote:
>> Machine tools are a little different from 3D printers because
>> 1) Printers are not built nearly are solidly are milling machines.  Milling 
>> machines do not flex very much
>> 2) the printer head moves in air and there is no resistance to movement.  
>> While an end mill has to have force applied to cut metal
>> 3) if anything causes the mill’s spindle to vibrate it is the teeth of the 
>> rotating end mill, not “spring” in the machine's structure
>> That said, I had planned to use accelerometers in the feet on my next robot 
>> project.  Robot legs are very much like 3D printers or milling machines.  
>> Each leg has three or more axes and needs to be precisely moved and while 
>> moving, the foot might unexpectedly collide with some object.  We can 
>> compute the expected acceleration on the foot and compare to the actual and 
>> find the difference.  The robot operates in the uncontrolled real-world and 
>> I expect many “surprises”.  The 3D printer is “bendy" and flexible so I 
>> would expect a difference between expected and actual.  But the milling 
>> machine is so sturdy, I’d expect little difference.
>> But still, it would be a very easy experiment.  Decent accelerometers cost 
>> less than $20 and you could simply place one in the jacobs chuck and then 
>> jog the mill around and see what the accelerometer says.   No software 
>> changes to LCNC would be needed, just put the little PCB in the chuck and 
>> look at some plots.
> 
> Depends on the mill or? In the case of my G0704, the accelerometer should go 
> on the table for xy motion, not the relatively stationary chuck which 
> generally only moves vertically. In the chuck on something like the 6040, a 
> medium sized gantry I have.  The acceleromter s/b on the moving part IOW.
> 
> Here is one that I have
>> https://www.amazon.com/HiLetgo-Gyroscope-Acceleration-Accelerator-Magnetometer/dp/B01I1J0Z7Y/ref=sr_1_1_sspa
>> HiLetgo MPU9250 GY-9250 9-Axis 9 DOF 16 Bit Gyroscope Acceleration Magnetic 
>> Sensor 9-Axis Attitude +Gyro+Accelerator+Magnetometer Sensor Module IIC/SPI
>> amazon.com
 On Dec 17, 2023, at 8:52 AM, gene heskett  wrote:
>>> 
>>> One of the not so quiet revolutions taking place in the 3d printer 
>>> landscape over the last couple years is called input shaping, something 
>>> probably done best in the cards like Peter Wallace makes.
>>> 
>>> A simplified explanation is fitting an accelerometer to to tool head, the 
>>> exciting each axis it turn withe an audio sweep of a small amplitude, 
>>> sweeping from 10 Hz to about 250 Hz while measuring the resulting movement 
>>> with an adxl345 recording the data it outputs for each of the axises 
>>> tested. Since a 3d printer works in slices, the z axis is generally much 
>>> slower on the 3d printer, so is left out in some versions.
>>> 
>>> This data is then run thru a forrier or butterfly transform to develop a 
>>> compensating acceleration curve that does not effect the overall speed, but 
>>> does reduce the fine detail or boost it, to essentially cancel the machines 
>>> natural vibrations. On a 3d printer, given enough heat to supply the head 
>>> with continuous hot plastic, the use of this compensation has taken the 3d 
>>> printer from 50 or 60mm/second maximum speeds to 200 mm/second over the 
>>> last 2 years. I can now buy a printer with this built into its OS for under 
>>> $1000.
>>> There is one obstacle, most 3d printers do not have an interpreter that 
>>> knows about G2/G3 and its ilk, so most slicer's converts those to tiny 
>>> straight line moves that look like a circle in plastic.
>>> 
>>> This is done in the default interpreter, Marlin, but is done better by 
>>> klipper in the better printers but can be reflashed into 99% of the 
>>> controller cards out there just like we can do with Peters cards.
>>> This interpreter runs on the controller cards, often stm32 based cards that 
>>> sell for, in the ones BTT makes for $59 for a low end octopus card, which 
>>> can drive up to 8 motors, 5 fans, 3 heaters and all our limit/home switches 
>>> and probing gizmo's.  Some of these even include the G2/G3 stuffs.  These 
>>> cards are nearly all designed to handle nema-17 motors at 24 vols and maybe 
>>> 3 amp max motors, but one line of the octopus family of cards has a 
>>> separate motor supply input that assumes 60 volt rated drivers so even 
>>> those tiny motors can be moved at amazing speeds.
>>> 
>>> Top that with signal stealing plugins that fit the driver socket of these 
>>> boards I'm rebuilding 2 bigger printers with nema-17 versions of the closed 
>>> loop servo/steppers with optical encoders that use drivers like we use with 
>>> linuxcnc, 2m542 sized stuff, but now rated for 90 volts and up so th

Re: [Emc-users] ot: slicing blade for table saw

[Thaddeus Waldner]

Fresh chicken cutting machines run at 2800rpm, I believe.

> On Dec 8, 2023, at 10:31 AM, fxkl47BF--- via Emc-users 
>  wrote:
> 
> i'm trying to find a slicing blade for a 10 inch table saw
> a blade that is smooth and sharp, no teeth
> for making smooth cuts in foam material and cardboard
> i guess if there's no such critter i could make one
> grind down the teeth on a cheap blade
> have any of y'all seen such
> 
> 
> 
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Re: [Emc-users] Run Fusion 360 on LInux

[Thaddeus Waldner]

Onshape is my go-to platform as of a number of years ago. I’ve done most of my 
work in onshape using an iPad and Apple Pencil.

My verdict? It’s great for simple stuff and highly mobile. You can design 
something on the spot, using an iPhone, while someone describes it to you or 
with tape measure/calipers on the other hand.

It’s not so good with complex models. Many of the design hints that make life 
easier are simply omitted. It has become more buggy gotten the feel of a 
back-burner project over the last year or so.

My main reason for avoiding it is an iOS issue: switching to another app for 
longer than about 3 seconds will promptly close the working document.



> On Dec 1, 2023, at 12:53 PM, Chris Albertson  
> wrote:
> 
> Next up is to try OnShape in a browser on the iPad.   


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Re: [Emc-users] Run Fusion 360 on LInux

[Thaddeus Waldner]

Yeah, I saw this after I posted. I use an educational account.

Cheapest option that works appears to be “startup” at $150/3 years. 



> On Dec 1, 2023, at 9:31 AM, Dave Matthews  wrote:
> 
> Unfortunately not available to the hobbyist level account.  Commercial and
> Education only.  I go this when I logged in:
> Autodesk Education or Commercial Account Required
> Dave
> 
> On Fri, Dec 1, 2023 at 9:26 AM Thaddeus Waldner  <mailto:thadw...@gmail.com>> wrote:
> 
>> I’m not sure if you’ve seen this, but Fusion 360 now has a run-in-browser
>> mode. It appears the same thing as the desktop app, which I believe was
>> just a browser-based app in the first place. It will run on Linux.
>> 
>> You can find it here:
>> 
>> https://fusion.online.autodesk.com/
>> 
>> Be advised that Fusion 360 is a processor and memory-intensive program. It
>> starts at about 5gb and goes up from there.
>> 
>> If you use Chrome (or safari on a Mac), you can free up the screen space
>> used by the browser tabs, address bar, shortcuts, etc. by saving the
>> address as web app that runs in its own window
>> 
>> In Chrome, click on menu (the three dots)->more tools->create shortcut …
>> give your shortcut a name and check the box that reads “Open as Window.”
>> 
>> Does Firefox have a similar feature?
>> 
>> 
>> 
>> 
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[Emc-users] Run Fusion 360 on LInux

[Thaddeus Waldner]

I’m not sure if you’ve seen this, but Fusion 360 now has a run-in-browser mode. 
It appears the same thing as the desktop app, which I believe was just a 
browser-based app in the first place. It will run on Linux. 

You can find it here:

https://fusion.online.autodesk.com/

Be advised that Fusion 360 is a processor and memory-intensive program. It 
starts at about 5gb and goes up from there.

If you use Chrome (or safari on a Mac), you can free up the screen space used 
by the browser tabs, address bar, shortcuts, etc. by saving the address as web 
app that runs in its own window

In Chrome, click on menu (the three dots)->more tools->create shortcut … give 
your shortcut a name and check the box that reads “Open as Window.”

Does Firefox have a similar feature?




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Re: [Emc-users] Reverse Pulse Control on Dust Collectors

[Thaddeus Waldner]

Pulse cleaning on commercial filter systems is accomplished with a blast of 
compressed air. The systems usually have large diameter air valves and piping 
leading from an accumulator to the clean side of the filter. The valves are 
triggered in stages, so that each stage receives the full volume of the 
accumulated air.

Ideally you want the blower to be stopped while cleaning takes place, so that 
the dust falls into the hopper instead of being sucked back into the filter. So 
a good practice is to run a cleaning cycle after every shutdown. Some systems 
also run a cleaning cycle based on system vacuum between the blower and filter. 
In this case you sometimes can’t stop the filter, so you would slow it down as 
a compromise while the cleaning takes place, as the OP described.

> On Aug 23, 2023, at 8:01 AM, Todd Zuercher  wrote:
> 
> Just curious how this could work physically.  I can't imagine how a dust 
> collector motor could reverse for a 10th of a second.  Every dust collector 
> I've worked with seems to take at least half a second (or more, sometimes a 
> lot more if it's a big one) just to spin up to speed let alone move an 
> appreciable amount of air.  I also can't imagine the impellers working well 
> with or liking being reversed.  Or are you talking about diverting the air 
> flow to reverse the air flow to the filtration unit somehow?  The large dust 
> collector systems I've worked with all use a separate blower contained within 
> the filter bag house system that blows a reverse pulse of air into the filter 
> bags to clean them, and the small ones don't have anything.
> 
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
> 
> -Original Message-
> From: Earl Weaver 
> Sent: Tuesday, August 22, 2023 11:41 AM
> To: emc-users@lists.sourceforge.net
> Subject: [Emc-users] Reverse Pulse Control on Dust Collectors
> 
> [EXTERNAL EMAIL] Be sure links are safe.
> 
> Hi everyone,
> 
> Does anyone have suggestions what would be a good option for reverse pulse 
> control on my dust collectors?
> 
> I have 3 separate dust collectors that use (two each) air solenoid valves to 
> give the filters an alternating 100 millisecond (1/10 second) pulse to remove 
> the dust from the filters.
> I have solid state switch relays (triac) to pulse the 120 volt AC solenoid 
> valves.
> 
> I already have this setup on my LinuxCNC Plasma cutter and have it working 
> with ClassicLadder in LinuxCNC.
> It seems somewhat overkill to use a full LinuxCNC setup to control these 
> other three dust collectors.
> 
> Would a micro-controller like Arduino be a better solution?
> I have no experience with Arduino.
> 
> What about a PLC?
> 
> Any input, or suggestions?
> 
> Thanks,
> Earl
> --
> 
> 
> 
> 
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Re: [Emc-users] CNC machining setup cards

[Thaddeus Waldner]

I’m getting a lot of hanging with large sketches. I’ve had to force quit it 3-4 
times in two days of using it.

But yeah, performance on apple silicon is impressive. When it works.

Thaddeus Waldner
Newdale School
Elkton, SD 57026

From: Ron Buck 
Sent: Wednesday, July 12, 2023 8:43:23 AM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] CNC machining setup cards

… chiming in on the native Apple Si version. The speed improvement is night and 
day difference. I’m on a M1 Max notebook and currently working with a large 
assembly imported from SW. Even small changes were getting slow enough to get 
up and stretch while it was thinking. No hint of even a pause so far with the 
insider release on anything.

Ron


> On Jul 12, 2023, at 4:08 AM, gene heskett  wrote:
>
> On 7/12/23 02:23, Chris Albertson wrote:
>>>> On Jul 11, 2023, at 5:42 PM, gene heskett  wrote:
>>>
>>> ... I'll bet real money that OpenSCAD is easier to learn.
>> Openscad is certainly easy for some simple things but impossible for others. 
>>  Try making a cordless power tool in OpenScad.
>> But in Fusion a power tool is used as an intermediate-level tutorial 
>> project.  The screenshot below is something a person could learn to make 
>> after some weeks of study.  I doubt anyone would even attempt it in 
>> OpenScad.   Then assuming you do make the OpenScad model, could you make 
>> changes in real-time as the client pointed out changed he would like
> You have an excellent point there Chris, were I to attempt that today, I 
> would probably be several weeks writing it for linuxcnc as that looks much 
> easier to do in a subtractive format. Either way, I at my age, would find it 
> difficult to make customer requested mods. 60 years younger with my better 
> memory then it would have been much easier.
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>
> Cheers, Gene Heskett.
> --
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> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
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> - Louis D. Brandeis
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>
>
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Re: [Emc-users] Installing From Debian?

[Thaddeus Waldner]

Yeah, I used the net installer. I didn’t install a different kernel because 
Bookworm preinstalls the preempt-rt kernel (version 6.1.27-1). Installing 
LinuxCNC configured grub to load it by default.


> On Jul 6, 2023, at 2:57 PM, Todd Zuercher  wrote:
> 
> I've been playing with it a bit today.
> 
> The first and biggest news that I've found is that the Debian live ISOs for 
> Bookworm seem to be borked somehow.  It seems to install and run fine until 
> you try to install a different kernel than the original one on the ISO.  Then 
> it get all huffy about some deb not installing correctly and remaining 
> unconfigured and makes it all but impossible to install the real time kernel. 
>  (It is a bit beyond the effort I was wanting to put into it to figure it 
> out.)
> 
> Using the Net Install ISO however worked fine and allowed the Preempt-RT 
> kernel to install correctly.  Latency is only OK but should work with the 
> Mesa card I plan to use.  (Still fiddling with getting the best latency, 
> right now the best I have is about 60us with ISOLCPUS=2,3 on an older i5 pc.)
> 
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
> 
> -Original Message-
> From: Thaddeus Waldner mailto:thadw...@gmail.com>>
> Sent: Wednesday, July 05, 2023 10:51 PM
> To: Enhanced Machine Controller (EMC)  <mailto:emc-users@lists.sourceforge.net>>
> Subject: Re: [Emc-users] Installing From Debian?
> 
> [EXTERNAL EMAIL] Be sure links are safe.
> 
> I just set up a replacement computer for an existing machine. The part I had 
> the most trouble with turned out to be caused by a wifi router being 
> misconfigured. Once that was ironed out, system took off without a hitch and 
> has been running trouble-free for several days now.
> 
> I followed the guide here:
> 
> http://linuxcnc.org/docs/2.9/html/getting-started/getting-linuxcnc.html
> 
> 
> I highly recommend this route.
> 
> To aid in figuring out which cores to isolate, I like to use lstopo. It is 
> part of the hwloc package.
> 
> I have found that on multicore machines, it helps to isolate the last core, 
> as well as any adjacent cores that it shares resources with. For example, 
> some low power quad core Intel processors share a L2 cache between 2 cores.
> 
> 
> 
>> On Jul 5, 2023, at 5:22 PM, Todd Zuercher  wrote:
>> 
>> I have a machine that I am starting to refit and I am considering trying to 
>> install that way rather than using one of the more obsolete Linuxcnc ISOs.
> 
> 
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Re: [Emc-users] CNC machining setup cards

[Thaddeus Waldner]

Would you mind detailing how to get this beta?

> 
> BTW, Fusion 360 has just come out with a Beta release that runs native on 
> Apple Silicon.   The new Apple processors are astonishingly fast.   The above 
> part is designed to be printed but it is fun to let Fusion great g-code files 
> for milling and see what it comes up with.
> 



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Re: [Emc-users] Installing From Debian?

[Thaddeus Waldner]

I just set up a replacement computer for an existing machine. The part I had 
the most trouble with turned out to be caused by a wifi router being 
misconfigured. Once that was ironed out, system took off without a hitch and 
has been running trouble-free for several days now. 

I followed the guide here:

http://linuxcnc.org/docs/2.9/html/getting-started/getting-linuxcnc.html


I highly recommend this route.

To aid in figuring out which cores to isolate, I like to use lstopo. It is part 
of the hwloc package.

I have found that on multicore machines, it helps to isolate the last core, as 
well as any adjacent cores that it shares resources with. For example, some low 
power quad core Intel processors share a L2 cache between 2 cores.



> On Jul 5, 2023, at 5:22 PM, Todd Zuercher  wrote:
> 
> I have a machine that I am starting to refit and I am considering trying to 
> install that way rather than using one of the more obsolete Linuxcnc ISOs.


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Re: [Emc-users] Medium voltage BLDC motor

[Thaddeus Waldner]

A friend of mine has refurbished a number of sewing machines with them. You 
can’t tell by looking at them whether they are induction or synchronous motors, 
but i suppose it doesn’t matter. Original equipment on industrial sewing 
machines usually involve some sort of clutch or belt tension device for stop-go 
control. This is a big improvement. It is low noise and Just Works. The 
controller has a robust lever that you hook up to your treadle. 

Problem for me is they are 6 times the power and size that I need.


A bit of searching on compact power supplies led me to this:

https://nexgenpowersystems.com/solutions/compute-solutions/
1” thick, 3.8” square 240W power supply. Their advertised secret sauce is 
gallium nitride transistors, allowing them to bring switching speeds to over 
2MHZ, which leads to smaller inductors and capacitors.

Anyone know where I can buy something like this?  

Thaddeus


> On Apr 26, 2023, at 10:06 AM, Roland Jollivet  
> wrote:
> 
> Actually, many of the sewing machine motors are now BLDC, with a controller
> containing one of those power bricks. Here's one of the motors
> 
> 
> They could be used as a spindle, but often the casing is so customised that
> the re-work wouldn't be worth the effort. Like this one
> 
> Re-working might be worth it if you buy it as used. Buying as new wouldn't
> be worth it.
> 
> Roland
> 


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Re: [Emc-users] Medium voltage BLDC motor

[Thaddeus Waldner]

This is correct to some degree. A motor controller wouldn’t need need the dc-dc 
controller, isolation transformer, and output diodes and filters, which 
accounts for about half of the space to my reckoning. 

Also, high voltage, low amperage motor controllers are usually more compact 
than their low voltage counterparts. For example, you can buy a 12mm x 12mm 
motor controller that includes pic+boost controller, motor sense circuitry, and 
output stage, that will run a 100-watt motor.

Yeah, I have bought similar rail-mounted supplies in the past, though usually 
it’s the Meanwell brand.

The application is refurbishing 1980s-era equipment. Original equipment has a 
6000rpm 110v universal motor, usually with worn out bushings and brushes, and 
faulty electronics. Replacement parts are generally available but getting 
prohibitively expensive. 
So a servo system would be overkill but nice, cheap, brushless motor with 
bearings is ideal. Works a treat too, except the power supply doesn’t fit.

I apologize for the off topic content here but I do appreciate the input.


> On Apr 25, 2023, at 10:26 AM, Todd Zuercher  wrote:
> 
> Unfortunately a drive built to run off of line AC will generally be 
> approximately the same amount larger as the size power supply you need.  
> Simply because you've stuck the power supply inside the drive.  You could try 
> looking for a smaller supply?  Can you combine the power supply with any 
> other power source needs in you're machine?
> 
> Here is a little 120w 24v one that mounts on a din rail and only takes up 
> about 1.5"x5"x4".  (But maybe that isn't any better than you have.)
> https://www.amazon.com/NVVV-EDR-120-24-24VDC-Industrial-Supplies/dp/B0932X2WHW/ref=sr_1_11?keywords=24v+5a+power+supply&qid=1682435519&s=electronics&sr=1-11
> 
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
> 
> -Original Message-
> From: Thaddeus Waldner 
> Sent: Tuesday, April 25, 2023 9:27 AM
> To: Enhanced Machine Controller (EMC) 
> Subject: Re: [Emc-users] Medium voltage BLDC motor
> 
> [EXTERNAL EMAIL] Be sure links are safe.
> 
> What I mean is that specific driver would not fit into my space. I am 
> currently using a custom 24v BLDC driver that I built. But the only option 
> for power supply at this point is a wall wart that is about twice the size of 
> your typical laptop charger, which I'd like to eliminate.
> 
> 
>> On Apr 25, 2023, at 7:00 AM, Todd Zuercher  wrote:
>> 
>> I'm a little confused, a BLDC motor is still going to need a drive/driver, 
>> weather or not it runs at line voltage, that you say you don't have space 
>> for.  How is that going to help you?
>> 
>> Todd Zuercher
>> P. Graham Dunn Inc.
>> 630 Henry Street
>> Dalton, Ohio 44618
>> Phone:  (330)828-2105ext. 2031
>> 
>> -Original Message-
>> From: Thaddeus Waldner 
>> Sent: Monday, April 24, 2023 5:40 PM
>> To: Enhanced Machine Controller (EMC) 
>> Subject: [Emc-users] Medium voltage BLDC motor
>> 
>> [EXTERNAL EMAIL] Be sure links are safe.
>> 
>> HI,
>> 
>> I have an application where I need a NEMA 23-size 80-120 watt brushless DC 
>> motor. The machine housing doesn't have space for a 100w DC 24v power 
>> supply, so I would like to use a controller and motor that runs at line 
>> voltage.
>> 
>> Does anyone know of a small BLDC/PMAC/Synchronous AC motor that is designed 
>> to run at about 150v coil voltage?
>> 
>> Motors this size/voltage are apparently quite common in kitchen appliances 
>> that use pumps or fans, but I cannot seem to find a plain motor with output 
>> shaft.
>> 
>> 
>> 
>> Thanks,
>> 
>> Thaddeus Waldner
>> 
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Re: [Emc-users] Medium voltage BLDC motor

[Thaddeus Waldner]

What I mean is that specific driver would not fit into my space. I am currently 
using a custom 24v BLDC driver that I built. But the only option for power 
supply at this point is a wall wart that is about twice the size of your 
typical laptop charger, which I’d like to eliminate.


> On Apr 25, 2023, at 7:00 AM, Todd Zuercher  wrote:
> 
> I'm a little confused, a BLDC motor is still going to need a drive/driver, 
> weather or not it runs at line voltage, that you say you don't have space 
> for.  How is that going to help you?
> 
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
> 
> -----Original Message-
> From: Thaddeus Waldner 
> Sent: Monday, April 24, 2023 5:40 PM
> To: Enhanced Machine Controller (EMC) 
> Subject: [Emc-users] Medium voltage BLDC motor
> 
> [EXTERNAL EMAIL] Be sure links are safe.
> 
> HI,
> 
> I have an application where I need a NEMA 23-size 80-120 watt brushless DC 
> motor. The machine housing doesn't have space for a 100w DC 24v power supply, 
> so I would like to use a controller and motor that runs at line voltage.
> 
> Does anyone know of a small BLDC/PMAC/Synchronous AC motor that is designed 
> to run at about 150v coil voltage?
> 
> Motors this size/voltage are apparently quite common in kitchen appliances 
> that use pumps or fans, but I cannot seem to find a plain motor with output 
> shaft.
> 
> 
> 
> Thanks,
> 
> Thaddeus Waldner
> 
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Re: [Emc-users] Medium voltage BLDC motor

[Thaddeus Waldner]

I would have space for the 125mm motor. 
I wouldn’t have space for the stepper driver though.
Nor for the DC power supply that it needs. Or is it line powered?

I need about 5000rpm,  and I’m hoping to cap the cost at around $100 

> On Apr 24, 2023, at 5:24 PM, gene heskett  wrote:
> 
> On 4/24/23 17:41, Thaddeus Waldner wrote:
>> HI,
>> I have an application where I need a NEMA 23-size 80-120 watt brushless DC 
>> motor. The machine housing doesn’t have space for a 100w DC 24v power 
>> supply, so I would like to use a controller and motor that runs at line 
>> voltage.
>> Does anyone know of a small BLDC/PMAC/Synchronous AC motor that is designed 
>> to run at about 150v coil voltage?
>> Motors this size/voltage are apparently quite common in kitchen appliances 
>> that use pumps or fans, but I cannot seem to find a plain motor with output 
>> shaft.
> How much length have you got? A 1 newton meter 2 or 3 phase stepper/servo is 
> about 80mm behind the flange, and 3 newton meter is about 125mm behind the 
> flange, both have 8mm shafts, and run on cl57 sized drivers for the 2 phase 
> versions, can turn more than 2k revs continuously but hot, stopped virtually 
> zero power and heat unless they are holding up a 300kg knee on a mill. They 
> get to where linuxcnc tells them to go or shuts linuxcnc down in its tracks, 
> the closest I've ever seen to a motor that Just Works. I'm using two of them 
> on my Sheldon 11x54 lathe, shutdown wired up, tested, has never happened 
> while making swarf. If suitably microstepped, /16  seems to be popular, 
> accuracy is cosiderably less than a micron. Whats not to like?
> 
> I also have 2 of them on a 6040 gantry mill, a one nm on the z cuz the std 
> motor can only slowly lift the heavier spindle motor, and a 3nm driving a 5/1 
> worm which drives the B axis chuck to carve the hard maple vise screws I am 
> making.
> 
> They are servo's, priced at stepper prices. If they lose home for any reason, 
> lcnc is stopped before the work is wrecked.  Can your much more costly 
> servo's do that?
> 
> The tech we use marches on.  Take care and stay well Thaddeous.
>> Thanks,
>> Thaddeus Waldner
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> 
> Cheers, Gene Heskett.
> -- 
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> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
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> - Louis D. Brandeis
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[Emc-users] Medium voltage BLDC motor

[Thaddeus Waldner]

HI,

I have an application where I need a NEMA 23-size 80-120 watt brushless DC 
motor. The machine housing doesn’t have space for a 100w DC 24v power supply, 
so I would like to use a controller and motor that runs at line voltage.

Does anyone know of a small BLDC/PMAC/Synchronous AC motor that is designed to 
run at about 150v coil voltage?

Motors this size/voltage are apparently quite common in kitchen appliances that 
use pumps or fans, but I cannot seem to find a plain motor with output shaft.



Thanks,

Thaddeus Waldner 

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Re: [Emc-users] Milling Strategies?

[Thaddeus Waldner]

Plunge milling might be an option?

https://www.sandvik.coromant.com/en-us/knowledge/milling/milling-holes-cavities-pockets/plunge-milling
Plunge milling
sandvik.coromant.com


This has the same chip issues as other pocket milling strategies but the 
federates can be much higher, particularly with small tool diameters and deep 
holes.
A horizontal mill uses gravity to help with the chip issue.


> On Feb 28, 2023, at 2:53 PM, Todd Zuercher  wrote:
> 
> I need to mill about a 3.75" hole through a piece of aluminum about 1.75" 
> thick.  What is the best strategy to accomplish this on a cnc mill.  Is it 
> best to us a pocketing strategy and mill out the entire hole from the center 
> out, or would it be better to use some kind of cutting strategy and mill some 
> size slug out of the middle?  I can see the first option being simpler, but 
> the 2nd option saves a potentially useful piece of material, but with the 
> added complication of how to hold and prevent the chunk of scrap from 
> wreaking havoc when cut free.
> 
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
> 
> 
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Re: [Emc-users] Servo motor in step mode reaches position after LCNC

[Thaddeus Waldner]

Windows software for tuning is pretty standard even on the more expensive 
integrated servo systems. Teknic Clearpath needs Windows software for 
configuration and tuning, as does one Chines brand that I’ve used.

> On Jan 24, 2023, at 8:50 PM, Leonardo Marsaglia  wrote:
> 
> Hi guys again and thanks for all the answers :)
> 
> Well, indeed the problem as Todd suggested is because of the driver
> limiting acceleration and velocity. I found in the manual that this can be
> changed and they recommend using a value 10 times higher than what LCNC
> commands. This is to avoid this peaking to max speed/acceleration problem
> of course.
> 
> The only drawback is that the only way to change these settings is using
> their software and a PC. At least that's what the manual shows.
> 
> 
> 
> El mar, 24 ene 2023 a las 17:19, gene heskett ()
> escribió:
> 
>> On 1/24/23 11:07, Sam Sokolik wrote:
>>> This is why I don't like smart servo drives..   lol..  You don't know how
>>> well the drive is following the path linuxcnc is commanding..
>> 
>> My experience has been the opposite Sam. I have no PID's in the config
>> to run my Sheldon 11x54, I put a 3NM on the Z cause the carriage weighs
>> around 20 maybe more pounds. In all cases here I'm using the 3 phase
>> version, turns 1.2 degree per full step cycle.
>> 
>> But I didn't have room for the length of a 3NM behind the new apron, so
>> I put a 2NM on to drive X.
>> 
>> I took off a 1200 inlb nema34 as it could only do a g0 at 60ipm on a
>> good day, and took a nema 24 off the x because its max w/o a stall was
>> maybe 29 ipm on a good day. And both were noisy as can be.
>> 
>> With the 2 nema-23 3 phase stepper/servo's, Z now moves at 120 ipm, and
>> x moves at 60 ipm, and at working speeds cannot be heard, only the belt
>> swish driving the spindle. Like watching Casper the ghost turning the
>> cranks now.
>> 
>> I can position a chuck jaw to be hit with a missdirected tool at 10 ipm,
>> it hits the jaw sees the stop, and stops lcnc in about a millisecond.
>> The chip in the tool isn't damaged, and the jaw wasn't marked.  The
>> motors run cold because the error controls the motor current. They WILL
>> GET to where they are told to go, or they will STOP LCNC in its tracks
>> midstep  before the part is damaged.  FWIW, that sort of a stop has yet
>> to happen while its working.
>> 
>> I have a 6040 gantry mill, and the Z was too puny even after I binned
>> the electronics that came with it and replaced it all with LCNC feeding
>> 2m542's running on 42 volts. It's xy went from 15 ipm to 200 ipm but z
>> could just barely lift that water cooled spindle, but a 1NM
>> stepper/servo acts like it could lift another 25 pounds at 30 ipm.
>> 
>> When I needed a B axis to make the vise screw I'm going to sell if I
>> can, I made several printed harmonic drives but could not get the speed
>> to spin the screw while I carved it. I had bought a 5/1 worm on spec 4
>> or 5 years ago, so I put a 3NM on it with a printed shaft adapter, and
>> printed the chuck for the slow end of the worm driving a 2x2 hard maple
>> stick about 2 feet long. I can carve a screw at 200 rpm on the screw.
>> 
>> There's more backlash in the cheap worm than motor error but I'm carving
>> a 2 start thread that fits perfectly by carving the 2nd start on its way
>> back to start a new 1st start. The hard maple stick is turning backwards
>> then. 180 degrees out of phase with the fwd motion.
>> 
>> And Ali-Express is getting plumb reasonable on them right now.
>> 
>> [snip Leonardo's problem, this isn't really part of that thread.]
>> 
>> Cheers, Gene Heskett.
>> --
>> "There are four boxes to be used in defense of liberty:
>>  soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author, 1940)
>> If we desire respect for the law, we must first make the law respectable.
>>  - Louis D. Brandeis
>> Genes Web page 
>> 
>> 
>> 
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Re: [Emc-users] ot: change ps 613u pots

[Thaddeus Waldner]

You could try rinsing the pots with alcohol first.

> On Jan 21, 2023, at 7:27 PM, fxkl47BF--- via Emc-users 
>  wrote:
> 
> i acquired a non-working ps 613u power supply
> two 2200uf caps had exploded
> i replaced them and it appears to be working
> my complaint is the voltage and current pots are very sensitive
> it's near impossible to adjust them with any precision
> i'm thinking to replace them with multi-turn pots
> is this a good idea or a waste of time
> 
> https://www.velleman.eu/downloads/2/ps613a502.pdf
> 
> 
> 
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Re: [Emc-users] Is this LCNC based?

[Thaddeus Waldner]

8) Interpolation Algorithm: S type, circular hard algorithem, circular soft 
algorithm:

I wonder what is meant by interpolation algorithm.

> On Jan 9, 2023, at 9:52 PM, Chris Albertson  wrote:
> 
> Amazon has a turn-keyCNC controller for $480.  This includes the whole kit,
> computer, FPGA, screen BoB and all except for power supply and the motors.
> 
> 
> Question:  Is this based on LCNC?   Seem like it might be   Below is a
> quote from their web page, I added the bold face.
> 
>> 
>>   - The DDCS Expert is a *5 axis motion controller for open or close
>>   stepper and servo systems* with 7" full color display screen. The
>>   highest output pulse per axis is 1MHz. The users can self-define the
>>   functional keys. This controller supports multiple spindle mode, support
>>   straight Tool Magazine, gantry type Magazine, disk type magazine. The
>>   Operation system interface even though very comprehensive, can be learned
>>   in very short time.
>> 
>> 
>>   - The DDCS Expert numerical control system *adopts the ARM+FPGA design
>>   framework*. ARM controls the human-computer interface and code
>>   analysis and the FPGA provides the underlying algorithms and creates the
>>   control pulse. This guarantees reliable control and easy operation.
>> 
>> 
>>   - *The internal operating system is Linux based.*
>> 
>> 
> Product: amazon.com/Axis-Controller-Handwheel-MPG-Emergency/dp/B09WLDKW53
> 
> User Manual:
> /nvcnc.net/pdf/DDCS%20Expert%20User's%20Manual%20V1%20(Part1)-nvcnc.pdf
> 
> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> 
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Re: [Emc-users] Touch screen for linux

[Thaddeus Waldner]

If decent colors at off-axis viewing angles are important, then add IPS to your 
search.

> On Jan 9, 2023, at 6:05 PM, Bari  wrote:
> 
> roblems with LCNC.


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Re: [Emc-users] Touch screen for linux

[Thaddeus Waldner]

IF you need a tiny screen AND don’t mind fabricating a bezel AND don’t mind 
creating a custom UI:
these work great 

HDMI 600 x 1024, 7” IPS, micro usb power and capacitive touch.

Caveats: None of the standard interfaces will work with only 600 vertical 
resolution. My application called for a custom UI. 

https://www.ebay.com/itm/325425917185?hash=item4bc4e56d01:g:66EAAOSwJ~RjdAne&amdata=enc%3AAQAH4K3R8lTxvx14EqH%2FkcCxWIX4pxO7zEijbHqzsnKfAgvwAMGDqusBJusuOQS5Ci4x%2Byj0xAaJ2xojWpCyAUICMsIlwLd8YYWkolEVBMS395SzDJftqRd7ZA6fMrkJTSgzMqvAJJpVOlDzvHFVbn%2FwL6RwUHc8oBnX%2FGgj7A7OZ%2FtvM37rH4K9WmgBY98PTyW2dtJlvWWru0LM30b59jaajSMk0VF7hQiM%2Fas0wEjMCjTCczNC%2Bmo416PiGqhwHLyPD42YTnPsW9k4t5R5Na3wqI2pKtDgd8Q1W%2FSmvjpDUUF%2F%7Ctkp%3ABFBM3JzXjLNh
7inch HDMI Pi Screen Capacitive Touch LCD (C) 1024×600 IPS USB Touch Brand New
ebay.com




> On Jan 9, 2023, at 3:46 PM, andrew beck  wrote:
> 
> Hey guys
> Looking for a Chinese industrial touch screen that people have checked
> works on Linux.
> 
> There was some links to AliExpress floating around but I lost them
> 
> They don't need to be massive but I'm trying to go touch screen style if I
> can
> 
> Regards
> 
> Andrew
> 
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Re: [Emc-users] Another of my silly? questions

[Thaddeus Waldner]

I think the design has several other issues:

There appears to be a pretty large imbalance between the motor inertia and axis 
inertia. You can fix this by using a reduction on the jackshaft. For reference, 
some of the older Stratasys systems have a nearly identical arrangement. They 
use about 3/4" steel tube as a shaft and a 3:1 belt reduction from the motor to 
the shaft. They also use the same reduction on the X axis.


The bigger issue, in my mind, is the lightweight frame.
Your motors might have around 2NM torque which translates to about 45 
pound-force on a 3/4” drive pulley. If you apply 45lbs of force to the side of 
the printer, it will bend sideways a lot. Add a 3:1 reduction to it and you get 
over 100lbf of side load at the top of a lightweight frame—that is if you 
actually use 2nm torque during acceleration. For reference, the Stratasys 
printers I refer to weigh around 150lbs and still the entire thing sways on its 
rubber feet when the axis motion syncs up with the machine resonance. And they 
do use stepper motors. This also illustrates why the humble stepper is still a 
good fit for lightweight printer frames. 


> On Dec 5, 2022, at 8:08 AM, gene heskett  wrote:
> 
> On 12/5/22 06:59, andy pugh wrote:
>> On Mon, 5 Dec 2022 at 02:20, Chris Albertson 
>> wrote:
>>> and we don't even know the exact kind of steel in the rod.  Without
>> knowing more it is a toss-up.
>> You don't need to know, all iron alloys have the same stiffness (to within
>> a couple of percent).
>> The shear modulus (G) for steel is 80 and for carbon fibre is around 5.
>> Steel is a lot stiffer than CF.
>> Anyway, with a 2Nm motor you might see 1.7 degrees of twist in an 8mm steel
>> shaft which is 500mm long.
>> Playing with numbers it would be 3 x less with a steel tube 12mm dia and
>> 1mm wall thickness.
>> To match the stiffness of the steel bar with a _round_ carbon tube it would
>> need to be 20mm dia and 1.5mm wall thickness.
>> https://amesweb.info/Torsion/torsion-of-shaft-calculator.aspx
>> Note that there is only any torsional load on the shaft when accelerating,
>> so the extruder will generally not deviate from the path very much, but
>> will be lagging along the correct path.
>> (This is true of milling machines too, the f-error is typically
>> approximately along the path, so has less effect on part geometry than the
>> raw numbers would indicate)
> 
> Thank you Andy. Bearing the difference in torsional rigidity of sq vs round 
> in mind, I just ordered, be here the 7nth, a 4 pack of 23x25x500mm round cf 
> tubes, one of which will replace the long coupling rod with the puny 
> motor in the middle of it, across the rear of an Ender5+, some pulleys I can 
> machine away half the weight of, some belt clamps, and a 10M roll of gt2 belt 
> 6mm wide. I'll put one of the 1NM 3 phase stepper/servo motors in the inside 
> corner of the frame with the controller close by, driving one end of this 
> tube. Not the middle.
> 
> FWIW, I'm fond of the gyroid pattern infill but its jiggle will be distorted 
> by the torsion give, so while I've got room for 2" tube, the biggest I can 
> buy seems to be 1", or 23x25. 2" would probably begin to affect inertia with 
> its weight, so 1mm wall, 25mm OD may be the best balance point.
> 
> All I need to do is get the step & dir out of an BTT Octopus-pro, which I'm 
> sure I can do. The belting will replace the x drive belt after I figure out 
> how to route one run of it thru the square cf tube. Different piece of the 
> project IOW.
> 
> Take care & stay well.
> 
> In the realm of motor theory, a chance reading of one of stepperonline's 
> .pdf's, explains better how they work, and its the same for 2 phase as 3 
> phase, they cannot lose home unless they can't move the load, AND will issue 
> an alm contact if they lose a step/home. I've got that rigged in .hal to stop 
> LCNC in about a millisecond everyplace I'm using them. Sweet.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> Genes Web page  >
> 
> 
> 
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Re: [Emc-users] R8 Collets question

[Thaddeus Waldner]

A key advantage of the shrink-fit toolholder is that the clamping part is much 
smaller than anything else. These holders are often specialized  for accessing 
deep pockets.

> On Nov 10, 2022, at 6:31 AM, Stuart Stevenson  wrote:
> 
> Gentlemen,
> I walked into a booth at IMTS a few cycles ago. This booth was a cutter
> manufacturer touting the shrink fit tooling and heat shrink machine they
> manufacture. All the propaganda focused on how the shrink fit process holds
> the tool better than any other method. As I was looking at the line of
> cutters in the display I saw an end mill with a spiral groove on the end of
> the shank portion. I asked what that was for. I was told this was developed
> to prevent the cutter from being pulled out of the adapter during high
> speed cutting. It also prevented cutter spin in the adapter.
> I have never owned or tried shrink fit tooling.
> I have wasted my money on the so-called "hydraulic" collet holders. The
> holders' performance was an absolute joke.
> The ONLY non spinning/pullout end mill holder(adapter) I have seen is a
> mechanical (ie weldon) style.
> I will say my high speed experience is limited to a 14,000 rpm 50 taper
> spindle but if the cutter manufacturer had to develop a mechanical slot to
> prevent spinning/pullout maybe the focus to prevent spinning/pullout should
> be mechanical even at the bridgeport level.
> Just sayin
> HTH
> Stuart
> 
> 
> On Thu, Nov 10, 2022 at 2:34 AM gene heskett  wrote:
> 
>> On 11/10/22 02:48, John Dammeyer wrote:
>>> 
 From: gene heskett [mailto:ghesk...@shentel.net]
 It works well John, on the go704. I'd like to come up with a qcth holder
 for them on the Sheldon as it has the torque to drive much bigger taps
 but haven't quite figured out how to make such a critter, plus the
 sheldon has no gibs to constrain the carriage from being lifted clear of
 the ways when huge gobs of the torque reaction comes into play. I'd need
 to hang another 30 lbs on the back end of the crossfeed to contain that
 for say a 3" tap. That in any event even though I have the tap that big,
 is a g76 job. But at a 3" size, I'd be longer shaping the boring tool
 that doing it, my CBN wheels are quite fine, 2500 grit but fine is also
 slow, fragile and expensive.
>>> 
>>> Hi Gene,
>>> I'm mostly using the TTS holders and some of my more expensive tooling
>> is still R8 so I'm not converting over completely.
>>> 
>>> I'm thinking that your approach with 4 set screws to hold the tap might
>> work well with TTS holders.  A custom holder with a hole for the tap shank
>> and 4 set screws keeps the tap from turning.
>>> 
>>> Now we're back to the original question I posed.  If this TTS holder
>> with a 3/4" shank into the custom R8 holder with say 20 ft-lbs torque on
>> the drawbar won't turn then it's fine for tapping up to the tap size.
>> Since the TTS come with at least 1/2" holes it makes for a reasonably large
>> tap.   Up to 7/8" shank which is once again listed as the limit for R8.
>>> 
>>> And it makes the tap holders a lot less expensive than using ER20
>> collets which are only good up to a certain size.  Purchase a TTS for 1/4"
>> shaft, mount in a lathe collet and bore to the size of the target tap.
>> Drill the 4 holes and tap them.  Now it's a TTS Tap holder.
>> 
>> And I'm having a hard time visualizing that, can you scribble up
>> something and put it on your web site?
>> 
>>> If one wanted to modify the spindle it would be possible to put a pin
>> hole just outside the diameter of the TTS tool.  Then modify the TTS tap
>> holder to have a flange like the pin on your holder that goes into the
>> collet.
>>> 
>>> In fact, modify all the TTS holders to have the flange and it's possible
>> to prevent all TTS tools from spinning in the R8 holders.  Not only that
>> but the M66 command can put the pin in the same place so installing TTS
>> indexed tools becomes trivial.
>> 
>> The word flange is confusing me unless its used to establish a constant
>> length to put in the tool table as TLO. And that would still be subject
>> to error from inconsistent tightening of the drawbar.
>> 
>> My next mechanical thing on the go704 will be stripping a 1/4 ratcheting
>> screwdriver motor out, and rigging it on old 3d printer screws to
>> reengage/disengage from the drawbar, It has the torque I think, to break
>> the drawbar or strip its threads in left to hammer the bar for more than
>> 1 or 2 seconds. Then rig M6 to run it for tool changing, possibly from
>> mid gcode file. I use the drywall screw driver to do that now but need
>> more hands, one to run the driver, one to hold the spindle still, and
>> one to catch the tool when it comes free. By my count that's three
>> hands. :o) Needs more thought...
>>> 
>>> John
>>> 
>>> 
>>> 
>>> 
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Re: [Emc-users] Fusion 360

[Thaddeus Waldner]

Keep in mind that my experiences are in a school setting with some new 
computers but mostly older ones.
Our project involved bitmap trace in Inkscape -> svg  -> cad/cam -> machine out 
of MDF on a small router.
Bitmap trace can produce huge files with little effort; in fact, most of the 
effort is in simplifying the vector artwork to make it manageable in CAD 
software.

From: Martin Dobbins 
Sent: Saturday, October 22, 2022 11:56:47 AM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Fusion 360

Your saying it is a "resource hog" does not bode well for running it on a 
virtual machine that doesn't have hardware horsepower.

Thanks, Thaddeus

________
From: Thaddeus Waldner

I’ve done Fusion 360 CAD/CAM classes with middle school kids (age 10-14). While 
it was mostly an exercise on how to follow instructions, many of them knew 
their way around the software and could begin making changes on their own by 
the time it was over.

I reiterate that it is a resource hog, much more so than Solidworks or Onshape. 
It becomes painfully slow on anything with less than 16gb memory or with 
mediocre single-threaded CPU performance.  It seems that none of those CAD 
packages are optimized much for multi-core processors.

> On Oct 21, 2022, at 6:04 PM, Matthew Herd  wrote:
>
> I use fusion on both windows and Mac. Mostly Mac.
>
> Matthew Herd
>
>
>> On Oct 21, 2022, at 6:52 PM, Martin Dobbins  wrote:
>>
>> So, following on from the CAM discussion and all the love shown to Fusion 
>> 360
>>
>> Has anyone tried:
>>
>> https://all3dp.com/2/fusion-360-for-linux-how-to-install-it/
>>
>> or something similar?
>>
>> Or do you all use Windows or Mac?
>>
>> Martin
>>
>>
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Re: [Emc-users] Fusion 360

[Thaddeus Waldner]

I’ve done Fusion 360 CAD/CAM classes with middle school kids (age 10-14). While 
it was mostly an exercise on how to follow instructions, many of them knew 
their way around the software and could begin making changes on their own by 
the time it was over. 

I reiterate that it is a resource hog, much more so than Solidworks or Onshape. 
It becomes painfully slow on anything with less than 16gb memory or with 
mediocre single-threaded CPU performance.  It seems that none of those CAD 
packages are optimized much for multi-core processors.

> On Oct 21, 2022, at 6:04 PM, Matthew Herd  wrote:
> 
> I use fusion on both windows and Mac. Mostly Mac. 
> 
> Matthew Herd
> 
> 
>> On Oct 21, 2022, at 6:52 PM, Martin Dobbins  wrote:
>> 
>> So, following on from the CAM discussion and all the love shown to Fusion 
>> 360
>> 
>> Has anyone tried:
>> 
>> https://all3dp.com/2/fusion-360-for-linux-how-to-install-it/
>> 
>> or something similar?
>> 
>> Or do you all use Windows or Mac?
>> 
>> Martin
>> 
>> 
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Re: [Emc-users] need plastic with stable dimensions

[Thaddeus Waldner]

The reason why PLA and PETG work so well with 3D printers in the first place is 
due to their low thermal expansion coefficient and relatively low melting 
temperature.

PC is much more difficult to print because it has a higher melting temperature 
and a higher thermal expansion coefficient. My experience with straight PC is 
that it will not print reliably unless you have an enclosure that you can bring 
up to near the glass transition temperature. This keeps the freshly-laid 
plastic from shrinking excessively because it doesn’t cool down as much. But 
more importantly, the whole part remains somewhat soft, so the shrinking forces 
are more easily overcome by your bed adhesion.

If you have a nice enough printer, I hear say you can even print stuff like 
PEEK. 

My experience is also that “high temperature build envelope” is also the thing 
that makes 3d printers much more expensive.
 


> On Oct 10, 2022, at 9:32 AM, gene heskett  wrote:
> 
> On 10/10/22 07:38, andy pugh wrote:
>> On Sun, 9 Oct 2022 at 11:10, Nicklas SB Karlsson  wrote:
>>> Polyoxymethylene (POM) https://en.wikipedia.org/wiki/Polyoxymethylene ?
>> I have a reel of POM filament. It's terrible to print with, and really
>> doesn't want to stick to the bed.
>> 
> I'm in that boat with a $50 roll of polycarb, aka PC. I even bought some 
> special glue stick for PC.
> That stuff bounces off everything including package tape.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> Genes Web page 
> 
> 
> 
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Re: [Emc-users] 2.9 ISO?

[Thaddeus Waldner]

> On Oct 10, 2022, at 4:12 AM, andy pugh  wrote:
> 
> On Mon, 10 Oct 2022 at 10:06, John Dammeyer  wrote:
>> 
>> Thank you Andy.
>> That clearly answers my question.

Ditto
Thanks
> 
> You can probably install the Buster .deb package on Bullseye, though.
> 
> -- 
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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Re: [Emc-users] 2.9 ISO?

[Thaddeus Waldner]

> On Oct 9, 2022, at 5:27 PM, andy pugh  wrote:
> 
> Yes, because you are not running Bookworm.
> 
> LinuxCNC only makes 2.9 packages for the things that you can find in here:
> 
> buildbot.linuxcnc.org/dists/
I’m confused; bookworm is not in that list.
Do you mean buster?

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[Emc-users] 2.9 ISO?

[Thaddeus Waldner]

Hi,
What is the quickest way to get an OS + realtime kernel + LinuxCNC 2.9 up
and running on an Intel system from scratch?

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Re: [Emc-users] losing encoder counts

[Thaddeus Waldner]

The solution to hard problems are always in the peripheral vision.


> On Oct 6, 2022, at 12:20 PM, gene heskett  wrote:
> 
> On 10/5/22 22:56, Jon Elson wrote:
>> Wow, it gets deeper!
>> 
>> It is NOT the encoder, or anything in the encoder-reading process.
>> 
>> I marked the motor shaft, and the motor is returning to the exact same 
>> position every cycle.
>> 
>> Well, I tried a different indicator and mount, and the problem was in the 
>> indicator mount!  I was using an old knock-off of an IndiCol that clamps 
>> around the spindle nose or end mill holder and has several rods with locking 
>> thumbnuts on them.  These swivel joints were slipping just a tiny bit each 
>> time the vise touched the indicator, even though they were PRETTY tight!  
>> Ugh, 3 days of going around in circles trying to tell where the issue was!
>> 
>> Jon
>> 
> Glad you found it, Jon. And don't feel like the lone stranger, I've been 
> caught out by such stuff lots of times.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> Genes Web page 
> 
> 
> 
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Re: [Emc-users] Making ApplePi

[Thaddeus Waldner]

I tried to set up an old (core 2 duo, circa 2007) mac mini as a dev platform 
using the LinuxCNC 2.8 iso. Axis failed to run due to lack of proper graphics 
support in the OS.


> On Oct 2, 2022, at 2:27 AM, John Dammeyer  wrote:
> 
> I have the Pi OS running on it.  Can't SSH into it yet.  Seems certificate 
> exchange is problematic.  
> 
> I believe what I have running on the Pi4 is 
> 2020-09-08-linuxcnc-2.8.0-pi4.img
> Likely I should update that.  
> 
> But I want the Pi OS on the laptop and then want to be able to install 
> LinuxCNC to essentially have the Pi4 user interface but also be able to run 
> LinuxCNC.
> 
> Just not sure how.
> John
> 
> 
> 
> 
> 
>> -Original Message-
>> From: Gregg Eshelman via Emc-users [mailto:emc-users@lists.sourceforge.net]
>> Sent: October-02-22 12:11 AM
>> To: Enhanced Machine Controller (EMC)
>> Cc: Gregg Eshelman
>> Subject: Re: [Emc-users] Making ApplePi
>> 
>> Intel CPU Macs can have a life well extended past their lack of OS X support 
>> from Apple. Install Linux, or
>> Windows, or some other Intel compatible OS. I picked up a 2011 Mac Mini with 
>> a bad 500 gig hard drive, got
>> a dual hard drive kit and a 2TB drive, put that and another 500 gig drive* I 
>> had in it, then made it an Open
>> Media Vault server.
>> 
>> *I pulled it from a laptop a few years ago with a password on it. Finally 
>> got around to setting up an old PC with
>> XP and the SATA controller in legacy mode so I could run password removal 
>> software. After all that it was one
>> click of a "remove password" button. I'd tried everything I could come up 
>> with and got nowhere, figured I
>> must have at least wiped the data on the drive. Nope, it was 100% all there.
>> 
>> On Saturday, October 1, 2022 at 10:25:56 PM MDT, Chris Albertson 
>>  wrote:
>> 
>> The Mac has an Ethernet port, does it not?� You say it is an older Mac, so
>> it likely does have one.� � Some of the newer Macs lack the port, and you
>> have to buy a USB-C to Ethernet dongle.
>> 
>> If it has the built-in RJ45 jack simply connect it. If not buy the Dongle
>> on Amazon.
>> 
>> At some point, you will want to install Linux on the Mac.� Running from the
>> USB drive is very slow.
>> 
>> It is odd to say the Mac acts like a Raspberry Pi.� No. Any computer boots
>> to Linux looks like a Linux PC
>> 
>>> On Sat, Oct 1, 2022 at 9:03 PM John Dammeyer  wrote:
>>> 
>>> I used my wife's old laptop now no longer supported by Apple. Even the
>>> battery needs to be replaced again if I can find one.� It's essentially
>>> trash.
>>> 
>>> Unless I make ApplePi.� Insert USB stick with the ISO.� Answer questions
>>> etc. And then reboot into Raspian looking just like a Pi.
>>> 
>>> Now the question.� How would one go about adding LinuxCNC connected to a
>>> 7i92H
>>> 
>>> John
>> 
>> 
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> 
> 
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[Emc-users] Intel NUC

[Thaddeus Waldner]

Hi,

I am looking for a viable alternative to the Raspberry Pi. I need this to fit 
inside a pretty small enclosure, so I can’t accommodate a much larger size than 
the Pi.

Has anyone tried the Intel NUK products?

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=intel+nuc&_sacat=0&LH_TitleDesc=0&_odkw=intel+nuk&_osacat=0&LH_PrefLoc=2
 



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[Emc-users] Auto-start gscreen on pi4

[Thaddeus Waldner]

Hi,

Does someone have a quick tutorial on how to auto-start Linuxcnc on a Raspberry 
Pi 4? I have a script that starts it when I manually run the script, but it 
fails when called from a systemd service.

Thanks,

Thaddeus Waldner

PS: cross-posting because I first posted this to the EMC Developers list by 
accident. 

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Re: [Emc-users] looking for a split tubing fitting

[Thaddeus Waldner]

I believe it’s called Corrugated Loom by some US distributors. 

Waytek sells Tees, splices, and fastener clips for that stuff but I can’t say 
I’’v ever seen box connectors.

https://www.waytekwire.com/item/21107/Aptiv-8911377-Conduit-Clip-for-Corrugated-Loom-/
 


An alternative option that I’ve used is the expandable braided sleeving. 

https://www.waytekwire.com/item/20301C/Techflex-PET-BLK-1-4-100-Standard-Expandable/
 


You can run this material through the standard waterproof box connectors. It’s 
great for tidying up wires inside control panels but I advise against using it 
on automotive applications where it is exposed to uv rays from the sun. It 
should be fine on a 3d printer.


> On Aug 10, 2022, at 12:01 PM, gene heskett  wrote:
> 
> Greetings all;
> 
> I'm rebuilding a dead Ender 5+ 3d printer, which is going to take at least 6 
> feet of 1/2" split
> corrugated tubing for wire looms.  This is both smaller, and half the weight 
> of the blue plastic
> sorta flexible conduit the electricians use.
> 
> But I need the equ of a half inch emt to box fitting, in plastic
> to anchor the ends of the piece connecting the hot end which has a 16x16 inch 
> motion envelope to its
> anchor point on the rear top frame rail. This is not something a cable chain 
> can solve, but I'm
> not sure what the thing would be called.
> 
> Is there somebody here who could tell me what to search for?
> 
> Thanks all.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> Genes Web page 
> 
> 
> 
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Re: [Emc-users] Pi4 SSD, MicroSD use

[Thaddeus Waldner]

Can you please detail how to reliably connect to a server?

On a few of my systems I connect via wifi and mount the network path on a
local folder. I have fstab set up to do this but it works only if I call
'mount -a' manually after logging in. This is presumably because the
network link is not up at the time when drives are mounted by the OS.

Is there a "wait for network" fstab switch?
Or would I need to set up a script that waits for the network?

My file server is a Samba system, if that makes a difference.


On Fri, Jul 1, 2022 at 3:27 AM Chris Albertson 
wrote:

> I solved this problem (using Pi4 as a development system) by placing all my
> files on a file server.  Development systems see near constant re-compiles
> and write to log files, source code edits and backups and so on.   The
> networking on the Pi4 is pretty fast, or "fast" compared to an SD card.
> The File Server is connected to a backup system that does a
> continuous real-time sync.  This means that if the server explodes I
> lose only a few minutes of work.
>
> On Thu, Jun 30, 2022 at 7:48 AM Thaddeus Waldner 
> wrote:
>
> > Here are some recent experiences with flash storage on a Pi4 as a
> > development environment running LinuxCNC 2.8.2.
> >
> > A while back I posted in this mailing list that using an SSD on the Pi4
> is
> > prohibitive because it causes latency issues. At the time, I tested this
> on
> > a heavily used, repurposed ssd. I later discovered that the SSD was
> failing
> > due to write wear. This is likely what caused the latency issues in the
> > first place.
> >
> > In the meantime I ran the Pi4 (2GB memory) as  a development platform,
> > running up to 3 instances of VS Code (1.5GB memory each) along with
> Glade,
> > browser, etc. This type of usage made short work of the Samsung EVO
> microSD
> > card. The card wear issue first showed up as spurious latency
> violations. A
> > bit later the entire system became maddeningly slow and unusable.
> >
> > Cloning to a fresh sd card solved the problem.
> >
> > In the process of making backups I also cloned the system to an SSD
> (intel
> > 320 this time) and to my surprise, it ran with zero latency issues. I
> will
> > be using SSDs from now on, thank you.
> >
> > Some takeaways:
> > 1) large page files are bad news for cheap flash storage
> > 2) "worn out" storage will cause latency issue on low latency systems
> > 3) latency tests on a low latency system might be a way to detect flash
> > write wear issues.
> >
> > Thaddeus
> >
> > ___
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> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
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Re: [Emc-users] Pi4 SSD, MicroSD use

[Thaddeus Waldner]

I am using this cable:

StarTech.com SATA to USB Cable -... 
https://www.amazon.com/dp/B00HJZJI84?ref=ppx_pop_mob_ap_share


> On Jun 30, 2022, at 11:33 AM, johnd  wrote:
> 
> Hi Thaddeus,Can you add some information? 1. What USB 3.0 to SATA adapter 
> are you using?2. Or is it a case that the SATA drive or SSD fits into?3. 
> Which specific SSD are you using?  Thanks JohnSent from my Samsung S10
>  Original message ----From: Thaddeus Waldner  
> Date: 2022-06-30  7:47 a.m.  (GMT-08:00) To: "Enhanced Machine Controller 
> (EMC)"  Subject: [Emc-users] Pi4 SSD, 
> MicroSD use Here are some recent experiences with flash storage on a Pi4 as 
> adevelopment environment running LinuxCNC 2.8.2.A while back I posted in this 
> mailing list that using an SSD on the Pi4 isprohibitive because it causes 
> latency issues. At the time, I tested this ona heavily used, repurposed ssd. 
> I later discovered that the SSD was failingdue to write wear. This is likely 
> what caused the latency issues in thefirst place.In the meantime I ran the 
> Pi4 (2GB memory) as  a development platform,running up to 3 instances of VS 
> Code (1.5GB memory each) along with Glade,browser, etc. This type of usage 
> made short work of the Samsung EVO microSDcard. The card wear issue first 
> showed up as spurious latency violations. Abit later the entire system became 
> maddeningly slow and unusable.Cloning to a fresh sd card solved the 
> problem.In the process of making backups I also cloned the system to an SSD 
> (intel320 this time) and to my surprise, it ran with zero latency issues. I 
> willbe using SSDs from now on, thank you.Some takeaways:1) large page files 
> are bad news for cheap flash storage2) "worn out" storage will cause latency 
> issue on low latency systems3) latency tests on a low latency system might be 
> a way to detect flashwrite wear 
> issues.Thaddeus___Emc-users 
> mailing 
> listEmc-users@lists.sourceforge.nethttps://lists.sourceforge.net/lists/listinfo/emc-users
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[Emc-users] Pi4 SSD, MicroSD use

[Thaddeus Waldner]

Here are some recent experiences with flash storage on a Pi4 as a
development environment running LinuxCNC 2.8.2.

A while back I posted in this mailing list that using an SSD on the Pi4 is
prohibitive because it causes latency issues. At the time, I tested this on
a heavily used, repurposed ssd. I later discovered that the SSD was failing
due to write wear. This is likely what caused the latency issues in the
first place.

In the meantime I ran the Pi4 (2GB memory) as  a development platform,
running up to 3 instances of VS Code (1.5GB memory each) along with Glade,
browser, etc. This type of usage made short work of the Samsung EVO microSD
card. The card wear issue first showed up as spurious latency violations. A
bit later the entire system became maddeningly slow and unusable.

Cloning to a fresh sd card solved the problem.

In the process of making backups I also cloned the system to an SSD (intel
320 this time) and to my surprise, it ran with zero latency issues. I will
be using SSDs from now on, thank you.

Some takeaways:
1) large page files are bad news for cheap flash storage
2) "worn out" storage will cause latency issue on low latency systems
3) latency tests on a low latency system might be a way to detect flash
write wear issues.

Thaddeus

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[Emc-users] Schematics

[Thaddeus Waldner]

Hi,

I need some advice on what program to use for creating machine  schematics. I 
am somewhat familiar with Autodesk Eagle for board design. 

I”d also like cad drawings for the Mesa 7i96 if they are available.



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Re: [Emc-users] Do we have an m-code with access to halcmd?

[Thaddeus Waldner]

Gene, can you share a link to the motor you are using?

Thanks

> On Apr 29, 2022, at 3:46 AM, gene heskett  wrote:
> 
> On Thursday, 28 April 2022 21:17:20 EDT gene heskett wrote:
>>> On Thursday, 28 April 2022 19:35:44 EDT andy pugh wrote:
>>> On Fri, 29 Apr 2022 at 00:20, gene heskett 
>> wrote:
> Surely you already know that? It's 360 x 100 x SCALE ?
 Sure Andy. But what is the scale?
>>> 200 * 16 * 40 * (60/53) / 360
>> But these motors are not 200, but 300, they are 3 phase, 1.2 degrees a
>> full step. 300 steps per rev for full step.
>> So by purely mechanical means, that would then be:
>> 300 * 16 * 40 * [60/53] / 360, or 603.7735849 according to my TI-36X
>> Pro. But thats about 5x what seems to be pretty close @ 125.x.
>> Something, someplace is lying like a rug. But where? You got the hal
>> file now, is it wrong?
> Two problems to fix before its right.
> 
> 1. These drivers have two microstep modes, digital and apparently powers 
> of 10. Only one switch is on, sw3, which claims it makes a full turn of 
> the motor in 6400 steps. Just one problem. A 300 full step per turn motor 
> cannot be made to equal 6400 with any integer multiplier. At /16, its not 
> 6400, but 4800 steps per turn. A value that's off either by .75, or 
> 1. depending on interchanging the numbers. If it is truely 
> actually 6400 microsteps/turn, what the hell kind of math is it useing? 
> Obviously NOT a power of 2. I think these little magic boxes are miss-
> marked. Obviously whoever drew up that silk screen was thinking in terms 
> of a 200 full steps per turn motor, and the 3 phase models are 300, not 
> 200. So that means 300*16 is 4800 steps per turn of the motor shaft. No 
> way in hell can I make the math work using thier silk screened figures.
> 
> So that's problem #1. And the correct answer can only be found if #2 is a 
> 1/1 answer.
> 
> [edited]
>> I just found the stepgen drawings in the docs and I think my hal file
>> is wrong, the values presented by the position.fb pins are not in the
>> same units as .count's. position.fb has been scaled.
> 
> 2. The $64k question then, since the step itself is not available to hal 
> for counting, is the stepgen a direct translator?, issueing 1 full step 
> per count it reports on the .count pin?
> (yes/no)
> If no, what is the ratio?
> 
>> And this needs counts. I'll fix that when I get it back together. Then
>> maybe it will make sense.
>> currently stepgen3.counts is  -173640,
>> whilestepgen3.position.fb is  1380.7
> 
> Fixed already, but not yet exersized for truthfullness. A sneakernet 
> mistake. :o(
> 
> Thank you, Andy.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
> 
> 
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Re: [Emc-users] Controlling DC motors.

[Thaddeus Waldner]

This idea is still in use today with proportional hydraulic valves; you use a 
PWM frequency that is low enough to induce a slight continuous vibration in the 
valve, to overcome stiction.

> On Apr 10, 2022, at 6:49 PM, Chris Albertson  
> wrote:
> 
> I'd say this thing was a vibrator with a DC component and not PWM control.
> 


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[Emc-users] High speed probing

[Thaddeus Waldner]

I have spent some time trying to speed up the probe cycle for a non-contact 
laser probe that I want to use as a kind of CMM.

I cannot seem to find ANY way to get access to encoder data from within a gcode 
file without first calling a pause and sync (G66), which halts all motion for a 
moment. I would like to avoid this.

I have tried setting the encoder to be axis feedback and reading parameter 
#<_z> or #5422. This parameter returns commanded position only.

I have tried setting up the encoder to be an external offset. I get the same 
results; none of the system parameters appear to change with an external 
offset. This kind of makes sense as it is an external offset, after all.

Any ideas?

Thaddeus Waldner

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Re: [Emc-users] Probing

[Thaddeus Waldner]

I am not at the machine right now but if memory serves me right, I used
G10 L20 P1 Z1.588

Ah! I just saw that P0 is for the active coordinate system. Is P optional?


Thaddeus Waldner

From: Andy Pugh 
Sent: Sunday, March 27, 2022 7:55:07 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Probing



> On 28 Mar 2022, at 00:26, Thaddeus Waldner  wrote:
>
> I was able to get this working. Thanks for the help. I ended up using a macro 
> and modifying G54 Z offset

If you use G10 then it will use the current coordinate system.

G10 is almost always the correct in to use for this.

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Re: [Emc-users] Probing

[Thaddeus Waldner]

I was able to get this working. Thanks for the help. I ended up using a macro 
and modifying G54 Z offset.

My probe is actually a mechanical switch with a touch plate. I use it by 
placing it on top of the workpiece, then probing with the cutter. This machine 
has the collet attached to the spindle, so I have to set the Z offset when I 
change tools. The probe speeds up a tool change considerably.

> On Mar 26, 2022, at 7:14 AM, gene heskett  wrote:
> 
> On Saturday, 26 March 2022 02:10:50 EDT Thaddeus Waldner wrote:
>> Hi,
>> 
>> I am in the process of installing a probe on my router. I want to use
>> this by placing it on an arbitrary location on top of the workpiece
>> and probing with the installed cutter.
>> 
>> I would like to configure an unused physical keypad button to run a
>> probing routine that will probe, then automatically adjust either a
>> workpiece offset or a tool offset.
>> 
>> At this point I have the probe connected and switching the
>> motion.probe-input signal; G38.2 works.
>> 
>> Can someone show me what is required to make the rest work? I imagine
>> that I should write the probing routine in g-code and run it at the
>> push of the button … somehow.
>> 
>> Thaddeus Waldner
> 
> Andy may have a better idea, but I would explore the idea of running a 
> named subroutine that captures the machines current xy position, (so you 
> can run it up the post and return to the saved xy position) moves to the 
> contact pad, starts the spindle slowly in reverse so it doesn't cut the 
> pad, does the g38.2, and uses the results to set the coordinate system Z, 
> probably with an offset from the known height of the pad. I use un-etched 
> pcb material for the pad which is about 1/16" thick. 99% of this, var 
> #numbers etc is in the Documentation.pdf. Okular will be your friend.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
> 
> 
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[Emc-users] Probing

[Thaddeus Waldner]

Hi,

I am in the process of installing a probe on my router. I want to use this by 
placing it on an arbitrary location on top of the workpiece and probing with 
the installed cutter. 

I would like to configure an unused physical keypad button to run a probing 
routine that will probe, then automatically adjust either a workpiece offset or 
a tool offset. 

At this point I have the probe connected and switching the motion.probe-input 
signal; G38.2 works. 

Can someone show me what is required to make the rest work? I imagine that I 
should write the probing routine in g-code and run it at the push of the button 
… somehow.

Thaddeus Waldner


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Re: [Emc-users] Using bb's for ball bearing balls while 3d printing.

[Thaddeus Waldner]

Z direction does not shrink so much because each layer is placed at an absolute 
position rather than relative to the previous layer. So the only shrinkage you 
should see in the z direction is the amount of thermal expansion from your 
build enclosure to ambiant.

XY shrinkage is a common issue with 3d printing. In the Stratasys software that 
I use, it’s something you set on each print—if you bother changing it, that is.

It would be difficult (for me, at least) to come up with a mathematical formula 
for calculating xy shrinkage. All the recommendation I have seen are to print, 
measure it, compensate using the scaling controls, and print again.

If you find that you use a consistent amount of scaling from one print to the 
next, you could change the X and Y stepper scale in firmware. Or maybe add a 
scale factor to your g-code preamble in Cura. But keep in mind that this would 
change your extrusion rate slightly.


[Image.jpeg]

Thaddeus Waldner

From: gene heskett 
Sent: Friday, March 25, 2022 9:15:23 PM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] Using bb's for ball bearing balls while 3d printing.

On Friday, 25 March 2022 16:59:37 EDT Thaddeus Waldner wrote:
> I would suggest that you calibrate the xy shrinkage, and z shrinkage in
> your printer slicer, instead of compensating for it in your design.

Cura doesn't make that obvious as how to do that, and AFAICT there is no
shrinkage or growth in Z. Its finest z layer is .12mm all the way up, or
dynamic depending on the layer but its not plain what might trigger the
thicker layer. If I tell it to make a part to fit inside a 24mm internal
housing with .125mm movement clearance on each side for two parts
totalling 23.85mm tall, it will measure 23.81" high for the stack when
done. That's about the right room for some synthetic plastic grease...

My reticence to messing with cura is that this is an end to end fix, and
that fix also adds that red layer of thickness to the actual plastic laid
when making the bearing races, making it stronger yet. Perhaps in newer
code I might fix cura if I knew precisely how to fix it instead.

This is all part of my $10 material cost for a miniature harmonic drive
to add to the 4th axis of a 6040 gantry mill. And I am probably going to
wear it out making a wooden (hard maple) vise screw for a woodworking
vise, I've already made the buttress thread nut, a 12mm pitch, 2 start
affair on the 3d printer.  Now I have to make the screw that fits it. And
then design and print the thrust bearings.

If you are familiar with how to make cura do that, plz advise as it would
be nice to spec a ball 4.35mm in diameter like a bb measures, to cut a
ball track, instead of the 4.56mm I'm currently using for such.  Any less
and its too tight a fit, won't roll well and will split either track at
the center, thin place before it rolls very far.

Thank you Thaddeus.

Take care and stay well.

> > On Mar 25, 2022, at 3:29 PM, gene heskett 
> > wrote:
> >
> > Greetings all;
> >
> > It has come to my attention that one of the potential failures in my
> > harmonic drive with a loose belt experimentation, which seems to be
> > caused by the unequal shrinkage in the xy direction as opposed to the
> > z direction is at least partially caused by the nozzle diameter. If
> > I attempt to achieve a zero clearance bearing simply by shrinking
> > the dummy ball from about .5mm bigger than the bearing, as it
> > shrinks, the wider edges of the bearing groove come into zero or a
> > slight preload condition, leading eventually to a race fatigue split
> > at the center of the races width. Working in openscad, a scale
> > command would fix this by shrinking the bb shape used for clearing
> > that groove, only in the x direction.
> >
> > Th question is how much would it take to transfer the majority of the
> > stresses on the race from being on the outer edges of the race, to be
> > more concentrated on the center of the race, with an eye toward
> > reducing the splitting force on the bearing race.
> >
> > 1% x shrink, 2%, 3%, what would be the ideal amount of shrink to
> > compensate for the printers .4mm nozzle, being used to only lay .12mm
> > per layer?
> >
> > Seems to me there ought to be a way to mathematically predict how
> > much
> > that shrinkage diff there is. Attached, an extra 2 lines to draw that
> > away from the bearing itself, showing how little the difference is
> > for a .97 x shrink.
> >
> > Comments plz?
> >
> > Cheers, Gene Heskett.
> > --
> > "There are four boxes to be used in defense of liberty:
> > soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author, 1940)
> > If 

Re: [Emc-users] Using bb's for ball bearing balls while 3d printing.

[Thaddeus Waldner]

I would suggest that you calibrate the xy shrinkage, and z shrinkage in your 
printer slicer, instead of compensating for it in your design.




> On Mar 25, 2022, at 3:29 PM, gene heskett  wrote:
> 
> Greetings all;
> 
> It has come to my attention that one of the potential failures in my 
> harmonic drive with a loose belt experimentation, which seems to be 
> caused by the unequal shrinkage in the xy direction as opposed to the z 
> direction is at least partially caused by the nozzle diameter. If I 
> attempt to achieve a zero clearance bearing simply by shrinking the dummy 
> ball from about .5mm bigger than the bearing, as it shrinks, the wider 
> edges of the bearing groove come into zero or a slight preload condition, 
> leading eventually to a race fatigue split at the center of the races 
> width. Working in openscad, a scale command would fix this by shrinking 
> the bb shape used for clearing that groove, only in the x direction.
> 
> Th question is how much would it take to transfer the majority of the 
> stresses on the race from being on the outer edges of the race, to be 
> more concentrated on the center of the race, with an eye toward reducing 
> the splitting force on the bearing race.
> 
> 1% x shrink, 2%, 3%, what would be the ideal amount of shrink to 
> compensate for the printers .4mm nozzle, being used to only lay .12mm per 
> layer?
> 
> Seems to me there ought to be a way to mathematically predict how much 
> that shrinkage diff there is. Attached, an extra 2 lines to draw that 
> away from the bearing itself, showing how little the difference is for a 
> .97 x shrink.
> 
> Comments plz?
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
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Re: [Emc-users] Laser measurement sensor

[Thaddeus Waldner]

Update on the laser probe.

Thanks to some input from this group and a discussion with Peter at Mesa tech, 
I now have a laser distance measuring device reading to within 0.001”. The 
range of my instrument is about 2” and I need only about 1/2”, so I can get the 
precision down to 1/4 of that. Not that I need it.

As I mentioned earlier, the laser instrument is a Keyence iA-1000/iA-060. The 
output from this device is a scalable analog 0.5-4V signal.

I built a small board that powers the laser, converts the voltage to a 
frequency, and feeds signal into an encoder configured for count mode. 24v 
Power enters the board via a pair of screw terminals. This power is filtered, 
regulated, then brought out to the laser. The analog voltage signal is 
converted to a frequency signal, which then goes through an isolator and is 
delivered to the mesa board via the P1 expansion socket

I used an Analog Devices AD7741 voltage to frequency converter. This device 
needs to be clocked with either a clock input or a crystal. I used a step 
generator output for this.

The isolator I used is a NVE IL-712-2E. This is a 2-channel “digital isolator” 
with channels running in opposite directions. This device is remarkably fast; 
propagation delay is 15ns and max pulse width distortion is 3ns. I have never 
before heard of digital isolators. Are they a new thing? Any reason why not to 
use them over optical isolators?


If I had been smart, I would have just purchased a mesa THCAD card. I would 
have accomplished more but learned less.

Thaddeus Waldner


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Re: [Emc-users] LinuxCNC simulator

[Thaddeus Waldner]

> I'd second that. For ease of deployment, I may favor a stock Debian
> netinstall with a linuxcnc install script, or even better a custom preseed.
> 
> No issue running preempt-rt kernel in VM.
> 
> BTW, when you talk about simulation, do you plan to use Vismach?
> This is a matter I'd like to extend and improve documentation about. Would
> tell us more about your plan please?
> 
> TY
> Jérémie
> 
I want to go over the UI basics and demonstrate  how the design-to-cutter  
toolchain works. I’ll be using the backplot, tool table, workpiece offsets, etc.



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Re: [Emc-users] LinuxCNC simulator

[Thaddeus Waldner]

> I installed LinuxCNC in my Virtualbox a number of times. RT kernel doesn't 
> have a problem running that way.
> 

I now have a running LinuxCNC on my VM host. There was no problem setting it up 
from the ISO. Thanks!
> 
> I assume you have computers in the classroom. What's on them? I hope not 
> trash OS. One way you could go around it with bootup from USB stick that 
> would run functional LinuxCNC.
> 

Trash OS all the way! I tried linux on some of my older machines but found it 
too difficult to configure Samba to work with AD logins. Also, I need some 
Mac/Windows-only software, such as Fusion 360.

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[Emc-users] LinuxCNC simulator

[Thaddeus Waldner]

Hi,

I would like to set up a linuxcnc vm box for simulation/training in my 
classroom. What is the easiest way to do that and not have to mess with special 
kernels?

I have access to a local exsi server so it would be a small matter to run an 
.iso. I also have a Debian bullseye vm running on it now, which I use for 
projects like this.

Thanks

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Re: [Emc-users] math challenged Q

[Thaddeus Waldner]

That’s one for the Babylonians, and later Pythagoras.

Sqrt(51.5^2 + 51.5^2) =72.83 will give you the diameter.

With trig, 51.5/sin(45) will give you the same number. 

> On Mar 11, 2022, at 9:44 PM, gene heskett  wrote:
> 
> Greetings all;
> 
> I need to setup a starting point, a preliminary turn operation, ahead of 
> the thread carving just to get that over with before the finer work of 
> actually carving the thread, with a .25" LOC 1/16th" round nosed tool.
> 
> This will involve cutting a 2x2", probably a few oversized, so a caliper 
> will measure it as 51.5x51.5mm square. My question seems like there ought 
> to be a tan involved since the answer is over unity, but I can't get 
> sensible answers out of my ti-36x pro using the tan function.
> 
> The max radius the corners of that stick, as its turned, ought to be some 
> figure plus the 26 starting point when the square has been turned 45 
> degrees, bringing its largest offset under the tool/probe. So assuming I 
> have it touched off at 25.75mm, what is the max circle radius the tips of 
> the square will describe as it turns?
> 
> 8th grade algebra was for me both 74 years ago and taught by a male 
> teacher who was far more interested in getting into the girls panties 
> than he was in teaching algebra. After I quit school and went to work 
> fixing them new-fangled things called tv's, he got caught and was invited 
> to leave town forever by one of the girls fathers who was carrying a 
> loaded 12 ga at the time the invite was issued. He was AH enough to leave 
> another older girl behind already pg with his child. My bitching about it 
> beforehand to the super because I felt I was being cheated out of an 
> education was ignored.  Kharma has a way of coming to roost. Apparently 
> schools only go downhill from there.
> 
> But I still need to know how to calculate that answer...
> 
> Thanks all.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
> 
> 
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Re: [Emc-users] pressure sensor?

[Thaddeus Waldner]

> But neither of the $23 sensors I bought, actually works. black to -, red
> to 5v, green to dvm on my test table, one rests at nominally 1 millivolt,
> the other at around 27 millivolts which doesn't change with the applied
> pressure.

What are the sensors? Are they possibly PWM output and need a pull-up?

They could also be current devices. Check if the current changes with pressure.

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Re: [Emc-users] Laser measurement sensor

[Thaddeus Waldner]

> I don't know if my reply got through. Look at Micro-Epsilon.

It did get through, thank you. 
Micro-Epsilon appear to be a premiere brand in this industry. 

I am a bit puzzled by some of the replies saying that it is very difficult to 
achieve 0.001 with these sensors. Perhaps I failed to mention the units, which 
are inches. I also failed to mention that the sensor will measure the height of 
an object that rests at a known position, from a working distance of >4”. So 
it’s not absolute accuracy that I’m after but relative displacement. These 
triangulation sensors are quite good at that, it would appear.


I decided to go with a Keyence Ia-060 head and Ia-1000 amplifier, because the 
whole kit can be had used off ebay for around $200.

The signal out of this device is 0.5V-4V. It is scalable to a specific working 
range, which should allow me to use the entire voltage scale instead of that 
scale being spread over the instrument’s working range.

Now I need to get this signal into LinuxCNC. I think the MESA THCAD device 
would work, though it’s a bit overkill. Does MESA have other 1 or 2-channel A-D 
options, perhaps without the high voltage protection?

I also have a few ADS1115 devices on hand. I saw that someone created a 
LinuxCNC component for these, as it would appear, by bit-banging the i2c 
protocol from a parallel port. I don’t run a base thread on this machine, 
though, and the computer is a pi4. Is it possible to use the native i2C bus on 
the pi4 in a LinuxCNC realtime component? If this sounds like a naive question, 
it’s because it is one. I code mostly by the copy-paste method. :)

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Re: [Emc-users] Laser measurement sensor

[Thaddeus Waldner]

The AR200-100 is the one recommended to me by their salesperson. 

> On Mar 7, 2022, at 3:06 PM, jeanfrancois  wrote:
> 
> Hi,
> 
> This one uses trigonometry I think, nothing that much fancy or
> technically difficult it appeare:
> 
> https://www.acuitylaser.com/wp-content/uploads/product-downloads/ar200-data-sheet.pdf
>  
> <https://www.acuitylaser.com/wp-content/uploads/product-downloads/ar200-data-sheet.pdf>
> 
> Regards
> 
> 
> Le 07/03/2022 à 21:01, gene heskett a écrit :
>> On Monday, 7 March 2022 12:44:21 EST Thaddeus Waldner wrote:
>>> Hi,
>>> 
>>> I’m looking for a laser distance sensor with about 1-3 thousandths
>>> resolution and about a 5-10” working range. I wouldn’t mind buying a
>>> used unit.
>> 1. I didn't know they came in that high a resolution w/o needing a quorum
>> of the US Senate to authorize the payment, then signed by the President.
>> 
>> If you want to know why, calculate the time difference of that 3
>> thousandths of an inch increment, remembering that it has to travel out,
>> and back to the measuring device, equal to C/2 in speed. You will I
>> suspect will come up with a very small fraction of a picosecond.
>> 
>> Interferometry can measure that change, but the mod function to detect
>> the individual null and count it has to start at zero, or a known micron
>> sized distance before it can count the nulls passing by as it moves from
>> zip distance, back to your point of interest at a 12" max range. Moving
>> slow enough to count, will take a 2048 bit counter and several days.
>> 
>> Technically, we can do it but you'll need a couple of dump trucks full of
>> gold to finance one neasurement. We can't yet buy a calibrated answer in
>> 10 milliseconds for a $500 bill.  Someday? Maybe, but it may take a new
>> method to be invented.
>> 
>>> Does anyone here know of some brands/ models to check out?
>>> 
>>> Google has pointed me at some Acuity products but I wondered if there
>>> were other options besides that.
>>> 
>>> ___
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>> 
>> Cheers, Gene Heskett.
> 
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Re: [Emc-users] Laser measurement sensor

[Thaddeus Waldner]

I need the small spot size of the measurement. I imagine US is not that well 
defined.

> On Mar 7, 2022, at 2:32 PM, jeanfrancois  wrote:
> 
> Are ultrasonic sensors doing the job in that tolerance ?
> 
> Jean-François
> 
> 
> Le 07/03/2022 à 21:01, gene heskett a écrit :
>> On Monday, 7 March 2022 12:44:21 EST Thaddeus Waldner wrote:
>>> Hi,
>>> 
>>> I’m looking for a laser distance sensor with about 1-3 thousandths
>>> resolution and about a 5-10” working range. I wouldn’t mind buying a
>>> used unit.
>> 1. I didn't know they came in that high a resolution w/o needing a quorum
>> of the US Senate to authorize the payment, then signed by the President.
>> 
>> If you want to know why, calculate the time difference of that 3
>> thousandths of an inch increment, remembering that it has to travel out,
>> and back to the measuring device, equal to C/2 in speed. You will I
>> suspect will come up with a very small fraction of a picosecond.
>> 
>> Interferometry can measure that change, but the mod function to detect
>> the individual null and count it has to start at zero, or a known micron
>> sized distance before it can count the nulls passing by as it moves from
>> zip distance, back to your point of interest at a 12" max range. Moving
>> slow enough to count, will take a 2048 bit counter and several days.
>> 
>> Technically, we can do it but you'll need a couple of dump trucks full of
>> gold to finance one neasurement. We can't yet buy a calibrated answer in
>> 10 milliseconds for a $500 bill.  Someday? Maybe, but it may take a new
>> method to be invented.
>> 
>>> Does anyone here know of some brands/ models to check out?
>>> 
>>> Google has pointed me at some Acuity products but I wondered if there
>>> were other options besides that.
>>> 
>>> ___
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>>> https://lists.sourceforge.net/lists/listinfo/emc-users
>> 
>> Cheers, Gene Heskett.
> 
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Re: [Emc-users] Laser measurement sensor

[Thaddeus Waldner]

Acuity sells what I need brand new for $1000.
Keyence appears to be a much more common brand, given by the number of eBay 
items. 
These are not time-of-flight devices; they work instead by measuring the 
position of an angled laser spot on the target.

I’m looking at the Keyence IA-065. The working range of 2.17" - 4.13” would 
work for my application. I’m a bit puzzled by the “linearity" spec on the data 
sheet. It reads as follows:
+- 0.1% of F.S (F.S.=+-10 mm 0.39”, 55 to 75mm 2.17 to 2.95”)

I read that as within the range of 55mm to 75mm, the linearity will be within 
0.2% of that range, which comes to 0.04mm or about 0.0016”. Is my logic and 
math correct?

Second question, what is the simplest (and cheapest!) way to get this analog 
voltage into LinuxCNC. I do have a couple of 24-bit I2C devices on hand 
(ADS1220). Is this workable without writing a driver or something like that?



> On Mar 7, 2022, at 2:01 PM, gene heskett  wrote:
> 
> On Monday, 7 March 2022 12:44:21 EST Thaddeus Waldner wrote:
>> Hi,
>> 
>> I’m looking for a laser distance sensor with about 1-3 thousandths
>> resolution and about a 5-10” working range. I wouldn’t mind buying a
>> used unit.
> 
> 1. I didn't know they came in that high a resolution w/o needing a quorum 
> of the US Senate to authorize the payment, then signed by the President.
> 
> If you want to know why, calculate the time difference of that 3 
> thousandths of an inch increment, remembering that it has to travel out, 
> and back to the measuring device, equal to C/2 in speed. You will I  
> suspect will come up with a very small fraction of a picosecond.
> 
> Interferometry can measure that change, but the mod function to detect 
> the individual null and count it has to start at zero, or a known micron 
> sized distance before it can count the nulls passing by as it moves from 
> zip distance, back to your point of interest at a 12" max range. Moving 
> slow enough to count, will take a 2048 bit counter and several days.
> 
> Technically, we can do it but you'll need a couple of dump trucks full of 
> gold to finance one neasurement. We can't yet buy a calibrated answer in 
> 10 milliseconds for a $500 bill.  Someday? Maybe, but it may take a new 
> method to be invented.
> 
>> Does anyone here know of some brands/ models to check out?
>> 
>> Google has pointed me at some Acuity products but I wondered if there
>> were other options besides that.
>> 
>> ___
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>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
> 
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
> 
> 
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[Emc-users] Laser measurement sensor

[Thaddeus Waldner]

Hi,

I’m looking for a laser distance sensor with about 1-3 thousandths resolution 
and about a 5-10” working range. 
I wouldn’t mind buying a used unit.

Does anyone here know of some brands/ models to check out?

Google has pointed me at some Acuity products but I wondered if there were 
other options besides that. 

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Re: [Emc-users] nother q re sensors

[Thaddeus Waldner]

This might help. I have a large print of this hanging on the wall.

https://ww2.gates.com/Turkey/file_save_common.cfm?thispath=Turkey%2Fdocuments%5Fmodule&file=50101%5FE2%5FCOUPL%5FIDENT%5FCHART%2Epdf

> On Mar 6, 2022, at 8:08 PM, gene heskett  wrote:
> 
> Greetings all;
> 
> I have obtained a couple 0-10 psi 3 wire sensors I'd like to use to 
> control a pwmgen to regulate the low air pressure a mister uses, as just 
> a couple lbs is plenty. Useing a 12 volt supply driving 5 of those teeny 
> compressors I bragged about finding.
> 
> But it has an unusual (to me) feed arrangement to get the pressure into 
> it, seems to be a std in the auto world, but I've never seen it before. 
> The thread is not a tapered thread, measureing 12.95mm in the threads 
> major diameter, and quite close to 1mm pitch, maybe .98mm? There is a 
> reduced diameter area between the inner end of the thread, and a smooth 
> flat face beyond it, as if an O ring is intended to be sealed in position 
> by having its outside contained in a rim around the socket it screws 
> into.
> 
> Has anyone a clue what this is known as in the trade? G1/4 seems to 
> relate somehow, but its nowhere near a 1/4 inch AMSTAN pipe thread for 
> pitch, and its not tapered like a pipe thread.
> 
> Wikipedia.org wasn't much help as no common threads for about that size 
> are anywhere near that pitch. There is a fine thread metric 12mm at 1mm 
> pitch, but no 13mm seems to exist.
> 
> Call me puzzled.
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> 
> 
> 
> 
> 
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Re: [Emc-users] Auxiliary axis DRO only

[Thaddeus Waldner]

I found a workaround; It's possible to read HAL pins from g-code. The
problem is they don't necessarily update after the program is started. But
according to the manual, a state sync command--M66E0L0-- forces it to
update. The problem is that this stops the motion, and now instead of a
non-stop scan, I have a stop-go at each point. I still get around 4
readings per second so it would be workable, just not ideal.

Configuration section)
G20(Inches)
F10 (probe speed)

#4=-1  (Y start)
#5=.01 (Y increment)
#6=101 (Y count)

(End configuration section)

(LOGOPEN,profile-results.ngc)
#9=0 #10=0
G0Z#7
(file preamble)
(LOG,G20)
(LOG,G64 P0.002)
(LOG,F30)
O1 while [#9 lt #6]
G1 Y[#4+#5*#9]
 (LOG, G1 X#<_hal[z-pos-fb]>Y#<_Y> )
 M66E0L0
#9=[#9+1]
O1 endwhile
(LOG,G0X0Y0)
(LOG,M2)
(LOGCLOSE)
G0Y#4
M2

On Fri, Feb 25, 2022 at 10:33 PM Thaddeus Waldner 
wrote:

>
>> I am not sure what the built-in parameters such as #<_Z> show in this
>> situation. I would suspect that it is commanded position but it's not
>> hard to find out.
>>
>
> I just ran the following gcode:
>
> (Configuration section)
> G20(Inches)
> F2(probe speed)
>
> #4=-1  (Y start)
> #5=.04 (Y increment)
> #6=51  (Y count)
>
> (End configuration section)
>
> (LOGOPEN,profile-results.ngc)
> #9=0
>
> O1 while [#9 lt #6]
> G0 Y[#4+#5*#9]
>  (LOG, G1 #<_Y>, #<_Z>)
> #9=[#9+1]
> O1 endwhile
>
> (LOGCLOSE)
> G0Y#4
> M2
>
> I manually moved the z encoder while this was happening.
> It produces a log file as expected, bu all the z-values are zero.
> some more testing with (DEBUG, #<_Z>) showed that #<_Z> stays zero until
> it is changed by motion. For example, using the jog keys will change it.
>
> Anything else I can try?
>

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Re: [Emc-users] Auxiliary axis DRO only

[Thaddeus Waldner]

>
>
> I am not sure what the built-in parameters such as #<_Z> show in this
> situation. I would suspect that it is commanded position but it's not
> hard to find out.
>

I just ran the following gcode:

(Configuration section)
G20(Inches)
F2(probe speed)

#4=-1  (Y start)
#5=.04 (Y increment)
#6=51  (Y count)

(End configuration section)

(LOGOPEN,profile-results.ngc)
#9=0

O1 while [#9 lt #6]
G0 Y[#4+#5*#9]
 (LOG, G1 #<_Y>, #<_Z>)
#9=[#9+1]
O1 endwhile

(LOGCLOSE)
G0Y#4
M2

I manually moved the z encoder while this was happening.
It produces a log file as expected, bu all the z-values are zero.
some more testing with (DEBUG, #<_Z>) showed that #<_Z> stays zero until it
is changed by motion. For example, using the jog keys will change it.

Anything else I can try?

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Re: [Emc-users] Auxiliary axis DRO only

[Thaddeus Waldner]


> In that case, I'd design the probe to be held in the x axis, or crossfeed 
> if this is a lathe, with its own self contained contact closer, move y by 
> whatever increment is needed to get the y accuracy you need, and use the 
> std g38.2 probe to record the trip position.

No, it’s not a camshaft :). The profile is continuous and I want to avoid 
having to build an actual powered axis in the direction that I am probing. I 
would like a simple roller-follower attached to an encoder that, pretends to be 
an axis—not that there’s a huge difference between the two. Though there will 
need to be a way to engage the roller from a stored position, but that can be a 
manual job.

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Re: [Emc-users] Auxiliary axis DRO only

[Thaddeus Waldner]



>> You don't need a joint at all.  You can just have an encoder
>> channel that doesn't connect to any joint.

I will look into the halsampler solution. Can you point me to a working 
example? The end goal is indeed a point cloud.
One issue that might make it simpler (or not!) to have an actual joint is that 
I have still not determined if the probe/wheel can work on a linear axis or if 
I need to do a trailing rotating arm so as better to roll over steep features 
without snagging.

> True, though there is something to be said for having a dummy axis
> just so that the LinuxCNC GUI will display the encoder position.
> 
> You don't need a stepgen, just set up the system as normal but leave
> joint.N.motor-pos-cmd unconnected. Connect motor-pos-fb to the encoder
> counter.
> Then set the following error limits to several miles, and you should
> get an onscreen readout of the probe position. (set the gui to actual,
> not commanded..)
This works with some caveats. The back plot updates to show movement of z 
position until I enable the joints. At which point it stops updating the back 
plot. The position readout does keep updating so maybe it will work.

> I am not sure what the built-in parameters such as #<_Z> show in this
> situation. I would suspect that it is commanded position but it's not
> hard to find out.

That would be the next step.. 

Thanks for the help, gentlemen.



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Re: [Emc-users] Auxiliary axis DRO only

[Thaddeus Waldner]

> That is likely because motion is aware its moving, but there is no 
> feedback of a signal showing that it has moved to show motion it is 
> following orders.  I have a pair of 100 ppr dials on my sheldons 
> replacement apron, which I use to drive it since there are no cranks on 
> mine, motors having replaced the cranks.  And I just spent 20 mins 
> studying my hal file to find that coupling, but that hal file is now 
> several years old, and apparently not well enough commented to let me get 
> my ancient head back into what I was thinking back then. At 87, can I 
> plead oldtimers?

I suspect you connected them as MPGs, as that would be the most logical thing 
to do. I don’t think I want MPGs because the axis need to move during NC moves. 

Perhaps if I were more clear as to what the purpose is of this axis …

I plan to use this axis with the linuxCNC probe features to automatically 
record the profile of a surface as the Y axis moves across that surface. The 
probe will have a roller on the end, which will be held in contact of the 
surface by gravity or a spring.

At this point, I am trying to find the correct hook to feed the 
position/velocity from the encoder into the joint, as Gene suggested, to get 
rid of the following error. Do I even need the stepgen? Can I have a joint 
without a motor? Can I configure the joint to ignore the following error and 
still get good position feedback?

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Re: [Emc-users] Auxiliary axis DRO only

[Thaddeus Waldner]

Which components do I need to get this working? I have it set up with a stepgen 
that is set up like the other axis. When I move the encoder the dro and 
backplot display changes but I get a following error.

> On Feb 24, 2022, at 2:08 PM, andy pugh  wrote:
> 
> On Thu, 24 Feb 2022 at 17:44, Thaddeus Waldner  wrote:
> 
>> Can anyone point me to a working example of this, or maybe point out what I 
>> need to do with homing?
> 
> Set HOME_SEARCH_VELOCITY to zero and it will home to zero wherever it
> is (ie, without attempting to move)
> You also need to add a HOME_SEQUENCE for the dummy axis.
> 
> -- 
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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[Emc-users] Auxiliary axis DRO only

[Thaddeus Waldner]

Hi,

I would like to add an unpowered manual axis with an encoder, just to get the 
DRO feature for position feedback. 

The machine has two axis (XY, both are steppers) and the third, unpowered axis 
would be Z. I have a homing sequence  for XY and I obviously can't home Z ...

Can anyone point me to a working example of this, or maybe point out what I 
need to do with homing?

Thanks,

Thaddeus 

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Re: [Emc-users] Graceful pi shutdown, power off

[Thaddeus Waldner]

I got this put together. 
https://youtu.be/tKHrTkvBHCg

One lingering question (for now).
The shutdown script calls “sudo shutdown -h now”

I’d like something a bit softer. For example, if there’s an unsaved change in 
an open program, the program should be able to interrupt the shutdown.  What 
should I call instead?



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Re: [Emc-users] Graceful pi shutdown, power off

[Thaddeus Waldner]

I think I may have found a simple solution.

According to the discussion here:
https://forums.raspberrypi.com/viewtopic.php?t=254875 
<https://forums.raspberrypi.com/viewtopic.php?t=254875>

The pi can be configured to turn off the 3.3v power when shut down. This is not 
configured by default as it also disables the option of starting the pi by any 
signal. You need to cycle the power, which is fine for this use case.

All I need to do now, is latch a relay that is held in the latched state by 
3.3v system power.

> On Feb 16, 2022, at 12:46 PM, Chris Albertson  
> wrote:
> 
> The shut off needs to have a delay otherwise you are killing the power in a
> running system.  The delay gives the OS time to do an actual shutdown.
> 
> On Wed, Feb 16, 2022 at 10:38 AM Roland Jollivet 
> wrote:
> 
>> On Wed, 16 Feb 2022 at 16:17, Thaddeus Waldner  wrote:
>> 
>>>> Just use a simple 10A relay with 5V coil
>>>> As a latch, you press a button to power up, ie power the coil, then the
>>>> same line gets dropped by the Pi to power off..
>>> 
>>> How does the pi drop the 5v line after shutting down?
>> 
>> 
>> The circuit can be similar to attached..
>> But I've got no idea if there are 'hooks' in Linux so you could add code to
>> drop the relay at the end-of-shutdown.
>> Or whether you can get Linux to pull in the relay on power-up
>> 
>> I presume this has to be in Linux, not LinuxCNC.
>> Ok, I did a quick search and found this;
>> 
>> https://stackoverflow.com/questions/45128655/where-does-acpi-hook-into-the-shutdown-sequence-on-linux-to-soft-off-the-pc
>> 
>> Roland
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> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> 
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Re: [Emc-users] Graceful pi shutdown, power off

[Thaddeus Waldner]

> Just use a simple 10A relay with 5V coil
> As a latch, you press a button to power up, ie power the coil, then the
> same line gets dropped by the Pi to power off..

How does the pi drop the 5v line after shutting down?

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Re: [Emc-users] Graceful pi shutdown, power off

[Thaddeus Waldner]

> Youu need a human to somehow
> kick-start the process.  But it should be automated after that.  Of course
> the computer *can* turn itself off.
> 
> I've managed to put the "on" button on a phone or indoor PC.
> 
…

This is the part that won’t work. The machine is small enough to pick up and 
carry off. It will be used in a construction environment without dependable 
wifi. It will have multiple users. I think it should have a power button or 
switch.

Thanks for the idea anyway… I’ve seen those smart plugs but it didn’t occur to 
me to have a computer operate them.

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Re: [Emc-users] Graceful pi shutdown, power off

[Thaddeus Waldner]

Thanks for all the ideas. 

I don’t think a WiFi solution will work because I want to completely power down 
the system. There’s not too much power, as I would only need to switch the 
control power; all the high power circuits need only be switched through their 
respective relays. 

One other idea is to latch the power on via the 3.3v power supply on the pi, 
which can apparently be configured to turn off when the pi is shut down. 

Then run a script that waits for a gpio input and shuts down.



> On Feb 15, 2022, at 11:57 AM, gene heskett  wrote:
> 
> On Tuesday, February 15, 2022 11:10:30 AM EST Greg Bernard wrote:
>> Perhaps this is what you're looking for?
>> http://www.mosaic-industries.com/embedded-systems/microcontroller-proje
>> cts/raspberry-pi/on-off-power-controller
> 
> Sweet, the perfect companion to my idea.
> Bookmarked for future reference, thanks Greg.
> 
>> On Tue, Feb 15, 2022 at 8:28 AM Thaddeus Waldner  
> wrote:
>>> On a small cnc machine run by a raspberry pi, I’d like to set up the
>>> main power to accomplish the following:
>>> 
>>> 1)pressing the power button/flipping the switch turns on the machine
>>> 
>>> 2) pressing the off button, the pi should first perform a shutdown
>>> then turn off the main power to all control power supplies.
>>> 
>>> 3) shutting down the pi via the user interface turns off main power
>>> to all control power supplies when finished.
>>> 
>>> I’m considering installing one of those powered mains disconnect
>>> switches, the likes of what you find in office photocopiers and
>>> industrial cnc machines.
>>> 
>>> Any ideas?
>>> 
>>> 
>>> 
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> 
> 
> Cheers, Gene Heskett.
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> Genes Web page <http://geneslinuxbox.net:6309/gene>
> 
> 
> 
> 
> 
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[Emc-users] Graceful pi shutdown, power off

[Thaddeus Waldner]

On a small cnc machine run by a raspberry pi, I’d like to set up the main power 
to accomplish the following:

1)pressing the power button/flipping the switch turns on the machine

2) pressing the off button, the pi should first perform a shutdown then turn 
off the main power to all control power supplies. 

3) shutting down the pi via the user interface turns off main power to all 
control power supplies when finished.

I’m considering installing one of those powered mains disconnect switches, the 
likes of what you find in office photocopiers and industrial cnc machines.

Any ideas?



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Re: [Emc-users] who has used thin client pcs

[Thaddeus Waldner]

On using an ssd.

Booting from an ssd is now supported by the pi but you need to configure the 
eeprom to enable it. This is pretty easy using the official raspberry pi imager.

I have this usb3 adapter and an intel pro 5450 ssd.

StarTech.com SATA to USB Cable - USB 3.0 to 2.5” SATA III Hard Drive Adapter - 
External Converter for SSD/HDD Data Transfer (USB3S2SAT3CB) 
https://www.amazon.com/dp/B00HJZJI84/ref=cm_sw_r_cp_api_glt_i_QJ8MJKXAVFV5RQNRRJ88?_encoding=UTF8&psc=1

Read/write performance is about 10 x as fast as the Samsung u3 sd card I’m 
using now.

However, I had little luck using the ssd with LinuxCNC because it caused the 
latency jitter to jump to 600,000 or higher. 

Has anyone had any luck with LinuxCNC on SSDs?

> On Feb 12, 2022, at 3:29 PM, Chris Albertson  
> wrote:
> 
> I'm not Gene, but can answer (let's see if he agrees...)
> 
> 1) the Pi4 is far better than the Pi3 in two ways,  The Pi3 had only 1GB
> RAM but you can buy a Pi4 with 1, 2, 4 or 8GB installed RAM.   4GB seems to
> be the price/performance sweet spot. and just as important the Pi4
> network and USB speed are dramatically increased.The CPU is only an
> incremental improvement over the Pi3.   But faster I/O and more RAM move
> the Pi4 into a different class.
> 
> 2) I am pretty sure Gene uses the SPI serial interface to connect the Mesa
> card.  This is a short-distance link.  I would keep the SPI wires to about
> 200mm at most but I don't know what Gene does.  SPI would use four short
> "Dupont" jumper wires.In theory you can go over a meter but, keep it as
> short as you can.
> 
> 3) the Pi4's I/O is now fast enough that the SD card is a bottleneck.   If
> using the Pi4 as a general purpose computer install a "real" SSD drive
> using USB3  A cheap 256GB SSD is better then any SD card and will last
> longer.   The other option for storage in the Pi4 is what I do, I use an
> NFS mount from a NAS.   using the NAS makes the Pi4 faster and it means I
> never have to move files between computers.   Any decent NAS box can
> "flood" a 1 gigabit Ethernet cable so so get 100MB/sec storage.
> 
>> On Fri, Feb 11, 2022 at 8:06 PM Martin Dobbins  wrote:
>> 
>> Hi Gene,
>> 
>> A couple of questions:
>> 
>> I think you started with a rpi3, how does the rpi4 compare?
>> 
>> How do you wire the gpio on the rpi4 to the 7i90HD? any links for cables
>> etc?
>> 
>> Thanks, Martin
>> 
>> 
>> 
>> 
>>> On Thursday, February 10, 2022 3:05:57 PM EST Chris Albertson wrote:
>>> Yes, "Mini ITX" is just a shape and a standard for where mounting holes
>>> go but it is a shape that is sold to a cost-sensitive market where low
>>> power ususage and low cost maters.  The ITX market is large enough
>>> that mass production drives prices down.  So it is a good fit to
>>> hobby-level machine control.   I would think a good place to look as
>>> Aliexpress as most of this stuff ships from China at very low cost.
>>> 
>>> If you are never going to use the computer as an interactive desktop
>>> you could use a Raspberry Pi4.Then use any standard PC notebook to
>>> remote log-in and run the display from the notebook over WiFi.   A Pi4
>>> is 1/2 the cost of the cheapest ITX board.
>> 
>> I did this just to see if I could, but the interfacing from the pi to the
>> lathe IS the cost of the ITX board over and above the 2 gig rpi4. When I
>> did it, the 7i90HD was suggested, but while it has numerous ways to
>> configure 72 i/o's, its fpga has no buffering and the 3 50 in i/o sockets
>> are a PITA to wire uo to, and leave the fpga wide open to being blown by
>> noise fron ground loops etc. Enter the 7i42TA, the protection magic for
>> the 7i90HD, but it takes 3 of them. Now I think it would survive the EMP
>> of a tactical nuke. And because the i/o is there, and now on green
>> terminal strips that are much easier to wire, I have all sorts of extra
>> stuff hooked up and running, like a pair of $20 100ppr dials to replace
>> the missing cranks, speed selectable on a 1,2,5 etc scale from .0001" to
>> 20 thou per click, one per powered axis. All the modular outputs were
>> used from gpio-0 to the end of the config installed, and I used the gpio
>> from gpio-71 down for such things as controlling ALL the lathe power with
>> a couple 40 amp AC SSR's which are switched by the state of F2. I could
>> go on, but if this lathe ever grows a controllable tool changer like the
>> EMCO-5 or similar I have buckets of i/o currently unused.
>> 
>> And that rpi4 is running the full desktop raspian buster install. With a
>> preempt-rt kernel I built on that rpi4. Obviously I shouldn't run FF at
>> the same time as LCNC as FF plays hell with the latency, but I have
>> carved air while running FF just to hear it stutter. And it does, but
>> nothing else seems to bother it that much.
>> 
>> I'm useing the SPI interface version of the mesa file for the 7i90HD and
>> the 3 wire interface has been bulletproof. No comm errors.
>> 
>> At about 25 

Re: [Emc-users] What Would You Suggest?

[Thaddeus Waldner]

> On Feb 5, 2022, at 6:48 PM, John Dammeyer  wrote:
> 
> No.  The motors are designed to handle N amperes although they get quite warm 
> that should be a 24/7 rating. Because they get so warm many drivers back the 
> current off when the motors have been idle for a period of time. 

Yes, N amperes.  Is that not the flat part of the graph? 

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Re: [Emc-users] What Would You Suggest?

[Thaddeus Waldner]

I believe the flat part of the curve is defined by the motor thermal limits. Is 
this correct?

> On Feb 5, 2022, at 11:44 AM, John Dammeyer  wrote:
> 
> All fine and good but doesn't help anyone choose a stepper motor.  For 
> example:
> https://www.geckodrive.com/support/step-motor-basics.html
> tries to explain corner speed but fakes the curves by showing that the torque 
> of a stepper motor is constant up to a certain speed.  I've yet to see any 
> curves of real motors that look like that.
> 
> Perhaps you can find some and post those that do show flat torque up to a 
> 'corner speed'?
> 
> In either case that doesn't really help anyone choose a motor so that Gecko 
> article and corner speed are effectively techo-babble framed in a way to help 
> them sell their drivers which are limited to 80VDC.
> 
> Similarly the stepper motor suppliers provide 1/2 step curves leaving out the 
> resonance point so unless you stay below this 'corner frequency' and never 
> reach that point the torque curves are somewhat obscure.
> 
> Perhaps explain how _you_ choose a stepper motor for a given axis?  What 
> process do you go through to do this?  That might help more.  
> 
> John
> 
> 
> 
>> From: Robin Szemeti via Emc-users [mailto:emc-users@lists.sourceforge.net]
>> 
>> "comment about corner frequency with stepper motors _might_ well be valid
>> as long as the maximum current for each step is reached before or at the
>> end of the ste"
>> 
>> Yes, that is exactly what the corne frequency is ... the step frequency at
>> which the current no longer reaches the desired value before the end of the
>> step. It's obviously dependent on inductance and maximum available drive
>> voltage.
>> 
>>> On Sat, 5 Feb 2022 at 11:50, Robin Szemeti  wrote:
>>> 
>>> John,
>>> 
>>> You are fundamentally incorrect when you state " the torque of the motor
>>> to drop off the faster it goes" .. although the back EMF is correct, with a
>>> modern current limited drive, the torque is flat until the corner
>>> frequency, then drops off  ... up to the corner frequency the torque is
>>> constant with a good current-limited drive, above the corner frequency the
>>> torque drops off, power is constant.  You are perhaps confusing the raw
>>> torque/speed curve of a motor fed from a constant voltage source, which is
>>> useful but is not how they are typically used in practice.
>>> 
>>> 
>>> https://res.cloudinary.com/engineering-com/image/upload/w_640,h_640,c_limit,q_auto,f_auto/image002_bezhrr.jpg
>>> 
 On Sat, 5 Feb 2022 at 09:00, John Dammeyer  wrote:
>>> 
 Hi Chris,
 My issue is that a comment about corner frequency with stepper motors
 _might_ well be valid as long as the maximum current for each step is
 reached before or at the end of the step.  But the motor is turning pretty
 slowly there compared to how they are used in real life.
 
 However the comment about corner frequency with respect to steppers
 perhaps is only backed by alternative facts?
 
 I must admit I've not investigated in detail the closed loop steppers.
 The price of an industrial version I worked with was more than the price of
 an AC servo and at higher speeds I could stop the pulley with my fingers.
 Yes. It faulted.  But that isn't really the point.  The DC and AC servos at
 higher speeds just work better.
 
 Stepper motors work great at low speeds usually directly coupled.
 Contrary to popular belief the micro-stepping doesn't improve resolution
 but gets rid of resonance and gives the appearance of better resolution.
 But it doesn't change the fact that the current still has to reverse every
 full step.  I believe that in fact Gecko drives improve high speed torque
 by switching back to full step mode above the resonance velocity.
 
 Now instead of 0.707 x max current in both windings (at the most) we're
 back to 100% in both with an increase in torque.  Absolutely nothing to do
 with corner frequencies whatever they might be or how they are determined.
 
 John
 
 
 
 
 
> From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> 
> John,
> 
> You described it correctly.  But I think what Robin meant by "Corner
> Frequency" might be the peak of the power vs. RPM graph.  Basically, the
> frequency where power output starts to fall with RPM.
> 
> But now it can get worse, or really better but more complex.   We have
> these so-called "closed loop stepper drivers and also a few people are
> running the steppers as if they were many-pole BLDC analog (continuous,
> non-stepping) mortors
> 
> On Fri, Feb 4, 2022 at 2:39 PM John Dammeyer 
 wrote:
> 
>> I disagree.  The physics of the motor, which include inductance along
 with
>> the generated back emf from the motor spinning in the magnetic field,
 is
>> what cause the torque of the motor to drop off the 

Re: [Emc-users] Stepper PID

[Thaddeus Waldner]

I admit that I don’t know exactly what you mean with the music reference. But 
it looks like the image compression obfuscated some of the information on the 
scope screen. So I’ll try to explain. 

What I set out to do was a fft on the step pulses, but apparently for $350 you 
can’t have a 4-channel 100mhz digital scope that also has a working fft feature.

But the scope does have a nice variable intensity display that makes it 
possible to see the timing jitter by simply looking at adjacent pulses. So I 
trigger on the pulse to the left. On the image that shows three complete 
pulses, the time scale is 50us/div. That sample shows about a 50us step-to-step 
jitter. I’d guess that it’s not actually a step-step jitter, but rather servo 
jitter, since the fpga is responsible for step timing. This is what happens if 
you run a Mesa Ethernet card with a Pi4 without DPLL configured.

The image that shows only the rising pulse edges is set up in a similar 
fashion; I focus on the pulse adjacent to the trigger and since I couldn’t see 
any jitter at all, so I “zoomed in” to 20ns/div. The capture shows pulse-pulse 
jitter of 80ns.

> On Feb 3, 2022, at 5:19 AM, Peter Blodow  wrote:
> Thaddaeus,
> in your image0, I count 7 beats to the bar, seven, is that right? (In image1 
> it is imposible to tell the pulses apart). This reminds me of the first time 
> I set up a stepper configuation using stepconf (in the early 2010's). I 
> encountered similar behaviour of the motors as you did and, after days of 
> fiddling around, finally detected that stepconf made a 5 beats to the bar 
> music. Took me quite a lot of convincing work to the programmer's community 
> then to get that fixed.
> 
> Peter
> 
> 
> Am 03.02.2022 um 00:54 schrieb Thaddeus Waldner:
>> In case anyone is interested, here’s a scope capture of the step pulse train 
>> with and without the DPLL configured.
>> 
>> 
>> 
>> 
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Re: [Emc-users] Stepper PID

[Thaddeus Waldner]

In case anyone is interested, here’s a scope capture of the step pulse train 
with and without the DPLL configured.


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Re: [Emc-users] Stepper PID

[Thaddeus Waldner]

>
>
> The problem is that the PID loop makes bogus velocity corrections because
> of
> position sample time jitter (which may be as high as a few hunderd usec on
> RPI4 Ethernet)
>
> I suspect that you are not using the DPLL, or that it is not setup
> properly.
> For a RPI4 I would suggest these settings:
>
> setp hm2_7i76e.0.dpll.01.timer-us -200
> setp hm2_7i76e.0.stepgen.timer-number 1
>
> These should reduce the stepgenb position sampling jitter to a
> fraction of 1 usec.
>


DPLL was not configured. Adding those two lines fixed it.

Thanks!

Attached are the configuration files, if anyone still wants to see them.
# Generated by PNCconf at Mon Jan 31 21:56:39 2022
# Using LinuxCNC version:  2.8
# If you make changes to this file, they will be
# overwritten when you run PNCconf again

[EMC]
MACHINE = Router
DEBUG = 0
VERSION = 1.1

[DISPLAY]
DISPLAY = gmoccapy
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
MAX_FEED_OVERRIDE = 2.00
MAX_SPINDLE_OVERRIDE = 1.00
MIN_SPINDLE_OVERRIDE = 0.50
INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 5
PROGRAM_PREFIX = /home/pi/linuxcnc/nc_files
INCREMENTS = .1in .01in .001in
POSITION_FEEDBACK = ACTUAL
DEFAULT_LINEAR_VELOCITY = 2
MAX_LINEAR_VELOCITY = 2.00
MIN_LINEAR_VELOCITY = 0.016670
DEFAULT_ANGULAR_VELOCITY = 12.00
MAX_ANGULAR_VELOCITY = 180.00
MIN_ANGULAR_VELOCITY = 1.67
EDITOR = gedit
GEOMETRY = xy

[FILTER]
PROGRAM_EXTENSION = .png,.gif,.jpg Greyscale Depth Image
PROGRAM_EXTENSION = .py Python Script
png = image-to-gcode
gif = image-to-gcode
jpg = image-to-gcode
py = python

[TASK]
TASK = milltask
CYCLE_TIME = 0.010

[RS274NGC]
PARAMETER_FILE = linuxcnc.var

[EMCMOT]
EMCMOT = motmod
COMM_TIMEOUT = 1.0
SERVO_PERIOD = 100

[HMOT]
CARD0=hm2_7i96.0

[HAL]
HALUI = halui
HALFILE = Router.hal
HALFILE = custom.hal
POSTGUI_HALFILE = postgui_call_list.hal
SHUTDOWN = shutdown.hal

[HALUI]

[KINS]
JOINTS = 2
KINEMATICS = trivkins coordinates=XY

[TRAJ]
COORDINATES =  XY
LINEAR_UNITS = inch
ANGULAR_UNITS = degree
DEFAULT_LINEAR_VELOCITY = 0.17
MAX_LINEAR_VELOCITY = 1.67
NO_FORCE_HOMING = 1

[EMCIO]
EMCIO = io
CYCLE_TIME = 0.100
TOOL_TABLE = tool.tbl

#**
[AXIS_X]
MAX_VELOCITY = 1.667
MAX_ACCELERATION = 50.0
MIN_LIMIT = -0.001
MAX_LIMIT = 4.0

[JOINT_0]
TYPE = LINEAR
HOME = 0.0
FERROR = 0.5
MIN_FERROR = 0.05
MAX_VELOCITY = 1.667
MAX_ACCELERATION = 50.0
# The values below should be 25% larger than MAX_VELOCITY and MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 2.08
STEPGEN_MAXACCEL = 62.50
P = 1000.0
I = 0.0
D = 0.0
FF0 = 0.0
FF1 = 1.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.0
MAX_OUTPUT = 0.0
# these are in nanoseconds
DIRSETUP   = 1
DIRHOLD= 1
STEPLEN= 5000
STEPSPACE  = 5000
STEP_SCALE = 3144.7618
MIN_LIMIT = -0.001
MAX_LIMIT = 4.0
HOME_OFFSET = 0.00
HOME_SEARCH_VEL = -0.05
HOME_LATCH_VEL = -0.016667
HOME_FINAL_VEL = 0.00
HOME_USE_INDEX = NO
#**

#**
[AXIS_Y]
MAX_VELOCITY = 1.667
MAX_ACCELERATION = 50.0
MIN_LIMIT = -0.001
MAX_LIMIT = 8.0

[JOINT_1]
TYPE = LINEAR
HOME = 0.0
FERROR = 0.5
MIN_FERROR = 0.05
MAX_VELOCITY = 1.667
MAX_ACCELERATION = 50.0
# The values below should be 25% larger than MAX_VELOCITY and MAX_ACCELERATION
# If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger.
STEPGEN_MAXVEL = 2.08
STEPGEN_MAXACCEL = 62.50
P = 1000.0
I = 0.0
D = 0.0
FF0 = 0.0
FF1 = 1.0
FF2 = 0.0
BIAS = 0.0
DEADBAND = 0.0
MAX_OUTPUT = 0.0
# these are in nanoseconds
DIRSETUP   = 1
DIRHOLD= 1
STEPLEN= 5000
STEPSPACE  = 5000
STEP_SCALE = 3144.7618
MIN_LIMIT = -0.001
MAX_LIMIT = 8.0
HOME_OFFSET = 0.00
HOME_SEARCH_VEL = -0.05
HOME_LATCH_VEL = -0.016667
HOME_FINAL_VEL = 0.00
HOME_USE_INDEX = NO
#**


Router.hal
Description: Binary data
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Re: [Emc-users] Stepper PID

[Thaddeus Waldner]

> 
> I suspect that you are not using the DPLL, or that it is not setup properly. 
> For a RPI4 I would suggest these settings:
> 
> 
> setp hm2_7i76e.0.dpll.01.timer-us -200
> set hm2_7i76e.0.stepgen.timer-number 1
> 
> These should reduce the stepgenb position sampling jitter to a
> fraction of 1 usec.

Thank you, Peter. I will check and see what the configuration looks like later 
when I get home. 
Is there any documentation on how this works? Also, what are the implications 
of increasing the dpll timer period? If I can get away with 2ms servo loop, 
should I set this to 400us?

@Sam. Sorry. I attached the .ini file twice and didn’t attache the .hal file. 
I’ll do this later too.

@Chris. Thank you for the suggestions. I believe I am aware of how harmonics 
affect stepper motors. Harmonics induced vibrations stand out as the noisy 
periods on a slow acceleration, such as when drawing a circle. It’s not that. 
It’s not harmonics at all. It’s irregular noisy shaking. It happens at all 
speeds, but at the lower speeds it’s less obvious because there is less inertia 
in the system. 


> Maybe try going back to P=1000 but drop the axis, joint and stepgen
> maxaccel down a bit.
@Andy I actually tried that first, with no success.

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Re: [Emc-users] Stepper PID

[Thaddeus Waldner]


copy-paste from terminal:
uname -a
Linux linuxcnc 4.19.71-rt24-v7l+ #1 SMP PREEMPT RT Fri Jan 1 21:15:16 GMT 2021 
armv7l GNU/Linux
As I said, this is the sd card image straight from the LinuxCNC website. I 
wanted to ask, is that the best route to go? I’m not terribly impressed with 
the latency numbers, though they appear to work when I don’t run anything else 
(i.e. LinuxCNC doesn’t abort). I plan to get this machine into service 
(operated by others) as soon as possible.

Here is a short video that illustrates the problem. 
https://youtu.be/DdYYpdC51Vs

I did try with P=0, as suggested by Sam, and it was also a big improvement over 
the default configuration. It may have had a bit more of an aggressive whine, 
but stable, to my ears.

When I have more time, I could use my scope to run an fft on the step signal to 
get data that is better than “sounds like bad bearings”.

Configs are attached. They are mostly straight from the pncconf wizard, with 
the z axis removed. I may have fat-fingered the servo period in this copy, just 
so you know.

On Wed, Feb 2, 2022 at 4:32 AM Sam Sokolik  wrote:
> Could you post your configs?  Could your hal functions be out of order?  I
> run pid steppers with RPI and don't notice this.
> 
> Sam
> 
> On Wed, Feb 2, 2022, 3:01 AM andy pugh  wrote:
> 
> > On Wed, 2 Feb 2022 at 07:44, Thaddeus Waldner  wrote:
> >
> > > 2) why is servo thread jitter even making into the stepper pulse train
> > with a Mesa Ethernet card and no communication errors? Do I have anything
> > misconfigured?
> >
> > The idea of using a PID is that it compensates for the fact that the
> > servo thread updates don't get to the card exactly every servo period.
> > Sometimes the feedback - calculate - send of the required step rate
> > will run early, sometimes late.
> >
> > I am hoping that PCW might pop up to explain exactly why the PID helps
> > here. It's not something I have paid that much attention to as I
> > rarely use steppers.
> >
> > It might be interesting to try a non-pid config. (or just set P to
> > zero which has about the same effect)
> >
> > --
> > atp
> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > designed for the especial use of mechanical geniuses, daredevils and
> > lunatics."
> > — George Fitch, Atlanta Constitution Newspaper, 1912
> >
> >
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> >
> 
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[Emc-users] Stepper PID

[Thaddeus Waldner]

Hi,

I have a pi4 running the 2.8.2 iso. I have it connected to a Mesa 7i96 and from 
there I’m driving small stepper motors with tmc2209 “stepstick” drivers. I 
think my step rate at max speed is around 8khz 

I get around +-70us? Max latency.

I’ve been having an issue with what I think is latency which makes the steppers 
sound like they have bad bearings. Raising the servo period to 2ms made it 
worse. So I tried a faster servo thread and discovered the issue pretty much 
goes away with the servo period at 250us. At that rate I start running into 
joint following issues.

I then learned that with the servo period at 1ms, if I lower the stepper PID P 
parameter to 100 instead of the 1000 set by the configuration wizard, the noise 
goes away completely and the steppers run buttery smooth.

I have a few questions:
1) what are the implications of running the PID stepper with p=100?
2) why is servo thread jitter even making into the stepper pulse train with a 
Mesa Ethernet card and no communication errors? Do I have anything 
misconfigured?

Thanks




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Re: [Emc-users] can I hide the nativecam interface

[Thaddeus Waldner]

I’m not sure if you can “hide” NativeCam once embedded, but it’s possible to 
use it as a standalone application. That way it won’t take up space on your CNC 
gui.


> On Jan 27, 2022, at 12:03 PM, fxkl47BF--- via Emc-users 
>  wrote:
> 
> I started playing with nativecam.
> It's pretty neat.
> With linuxcnc running is there a way to "hide" the nativecam interface?
> 
> 
> 
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Re: [Emc-users] UI options for small screen

[Thaddeus Waldner]

Sorry! 1024x600

This is a simple, purpose built machine for coping a profile into the end of a 
workpiece. Many of the general-use cnc UI features don’t make sense for it. I 
plan to start it out with those in place and then eventually refine it. Is it 
possible to modify Gscreen and remove/hide buttons and other features in a way 
that will not be reversed with updates? For example, 

the machine auto-homes when turned on so no homing buttons
there are no tools to change, so no tool tables
no coolant, (but vacuum dust extraction)
Prominent DRO readout is not a priority.
Spindle is on/off only; no speed change and non Reversible
E-stop, nc power, cycle start are probably physical buttons
Etc 
I actually considered not installing a screen on the machine but decided 
against it because the screen simplifies how I load new coping profiles. 



> On Jan 22, 2022, at 5:11 AM, andy pugh  wrote:
> 
> On Sat, 22 Jan 2022 at 06:00, Thaddeus Waldner  wrote:
> 
>> I’d be happy with the gmoccapy UI but it simply doesn’t fit on the screen. 
>> My plan for now is to edit it and remove some of the manual control 
>> elements. Any suggestions?
> 
> Try Gscreen, it is designed for editability.
> Do you really mean 124x600?
> 
> -- 
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
> 
> 
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[Emc-users] UI options for small screen

[Thaddeus Waldner]

Hi,
I’m working on a small cnc machine with a 124x600 display. I anticipate most of 
the use to be selecting a new file and adjusting work offsets.

I’d be happy with the gmoccapy UI but it simply doesn’t fit on the screen. My 
plan for now is to edit it and remove some of the manual control elements. Any 
suggestions?

Thanks,
Thaddeus

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Re: [Emc-users] motor coolant for water cooled spindles.

[Thaddeus Waldner]

The color is a dye to identify what kind of additives are added. In general, 
green is the older concoction and is designed for steel and copper, whereas the 
yellow or orange stuff has additives that are better suited for the plastic and 
aluminum coolant system parts in modern vehicles. I don’t think there are any 
standards for these colors so OEMs don’t necessarily stick to them.

Many 3rd party suppliers have a variety of colors and they usually specify the 
additives for each.

Word is that you shouldn’t mix different types because the additives can react 
and gel.

 

> On Jan 17, 2022, at 5:05 PM, gene heskett  wrote:
> 
> You've not had any mold or other growth in it in 5 years? I can't get 
> past 4 months here. But I've not tried the above yet. I've a couple 
> gallons of an orange 50-50 mix, what the diff between green and yellow/
> orange?


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Re: [Emc-users] CNC controlled, plasma torch

[Thaddeus Waldner]

Use a submerged torch. This will also take care of the smoke.


Thaddeus Waldner
Newdale School
Elkton, SD 57026

From: Nicklas SB Karlsson 
Sent: Friday, January 7, 2022 3:13:17 PM
To: emc-users@lists.sourceforge.net 
Subject: [Emc-users] CNC controlled, plasma torch

Anyone used Linuxcnc with plasma torch here.


There is another major problem, one third of building is allocated for
firewood storage. Need a good way to keep sparks away from it.


Nicklas Karlsson



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Re: [Emc-users] Spindle positioning.

[Thaddeus Waldner]

Some of those hammers have a thru-hole for pinning the socket.

> On Nov 23, 2021, at 1:14 PM, John Dammeyer  wrote:
> 
> I've ordered a retaining ring set for it.  May help.  The socket has a recess 
> for this ring to expand into but at the moment it almost falls out by itself. 
>  The wrench is 10 years old and although not used during that period the 
> rubber had likely hardened and is no longer providing the spring action.
> 
> You can see in the photo that I've used the Dremel to create a dimple for the 
> retaining screw that is in the side of the socket.  However it loosens with 
> the impact driver vibration.  I don't have room to put in a locking set screw 
> and it's too early for Loctite.
> 
> John
> 
> 
>> -Original Message-
>> From: Gene Heskett [mailto:ghesk...@shentel.net]
>> Sent: November-23-21 4:04 AM
>> To: emc-users@lists.sourceforge.net
>> Subject: Re: [Emc-users] Spindle positioning.
>> 
>> On Tuesday 23 November 2021 02:47:59 andy pugh wrote:
>> 
>>> On Tue, 23 Nov 2021 at 01:05, John Dammeyer 
>> wrote:
  Likely why the set screw works loose after a number of cycles.
>>> 
>>> I am surprised that the air wrench doesn't have the usual ball-detente
>>> to retain the socket.
>> 
>> I have seen some that utilize a spring encircling the end of the driver
>> square, and it works moderately well, with sockets made with an internal
>> cutaway at the bottom of the square well.
>> 
>> But we haven't seen a pix of his setup w/o the socket.
>> 
>> Satire intended: Thats I think to encourage the sales of sockets using
>> that scheme, also convieniently made by the wrench peddlar of course.
>> 
>> That could be Johns problem. In that case John, you may be able to
>> machine the socket or better a new one to utilise that retainer method,
>> but take care, too deep a groove and the socket may be stuck on forever.
>> Show us a closeup pix with the socket removed.
>> 
>> Cheers, Gene Heskett.
>> --
>> "There are four boxes to be used in defense of liberty:
>> soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author, 1940)
>> If we desire respect for the law, we must first make the law respectable.
>> - Louis D. Brandeis
>> Genes Web page 
>> 
>> 
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Re: [Emc-users] VFD Recomendation

[Thaddeus Waldner]

800hz would be the frequency if counting poles as pole pairs, no?

If this is a 4-pole motor, counting both the N and S poles, and hz = rpm / 60 * 
poles / 2, I get 400hz.

Because there are two poles per pole pair. I am not sure that all manufacturers 
use the same convention.


> On Sep 24, 2021, at 10:49 AM, Todd Zuercher  wrote:
> 
> They cost about $6500, but that cost is about half any competitors 
> equivalent. (such as HSD, Omlat...)
> 
> The motor name plate says 800hz for 24000rpm, (guess I assumed that info was 
> on that page I linked to.)
> 
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street 
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
> 
> -Original Message-
> From: Gene Heskett  
> Sent: Friday, September 24, 2021 11:26 AM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] VFD Recomendation
> 
> [EXTERNAL EMAIL] Be sure links are safe.
> 
> On Friday 24 September 2021 10:47:49 Todd Zuercher wrote:
> 
>> Yes.
>> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.
>> hsspindles.com%2Fwp-content%2Fuploads%2F2019%2F03%2Fspecs-13.pdf&d
>> ata=04%7C01%7Ctoddz%40pgrahamdunn.com%7Cbcf7b99cdd484b02ab9608d97f6fc7
>> 65%7C5758544c573f47cebee96c3e0806fb43%7C0%7C0%7C637680941219090280%7CU
>> nknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha
>> WwiLCJXVCI6Mn0%3D%7C3000&sdata=bTAaxaFe%2B1kE2WR9jCTqyi2ILgw1x7Jzc
>> wvl%2FbzBYAc%3D&reserved=0
>> 
> Nice chart. But doesn't mention at any place, rpms vs frequency.
> I don't imagine they give that puppy away either.
> 
> I tend to run the cheaper stuff, only having a 254 volt center tapped at 
> ground single phase feed at my location.
> 
>> Todd Zuercher
>> P. Graham Dunn Inc.
>> 630 Henry Street
>> Dalton, Ohio 44618
>> Phone:  (330)828-2105ext. 2031
>> 
>> -Original Message-
>> From: Gene Heskett 
>> Sent: Friday, September 24, 2021 10:27 AM
>> To: emc-users@lists.sourceforge.net
>> Subject: Re: [Emc-users] VFD Recomendation
>> 
>> [EXTERNAL EMAIL] Be sure links are safe.
>> 
>> On Friday 24 September 2021 09:37:32 Todd Zuercher wrote:
>>> Anyone have a recommendation for a good VFD and supplier that can 
>>> run a 15kw 4pole spindle at 24000rpm?
>> 
>> Thats going to be a tough one Todd, its 10x the power of anything I 
>> have, and would need to get to 800 hz to run a 4 pole at 24k revs.
>> 
>> Are you sure its a 4 pole? All of my 24k's have been 2 pole, doing 24k 
>> on 400 hz. 3600 on 60 hz, but needing better cooling to run that slow 
>> for long jobs. The one I'm running now, will be spitting steam back 
>> into the 5 gallon tank in an hours running at 4k. But is fine for 
>> longer jobs at 14k-20k with the mister on. At the higher revs, it 
>> never gets the tank above 36C.
>> 
>>> Todd Zuercher
>>> P. Graham Dunn
>>> 
>>> Inc.>> 5
>>> 2F
>>> 
>>> https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.
>>> pgrahamdunn.com%2F&data=04%7C01%7Ctoddz%40pgrahamdunn.com%7Cbcf7b
>>> 99cdd484b02ab9608d97f6fc765%7C5758544c573f47cebee96c3e0806fb43%7C0%7C
>>> 0%7C637680941219090280%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLC
>>> JQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=9shskfk
>>> ovi8mTo6%2BL%2BIZfMXKdYXnOIrzDwj1UoyQTRw%3D&reserved=0%2Findex.ph
>>> p&data=04%7C01%7Ctoddz%40pgrahamdu
>>> nn
>>> .com%7C4727423beae5413ddb1008d97f67884b%7C5758544c573f47cebee96c3e08
>>> 06
>>> fb43%7C0%7C0%7C637680905784414687%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC
>>> 4w
>>> LjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sd
>>> at
>>> a=Nx%2BJRwnxdrUALX1Gr268XqM%2BcVZ49OAy2BChgj9K%2BOs%3D&reserved=
>>> 0> 630 Henry Street
>>> Dalton, Ohio 44618
>>> Phone:  (330)828-2105ext. 2031
>>> 
>>> 
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>>> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fli
>>> st
>>> s.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7C
>>> to
>>> ddz%40pgrahamdunn.com%7C4727423beae5413ddb1008d97f67884b%7C5758544c5
>>> 73
>>> f47cebee96c3e0806fb43%7C0%7C0%7C637680905784414687%7CUnknown%7CTWFpb
>>> GZ
>>> sb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0
>>> %3
>>> D%7C3000&sdata=ZJy9nGS8vpOxvQSNzrWWYuioxOvg%2BKMmPuNAeF%2FRFaQ%3
>>> D& amp;reserved=0
>> 
>> --
>> "There are four boxes to be used in defense of liberty:
>> soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author, 1940)
>> If we desire respect for the law, we must first make the law  
>> respectable. - Louis D. Brandeis  Genes Web page  
>> > slinuxbox.net%3A6309%2Fgene&data=04%7C01%7Ctoddz%40pgrahamdunn.com%
>> 7C4727423beae5413ddb1008d97f67884b%7C5758544c573f47cebee96c3e0806fb43%7
>> C0%7C0%7C637680905784424735%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDA
>> iLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI

Re: [Emc-users] Meanwell SE600-48 Power Supply

[Thaddeus Waldner]

Is it a 3-wire fan?

The yellow wire on those fans is a reverse-acting PWM control line (0 = full 
on, 90% = 10% on, etc.). It’s possible that the controller turns off the fan 
when it doesn’t need cooling.

> On Jul 19, 2021, at 8:50 AM, Alan Condit  wrote:
> 
> Gene, Chris, Milosz and everybody who has tried to help,
> 
> I am reposting this because I screwed up earlier and failed to change the 
> Subject line.
> 
> I took the power supply out of the controller cabinet and set it up on the 
> bench. I used a small screw driver to turn the fan a few times, then I turned 
> it on and the fan ran. Like Milosz said it was loud. I turned it off and 
> turned it back on again and the fan ran, Great problem fixed (yeah, right). I 
> put it back in the cabinet and turned it on (silence). So I will take it back 
> out of the cabinet and see if I can get it to run and start reliably after a 
> period of rest. Otherwise it looks like replacing the fan is the answer.
> 
> Thanks all,
> Alan
> 
>> 
>> From: Dave Cole 
>> Subject: Re: [Emc-users] Meanwell SE600-48 Power Supply
>> Date: July 15, 2021 at 6:33:23 PM CDT
>> To: emc-users@lists.sourceforge.net
>> 
>> 
>> You may have a bad power supply.  Do you have any output voltage?
>> I'd attach a load and see if it holds voltage.   I cant think of anything 
>> that should be clicking in there.   Arcing can sound like clicking.
>> 
>> The spec sheet says nothing about fan control and I would expect they would 
>> flaunt that feature if they had it.
>> https://www.meanwell.com/productPdf.aspx?i=469#1
>> 
>>> On 7/15/2021 12:16 PM, Alan Condit wrote:
>>> I am building a new controller cabinet. I installed a Meanwell SE600-48 
>>> power supply. When I turn on the power supply the fan doesn’t turn on. If I 
>>> leave the power supply on for a little while I hear an intermittent 
>>> clicking (like a relay) but no fan. Does it have some kind of temperature 
>>> control on the fan? Is it not turning on because I currently have virtually 
>>> no load on the power supply?
>>> 
>>> Thanks,
>>> Alan
>>> 
>>> ___
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>> 
>> 
>> 
>> 
>> 
>> From: Nicklas SB Karlsson 
>> Subject: Re: [Emc-users] Meanwell SE600-48 Power Supply
>> Date: July 16, 2021 at 5:37:56 AM CDT
>> To: "Enhanced Machine Controller \(EMC\)" 
>> 
>> 
>>> I am building a new controller cabinet. I installed a Meanwell SE600-48 
>>> power supply. When I turn on the power supply the fan doesn’t turn on. If I 
>>> leave the power supply on for a little while I hear an intermittent 
>>> clicking (like a relay) but no fan. Does it have some kind of temperature 
>>> control on the fan? Is it not turning on because I currently have virtually 
>>> no load on the power supply?
>> 
>> Short circuit? Or overloaded?
>> 
>> Some power supplys enter som kind of "power down" mode if overloaded.
>> 
>> 
>> Nicklas Karlsson
> 
> 
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Re: [Emc-users] OT: power, horsepower, and a bad brain

[Thaddeus Waldner]

I second the suggestion to change your pulleys to slow down the alternator. 
Maybe try to find the rpm/amperage chart for your specific alternator AND the 
rpm/power chart for you engine. Then configure the pulleys so that the power 
output never exceeds the available power at any rpm.

Thaddeus Waldner
Newdale School
Elkton, SD 57026

From: ken.stra...@gmail.com 
Sent: Sunday, June 27, 2021 1:06:01 PM
To: 'Enhanced Machine Controller (EMC)' 
Subject: Re: [Emc-users] OT: power, horsepower, and a bad brain

With the demise of Sears, the new term is "Chinese horsepower". They have
smaller horses...

-Original Message-
From: John Dammeyer 
Sent: June 27, 2021 1:54 PM
To: 'fxkl47BF' ; 'Enhanced Machine Controller
(EMC)' 
Subject: Re: [Emc-users] OT: power, horsepower, and a bad brain

Your engine might be rated at what we used to call 'Sears Horsepower' where
their compressors had 4HP rated motors for 115VAC 15A circuit which isn't
possible of course.  They'd rate the max surge current for a few
milliseconds I think.

Anyway, your alternator is rated at 2200 RPM for max current.  Without
knowing your engine RPM it's hard to compare but 1:2 is likely too high for
this alternator.  And if you slow down the engine to 1100 RPM to create 2200
RPM you won't get the rated power.   I'd go the other direction with 2:1 or
even 3:1 depending on what max engine RPM is.

The systems I've designed that used a 10KW ONAN genset created 110VAC into
an 80A charger.  And even then I could control the charger to limit charge
current which in turn limited load on the generator.

You will find even with sealed lead acid batteries that the max current will
only be there for a very short time so trying to achieve that level of power
output for charging is likely not needed.  Lithiums are a different story.

John


> -Original Message-
> From: fxkl47BF via Emc-users [mailto:emc-users@lists.sourceforge.net]
> Sent: June-27-21 7:21 AM
> To: Enhanced Machine Controller \(EMC\)
> Cc: fxkl47BF
> Subject: Re: [Emc-users] OT: power, horsepower, and a bad brain
>
> --- Original Message ---
>
> On Sunday, June 27th, 2021 at 8:07 AM, fxkl47BF 
wrote:
>
> > --- Original Message ---
> >
> > On Sunday, June 27th, 2021 at 7:19 AM, andy pugh bodge...@gmail.com
wrote:
> >
> > > On Sun, 27 Jun 2021 at 12:44, fxkl47BF via Emc-users
> > >
> > > emc-users@lists.sourceforge.net wrote:
> > >
> > > > all of my feeble calculations led me to believe that a 6.5 hp
> > > > gasoline engine was more than enough to power a 220 amp 12 volt
> alternator. either my 6.5 hp engine is more feeble than my brain or my
calculations are way off.
> > > >
> > > > 220A x 12V = 2.640kW = 3.5hp. So it should be able to manage it.
> > > >
> > > > You might need to look at the pulley ratios. Do you have a
> > > > performance
> > > >
> > > > curve for the engine and the alternator? You need to consider
> > > > the
> > > >
> > > > relative torques for your chosen speed.
>
> i have about a 2:1 increase belt drive i was running the engine at
> full speed
>
>
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Re: [Emc-users] Machining question

[Thaddeus Waldner]

I agree that you can’t get away from it. But you can minimize it and I wanted 
to provide what I thought is an interesting data point; the extent to which 
some engineers go to minimize it.

I doubt that they actually lines at those speeds. They use absolute encoders 
and likely just read the position on every control loop.

Seriously you can't get away from it.   With 40 million lines if the shaft
turns at 60 RPM or one revolution per second it is moving slow but the
total number of edges is 16 million per second and you could find hardware
fast enough but at 3,000 RPM it would be a lot harder.

The entire reason I brought up the subject is because people started
posting about shielding and star grounds.   That is not the kind of noise
we are talking about.  Quantization happens even in an electrically quiet
environment and results from design decisions made such as the sample
interval, number of lines of the sensor, and the rotation speed.  It gets
worse as you go slower.

On Mon, Jun 21, 2021 at 1:15 PM Thaddeus Waldner  wrote:

>
> Okuma machine builders really don’t like quantization noise so they use 40
> million CPR encoders on the axis motors.
>
> > On Jun 21, 2021, at 11:34 AM, Chris Albertson 
> wrote:
> >
> > Quantization noise is fundamental and present in all digital systems.
> > There is absolutely no way to avoid it.  All you can do is minimize it.
> >
> > To know how fast a shaft is spinning or how far it moves, you have to
> count
> > edges and if you get 100 counts you just can not know if you are closer
> to
> > 100 or to 101 counts.  Basically the counter always rounds down even if
> at
> > 100.9 it tells you "100".So the cound is "wrong" 50% of the time.
> > This applies not only to encoders, but A/D converts and every other kind
> of
> > measurement.
> >
> > This is the nature of digital data, of representing the world  with a
> fixed
> > number of bits.
> >
> >> On Sat, Jun 19, 2021 at 4:00 PM John Dammeyer 
> >> wrote:
> >>
> >> But doesn't the 7i92 FPGA deal with quadrature encoders and therefore
> >> doesn't really need to deal with a sampling process but instead looks at
> >> edges?  And because of the way quadrature works, with the A/B phasing
> you
> >> don't get the same types of errors compared to polling a bit level X
> times
> >> per second and trying to decide when it's high/low.
> >>
> >> John
> >>
> >>
> >>> -Original Message-
> >>> From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> >>> Sent: June-19-21 3:21 PM
> >>> To: Enhanced Machine Controller (EMC)
> >>> Subject: Re: [Emc-users] Machining question
> >>>
> >>> There are two kinds of noise,
> >>> 1) electrical noise superimposed on the signal.
> >>> 2) quantization noise from the sampling process.  What happens here is
> >> that
> >>> the computer counts the number of line crossings during a given time.
> it
> >>> is just random luck when the time starts so on average there is a plus
> or
> >>> minus one count error.
> >>>
> >>> So a one count error sounds small but lets say we have a 600 count
> >>> encoder and we are running at 500 RPM and sampling 100 times per
> second.
> >>> This works out to 50 counts per period.  a one count error is a 2%
> >> error.
> >>>   You will see a larger percent error at slower speeds or with a lower
> >>> resolution encoder.
> >>>
> >>> So even with perfect wires and perfect grounding and zero electrical
> >> noise
> >>> the RPM speed is going to jump around randomly over a 4 RPM range
> because
> >>> of unavoidable quantization error.
> >>>
> >>> The solutions either the use a larger sample time apply a low-pass
> >> DIGITAL
> >>> filter to the signal.  No amount of analog filters on the wires will
> >> work.
> >>>
> >>> On Sat, Jun 19, 2021 at 2:55 PM Gene Heskett 
> >> wrote:
> >>>
> >>>> On Saturday 19 June 2021 12:59:19 John Dammeyer wrote:
> >>>>
> >>>>> I need to do a couple of things.  For one the AC Servo makes a lot of
> >>>>> electrical noise.  The frame of the motor is connected to earth
> >>>>> through power line ground.  But my bench setup has the control side
> >> 5V
> >>>>> not isolated from the 'PC' side (optos are kind of useless here) and
> >

Re: [Emc-users] Machining question

[Thaddeus Waldner]

Okuma machine builders really don’t like quantization noise so they use 40 
million CPR encoders on the axis motors.

> On Jun 21, 2021, at 11:34 AM, Chris Albertson  
> wrote:
> 
> Quantization noise is fundamental and present in all digital systems.
> There is absolutely no way to avoid it.  All you can do is minimize it.
> 
> To know how fast a shaft is spinning or how far it moves, you have to count
> edges and if you get 100 counts you just can not know if you are closer to
> 100 or to 101 counts.  Basically the counter always rounds down even if at
> 100.9 it tells you "100".So the cound is "wrong" 50% of the time.
> This applies not only to encoders, but A/D converts and every other kind of
> measurement.
> 
> This is the nature of digital data, of representing the world  with a fixed
> number of bits.
> 
>> On Sat, Jun 19, 2021 at 4:00 PM John Dammeyer 
>> wrote:
>> 
>> But doesn't the 7i92 FPGA deal with quadrature encoders and therefore
>> doesn't really need to deal with a sampling process but instead looks at
>> edges?  And because of the way quadrature works, with the A/B phasing you
>> don't get the same types of errors compared to polling a bit level X times
>> per second and trying to decide when it's high/low.
>> 
>> John
>> 
>> 
>>> -Original Message-
>>> From: Chris Albertson [mailto:albertson.ch...@gmail.com]
>>> Sent: June-19-21 3:21 PM
>>> To: Enhanced Machine Controller (EMC)
>>> Subject: Re: [Emc-users] Machining question
>>> 
>>> There are two kinds of noise,
>>> 1) electrical noise superimposed on the signal.
>>> 2) quantization noise from the sampling process.  What happens here is
>> that
>>> the computer counts the number of line crossings during a given time.  it
>>> is just random luck when the time starts so on average there is a plus or
>>> minus one count error.
>>> 
>>> So a one count error sounds small but lets say we have a 600 count
>>> encoder and we are running at 500 RPM and sampling 100 times per second.
>>> This works out to 50 counts per period.  a one count error is a 2%
>> error.
>>>   You will see a larger percent error at slower speeds or with a lower
>>> resolution encoder.
>>> 
>>> So even with perfect wires and perfect grounding and zero electrical
>> noise
>>> the RPM speed is going to jump around randomly over a 4 RPM range because
>>> of unavoidable quantization error.
>>> 
>>> The solutions either the use a larger sample time apply a low-pass
>> DIGITAL
>>> filter to the signal.  No amount of analog filters on the wires will
>> work.
>>> 
>>> On Sat, Jun 19, 2021 at 2:55 PM Gene Heskett 
>> wrote:
>>> 
 On Saturday 19 June 2021 12:59:19 John Dammeyer wrote:
 
> I need to do a couple of things.  For one the AC Servo makes a lot of
> electrical noise.  The frame of the motor is connected to earth
> through power line ground.  But my bench setup has the control side
>> 5V
> not isolated from the 'PC' side (optos are kind of useless here) and
> although the Pi4 doesn't appear to have any trouble the scope shows a
> pretty noisy encoder signal.
 
 You are about to learn the star ground system I think.
 
 Thats where all grounds go to a single bolt, and no other grounds are
 allowed anyplace.
 
 Shielding in motor cables ends without touching the motor, only
>> connected
 to this same single bolt which is grounded. The common line of any
>> power
 supply is connected only to this bolt, and the common grounds to every
 piece of pcb in the system comes from that bolt. The used to be green
 static ground wire in any power cord is rerouted to this bolt. And
 static grounds on a power supply are fed from this single bolt. Because
 the psu case is usually bolted down wherever its at, you may have to
 uncover the supply and remove any connection from the earth labeled
 terminal, and the psu's case. It may be a screw in the corner of a pcb,
 but it needs to be removed.
 
 Anything connected to ground at some other point in addition to that
>> bolt
 becomes an antenna, is called a ground loop, picking up both magnetic
 and electrostatic noises. I had to learn that the hard way while
 building the Sheldon, blowing two 7i90HD boards out by picking up 80
 volts p-p of switching noise that reached up to the bandwidth limits of
 both of my 100mhz scopes. Hell on an fpga with a 3 volt limit.  I
>> killed
 the power and redid it to the single bolt model, and that 80 volts of
 noise was reduced to under 100 millivolts. Took me about a week to find
 all the connections that should not have been made. Even a small bypass
 capacitor to a local ground instead of back to that bolt can become a
 lethal weapon to the elecronics.  Its a noise injector in that case.
 
 The whole idea is to make the ground, if it bounces from a lightning
 strike on the can on the pole that powers your place, which may make
>> the

Re: [Emc-users] Spindle Control

[Thaddeus Waldner]

Router with 2.2 KW elte spindle run by a GS2 VFD via modbus.

Thaddeus Waldner
Newdale School
Elkton, SD 57026

From: Gene Heskett 
Sent: Sunday, June 13, 2021 4:24:04 PM
To: emc-users@lists.sourceforge.net 
Subject: Re: [Emc-users] Spindle Control

On Sunday 13 June 2021 15:49:44 John Dammeyer wrote:

> Quick little survey on what everyone has on their machine for spindle
> control.
>
> 1. Do you have a VFD on a 3 phase motor for Lathe or Mill.

2 of my 4 machines follow that recipe.

The Sheldon lathe, with a 30 some lb 8" 4 jaw mounted, can do the
reversal at the bottom of a rigid tap with an overshoot of .25 turns at
100 rpm. The motor is a 1hp 3 phase about 50 years old I had to put
bearings in. The 6040 motor died of bad bearings quickly, so both the
120 volt vfd and the motor were replaced with 250 volt equ's. No
encoder, not enough cajones to tap a hole anyway, but sure did a nice
job cutting out motor mounts and wrenches from 1/2" alu

The other 2 machines have 90 volt, 9.7 amps at full song 1hp PMDC brushed
motors and use Jon Elson's Pico Systems pwm-servo, both with big ugly
125 volt supplies and all get faster than expected control. Either
supply is good for 30 amps surge. Jon's servo makes them both behave
themselves well. They don't really have a choice with that kind of power
banging on them.

> 2. Does the CNC controller drive the spindle or do you set the speed
> and ON/OFF manually?

LCNC does it all.

> Just curious
> John
>
>
>
> "ELS! Nothing else works as well for your Lathe"
> Automation Artisans Inc.
> www dot autoartisans dot com
>
>
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Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>


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Re: [Emc-users] OT: About a chat here on vacuum table ideas

[Thaddeus Waldner]

Some CNC lasers and plasma cutters use zoned smoke collection system that opens 
different shutters depending on the gantry position. Might something similar 
work for holding  the workpiece?

Thaddeus Waldner
Newdale School
Elkton, SD 57026

From: Roland Jollivet 
Sent: Wednesday, June 9, 2021 10:31:01 AM
To: Enhanced Machine Controller (EMC) 
Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas

A friend was complaining about the need for 6kW vacuum system on a large
table and this got me thinking

Another way is to divide the table up into squares, grid wise, and have a
.. separate.. vacuum motor for each section. The motor is mounted under the
table at the bottom of each 'box'.
You can get ~1.5kW motors really cheap, and now it's easy to make up a
system with as many kW as you want.

Far easier to find 4 vacuum motors than a 6kW pump.

Roland



On Wed, 9 Jun 2021 at 17:13, Todd Zuercher  wrote:

> For milling sheet material on a large table, an MDF spoil board on top of
> a vacuum grid is usually the best option.  But for small parts such as
> solid wood items vacuum pods are usually a better choice.  In a pod
> arrangement with  the part held directly is where the valves are useful.
>
> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
>
> -Original Message-
> From: Leonardo Marsaglia 
> Sent: Tuesday, June 08, 2021 10:47 PM
> To: Enhanced Machine Controller (EMC) 
> Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas
>
> [EXTERNAL EMAIL] Be sure links are safe.
>
> Thank you guys for your answers!
>
> I've been reading and apparently MDF with a skim cut is pretty good to
> distribute the vacuum all around it's surface given its porosity. I think
> I'm gonna try that option first to see how severe is the vacuum loss when
> the cuts are made.
>
> Second option would be what Todd suggests, wich is a little trickier
> mostly because my surface needs to be 3000 mm x 2000 mm, so that's a lot of
> springs...
>
> I'll keep you informed as the project progresses.
>
> Thanks as always for your help :)
>
> El lun, 7 jun 2021 a las 17:11, Todd Zuercher ()
> escribió:
>
> > It might work, but you may have trouble with the pellet sticking in
> > the seat and not opening when you need it to, or worse yet if your
> > part doen't quite seal good enough to the table, sucking shut and
> > losing all holding power.
> >
> > What I've seen more commonly used is a spring loaded valve where a
> > spring pushes the pellet(ball) up to seal the vacuum port.  When no
> > part is in place the spring pushes the ball up to seal the vacuum
> > port, and the ball sticks up a bit above the part sealing surface.
> > When the part is placed on top, it pushes the ball down opening the
> > valve and allowing the vacuum to flow.
> >
> > Todd Zuercher
> > P. Graham Dunn Inc.
> > 630 Henry Street
> > Dalton, Ohio 44618
> > Phone:  (330)828-2105ext. 2031
> >
> > -Original Message-
> > From: Leonardo Marsaglia 
> > Sent: Saturday, June 05, 2021 11:50 PM
> > To: Enhanced Machine Controller (EMC)
> > 
> > Subject: Re: [Emc-users] OT: About a chat here on vacuum table ideas
> >
> > [EXTERNAL EMAIL] Be sure links are safe.
> >
> > I meant to say:
> >
> > When there is a part over that hole and before the pump is on, the
> > pellet will be resting on the groove. As soon as the pump is on the
> > vacuum will be immediately sealed by the part, not allowing the
> > suction to suck the pellet
> >
> > El dom, 6 jun 2021 a las 0:48, Leonardo Marsaglia
> > ( > >)
> > escribió:
> >
> > > Hello guys,
> > >
> > > I hope you're all doing well.
> > >
> > > Not so long ago (or may be yes) I recall reading someone on this
> > > list talking about an idea of using plastic pellets as closing
> > > valves for an MDF vacuum table.
> > >
> > > The basic idea was: The pellet falls into a spherical hole that has
> > > a round groove with a slight angle on its side. So when the vacuum
> > > is not applied the plastic pellet can slide thru the groove and
> > > leave the hole open (I imagine that the vacuum pump could be
> > > reversed so one can blow to clear the holes and force the pellets to
> the groove quicker).
> > > When there is a part over that hole and before the pump is on, the
> > > vacuum will be immediately sealed by the part, not allowing the
> > > 

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Thaddeus Waldner]

So these are actual stepper motors and not 3-phase BLDC motors with 
step/direction input?

I always assumed that it’s the latter, with the difference being lost in 
translation.


> On Apr 30, 2021, at 11:23 PM, Gene Heskett  wrote:
> 
> On Friday 30 April 2021 23:25:43 ken.stra...@gmail.com wrote:
> 
>> I haven't been following your project recently but am intrigued by
>> "And it turns the armature easy enough the 3NM 3 phase motor (those
>> are magic folks, running 50C cooler than 2 phase stuff) I'll use will
>> not be a bit overstressed." Where did you end up getting your motors
>> and what are you using for drivers?
>> 
> Ebay for all of them.  There are 2 phase with feedback but they work at 
> full motor currants all the time. The only driver that counts and really 
> is 3 phase is the LCDA357H although I expect it will grow bigger brother 
> versions as time goes by and folks become aware of them. The chinese are 
> not heavly advertizing that, the difference getting lost in the 
> translation or ???.
> 
> Motor wires are labeled UVW just like a vfd. And a full step is 1.2 
> degrees, not 1.8.
> 
> An encoder on the back of the motor talks to the driver, not to LCNC, and 
> you drive them exactly as you would any other stepper setup.
> 
> Step speeds are still limited by the input opto's to maybe 250 kilohertz. 
> It, the LCDA3576H driver is small, about the size of a 100 mil pack of 
> smokes, has no currant setting switches because the motor current is 
> determined by the magnitude of the error.  Makes it at least 5x more 
> efficient. Rated at 20-50 VDC input, there are 1,2, & 3 NM sizes that I 
> know of right now. Running my 11x54 Sheldon with rapids 2x faster than 
> the 2 phase stuff I took off, motor heating might be 5F. And if they 
> lose a step, they have an error out that can shut down LCNC with the 
> e-stop circuit.
> 
> Highly recommended by great, great, grandpa Gene as a genuine improvement 
> in stepper technology.
> 
>> -Original Message-
>> From: Gene Heskett 
>> Sent: April 30, 2021 10:45 PM
>> To: emc-users@lists.sourceforge.net
>> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
>> 
>>> On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:
>>> 202,200 for the outside spline and the flex gear is 200.  In this
>>> situation - the 202 tooth spline is stationary to the stepper.  The
>>> 200 tooth outside spline is mounted to the faceplate.  In this
>>> layout - the ratio apears to be 101:1
>>> 
>>> In this situation the stepper motor and the face plate spin the same
>>> direction.
>>> 
>>> With the same set of outside spines swapped - the ratio is 100:1
>>> 
>>> I am sure Andy can explain it.  It doesn't make sense to me.
>>> 
>>> Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
>>> 
>>> sam
>> 
>> I am running some behind you Sam, with my project, having printer
>> problems kills time and money. Finally settled on an ender 5 Plus,
>> which is working passably well but I've wasted $3k getting there.
>> 
>> Any way, I changed the design some from yours, to a 30/1 because those
>> big spines print better, and by making my own bearings in openscad,
>> useing crosman bb's for balls. I put a huge one with over 150 loose
>> bb's directly on the outside of the moving spline, with only the lip
>> of the output coupling disc (printed of course) interposed. And the
>> floating spline has 3 more of those, sized for a good friction fit
>> inside that spline, with both the spline and the bearings made as thin
>> as practical to improve the flex life, and I just took the eliptical
>> armature off the build plate and wiggled in into those 3 bearings
>> inside the loose spline, so thats the driver armature, no commercial
>> ball bearings anyplace like yours.  I've made the 8mm hole in the
>> plastic for the motor shaft into a prominent D-flat, and used a cbn
>> wheel to make the flat much wider on the motor shaft, and this
>> armature will be driven onto the motor shaft without any grub screws
>> at all. No clue how long it will run before it bores that hole out and
>> I have to make an alu inner for it. :(
>> 
>> But I just now assembled it without the motor, turning the armature by
>> hand, and it works, with no detectable backlash. And it turns the
>> armature easy enough the 3NM 3 phase motor (those are magic folks,
>> running 50C cooler than 2 phase stuff) I'll use will not be a bit
>> overstressed.  Those bb's will pound the plastic smooth and get
>> smoother with use.
>> 
>> So now its time to finish the output shaft, and make the rest of the
>> housing. Which will be supported by the big bearing at the spline end,
>> and 4 of the printed bearings at the load end. I've got the motor end
>> gnawed out of some 1" stock I had, and I bought a foot of 3.125" thick
>> by 6" wide stuff so I can make 2 output housings. That showed me the
>> current price for extruded alu, scary. I also bought enough rod to
>> make about 4 output shafts, over $200. And I'

Re: [Emc-users] Worn Ball Screw?

[Thaddeus Waldner]

It would technically still have thrust bearings, no? But on the nut instead of 
on the screw. I’m not sure this changes anything.

> On Apr 12, 2021, at 3:55 PM, Gene Heskett  wrote:
> 
> On Monday 12 April 2021 14:55:18 Ralph Stirling wrote:
> 
>> Thrust bearings at the ball screw ends perhaps?
>> 
> You may want to read it again Ralph, the screw is fixed, with a rotating 
> nut.
> 
> I had one like that I built once. I think Todd is correct and the screw 
> needs to go to a rebuilder. With the nut still on it because they may 
> have to work on both. My $0.02 of coarse.
>> -- Ralph
>> 
>> From: Todd Zuercher [to...@pgrahamdunn.com]
>> Sent: Monday, April 12, 2021 7:48 AM
>> To: Enhanced Machine Controller (EMC)
>> Subject: [Emc-users] Worn Ball Screw?
>> 
>> CAUTION: This email originated from outside the Walla Walla University
>> email system.
>> 
>> 
>> Those here who have had to deal with a worn out ball screw.  How is
>> this normally manifested.  I have a machine that is only showing
>> backlash under load.  Is that normally how a worn out screw shows it's
>> age?  I was expecting it to be normal loose backlash that you can
>> measure.  But this is showing up as springy softness that you have to
>> give a pretty hard shove against to move the dial indicator, then it
>> snaps back to zero when you let go.  Using the usual jogging methods
>> to read backlash, the machine reads zero backlash and positions well. 
>> But dynamically it is awful, with loud clucking noises on direction
>> changes and horribly wavy marks left on the pieces milled at those
>> changes.  Giving a shove on the table, I can measure more than
>> +/-0.01" of this  "springy" backlash, but moving the screw to a
>> normally unused position I can only measure about 0.001".  This is a
>> big fixed screw (about 2" diameter and more than 14ft long) with
>> rotating nut, is there any hope of fixing it?  I'm considering trying
>> to send the screw out to one of those screw refurbishing places.  The
>> machine manufacturer quoted us over $18,000 to replace it.
>> 
>> Todd Zuercher
>> P. Graham Dunn
>> Inc.> www.pgrahamdunn.com%2Findex.php&data=04%7C01%7Cralph.stirling%40wal
>> lawalla.edu%7C58338609df8b45b6914308d8fde00b00%7Cd958f048e43142779c8deb
>> fb75e7aa64%7C0%7C0%7C637538485997249904%7CUnknown%7CTWFpbGZsb3d8eyJWIjo
>> iMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&
>> sdata=Ld9xm92SAMAjLkMiiIF8IUVaEr%2FNPwfF0CkiXtceb3E%3D&reserved=0>
>> 630 Henry Street
>> Dalton, Ohio 44618
>> Phone:  (330)828-2105ext. 2031
>> 
>> 
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> 
> Cheers, Gene Heskett
> -- 
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
> Genes Web page  >
> 
> 
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