[Emc-users] steppers with linear mag scales

2021-12-01 Thread Thomas J Powderly

there's a user in Japan, Mr AkiraHitosi

who has some nice videos using CamPy and CamView

but I noticed he was using steppers with linear scales ( magnetic)

https://www.youtube.com/watch?v=G6ZcdvOgX1s

afaict...

google xl8 says

"

A USB camera is attached to the NC router frame using Linuxcnc, which is 
driven by a stepping motor


and fed back by a linear encoder, and the scales are squealed.JOG feed 
100 mm unit.


The memory error of the linear encoder is the value of FeedError placed 
on the Axis of Linux cnc.


The linear encoder is a magnetic type with a memory of 1/512 mmt unit, 
and the scale error


is 1 m / 10 μm as indicated by the manufacturer.  


"

I asked him to share hal and ini

but i asked in english :-/




tomp



___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-27 Thread Todd Zuercher
- Original Message -
> From: "Valerio Bellizzomi" 
> To: "Enhanced Machine Controller (EMC)" 
> Sent: Tuesday, June 27, 2017 3:58:34 AM
> Subject: Re: [Emc-users] steppers with encoders in closed loop
> 
> I have the P parameter set to 1000 and the motors are quiet.
> Previously
> pncconf had set P to 1 and the motors made noise like hell and
> vibrated.

P = 1000 Will usually only work for an open loop stepper setup using the sudo 
feedback from the hardware stepgen.

--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-27 Thread Valerio Bellizzomi
On Mon, 2017-06-26 at 16:27 -0400, tom-...@bgp.nu wrote:
> Thanks Todd, your suggestion lead me to the issue.  Turns out PNConfig sets 
> the P term to 1000 (and Deadband to 0.0) at which point I got a terrible nose 
> from the motors.  Setting the P term down to 10, and setting Deadband to 
> 0.0005 has it running quite smoothly.  Now to run Halscope and get the tuning 
> right…
> 
> -Tom


I have the P parameter set to 1000 and the motors are quiet. Previously
pncconf had set P to 1 and the motors made noise like hell and
vibrated.



>  
> 
> > On Jun 26, 2017, at 10:28 AM, Todd Zuercher  wrote:
> > 
> > Maybe you've already tried this, but I would think the easiest way is to 
> > use PNCcofig to create an ordinary stepper configuration.  It will set up a 
> > velocity mode config with the hardware stepgen sending the feedback to 
> > close the pid loop.  Get that working.  Then modify that config by adding 
> > the encoder reading, and replace the stepgen's feed back with the encoder's 
> > feedback to the pid loop and to the axis.N.pos-fb (or joint.N.pos-fb in 
> > Master)  Then adjust the P tuning till it "works".  I have such a setup on 
> > a machine using step/dir servos, and using it with step motors would be 
> > exactly the same (except for the PID tuning.)
> > 
> > The trick is to only try making one major modification at a time.  So first 
> > get a velocity mode stepgen config working (without encoder feedback), Then 
> > add encoder feedback (do it one axis at a time.) First get the DRO's 
> > working with the encoder feedback.  Then connect the encoders to the PID 
> > loops.
> > 
> > ----- Original Message -
> > From: "Tom Easterday" 
> > To: "Enhanced Machine Controller (EMC)" 
> > Sent: Monday, June 26, 2017 8:37:47 AM
> > Subject: Re: [Emc-users] steppers with encoders in closed loop
> > 
> > Exactly, and any help in getting my stall detection and position tracking 
> > working using velocity mode would be greatly appreciated 😀
> > 
> > -Tom
> > 
> >> On Jun 26, 2017, at 6:52 AM, Rene Hopf  wrote:
> >> 
> >> there is no benefit in using them in linuxcnc, apart from stall detection 
> >> or position tracking.
> >> 
> > 
> > 
> > --
> > Check out the vibrant tech community on one of the world's most
> > engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> > 
> > --
> > Check out the vibrant tech community on one of the world's most
> > engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> 
> 
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users




--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread tom-emc
Latest plot (on X axis):  http://bgp.nu/~tom/pub/pid-X-ff2.png


--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread tom-emc
Thanks Peter,
It did help a small bit.  Max f-error is now .00014 to .00015 (vs .00018 to 
.00019).  That is a sensitive parameter.  I played with FF2 = .001 (bad), .0006 
(bad), .00055 ok but ferror was .00016-.00017, so I left it at .0005.
-Tom

> On Jun 26, 2017, at 7:35 PM, Peter C. Wallace  wrote:
> 
> You might improve the tuning a bit with a teeny amount of FF2
> 
> 
> maybe .0005 as a start


--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread Peter C. Wallace

On Mon, 26 Jun 2017, tom-...@bgp.nu wrote:


Date: Mon, 26 Jun 2017 19:20:14 -0400
From: tom-...@bgp.nu
Reply-To: "Enhanced Machine Controller (EMC)"

To: "Enhanced Machine Controller (EMC)" 
Subject: Re: [Emc-users] steppers with encoders in closed loop

And for those following along at home, I got the machine set up in velocity 
mode and the pid tuned fairly well.  The following error is less than .0002 and 
the machine runs very nicely, and I can now Home to the index pulse on the 
encoder (which is where this all began)!  Yay.

Below are links to my .ini and .hal and plots of the f-error for each axis in 
case it helps someone in the future.

Thanks,
-Tom

http://bgp.nu/~tom/pub/EMCO-CL.hal
http://bgp.nu/~tom/pub/EMCO-CL.ini

http://bgp.nu/~tom/pub/pid-X.png
http://bgp.nu/~tom/pub/pid-Y.png
http://bgp.nu/~tom/pub/pid-Z.png



You might improve the tuning a bit with a teeny amount of FF2


maybe .0005 as a start




--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users



Peter Wallace
Mesa Electronics

(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.


--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread tom-emc
And for those following along at home, I got the machine set up in velocity 
mode and the pid tuned fairly well.  The following error is less than .0002 and 
the machine runs very nicely, and I can now Home to the index pulse on the 
encoder (which is where this all began)!  Yay.

Below are links to my .ini and .hal and plots of the f-error for each axis in 
case it helps someone in the future.

Thanks,
-Tom

http://bgp.nu/~tom/pub/EMCO-CL.hal
http://bgp.nu/~tom/pub/EMCO-CL.ini

http://bgp.nu/~tom/pub/pid-X.png
http://bgp.nu/~tom/pub/pid-Y.png
http://bgp.nu/~tom/pub/pid-Z.png



--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread tom-emc
Thanks Todd, your suggestion lead me to the issue.  Turns out PNConfig sets the 
P term to 1000 (and Deadband to 0.0) at which point I got a terrible nose from 
the motors.  Setting the P term down to 10, and setting Deadband to 0.0005 has 
it running quite smoothly.  Now to run Halscope and get the tuning right…

-Tom
 

> On Jun 26, 2017, at 10:28 AM, Todd Zuercher  wrote:
> 
> Maybe you've already tried this, but I would think the easiest way is to use 
> PNCcofig to create an ordinary stepper configuration.  It will set up a 
> velocity mode config with the hardware stepgen sending the feedback to close 
> the pid loop.  Get that working.  Then modify that config by adding the 
> encoder reading, and replace the stepgen's feed back with the encoder's 
> feedback to the pid loop and to the axis.N.pos-fb (or joint.N.pos-fb in 
> Master)  Then adjust the P tuning till it "works".  I have such a setup on a 
> machine using step/dir servos, and using it with step motors would be exactly 
> the same (except for the PID tuning.)
> 
> The trick is to only try making one major modification at a time.  So first 
> get a velocity mode stepgen config working (without encoder feedback), Then 
> add encoder feedback (do it one axis at a time.) First get the DRO's working 
> with the encoder feedback.  Then connect the encoders to the PID loops.
> 
> - Original Message -
> From: "Tom Easterday" 
> To: "Enhanced Machine Controller (EMC)" 
> Sent: Monday, June 26, 2017 8:37:47 AM
> Subject: Re: [Emc-users] steppers with encoders in closed loop
> 
> Exactly, and any help in getting my stall detection and position tracking 
> working using velocity mode would be greatly appreciated 😀
> 
> -Tom
> 
>> On Jun 26, 2017, at 6:52 AM, Rene Hopf  wrote:
>> 
>> there is no benefit in using them in linuxcnc, apart from stall detection or 
>> position tracking.
>> 
> 
> 
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
> 
> --
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread Todd Zuercher
Maybe you've already tried this, but I would think the easiest way is to use 
PNCcofig to create an ordinary stepper configuration.  It will set up a 
velocity mode config with the hardware stepgen sending the feedback to close 
the pid loop.  Get that working.  Then modify that config by adding the encoder 
reading, and replace the stepgen's feed back with the encoder's feedback to the 
pid loop and to the axis.N.pos-fb (or joint.N.pos-fb in Master)  Then adjust 
the P tuning till it "works".  I have such a setup on a machine using step/dir 
servos, and using it with step motors would be exactly the same (except for the 
PID tuning.)

The trick is to only try making one major modification at a time.  So first get 
a velocity mode stepgen config working (without encoder feedback), Then add 
encoder feedback (do it one axis at a time.) First get the DRO's working with 
the encoder feedback.  Then connect the encoders to the PID loops.

- Original Message -
From: "Tom Easterday" 
To: "Enhanced Machine Controller (EMC)" 
Sent: Monday, June 26, 2017 8:37:47 AM
Subject: Re: [Emc-users] steppers with encoders in closed loop

Exactly, and any help in getting my stall detection and position tracking 
working using velocity mode would be greatly appreciated 😀

-Tom

> On Jun 26, 2017, at 6:52 AM, Rene Hopf  wrote:
> 
> there is no benefit in using them in linuxcnc, apart from stall detection or 
> position tracking.
> 


--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread Tom Easterday
Exactly, and any help in getting my stall detection and position tracking 
working using velocity mode would be greatly appreciated 😀

-Tom

> On Jun 26, 2017, at 6:52 AM, Rene Hopf  wrote:
> 
> there is no benefit in using them in linuxcnc, apart from stall detection or 
> position tracking.
> 


--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-26 Thread Rene Hopf

> On 26. Jun 2017, at 00:12, tom-...@bgp.nu wrote:
> 
> I would like to attempt to get my machine with stepper motors running in 
> velocity mode with feedback from the encoders.

this setup makes absolutely no sense.
if the drive does not use the encoder, there is no benefit in using them in 
linuxcnc, apart from stall detection or position tracking.
proper closed loop drives will use the encoder for commutation, and operate the 
stepper more like a servo.
you cannot achieve that using your setup.

Rene
--
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers with encoders in closed loop

2017-06-25 Thread Gene Heskett
On Sunday 25 June 2017 22:13:04 Tom Easterday wrote:

> Gene,
> Thanks for the response.  The machine has been running great for years
> on those values but in position mode, not in velocity mode.  I
> wouldn't think that any of the step-gen parameters would need to
> change when changing to velocity mode...?

I wouldn't either if its been running that way, but they are, shall we 
say, settings that can push the envelope.

My motor drivers are generally in the 2M542 category, with a DM860 (junk, 
the microstep size mapping sucks) thrown in, and none of my steplengths 
are under 2000, with dir controls averaging twice that.  The opto's in 
these drivers preclude more than a 200-250 kilohertz drive with the 
motor laying loose on the table.  At a microstep divisor of 8, thats a 
leasurely 2000 rpm or so, with very little usable torque at those 
speeds. At the higher rotational speeds, the microstepping effect gets 
lost as the motors inductance becomes the current controlling factor. 
The driver can only do what its has the available voltage to do.

> I suspect the PID parameters I am using, DEADBAND?, MAX_OUTPUT? (not
> sure what these should be) or perhaps I have mis-wired, or not wired,
> an encoder or velocity parameter in the Hal config

Deadband we have been told, if its used in a stepper setup with encoders, 
must be greater than one step, else it will hunt. For servo's, I'd 
assume a deadband greater than the encoder resolution. I don't believe 
I'm using a non-zero value anyplace as my only encoders are for spindle 
control.  Rigid tapping, threading etc.

MAX_OUTPUT I normally use non-zero in pwm/pdm servo setups, to limit the 
PWM/PDM output duty cycle to around 98% as the driver needs the pulses 
for driver gate charging, and it it goes to a solid, 100% signal, the 
servo amp will shut itself off to protect the output transistors. I have 
2 of the pico pwm-servo drivers running nominally 1 hp motors. Works 
well on both TLM and the G0704.

The latter condition (missing hal connection) might be easier to see on a 
rockhopper report, but we don't have a viewer for those that will let 
you blow it up to a readable size, and then let you scan around on what 
would be if printed out and pasted up, nearly the size of a sheet of 
plywood. So I generally use the ctl-f (find) function of geany to check 
that sort of stuff.

Unless you've a bare barn door to tack them to, a printout is a bit hard 
to store in the average shop. :)

No clue if any of prattling on this helps but I hope so.

> -Tom
>
> > On Jun 25, 2017, at 9:11 PM, Gene Heskett  
wrote:
> >> On Sunday 25 June 2017 18:12:14 tom-...@bgp.nu wrote:
> >>
> >> I would like to attempt to get my machine with stepper motors
> >> running in velocity mode with feedback from the encoders.  Below
> >> are the relevant parts of my Hal and Ini files for just the X-Axis.
> >>  I figured I would do one axis at a time.  Currently nothing
> >> happens when I try to jog the X axis except if I hold it long
> >> enough it gives a following error.  If I try to home it, it faults
> >> with a following error.  I was trying to look various parameters on
> >> Halscope, triggering off of axis.0.f-error but nothing appears for
> >> any of the pins I was monitoring.   Are there any obvious errors in
> >> the config below to start with?
> >>
> >> -Tom
> >>
> >>  HAL 
> >> loadrt trivkins
> >> loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD
> >> num_joints=[TRAJ]AXES loadrt hostmot2
> >> loadrt hm2_7i43  config="firmware=hm2/7i43/SVST2_4_7I47B.BIT
> >> num_encoders=3 num_pwmgens=0 num_stepgens=4" loadrt pid
> >> names=pid.x,pid.y,pid.z
> >>
> >> addf hm2_7i43.0.read servo-thread
> >> addf motion-command-handler servo-thread
> >> addf motion-controller servo-thread
> >> addf pid.x.do-pid-calcsservo-thread
> >> addf pid.y.do-pid-calcsservo-thread
> >> addf pid.z.do-pid-calcsservo-thread
> >> addf hm2_7i43.0.write servo-thread
> >>
> >>
> >> #***
> >> #  AXIS X
> >> #***
> >> # axis enable chain
> >>
> >> setppid.x.Pgain[AXIS_0]P
> >> setppid.x.Igain[AXIS_0]I
> >> setppid.x.Dgain[AXIS_0]D
> >> setppid.x.bias[AXIS_0]BIAS
> >> setppid.x.FF0[AXIS_0]FF0
> >> setppid.x.FF1[AXIS_0]FF1
> >> setppid.x.FF2[AXIS_0]FF2
> >> setppid.x.deadband[AXIS_0]DEADBAND
> >> setppid.x.maxoutput[AXIS_0]MAX_OUTPUT
> >>
> >> net x-index-enable <=> pid.x.index-enable
> >> net x-enable => pid.x.enable
> >> net x-ouput => pid.x.output
> >> net x-pos-cmd => pid.x.command
> >> net x-vel-fb => pid.x.feedback-deriv
> >> net x-pos-fb => pid.x.feedback
> >>
> >> # Step Gen signals/setup
> >> setp hm2_7i43.0.stepgen.00.dirsetup[AXIS_0]DIRSETUP
> >> setp hm2_7i43.0.stepgen.00.dirhold [AXIS_0]DIRHOLD
> >> setp hm2_7i43.0.stepgen.00.steplen [AXIS_0]STEPLEN
> >> setp hm2_7i43.0.stepgen.00.stepspace   [A

Re: [Emc-users] steppers with encoders in closed loop

2017-06-25 Thread Tom Easterday
Gene,
Thanks for the response.  The machine has been running great for years on those 
values but in position mode, not in velocity mode.  I wouldn't think that any 
of the step-gen parameters would need to change when changing to velocity 
mode...?

I suspect the PID parameters I am using, DEADBAND?, MAX_OUTPUT? (not sure what 
these should be) or perhaps I have mis-wired, or not wired, an encoder or 
velocity parameter in the Hal config

-Tom

> On Jun 25, 2017, at 9:11 PM, Gene Heskett  wrote:
> 
>> On Sunday 25 June 2017 18:12:14 tom-...@bgp.nu wrote:
>> 
>> I would like to attempt to get my machine with stepper motors running
>> in velocity mode with feedback from the encoders.  Below are the
>> relevant parts of my Hal and Ini files for just the X-Axis.  I figured
>> I would do one axis at a time.  Currently nothing happens when I try
>> to jog the X axis except if I hold it long enough it gives a following
>> error.  If I try to home it, it faults with a following error.  I was
>> trying to look various parameters on Halscope, triggering off of
>> axis.0.f-error but nothing appears for any of the pins I was
>> monitoring.   Are there any obvious errors in the config below to
>> start with?
>> 
>> -Tom
>> 
>>  HAL 
>> loadrt trivkins
>> loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD
>> num_joints=[TRAJ]AXES loadrt hostmot2
>> loadrt hm2_7i43  config="firmware=hm2/7i43/SVST2_4_7I47B.BIT
>> num_encoders=3 num_pwmgens=0 num_stepgens=4" loadrt pid
>> names=pid.x,pid.y,pid.z
>> 
>> addf hm2_7i43.0.read servo-thread
>> addf motion-command-handler servo-thread
>> addf motion-controller servo-thread
>> addf pid.x.do-pid-calcsservo-thread
>> addf pid.y.do-pid-calcsservo-thread
>> addf pid.z.do-pid-calcsservo-thread
>> addf hm2_7i43.0.write servo-thread
>> 
>> 
>> #***
>> #  AXIS X
>> #***
>> # axis enable chain
>> 
>> setppid.x.Pgain[AXIS_0]P
>> setppid.x.Igain[AXIS_0]I
>> setppid.x.Dgain[AXIS_0]D
>> setppid.x.bias[AXIS_0]BIAS
>> setppid.x.FF0[AXIS_0]FF0
>> setppid.x.FF1[AXIS_0]FF1
>> setppid.x.FF2[AXIS_0]FF2
>> setppid.x.deadband[AXIS_0]DEADBAND
>> setppid.x.maxoutput[AXIS_0]MAX_OUTPUT
>> 
>> net x-index-enable <=> pid.x.index-enable
>> net x-enable => pid.x.enable
>> net x-ouput => pid.x.output
>> net x-pos-cmd => pid.x.command
>> net x-vel-fb => pid.x.feedback-deriv
>> net x-pos-fb => pid.x.feedback
>> 
>> # Step Gen signals/setup
>> setp hm2_7i43.0.stepgen.00.dirsetup[AXIS_0]DIRSETUP
>> setp hm2_7i43.0.stepgen.00.dirhold [AXIS_0]DIRHOLD
>> setp hm2_7i43.0.stepgen.00.steplen [AXIS_0]STEPLEN
>> setp hm2_7i43.0.stepgen.00.stepspace   [AXIS_0]STEPSPACE
>> setp hm2_7i43.0.stepgen.00.position-scale  [AXIS_0]SCALE
>> setp hm2_7i43.0.stepgen.00.maxaccel   [AXIS_0]STEPGEN_MAXACCEL
>> setp hm2_7i43.0.stepgen.00.maxvel   [AXIS_0]STEPGEN_MAXVEL
>> setp hm2_7i43.0.stepgen.00.step_type0
>> setp hm2_7i43.0.stepgen.00.control-type1
>> 
>> # --closed loop stepper signals--
>> net x-pos-cmd axis.0.motor-pos-cmd
>> net x-output => hm2_7i43.0.stepgen.00.velocity-cmd
>> net x-enable axis.0.amp-enable-out => hm2_7i43.0.stepgen.00.enable
>> 
>> # ---Encoder feedback signals/setup---
>> setp hm2_7i43.0.encoder.00.counter-mode 0
>> setp hm2_7i43.0.encoder.00.filter 1
>> setp hm2_7i43.0.encoder.00.index-invert 0
>> setp hm2_7i43.0.encoder.00.index-mask 0
>> setp hm2_7i43.0.encoder.00.index-mask-invert 0
>> setp hm2_7i43.0.encoder.00.scale  [AXIS_0]INPUT_SCALE
>> 
>> net x-pos-fb <= hm2_7i43.0.encoder.00.position
>> net x-vel-fb <= hm2_7i43.0.encoder.00.velocity
>> net x-pos-fb => axis.0.motor-pos-fb
>> net x-index-enable axis.0.index-enable <=>
>> hm2_7i43.0.encoder.00.index-enable net x-pos-rawcounts <=
>> hm2_7i43.0.encoder.00.rawcounts
>> 
>> # ---setup home / limit switch signals---
>> net x-home-sw =>  axis.0.home-sw-in
>> net x-neg-limit =>  axis.0.neg-lim-sw-in
>> net x-pos-limit =>  axis.0.pos-lim-sw-in
>> 
>>  end HAL 
>> 
>>  INI 
>> [EMC]
>> MACHINE = EMCO
>> DEBUG = 0
>> 
>> [DISPLAY]
>> DISPLAY = axis
>> EDITOR = gedit
>> PYVCP = custom_pyvcp.xml
>> POSITION_OFFSET = RELATIVE
>> POSITION_FEEDBACK = ACTUAL
>> MAX_FEED_OVERRIDE = 2.0
>> MAX_SPINDLE_OVERRIDE = 1.5
>> MIN_SPINDLE_OVERRIDE = 0.50
>> INTRO_GRAPHIC = linuxcnc.gif
>> INTRO_TIME = 2
>> PROGRAM_PREFIX = /home/tom/linuxcnc/nc_files
>> INCREMENTS = .1in .05in .01in .005in .001in .0005in .0001in
>> POSITION_OFFSET = RELATIVE
>> POSITION_FEEDBACK = ACTUAL
>> DEFAULT_LINEAR_VELOCITY = 0.25
>> MAX_LINEAR_VELOCITY = 1.00
>> MIN_LINEAR_VELOCITY = 0.01
>> DEFAULT_ANGULAR_VELOCITY = 0.25
>> MAX_ANGULAR_VELOCITY = 1.00
>> MIN_ANGULAR_VELOCITY = 0.01
>> GEOMETRY = xyz
>> 
>> [FILTER]
>> PROGRAM_EXTENSION = .pn

Re: [Emc-users] steppers with encoders in closed loop

2017-06-25 Thread Gene Heskett
On Sunday 25 June 2017 18:12:14 tom-...@bgp.nu wrote:

> I would like to attempt to get my machine with stepper motors running
> in velocity mode with feedback from the encoders.  Below are the
> relevant parts of my Hal and Ini files for just the X-Axis.  I figured
> I would do one axis at a time.  Currently nothing happens when I try
> to jog the X axis except if I hold it long enough it gives a following
> error.  If I try to home it, it faults with a following error.  I was
> trying to look various parameters on Halscope, triggering off of
> axis.0.f-error but nothing appears for any of the pins I was
> monitoring.   Are there any obvious errors in the config below to
> start with?
>
> -Tom
>
>  HAL 
> loadrt trivkins
> loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD
> num_joints=[TRAJ]AXES loadrt hostmot2
> loadrt hm2_7i43  config="firmware=hm2/7i43/SVST2_4_7I47B.BIT
> num_encoders=3 num_pwmgens=0 num_stepgens=4" loadrt pid
> names=pid.x,pid.y,pid.z
>
> addf hm2_7i43.0.read servo-thread
> addf motion-command-handler servo-thread
> addf motion-controller servo-thread
> addf pid.x.do-pid-calcs   servo-thread
> addf pid.y.do-pid-calcs   servo-thread
> addf pid.z.do-pid-calcs   servo-thread
> addf hm2_7i43.0.write servo-thread
>
>
> #***
> #  AXIS X
> #***
> # axis enable chain
>
> setp  pid.x.Pgain [AXIS_0]P
> setp  pid.x.Igain [AXIS_0]I
> setp  pid.x.Dgain [AXIS_0]D
> setp  pid.x.bias  [AXIS_0]BIAS
> setp  pid.x.FF0   [AXIS_0]FF0
> setp  pid.x.FF1   [AXIS_0]FF1
> setp  pid.x.FF2   [AXIS_0]FF2
> setp  pid.x.deadband  [AXIS_0]DEADBAND
> setp  pid.x.maxoutput [AXIS_0]MAX_OUTPUT
>
> net x-index-enable <=> pid.x.index-enable
> net x-enable => pid.x.enable
> net x-ouput => pid.x.output
> net x-pos-cmd => pid.x.command
> net x-vel-fb => pid.x.feedback-deriv
> net x-pos-fb => pid.x.feedback
>
> # Step Gen signals/setup
> setp hm2_7i43.0.stepgen.00.dirsetup[AXIS_0]DIRSETUP
> setp hm2_7i43.0.stepgen.00.dirhold [AXIS_0]DIRHOLD
> setp hm2_7i43.0.stepgen.00.steplen [AXIS_0]STEPLEN
> setp hm2_7i43.0.stepgen.00.stepspace   [AXIS_0]STEPSPACE
> setp hm2_7i43.0.stepgen.00.position-scale  [AXIS_0]SCALE
> setp hm2_7i43.0.stepgen.00.maxaccel  [AXIS_0]STEPGEN_MAXACCEL
> setp hm2_7i43.0.stepgen.00.maxvel[AXIS_0]STEPGEN_MAXVEL
> setp hm2_7i43.0.stepgen.00.step_type  0
> setp hm2_7i43.0.stepgen.00.control-type   1
>
> # --closed loop stepper signals--
> net x-pos-cmd axis.0.motor-pos-cmd
> net x-output => hm2_7i43.0.stepgen.00.velocity-cmd
> net x-enable axis.0.amp-enable-out => hm2_7i43.0.stepgen.00.enable
>
> # ---Encoder feedback signals/setup---
> setp hm2_7i43.0.encoder.00.counter-mode 0
> setp hm2_7i43.0.encoder.00.filter 1
> setp hm2_7i43.0.encoder.00.index-invert 0
> setp hm2_7i43.0.encoder.00.index-mask 0
> setp hm2_7i43.0.encoder.00.index-mask-invert 0
> setp hm2_7i43.0.encoder.00.scale  [AXIS_0]INPUT_SCALE
>
> net x-pos-fb <= hm2_7i43.0.encoder.00.position
> net x-vel-fb <= hm2_7i43.0.encoder.00.velocity
> net x-pos-fb => axis.0.motor-pos-fb
> net x-index-enable axis.0.index-enable <=>
> hm2_7i43.0.encoder.00.index-enable net x-pos-rawcounts <=
> hm2_7i43.0.encoder.00.rawcounts
>
> # ---setup home / limit switch signals---
> net x-home-sw =>  axis.0.home-sw-in
> net x-neg-limit =>  axis.0.neg-lim-sw-in
> net x-pos-limit =>  axis.0.pos-lim-sw-in
>
>  end HAL 
>
>  INI 
> [EMC]
> MACHINE = EMCO
> DEBUG = 0
>
> [DISPLAY]
> DISPLAY = axis
> EDITOR = gedit
> PYVCP = custom_pyvcp.xml
> POSITION_OFFSET = RELATIVE
> POSITION_FEEDBACK = ACTUAL
> MAX_FEED_OVERRIDE = 2.0
> MAX_SPINDLE_OVERRIDE = 1.5
> MIN_SPINDLE_OVERRIDE = 0.50
> INTRO_GRAPHIC = linuxcnc.gif
> INTRO_TIME = 2
> PROGRAM_PREFIX = /home/tom/linuxcnc/nc_files
> INCREMENTS = .1in .05in .01in .005in .001in .0005in .0001in
> POSITION_OFFSET = RELATIVE
> POSITION_FEEDBACK = ACTUAL
> DEFAULT_LINEAR_VELOCITY = 0.25
> MAX_LINEAR_VELOCITY = 1.00
> MIN_LINEAR_VELOCITY = 0.01
> DEFAULT_ANGULAR_VELOCITY = 0.25
> MAX_ANGULAR_VELOCITY = 1.00
> MIN_ANGULAR_VELOCITY = 0.01
> GEOMETRY = xyz
>
> [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 = emc.var
>
> [EMCMOT]
> EMCMOT = motmod
> COMM_TIMEOUT = 1.0
> COMM_WAIT = 0.010
> #BASE_PERIOD = 5
> SERVO_PERIOD = 100
>
> # [HOSTMOT2]
> # This is for info only - config line is in the .hal file
> # DRIVER0=hm2_7i43
> # BOARD0=7i43
> # CONFIG0="firmware=hm2/7i43/SVST2_4_7I47B.BIT num_encoders=3
> num_pwmgens=0 num_stepgens=4"
>
> [HAL]
> HALUI = halui
> HALFILE = EMCO-CL.hal
> HALFILE = custom.ha

[Emc-users] steppers with encoders in closed loop

2017-06-25 Thread tom-emc
I would like to attempt to get my machine with stepper motors running in 
velocity mode with feedback from the encoders.  Below are the relevant parts of 
my Hal and Ini files for just the X-Axis.  I figured I would do one axis at a 
time.  Currently nothing happens when I try to jog the X axis except if I hold 
it long enough it gives a following error.  If I try to home it, it faults with 
a following error.  I was trying to look various parameters on Halscope, 
triggering off of axis.0.f-error but nothing appears for any of the pins I was 
monitoring.   Are there any obvious errors in the config below to start with?

-Tom

 HAL 
loadrt trivkins
loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD 
num_joints=[TRAJ]AXES
loadrt hostmot2
loadrt hm2_7i43  config="firmware=hm2/7i43/SVST2_4_7I47B.BIT num_encoders=3 
num_pwmgens=0 num_stepgens=4"
loadrt pid names=pid.x,pid.y,pid.z

addf hm2_7i43.0.read servo-thread
addf motion-command-handler servo-thread
addf motion-controller servo-thread
addf pid.x.do-pid-calcs servo-thread
addf pid.y.do-pid-calcs servo-thread
addf pid.z.do-pid-calcs servo-thread
addf hm2_7i43.0.write servo-thread


#***
#  AXIS X
#***
# axis enable chain

setppid.x.Pgain [AXIS_0]P
setppid.x.Igain [AXIS_0]I
setppid.x.Dgain [AXIS_0]D
setppid.x.bias  [AXIS_0]BIAS
setppid.x.FF0   [AXIS_0]FF0
setppid.x.FF1   [AXIS_0]FF1
setppid.x.FF2   [AXIS_0]FF2
setppid.x.deadband  [AXIS_0]DEADBAND
setppid.x.maxoutput [AXIS_0]MAX_OUTPUT

net x-index-enable <=> pid.x.index-enable
net x-enable => pid.x.enable
net x-ouput => pid.x.output
net x-pos-cmd => pid.x.command
net x-vel-fb => pid.x.feedback-deriv
net x-pos-fb => pid.x.feedback

# Step Gen signals/setup
setp hm2_7i43.0.stepgen.00.dirsetup[AXIS_0]DIRSETUP
setp hm2_7i43.0.stepgen.00.dirhold [AXIS_0]DIRHOLD
setp hm2_7i43.0.stepgen.00.steplen [AXIS_0]STEPLEN
setp hm2_7i43.0.stepgen.00.stepspace   [AXIS_0]STEPSPACE
setp hm2_7i43.0.stepgen.00.position-scale  [AXIS_0]SCALE
setp hm2_7i43.0.stepgen.00.maxaccel[AXIS_0]STEPGEN_MAXACCEL
setp hm2_7i43.0.stepgen.00.maxvel  [AXIS_0]STEPGEN_MAXVEL
setp hm2_7i43.0.stepgen.00.step_type0
setp hm2_7i43.0.stepgen.00.control-type 1

# --closed loop stepper signals--
net x-pos-cmd axis.0.motor-pos-cmd
net x-output => hm2_7i43.0.stepgen.00.velocity-cmd
net x-enable axis.0.amp-enable-out => hm2_7i43.0.stepgen.00.enable

# ---Encoder feedback signals/setup---
setp hm2_7i43.0.encoder.00.counter-mode 0
setp hm2_7i43.0.encoder.00.filter 1
setp hm2_7i43.0.encoder.00.index-invert 0
setp hm2_7i43.0.encoder.00.index-mask 0
setp hm2_7i43.0.encoder.00.index-mask-invert 0
setp hm2_7i43.0.encoder.00.scale  [AXIS_0]INPUT_SCALE

net x-pos-fb <= hm2_7i43.0.encoder.00.position
net x-vel-fb <= hm2_7i43.0.encoder.00.velocity
net x-pos-fb => axis.0.motor-pos-fb
net x-index-enable axis.0.index-enable <=> hm2_7i43.0.encoder.00.index-enable
net x-pos-rawcounts <= hm2_7i43.0.encoder.00.rawcounts

# ---setup home / limit switch signals---
net x-home-sw =>  axis.0.home-sw-in
net x-neg-limit =>  axis.0.neg-lim-sw-in
net x-pos-limit =>  axis.0.pos-lim-sw-in

 end HAL 

 INI 
[EMC]
MACHINE = EMCO
DEBUG = 0

[DISPLAY]
DISPLAY = axis
EDITOR = gedit
PYVCP = custom_pyvcp.xml
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
MAX_FEED_OVERRIDE = 2.0
MAX_SPINDLE_OVERRIDE = 1.5
MIN_SPINDLE_OVERRIDE = 0.50
INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 2
PROGRAM_PREFIX = /home/tom/linuxcnc/nc_files
INCREMENTS = .1in .05in .01in .005in .001in .0005in .0001in
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
DEFAULT_LINEAR_VELOCITY = 0.25
MAX_LINEAR_VELOCITY = 1.00
MIN_LINEAR_VELOCITY = 0.01
DEFAULT_ANGULAR_VELOCITY = 0.25
MAX_ANGULAR_VELOCITY = 1.00
MIN_ANGULAR_VELOCITY = 0.01
GEOMETRY = xyz

[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 = emc.var

[EMCMOT]
EMCMOT = motmod
COMM_TIMEOUT = 1.0
COMM_WAIT = 0.010
#BASE_PERIOD = 5
SERVO_PERIOD = 100

# [HOSTMOT2]
# This is for info only - config line is in the .hal file
# DRIVER0=hm2_7i43 
# BOARD0=7i43
# CONFIG0="firmware=hm2/7i43/SVST2_4_7I47B.BIT num_encoders=3 num_pwmgens=0 
num_stepgens=4" 

[HAL]
HALUI = halui
HALFILE = EMCO-CL.hal
HALFILE = custom.hal
POSTGUI_HALFILE = custom_postgui.hal

[HALUI]
MDI_COMMAND = G53 G0 X0 Y0 Z0
MDI_COMMAND = o call

[TRAJ]
AXES = 3
COORDINATES = X Y Z
LINEAR_UNITS = inch
ANGULAR_UNITS = degree
CYCLE_TIME = 0.010
DEFAULT_VELOCITY = 0.5
MAX_LINEAR_VELOCITY = 2
DEFAULT_ANGULAR_VELOCITY = 0.25
MAX_ANGULAR_VELOCITY = 1.0

[EMCIO]
EMCIO = io

Re: [Emc-users] Steppers losing position

2014-09-04 Thread Gregg Eshelman
On 9/4/2014 9:07 AM, Viesturs Lācis wrote:
> Hello!
>
> I have a strange situation:
> Stepper motor of Z axis on a cnc router is losing it's position -
> doing a series of numerous holes in material will end up with various
> depths of holes.

Just thought of this, have you tried homing the Z axis up before 
drilling each hole? That would reset the position so the control will 
always start from the same known position each time.


---
This email is free from viruses and malware because avast! Antivirus protection 
is active.
http://www.avast.com


--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread Gregg Eshelman
On 9/4/2014 9:07 AM, Viesturs Lācis wrote:
> Hello!
>
> I have a strange situation:
> Stepper motor of Z axis on a cnc router is losing it's position -
> doing a series of numerous holes in material will end up with various
> depths of holes.
>
> The strange part is:
> 1) for each time, when machine is running, it will lose position only
> in one direction; if holes are getting deeper, then they only get
> deeper, not the other way;
> 2) the direction of "drift" will change randomly as machine is
> restarted and only then; simply running another g-code file will not
> change the direction of "drift";

First thing I'd look at is your spindle speed and feed rate.

If the bit is pulling itself into the work faster than the control is 
commanding, it can force the motor to 'run ahead' of the commanded steps.

If the control is trying to push the bit in faster than it can cut, the 
effect is a 'push back' where the step signals go to the motor but it 
doesn't actually move.

Combine either or both with a slight variance in density of the material 
and you'll get randomness.

If tweaking the speed and feed doesn't completely cure it there are 
hardware solutions.

Were this my machine I'd find a way to put a scale (magnetic type, crud 
and fluids don't mess them up and can be cut to length) or rotary 
encoder on so the control always knows where the axis is.

Another possibility is more power. Put on a larger stepper with more 
torque so it can't be pulled ahead of or pushed behind the stream of 
step signals.

Another cause of it might be variability of chip loading in the bit. 
What do you have for keeping the bit clear? For material that can't take 
liquids use an air nozzle and vacuum.

---
This email is free from viruses and malware because avast! Antivirus protection 
is active.
http://www.avast.com


--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread John Prentice (FS)
Greetings

>-Original Message-
>From: Viesturs Lācis [mailto:viesturs.la...@gmail.com] 
>2014-09-04 18:16 GMT+03:00 alex chiosso :
>> If the holes are deeper doesn't it means that the motor is making "more"
>> steps and not "less" ?
>> Is it possible that you have extra steps due to noises or bad 
>> connections PC ---> BoB ---> Gecko Drive ?

>Yes, as I said, motor is "drifting" in particular direction, which may
change (not always), if system is restarted, but the direction of drift does
not change, once the >system is running - if it gradually goes up, then it
does so; if down, then it keeps getting deeper.

>There is no BoB, step/dir signals go directly from 5i23 to Gecko.

Two thoughts - sadly neither addressing the "direction of drift constant for
a given boot" symptom:

(a) It is not possible to infer if steps are being lost or gained from a
series of holes. Noise might give additional steps - but IMO this is unusual
-  but this might be when going down when holes get deeper or going up when
holes get shallower.

(b) It might be worth checking that the 5i23 pullups are set to 5volt for
the connector you are using. The 5i20 manual says that, with 3v3 pullups,
optos connected to a 5 volt rail may not fully turn off.

John Prentice




--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread andy pugh
On 4 September 2014 16:07, Viesturs Lācis  wrote:

> There is Nema23 stepper motor and Gecko stepper driver.

A vaguely recall hearing of one channel of the G540 going "bad" and
then also that inverting the step signals makes it good again.
It certainly seems that it might be worth at least attempting an
inversion of the step pin. (both the parport and Mesa drivers allow an
output pin to be inverted)

-- 
atp
If you can't fix it, you don't own it.
http://www.ifixit.com/Manifesto

--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread alex chiosso
This seems to be an electrical problem .
Have you tried to perform the machine cycle (i.e the holes drilling) in
"dry mode" (no material) and with a reduced feed rate ?
Just to understand if is related to the step frequency and torque .

Alex


On Thu, Sep 4, 2014 at 5:37 PM, Viesturs Lācis 
wrote:

> 2014-09-04 18:32 GMT+03:00 alex chiosso :
> >
> > Means that the "drift" in is both directions. But the axis (motor) is
> > always making more space than expected , isn't it ?
>
> Yes, "drift" can be in any direction, but the change of direction
> happens only on system restart.
>
> Viesturs
>
>
> --
> Slashdot TV.
> Video for Nerds.  Stuff that matters.
> http://tv.slashdot.org/
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread Viesturs Lācis
2014-09-04 18:32 GMT+03:00 alex chiosso :
>
> Means that the "drift" in is both directions. But the axis (motor) is
> always making more space than expected , isn't it ?

Yes, "drift" can be in any direction, but the change of direction
happens only on system restart.

Viesturs

--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread Viesturs Lācis
2014-09-04 18:29 GMT+03:00 alex chiosso :
> A question for you ... the router is brand new (I mean that you have
> finished the setup) or is a "already working" machine ?

I built that machine 3 years ago.

Viesturs

--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread alex chiosso
As you sad :
"Yes, as I said, motor is "drifting" in particular direction, which may
change (not always), if system is restarted, but the direction of
drift does not change, once the system is running - if it gradually
goes up, then it does so; if down, then it keeps getting deeper."

Means that the "drift" in is both directions. But the axis (motor) is
always making more space than expected , isn't it ?

Alex


On Thu, Sep 4, 2014 at 5:29 PM, alex chiosso  wrote:

> As Gene is suggesting , here
> 
> is a discussion on the forum regarding problems with "steps" and Gecko
> Drive .
> A question for you ... the router is brand new (I mean that you have
> finished the setup) or is a "already working" machine ?
> This question is to understand if the machine was working fine before and
> later start with the problem you are mentioning.
>
> Alex
>
>
> On Thu, Sep 4, 2014 at 5:21 PM, Gene Heskett  wrote:
>
>> On Thursday 04 September 2014 11:07:07 Viesturs Lācis did opine
>> And Gene did reply:
>> > Hello!
>> >
>> > I have a strange situation:
>> > Stepper motor of Z axis on a cnc router is losing it's position -
>> > doing a series of numerous holes in material will end up with various
>> > depths of holes.
>> >
>> > The strange part is:
>> > 1) for each time, when machine is running, it will lose position only
>> > in one direction; if holes are getting deeper, then they only get
>> > deeper, not the other way;
>> > 2) the direction of "drift" will change randomly as machine is
>> > restarted and only then; simply running another g-code file will not
>> > change the direction of "drift";
>> >
>> > There is Nema23 stepper motor and Gecko stepper driver.
>> > Motor cable is checked for loose contact, step/dir signal lines are
>> > checked for loose contact, ballscrew and linear rails are checked for
>> > any damage to cause extra resistance in particular direction, the
>> > clutch between motor and ballscrew is checked not to slip.
>> >
>> > I am totally out of ideas, where to look. Has anyone ever experienced
>> > anything like that? What puzzles me most is the consistency to
>> > maintain direction of "drift" and yet randomly change, when whole
>> > system is restarted, so any suggestions will be appreciated.
>> >
>> > Viesturs
>>
>> Can we assume you have lengthened the dirsetup and dirhold settings?
>>
>> I don't have any gecko's, but this sure seems to be an ongoing problem
>> with them.
>>
>> From previous messages, it seems a trip to gecko for repairs fixes it, but
>> a random direction fixed at machine boot?  Thats weird, and I've no clue.
>>
>> 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)
>> Genes Web page 
>> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS
>>
>>
>> --
>> Slashdot TV.
>> Video for Nerds.  Stuff that matters.
>> http://tv.slashdot.org/
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>
>
--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread alex chiosso
As Gene is suggesting , here

is a discussion on the forum regarding problems with "steps" and Gecko
Drive .
A question for you ... the router is brand new (I mean that you have
finished the setup) or is a "already working" machine ?
This question is to understand if the machine was working fine before and
later start with the problem you are mentioning.

Alex


On Thu, Sep 4, 2014 at 5:21 PM, Gene Heskett  wrote:

> On Thursday 04 September 2014 11:07:07 Viesturs Lācis did opine
> And Gene did reply:
> > Hello!
> >
> > I have a strange situation:
> > Stepper motor of Z axis on a cnc router is losing it's position -
> > doing a series of numerous holes in material will end up with various
> > depths of holes.
> >
> > The strange part is:
> > 1) for each time, when machine is running, it will lose position only
> > in one direction; if holes are getting deeper, then they only get
> > deeper, not the other way;
> > 2) the direction of "drift" will change randomly as machine is
> > restarted and only then; simply running another g-code file will not
> > change the direction of "drift";
> >
> > There is Nema23 stepper motor and Gecko stepper driver.
> > Motor cable is checked for loose contact, step/dir signal lines are
> > checked for loose contact, ballscrew and linear rails are checked for
> > any damage to cause extra resistance in particular direction, the
> > clutch between motor and ballscrew is checked not to slip.
> >
> > I am totally out of ideas, where to look. Has anyone ever experienced
> > anything like that? What puzzles me most is the consistency to
> > maintain direction of "drift" and yet randomly change, when whole
> > system is restarted, so any suggestions will be appreciated.
> >
> > Viesturs
>
> Can we assume you have lengthened the dirsetup and dirhold settings?
>
> I don't have any gecko's, but this sure seems to be an ongoing problem
> with them.
>
> From previous messages, it seems a trip to gecko for repairs fixes it, but
> a random direction fixed at machine boot?  Thats weird, and I've no clue.
>
> 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)
> Genes Web page 
> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS
>
>
> --
> Slashdot TV.
> Video for Nerds.  Stuff that matters.
> http://tv.slashdot.org/
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread Viesturs Lācis
2014-09-04 18:16 GMT+03:00 alex chiosso :
> If the holes are deeper doesn't it means that the motor is making "more"
> steps and not "less" ?
> Is it possible that you have extra steps due to noises or bad connections
> PC ---> BoB ---> Gecko Drive ?

Yes, as I said, motor is "drifting" in particular direction, which may
change (not always), if system is restarted, but the direction of
drift does not change, once the system is running - if it gradually
goes up, then it does so; if down, then it keeps getting deeper.

There is no BoB, step/dir signals go directly from 5i23 to Gecko.

Viesturs

--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread Gene Heskett
On Thursday 04 September 2014 11:07:07 Viesturs Lācis did opine
And Gene did reply:
> Hello!
> 
> I have a strange situation:
> Stepper motor of Z axis on a cnc router is losing it's position -
> doing a series of numerous holes in material will end up with various
> depths of holes.
> 
> The strange part is:
> 1) for each time, when machine is running, it will lose position only
> in one direction; if holes are getting deeper, then they only get
> deeper, not the other way;
> 2) the direction of "drift" will change randomly as machine is
> restarted and only then; simply running another g-code file will not
> change the direction of "drift";
> 
> There is Nema23 stepper motor and Gecko stepper driver.
> Motor cable is checked for loose contact, step/dir signal lines are
> checked for loose contact, ballscrew and linear rails are checked for
> any damage to cause extra resistance in particular direction, the
> clutch between motor and ballscrew is checked not to slip.
> 
> I am totally out of ideas, where to look. Has anyone ever experienced
> anything like that? What puzzles me most is the consistency to
> maintain direction of "drift" and yet randomly change, when whole
> system is restarted, so any suggestions will be appreciated.
> 
> Viesturs

Can we assume you have lengthened the dirsetup and dirhold settings?

I don't have any gecko's, but this sure seems to be an ongoing problem 
with them.

From previous messages, it seems a trip to gecko for repairs fixes it, but 
a random direction fixed at machine boot?  Thats weird, and I've no clue.

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)
Genes Web page 
US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS

--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers losing position

2014-09-04 Thread alex chiosso
If the holes are deeper doesn't it means that the motor is making "more"
steps and not "less" ?
Is it possible that you have extra steps due to noises or bad connections
PC ---> BoB ---> Gecko Drive ?

Alex


On Thu, Sep 4, 2014 at 5:07 PM, Viesturs Lācis 
wrote:

> Hello!
>
> I have a strange situation:
> Stepper motor of Z axis on a cnc router is losing it's position -
> doing a series of numerous holes in material will end up with various
> depths of holes.
>
> The strange part is:
> 1) for each time, when machine is running, it will lose position only
> in one direction; if holes are getting deeper, then they only get
> deeper, not the other way;
> 2) the direction of "drift" will change randomly as machine is
> restarted and only then; simply running another g-code file will not
> change the direction of "drift";
>
> There is Nema23 stepper motor and Gecko stepper driver.
> Motor cable is checked for loose contact, step/dir signal lines are
> checked for loose contact, ballscrew and linear rails are checked for
> any damage to cause extra resistance in particular direction, the
> clutch between motor and ballscrew is checked not to slip.
>
> I am totally out of ideas, where to look. Has anyone ever experienced
> anything like that? What puzzles me most is the consistency to
> maintain direction of "drift" and yet randomly change, when whole
> system is restarted, so any suggestions will be appreciated.
>
> Viesturs
>
>
> --
> Slashdot TV.
> Video for Nerds.  Stuff that matters.
> http://tv.slashdot.org/
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


[Emc-users] Steppers losing position

2014-09-04 Thread Viesturs Lācis
Hello!

I have a strange situation:
Stepper motor of Z axis on a cnc router is losing it's position -
doing a series of numerous holes in material will end up with various
depths of holes.

The strange part is:
1) for each time, when machine is running, it will lose position only
in one direction; if holes are getting deeper, then they only get
deeper, not the other way;
2) the direction of "drift" will change randomly as machine is
restarted and only then; simply running another g-code file will not
change the direction of "drift";

There is Nema23 stepper motor and Gecko stepper driver.
Motor cable is checked for loose contact, step/dir signal lines are
checked for loose contact, ballscrew and linear rails are checked for
any damage to cause extra resistance in particular direction, the
clutch between motor and ballscrew is checked not to slip.

I am totally out of ideas, where to look. Has anyone ever experienced
anything like that? What puzzles me most is the consistency to
maintain direction of "drift" and yet randomly change, when whole
system is restarted, so any suggestions will be appreciated.

Viesturs

--
Slashdot TV.  
Video for Nerds.  Stuff that matters.
http://tv.slashdot.org/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-17 Thread gene heskett
On Wednesday, January 18, 2012 12:16:45 AM cogoman did opine:

> > Could you give me some idea of what the advantage is of using 2 and 3
> > 
> > >  stack steppers?
> 
>Perhaps I'm in over my head here, but I'll share what I think I
> know.  The tendency for 2 to 3 stack steppers is for the magnetic
> circuit inside to get too long, and create high inductance for the
> amount of field strength it produces.  This limits the top speed of the
> stepper (the assumption here is standard 200 steps per rev steppers).
> There's a point where stepping up to a NEMA34 from a NEMA23 will get the
> torque needed with less inductance, which allows for more speed.
>This, is more theoretical than practical, since it is quite possible
> to design a slow stepper in both NEMA23 and NEMA34 sizes, and many do
> just that.  While a fast stepper motor needs to have less than 3 mH
> inductance per coil, I have seen even small steppers with over 10 mH.
> 
> Rexstep stepper motors
>  owse&category_id=1&Itemid=1> and usa stepper motors
>  seem to have low
> inductance per torque, assuming you can trust their specs.
> 
> This one
>  />, and this one
>  /> seem to have too much inductance for fast operation.

Probably one of the reasons Marlin has those at what looks like a decent 
price.  TANSTAAFL applies.

> So practically
> speaking, you need to evaluate each motor separately.

That takes some knowledge of the motors else you don't really know what is 
important for a given job.  Frankly I am not beyond that stage myself.

Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: 
She always believed in the old adage -- leave them while you're looking 
good.
-- Anita Loos, "Gentlemen Prefer Blondes"

--
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-17 Thread cogoman

> Could you give me some idea of what the advantage is of using 2 and 3
> >  stack steppers?
   Perhaps I'm in over my head here, but I'll share what I think I 
know.  The tendency for 2 to 3 stack steppers is for the magnetic 
circuit inside to get too long, and create high inductance for the 
amount of field strength it produces.  This limits the top speed of the 
stepper (the assumption here is standard 200 steps per rev steppers).  
There's a point where stepping up to a NEMA34 from a NEMA23 will get the 
torque needed with less inductance, which allows for more speed.
   This, is more theoretical than practical, since it is quite possible 
to design a slow stepper in both NEMA23 and NEMA34 sizes, and many do 
just that.  While a fast stepper motor needs to have less than 3 mH 
inductance per coil, I have seen even small steppers with over 10 mH.

Rexstep stepper motors 

 
and usa stepper motors  
seem to have low inductance per torque, assuming you can trust their specs.

This one 
, 
and this one 
 
seem to have too much inductance for fast operation.  So practically 
speaking, you need to evaluate each motor separately.

--
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-16 Thread gene heskett
On Monday, January 16, 2012 05:19:37 PM Cathrine Hribar did opine:

> On Mon, 16 Jan 2012 16:28:58 -0500
> 
>   gene heskett  wrote:
> > On Monday, January 16, 2012 04:07:22 PM Cathrine Hribar did opine:
> >> Hi Gene:
> >> 
> >> Could you give me some idea of what the advantage is of using 2 and 3
> >> stack steppers?  You seem to know a lot and I hope you don't mind me
> >> asking dumb questions.
> >> 
> >> Thanks
> >> 
> >> Bill
> > 
> > As I see it, its a tradeoff, you can get torque approaching a nema 34
> > motor in the nema 23 size form, that because the armature has a
> > smaller OD, can probably run at faster accelerating rates than the
> > larger nema 34.  Weight hanging on the end of the table looks like it
> > might be less, even with the so-called triple stack, longer &
> > therefore heavier motors. In my case, figuring out how to make
> > couplings that are shorter would have allowed me to put mine closer
> > to the end of the tables, reducing the lever arm of the weight whose
> > cg is likely a good 6" outward.  Moving that inward an inch and a
> > half would I'm sure make a detectable improvement.
> > 
> > All this is pure opinion however, and there are folks here on this
> > list that can stand on much firmer ground when they write on the
> > subject.  OTOH, it also seems to me that the nema 34 motor should be
> > a wee bit more efficient in terms of amps in vs oz/in out.  But I'd
> > expect one can get arguments started just on that aspect alone.
> > 
> > An true expert I am not at this, I am a 100% self taught (and poor
> > teacher at times too) retired tv broadcast engineer with only a GED,
> > CET on the wall.  And a degree UHK (University of Hard Knocks) since
> > I'm only 30 miles from them & had a few bucks to spare.
> > 
> > There are some decent tutorials on steppers available on the net, many
> > of which I think start at a bit too basic a level, but they do fairly
> > well cover the subject.  But I'd also expect that you've done that
> > bit of homework already.
> > 
> > Cheers, Gene
> 
> Thanks for ur reply..
> 
> are u saying that the nema 34 would be equal to a nema 23 three stack?
> 
A short one maybe.  There are 34's out there that could twist the shaft out 
of a 23.  But to get real speeds I'd expect to see 80+ volt power supplies.

> Bill
> 
> 
> -- Keep Your Developer Skills Current with LearnDevNow!
> The most comprehensive online learning library for Microsoft developers
> is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
> Metro Style Apps, more. Free future releases when you subscribe now!
> http://p.sf.net/sfu/learndevnow-d2d
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: 
"The jig's up, Elman."
"Which jig?"
-- Jeff Elman

--
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-16 Thread andy pugh
On 16 January 2012 22:06, Cathrine Hribar  wrote:

> are u saying that the nema 34 would be equal to a nema 23 three stack?

Three-stack steppers in 23 size seem to be quite slow. I haven't ever
tried a 34, but I understand that they have the same problem.
I think you need to look at your critical rpm and and make a decision
on torque at that rpm, at your voltage.

My lathe has a 3-stack 23 on the Z with a 3:1 reduction and a 5mm
pitch screw. The X has a 2-stack 1:1 and a 2.5mm screw. The X is
faster, and stalls less. But then the X has an easier life..

-- 
atp
The idea that there is no such thing as objective truth is, quite simply, wrong.

--
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-16 Thread Cathrine Hribar


On Mon, 16 Jan 2012 16:28:58 -0500
  gene heskett  wrote:
> On Monday, January 16, 2012 04:07:22 PM Cathrine Hribar did opine:
> 
>> Hi Gene:
>> 
>> Could you give me some idea of what the advantage is of using 2 and 3
>> stack steppers?  You seem to know a lot and I hope you don't mind me
>> asking dumb questions.
>> 
>> Thanks
>> 
>> Bill
>> 
> 
> As I see it, its a tradeoff, you can get torque approaching a nema 34 motor 
> in the nema 23 size form, that because the armature has a smaller OD, can 
> probably run at faster accelerating rates than the larger nema 34.  Weight 
> hanging on the end of the table looks like it might be less, even with the 
> so-called triple stack, longer & therefore heavier motors. In my case, 
> figuring out how to make couplings that are shorter would have allowed me 
> to put mine closer to the end of the tables, reducing the lever arm of the 
> weight whose cg is likely a good 6" outward.  Moving that inward an inch 
> and a half would I'm sure make a detectable improvement.
> 
> All this is pure opinion however, and there are folks here on this list 
> that can stand on much firmer ground when they write on the subject.  OTOH, 
> it also seems to me that the nema 34 motor should be a wee bit more 
> efficient in terms of amps in vs oz/in out.  But I'd expect one can get 
> arguments started just on that aspect alone.
> 
> An true expert I am not at this, I am a 100% self taught (and poor teacher 
> at times too) retired tv broadcast engineer with only a GED, CET on the 
> wall.  And a degree UHK (University of Hard Knocks) since I'm only 30 miles 
> from them & had a few bucks to spare.
> 
> There are some decent tutorials on steppers available on the net, many of 
> which I think start at a bit too basic a level, but they do fairly well 
> cover the subject.  But I'd also expect that you've done that bit of 
> homework already.
> 
> Cheers, Gene


Thanks for ur reply..

are u saying that the nema 34 would be equal to a nema 23 three stack?

Bill

--
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-16 Thread gene heskett
On Monday, January 16, 2012 04:07:22 PM Cathrine Hribar did opine:

> Hi Gene:
> 
> Could you give me some idea of what the advantage is of using 2 and 3
> stack steppers?  You seem to know a lot and I hope you don't mind me
> asking dumb questions.
> 
> Thanks
> 
> Bill
> 

As I see it, its a tradeoff, you can get torque approaching a nema 34 motor 
in the nema 23 size form, that because the armature has a smaller OD, can 
probably run at faster accelerating rates than the larger nema 34.  Weight 
hanging on the end of the table looks like it might be less, even with the 
so-called triple stack, longer & therefore heavier motors. In my case, 
figuring out how to make couplings that are shorter would have allowed me 
to put mine closer to the end of the tables, reducing the lever arm of the 
weight whose cg is likely a good 6" outward.  Moving that inward an inch 
and a half would I'm sure make a detectable improvement.

All this is pure opinion however, and there are folks here on this list 
that can stand on much firmer ground when they write on the subject.  OTOH, 
it also seems to me that the nema 34 motor should be a wee bit more 
efficient in terms of amps in vs oz/in out.  But I'd expect one can get 
arguments started just on that aspect alone.

An true expert I am not at this, I am a 100% self taught (and poor teacher 
at times too) retired tv broadcast engineer with only a GED, CET on the 
wall.  And a degree UHK (University of Hard Knocks) since I'm only 30 miles 
from them & had a few bucks to spare.

There are some decent tutorials on steppers available on the net, many of 
which I think start at a bit too basic a level, but they do fairly well 
cover the subject.  But I'd also expect that you've done that bit of 
homework already.

Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: 
God grant us the serenity to accept the things we cannot change, courage to
change the things we can, and wisdom to know the difference.

--
Keep Your Developer Skills Current with LearnDevNow!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-16 Thread Cathrine Hribar


Hi Gene:

Could you give me some idea of what the advantage is of using 2 and 3 stack 
steppers?  You seem to know a lot and I hope you don't mind me asking dumb 
questions.

Thanks

Bill

--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread gene heskett
On Friday, January 13, 2012 07:42:17 PM Cathrine Hribar did opine:

> On Fri, 13 Jan 2012 15:22:26 -0500
> 
>   gene heskett  wrote:
> > On Friday, January 13, 2012 03:00:21 PM Cathrine Hribar did opine:
> >> Hi Gene:
> >> 
> >> Tnx for the info on ur steppers.
> >> 
> >> I have 8 wire steppers and have wired them series.  From what you
> >> said about your steppers, and controller, you wired in parallel,
> >> true?
> >> 
> >> My controller is, like yours, 2.8 amp limit. As I think about it, if
> >> the steppers are wired in series, like I wired mine, they would
> >> require twice as much current to give the most torque, right?.
> > 
> > No Bill, wired in series, that is the current that flows through both
> > coils so you get 2x the magnetic field.
> > 
> > Wired in parallel, it would need twice the current, because it would
> > be split between the 2 coils, each getting half the set current then,
> > or 1.4 amps.  OTOH, the parallel wiring would, at a given supply
> > voltage, be able to run the motor nearly twice as fast at that same
> > supply voltage, since you would then have the full voltage across
> > each coil.  You would need a slightly bigger supply in terms of amps,
> > and a driver you could turn up to 5.6 amps in order to get the best
> > torque that speed.  On The Third Hand, its likely that the motor
> > would run under the typical load, faster when wired parallel, but a
> > little drag will stall it easier too.
> > 
> > The torque output would be lower but flatter, controlled by the
> > available current, with the fade knee starting at the applied voltage
> > vs torque intersection on the graph.
> > 
> > It is also something I haven't experimented with a lot since my Z axis
> > was made to drive a drill bit, I can put 150 lbs of push on a
> > stubborn bit wired in series at 5"/min feed rates with low (200 or
> > so) spindle rpms cutting a decent sized continuous string out of the
> > hole.
> > 
> >> I use to think I understood what I was doing, but I find with age
> >> understanding don't always increase.
> > 
> > Its painfully obvious to me at my years too Bill, it goes with the
> > number of calendars thrown out on our watches.  77 so far for me.
> > 
> > Thanks Bill.
> > 
> > Cheers, Gene
> 
> Tnx Gene for the feedback.
> 
> Well I wired the steppers series when I set up the system.  I guess I
> was hoping for more from these little motors.
> 
> Ur wright, too many calendars, I've had 69 this year and only one heart
> attack!!
> 
> thanks for the help
> 
> Bill

I haven't had any heart attacks the sawbones types have detected, but they 
do tell me that us diabetics usually roll the dice daily.  I replied that's 
damned encouraging now, isn't it?  But I have faith, I made some 
arrangements this summer to try & get the boys together for my 80th.  They 
are all in Nebraska or Kansas, so it'll be a slight logistics problem to 
get them 'all in the same sock' in another 3 years, and I signed a contract 
& wrote a check to Orkin to keep the termites cleaned out of here till at 
least 2016.

Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: 
Patriotism is the virtue of the vicious.
-- Oscar Wilde

--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread Cathrine Hribar


On Fri, 13 Jan 2012 15:22:26 -0500
  gene heskett  wrote:
> On Friday, January 13, 2012 03:00:21 PM Cathrine Hribar did opine:
> 
>> Hi Gene:
>> 
>> Tnx for the info on ur steppers.
>> 
>> I have 8 wire steppers and have wired them series.  From what you said
>> about your steppers, and controller, you wired in parallel, true?
>> 
>> My controller is, like yours, 2.8 amp limit. As I think about it, if the
>> steppers are wired in series, like I wired mine, they would require
>> twice as much current to give the most torque, right?.
> 
> No Bill, wired in series, that is the current that flows through both coils 
> so you get 2x the magnetic field.
> 
> Wired in parallel, it would need twice the current, because it would be 
> split between the 2 coils, each getting half the set current then, or 1.4 
> amps.  OTOH, the parallel wiring would, at a given supply voltage, be able 
> to run the motor nearly twice as fast at that same supply voltage, since 
> you would then have the full voltage across each coil.  You would need a 
> slightly bigger supply in terms of amps, and a driver you could turn up to 
> 5.6 amps in order to get the best torque that speed.  On The Third Hand, 
> its likely that the motor would run under the typical load, faster when 
> wired parallel, but a little drag will stall it easier too.
> 
> The torque output would be lower but flatter, controlled by the available 
> current, with the fade knee starting at the applied voltage vs torque 
> intersection on the graph.
> 
> It is also something I haven't experimented with a lot since my Z axis was 
> made to drive a drill bit, I can put 150 lbs of push on a stubborn bit 
> wired in series at 5"/min feed rates with low (200 or so) spindle rpms 
> cutting a decent sized continuous string out of the hole.
> 
>> I use to think I understood what I was doing, but I find with age
>> understanding don't always increase.
> 
> Its painfully obvious to me at my years too Bill, it goes with the number 
> of calendars thrown out on our watches.  77 so far for me.
> 
> Thanks Bill.
> 
> Cheers, Gene
> -- 


Tnx Gene for the feedback.

Well I wired the steppers series when I set up the system.  I guess I was 
hoping for more from these little motors.

Ur wright, too many calendars, I've had 69 this year and only one heart 
attack!!

thanks for the help

Bill

--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread Cathrine Hribar



On Fri, 13 Jan 2012 16:59:48 -0500
  Ed Nisley  wrote:
> On Fri, 2012-01-13 at 10:09 -0700, Cathrine Hribar wrote:
>> if the steppers are wired in series, like I wired mine, 
>> they would require twice as much current 
> 
> Having waded through this mess not too long ago, here's what I (think I)
> know...
> 
> Putting the two halves of a single pole's winding in series doubles the
> number of turns, doubles the winding resistance, and increases the
> inductance by a factor of four.
> 
> Doubling the turns doubles the magnetic flux density in the pole, which
> is easier to see with the old-school unit of Ampere-turn instead of the
> fancy-pants metric Gauss or Tesla. Because torque is proportional to
> magnetic flux, you should get twice the torque for the same current.
> 
> Unfortunately, the armature will probably saturate because you're now
> running it at twice its design flux, which will kill the torque and
> perhaps the motor, too. That's not a desirable outcome, so,
> paradoxically, a motor rated at 2.8 A per winding should run at 1.4 A
> with two windings in series.
> 
> The resistive power losses would double at the same current, but will go
> down by a factor of 2 at half that current. If the motor has enough
> magnetic headroom, you can reduce the current by 1/sqrt(2) to dissipate
> the same amount of power: 2.8 A * 0.707 = 2 A.
> 
> The increased inductance increases the overall L/R rise time by a factor
> of 4, assuming the external circuit is supplying substantial resistance
> (as in antique L/5R DC drives with hulking power resistors). With modern
> current-limiting chopper drivers, however, the rise time depends mostly
> on the winding's internal resistance, which increases by a factor of 2,
> so the net L/R increases by a factor of only 4/2 = 2.
> 
> So, with the series-wired windings connected to the same supply voltage,
> the current rise time doubles. If you were pushing the motor's upper
> speed limit, the torque will fall off because the current reaches the
> limit set by the driver much later in each microstep. In the worst case,
> it no longer reaches the limit at all.
> 
> It's enough to make your (well, my) head spin...
> 
> -- 
> Ed
> http://softsolder.com


Hi Ed:

What u wrote makes a lot of sense...  While I don't have the equpment here at 
my shop to check the torque that I used at work,  I did some expearmenting 
with the amp adj. control.  When I increased from 1.8 to 2 amps the torque 
felt liked it doubled while holding the hand wheel.
> 
> 



--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread Cathrine Hribar



On Fri, 13 Jan 2012 17:48:42 +
  andy pugh  wrote:
> On 13 January 2012 17:09, Cathrine Hribar  wrote:
> 
>> My controller is, like yours, 2.8 amp limit. As I think about it, if the
>> steppers are wired in series, like I wired mine, they would require twice as
>> much current to give the most torque, right?.
> 
> No. In series you get twice the current through each winding as you do
> in parallel for the same total current.
> You also get twice the back-EMF, so less speed, but more torque.
> 
> -- 
> atp
> The idea that there is no such thing as objective truth is, quite simply, 
>wrong.
>


Thanks Andy for the info!!!

Bill

  
> --
> RSA(R) Conference 2012
> Mar 27 - Feb 2
> Save $400 by Jan. 27
> Register now!
> http://p.sf.net/sfu/rsa-sfdev2dev2
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread Ed Nisley
On Fri, 2012-01-13 at 10:09 -0700, Cathrine Hribar wrote:
> if the steppers are wired in series, like I wired mine, 
> they would require twice as much current 

Having waded through this mess not too long ago, here's what I (think I)
know...

Putting the two halves of a single pole's winding in series doubles the
number of turns, doubles the winding resistance, and increases the
inductance by a factor of four.

Doubling the turns doubles the magnetic flux density in the pole, which
is easier to see with the old-school unit of Ampere-turn instead of the
fancy-pants metric Gauss or Tesla. Because torque is proportional to
magnetic flux, you should get twice the torque for the same current.

Unfortunately, the armature will probably saturate because you're now
running it at twice its design flux, which will kill the torque and
perhaps the motor, too. That's not a desirable outcome, so,
paradoxically, a motor rated at 2.8 A per winding should run at 1.4 A
with two windings in series.

The resistive power losses would double at the same current, but will go
down by a factor of 2 at half that current. If the motor has enough
magnetic headroom, you can reduce the current by 1/sqrt(2) to dissipate
the same amount of power: 2.8 A * 0.707 = 2 A.

The increased inductance increases the overall L/R rise time by a factor
of 4, assuming the external circuit is supplying substantial resistance
(as in antique L/5R DC drives with hulking power resistors). With modern
current-limiting chopper drivers, however, the rise time depends mostly
on the winding's internal resistance, which increases by a factor of 2,
so the net L/R increases by a factor of only 4/2 = 2.

So, with the series-wired windings connected to the same supply voltage,
the current rise time doubles. If you were pushing the motor's upper
speed limit, the torque will fall off because the current reaches the
limit set by the driver much later in each microstep. In the worst case,
it no longer reaches the limit at all.

It's enough to make your (well, my) head spin...

-- 
Ed
http://softsolder.com



--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread gene heskett
On Friday, January 13, 2012 03:00:21 PM Cathrine Hribar did opine:

> Hi Gene:
> 
> Tnx for the info on ur steppers.
> 
> I have 8 wire steppers and have wired them series.  From what you said
> about your steppers, and controller, you wired in parallel, true?
> 
> My controller is, like yours, 2.8 amp limit. As I think about it, if the
> steppers are wired in series, like I wired mine, they would require
> twice as much current to give the most torque, right?.

No Bill, wired in series, that is the current that flows through both coils 
so you get 2x the magnetic field.

Wired in parallel, it would need twice the current, because it would be 
split between the 2 coils, each getting half the set current then, or 1.4 
amps.  OTOH, the parallel wiring would, at a given supply voltage, be able 
to run the motor nearly twice as fast at that same supply voltage, since 
you would then have the full voltage across each coil.  You would need a 
slightly bigger supply in terms of amps, and a driver you could turn up to 
5.6 amps in order to get the best torque that speed.  On The Third Hand, 
its likely that the motor would run under the typical load, faster when 
wired parallel, but a little drag will stall it easier too.

The torque output would be lower but flatter, controlled by the available 
current, with the fade knee starting at the applied voltage vs torque 
intersection on the graph.

It is also something I haven't experimented with a lot since my Z axis was 
made to drive a drill bit, I can put 150 lbs of push on a stubborn bit 
wired in series at 5"/min feed rates with low (200 or so) spindle rpms 
cutting a decent sized continuous string out of the hole.

> I use to think I understood what I was doing, but I find with age
> understanding don't always increase.

Its painfully obvious to me at my years too Bill, it goes with the number 
of calendars thrown out on our watches.  77 so far for me.
 
Thanks Bill.

Cheers, Gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
My web page: 
Give a man a fish, and you feed him for a day.  Teach a man to fish,
and he'll invite himself over for dinner.
-- Calvin Keegan

--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread andy pugh
On 13 January 2012 17:09, Cathrine Hribar  wrote:

> My controller is, like yours, 2.8 amp limit. As I think about it, if the
> steppers are wired in series, like I wired mine, they would require twice as
> much current to give the most torque, right?.

No. In series you get twice the current through each winding as you do
in parallel for the same total current.
You also get twice the back-EMF, so less speed, but more torque.

-- 
atp
The idea that there is no such thing as objective truth is, quite simply, wrong.

--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers

2012-01-13 Thread Cathrine Hribar



Hi Gene:

Tnx for the info on ur steppers.

I have 8 wire steppers and have wired them series.  From what you said about 
your steppers, and controller, you wired in parallel, true?

My controller is, like yours, 2.8 amp limit. As I think about it, if the 
steppers are wired in series, like I wired mine, they would require twice as 
much current to give the most torque, right?.

I use to think I understood what I was doing, but I find with age 
understanding don't always increase.

Thanks

Bill

--
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers/encoders

2011-02-18 Thread Jon Elson
Bill Hribar wrote:
> Hi all:
>
> Is it possible for EMC2 to be setup to use info from encoders to stop 
> movement 
> of a cnc machine when the EMC2 system is driving steppers?
>
> I have read the wiki; Steppers with encoders - jlmjvm's story, the author 
> said 
> he is able to do just that!
>
> I noted that he said he would post his .hal and .ini files, but I have not 
> been 
> able to find where he has posted them or his e-mail address.
>   
It is most certainly possible.  My Universal Stepper Controller provides 
a capability to do that.
It was more aimed at step/servos like the Gecko 320, but can definitely 
be used to monitor stepper
position and cause a following error when there is a loss of position.  
Normally, the USC board
counts step pulses going out, and reports that back to EMC.  By flipping 
a switch on the board,
each axis can be selected to read an encoder for actual position 
instead.  This will not allow you
to recover from a stall, but will alert EMC that a stall has occurred.  
It will allow EMC to correct
occasional single step errors due to timing problems when reversing 
direction and such things.

See http://pico-systems.com/codes/univstep/ for a set of configs files 
using the USC board.
The only change in the configs files would be to set the correct value 
of the SCALE parameter
for the encoder you are using.


Jon

--
The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
Pinpoint memory and threading errors before they happen.
Find and fix more than 250 security defects in the development cycle.
Locate bottlenecks in serial and parallel code that limit performance.
http://p.sf.net/sfu/intel-dev2devfeb
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] steppers/encoders

2011-02-18 Thread Bill Hribar
Hi all:

Is it possible for EMC2 to be setup to use info from encoders to stop movement 
of a cnc machine when the EMC2 system is driving steppers?

I have read the wiki; Steppers with encoders - jlmjvm's story, the author said 
he is able to do just that!

I noted that he said he would post his .hal and .ini files, but I have not been 
able to find where he has posted them or his e-mail address.

Does anyone know where these files are posted and if in fact what he said is 
possible?

Thanks

Bill


  
--
The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
Pinpoint memory and threading errors before they happen.
Find and fix more than 250 security defects in the development cycle.
Locate bottlenecks in serial and parallel code that limit performance.
http://p.sf.net/sfu/intel-dev2devfeb
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers as encoders (was Re: Do I understand the EMC/HAL/UI architecture properly)

2010-08-30 Thread Gene Heskett
On Monday, August 30, 2010 09:50:36 am Kent A. Reed did opine:

>   On 8/30/2010, Gene wrote
> 
> >> >  Guys, would you recommend some inexpensive encoder type hand
> >> >  controls? I would like to control "speed override" with a rugged
> >> >  encoder type rotary control.
> > 
> > A thought that I have played with in my mind, and gone as far as to
> > order a few parts, is to use a more or less std small stepper motor
> > with 12 or 24 volt rated coils, as an encoder by feeding it to a pair
> > of comparators which should give a quadrature A&  B output.  I
> > haven't worked out a 100% reliable method of protecting the
> > comparator inputs from the over-voltage a fast spin of the knob on
> > the motor shaft would feed them, nor have I worked out the most
> > reliable hysteresis feedback to prevent low level vibrations and such
> > from outputting spurious signals.  But, based on the fact that the
> > average $3 stepper motor is also a heck of a good generator, I see no
> > reason why it couldn't be done.
> 
> Gene:
> 
> I had what seemed a brilliant "aha" several years ago while idly
> spinning a stepper motor in my hands and feeling the detent-like
> resistance. Gee, it could almost be an electromagnetic encoder, I
> thought. My sense of discovery dimmed when I went Googling and
> discovered that only about a gazillion others had got there before me
> :-(

I know that feeling well.

> Still, the advantage of being a johnny-come-lately is that I could
> profit from the experiences of others. I particularly liked the notion I
> came across of biasing a motor winding to improve the signal-to-noise
> ratio. I doubt I would have come up with that by myself.
> 
> See, for example,
> http://www.piclist.com/techref/io/sensor/pos/enc/stepper_as_encoder.htm

That is ingenius. My thoughts were more along the lines of the schmidt 
trigger's deadband, but this would obviously work at reasonable rotation 
speeds too.   Basically, anything to get away from the noise at rest by 
biasing the comparator one way or the other would suffice to kill the thermal 
noise. Its the creeping along, one bump at a time where I believe the 
schmidt trigger may be the better solution.  Or maybe its the NIH syndrome?

The motors I have output several hundred millivolts at one bump at a time 
speeds.

> Regards,
> Kent
> 
> PS - I got bogged down in family health crises and never got around to
> testing the approach and posting the results, at least not yet. Maybe
> someday.
> 
> 
> -- Sell apps to millions through the Intel(R) Atom(Tm) Developer
> Program Be part of this innovative community and reach millions of
> netbook users worldwide. Take advantage of special opportunities to
> increase revenue and speed time-to-market. Join now, and jumpstart your
> future.
> http://p.sf.net/sfu/intel-atom-d2d
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Once is happenstance,
Twice is coincidence,
Three times is enemy action.
-- Auric Goldfinger

--
Sell apps to millions through the Intel(R) Atom(Tm) Developer Program
Be part of this innovative community and reach millions of netbook users 
worldwide. Take advantage of special opportunities to increase revenue and 
speed time-to-market. Join now, and jumpstart your future.
http://p.sf.net/sfu/intel-atom-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


[Emc-users] Steppers as encoders (was Re: Do I understand the EMC/HAL/UI architecture properly)

2010-08-30 Thread Kent A. Reed
  On 8/30/2010, Gene wrote
>> >  Guys, would you recommend some inexpensive encoder type hand controls?
>> >  I would like to control "speed override" with a rugged encoder type
>> >  rotary control.
>> >  
> A thought that I have played with in my mind, and gone as far as to order a
> few parts, is to use a more or less std small stepper motor with 12 or 24
> volt rated coils, as an encoder by feeding it to a pair of comparators
> which should give a quadrature A&  B output.  I haven't worked out a 100%
> reliable method of protecting the comparator inputs from the over-voltage a
> fast spin of the knob on the motor shaft would feed them, nor have I worked
> out the most reliable hysteresis feedback to prevent low level vibrations
> and such from outputting spurious signals.  But, based on the fact that the
> average $3 stepper motor is also a heck of a good generator, I see no
> reason why it couldn't be done.
Gene:

I had what seemed a brilliant "aha" several years ago while idly 
spinning a stepper motor in my hands and feeling the detent-like 
resistance. Gee, it could almost be an electromagnetic encoder, I 
thought. My sense of discovery dimmed when I went Googling and 
discovered that only about a gazillion others had got there before me :-(

Still, the advantage of being a johnny-come-lately is that I could 
profit from the experiences of others. I particularly liked the notion I 
came across of biasing a motor winding to improve the signal-to-noise 
ratio. I doubt I would have come up with that by myself.

See, for example, 
http://www.piclist.com/techref/io/sensor/pos/enc/stepper_as_encoder.htm

Regards,
Kent

PS - I got bogged down in family health crises and never got around to 
testing the approach and posting the results, at least not yet. Maybe 
someday.

--
Sell apps to millions through the Intel(R) Atom(Tm) Developer Program
Be part of this innovative community and reach millions of netbook users 
worldwide. Take advantage of special opportunities to increase revenue and 
speed time-to-market. Join now, and jumpstart your future.
http://p.sf.net/sfu/intel-atom-d2d
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers

2009-10-16 Thread Kirk Wallace
On Fri, 2009-10-16 at 16:03 +0100, Ian W. Wright wrote:
> Hi,
> 
> I fixed the problem - I hadn't realised that the L297/L298 
> board had a current adjustment on it - don! It must have 
> been just below a critical value as this morning neither 
> motor would run on that driver and it only took a little 
> tweak to get it to drive the motors at full power. It does 
> have the unfortunate problem of making the motor 'sing' 
> quite loudly when its at rest but I guess I'll have to live 
> with that until I can change the driver for something a bit 
> better.
> 
> Ian

Singing might be normal. My mill stepper motors sing at rest too. My
stepper drivers have a PWM output (for current limiting) at an audio
frequency. Even though they are not rotating, the motors are being
driven just as hard as when moving. Some drivers will go into a
"holding" mode, where the power is reduced after a period of inactivity.
-- 
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA


--
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers

2009-10-16 Thread Ian W. Wright
Hi,

I fixed the problem - I hadn't realised that the L297/L298 
board had a current adjustment on it - don! It must have 
been just below a critical value as this morning neither 
motor would run on that driver and it only took a little 
tweak to get it to drive the motors at full power. It does 
have the unfortunate problem of making the motor 'sing' 
quite loudly when its at rest but I guess I'll have to live 
with that until I can change the driver for something a bit 
better.

Ian

--
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers

2009-10-15 Thread John Harris
Hi,
From your description 'the spindle rotated feebly but the slightest 
touch on the spindle stopped it and it just sat there quivering  and buzzing 
gently'. This is the exactly the effect you get with a bi-phase stepmotor if 
one wire is not connect to the driver. Check your connections carefully. 
Measure coil resistance from the driver side of the driver to motor 
connector.

Regards

John Harris Ex-Brit

- Original Message - 
From: "Ian W. Wright" 
To: 
Sent: Thursday, October 15, 2009 3:02 PM
Subject: [Emc-users] Steppers


> Hi,
>
> I am totally perplexed! I have two apparently very similar
> stepper motors - i.e. made by the same company ( Oriental
> Stepper), both 32 size and single stack although one is
> about 1/4in longer than the other. Lets call them X and Y to
> avoid confusion. I also have two driver boards - not
> identical as I blew one up recently :_{ - one is a
> commercial microstepping board, set to abut 1.5A capacity
> and the other is a L297/L298 board - both are set to half
> stepping. Lets call these A and B. I had them connected up
> on a little machine with motor X driven by board A and Motor
> Y by board B and everything ran fine. I decided that I
> wanted to swap the axes over and so I unplugged motor X from
> board A and plugged it into board B and vice versa for motor
> Y. Now motor Y connected to the L297/l298 board had no power
> at all - the spindle rotated feebly but the slightest touch
> on the spindle stopped it and it just sat there quivering
> and buzzing gently. Motor X was quite happy and running at
> full power. I changed them back again and once again both
> motors ran at full power  I did the changing over
> several times to verify that it wasn't due to a bad
> connection or something and I double checked that both
> motors were wired in exactly the same way - also that the
> EMC2 settings in the .INI file were the same for each axis.
>
> I can't find any data on the motors  as they are obsolete,
> so I can't tell if there are any differences in the windings
> but both sets of coils ( they are 8 wire motors wired as 2
> series pairs of coils and the pair colours correspond on
> both motors) seem to be wired the same and have the same
> resistance on both motors.
>
> Does anyone have any words of wisdom to explain this
> phenomenon? It has me completely baffled
>
> Thanks,  Ian
>
> --
> Come build with us! The BlackBerry(R) Developer Conference in SF, CA
> is the only developer event you need to attend this year. Jumpstart your
> developing skills, take BlackBerry mobile applications to market and stay
> ahead of the curve. Join us from November 9 - 12, 2009. Register now!
> http://p.sf.net/sfu/devconference
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
> 


--
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers

2009-10-15 Thread Dave Caroline
On Thu, Oct 15, 2009 at 10:02 PM, Ian W. Wright  wrote:
> Hi,
>
> I am totally perplexed! I have two apparently very similar
> stepper motors - i.e. made by the same company ( Oriental
> Stepper), both 32 size and single stack although one is
> about 1/4in longer than the other. Lets call them X and Y to
> avoid confusion. I also have two driver boards - not
> identical as I blew one up recently :_{ - one is a
> commercial microstepping board, set to abut 1.5A capacity
> and the other is a L297/L298 board - both are set to half
> stepping. Lets call these A and B.

you didnt state current for driver B

 I had them connected up
> on a little machine with motor X driven by board A and Motor
> Y by board B and everything ran fine. I decided that I
> wanted to swap the axes over and so I unplugged motor X from
> board A and plugged it into board B and vice versa for motor
> Y. Now motor Y connected to the L297/l298 board had no power
> at all - the spindle rotated feebly but the slightest touch
> on the spindle stopped it and it just sat there quivering
> and buzzing gently. Motor X was quite happy and running at
> full power. I changed them back again and once again both
> motors ran at full power  I did the changing over
> several times to verify that it wasn't due to a bad
> connection or something and I double checked that both
> motors were wired in exactly the same way - also that the
> EMC2 settings in the .INI file were the same for each axis.
>
> I can't find any data on the motors  as they are obsolete,
> so I can't tell if there are any differences in the windings
> but both sets of coils ( they are 8 wire motors wired as 2
> series pairs of coils and the pair colours correspond on
> both motors) seem to be wired the same and have the same
> resistance on both motors.

but what resistance

>
> Does anyone have any words of wisdom to explain this
> phenomenon? It has me completely baffled


also the inductance of the coils will effect the amount of current the
drivers can supply

Dave Caroline

by the way Midland Model Enginerr ex TOMORROW some of us brits meeting
near the Arc Eurotrade cnc stand around 11:30

--
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


[Emc-users] Steppers

2009-10-15 Thread Ian W. Wright
Hi,

I am totally perplexed! I have two apparently very similar 
stepper motors - i.e. made by the same company ( Oriental 
Stepper), both 32 size and single stack although one is 
about 1/4in longer than the other. Lets call them X and Y to 
avoid confusion. I also have two driver boards - not 
identical as I blew one up recently :_{ - one is a 
commercial microstepping board, set to abut 1.5A capacity 
and the other is a L297/L298 board - both are set to half 
stepping. Lets call these A and B. I had them connected up 
on a little machine with motor X driven by board A and Motor 
Y by board B and everything ran fine. I decided that I 
wanted to swap the axes over and so I unplugged motor X from 
board A and plugged it into board B and vice versa for motor 
Y. Now motor Y connected to the L297/l298 board had no power 
at all - the spindle rotated feebly but the slightest touch 
on the spindle stopped it and it just sat there quivering 
and buzzing gently. Motor X was quite happy and running at 
full power. I changed them back again and once again both 
motors ran at full power  I did the changing over 
several times to verify that it wasn't due to a bad 
connection or something and I double checked that both 
motors were wired in exactly the same way - also that the 
EMC2 settings in the .INI file were the same for each axis.

I can't find any data on the motors  as they are obsolete, 
so I can't tell if there are any differences in the windings 
but both sets of coils ( they are 8 wire motors wired as 2 
series pairs of coils and the pair colours correspond on 
both motors) seem to be wired the same and have the same 
resistance on both motors.

Does anyone have any words of wisdom to explain this 
phenomenon? It has me completely baffled

Thanks,  Ian

--
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay 
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-06 Thread Peter C. Wallace
On Tue, 6 Jan 2009, Jon Elson wrote:

> Date: Tue, 06 Jan 2009 21:30:20 -0600
> From: Jon Elson 
> Reply-To: "Enhanced Machine Controller (EMC)"
> 
> To: "Enhanced Machine Controller (EMC)" 
> Subject: Re: [Emc-users] Steppers with Encoders
> 
> Stuart Stevenson wrote:
>> Gentlemen,
>>My suggestion was to use a stepper of a type built like an
>> alternator. If that concept would be useful. Just throwing out ideas.
>> It may not be feasible but who knows? Definitely not me. :)
>>
> Even an 8-pole alternator would only have 32 full steps/rev.  Since it
> wasn't designed as a stepper, who knows if it would even give properly
> spaced full steps, or what would happen if you tried to microstep it.
> One could try it and see.  Of course, it is a 3-phase motor, so it would
> not work with any standard step motor driver.

48 steps maybe?

>
> On the other hand, using it as a brushless servo motor (except for the
> field brushes, of course) has some promise.  The encoder would at least
> try to solve any problems with position error.  One would have to add
> Hal sensors or use an encoder with commutation tracks.
>
> Jon
>
You can get away without Hall or commutation tracks if you have a relatively 
high resolution encoder. This just requires rotor-encoder alignment at startup

One thing I would worry about a little is that the field winding is on the 
armature, generating heat thats hard to dissipate when the rotor is static.
I guess you could reduce the field current when idle but that complicates
the drive circuitry



> --
> Check out the new SourceForge.net Marketplace.
> It is the best place to buy or sell services for
> just about anything Open Source.
> http://p.sf.net/sfu/Xq1LFB
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

Peter Wallace
Mesa Electronics

(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.


--
Check out the new SourceForge.net Marketplace.
It is the best place to buy or sell services for
just about anything Open Source.
http://p.sf.net/sfu/Xq1LFB
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-06 Thread Andre B.
The biggest problem with stepper motors is they are designed to have 
a given DC resistance so that some DC voltage can be applied without 
the current going it infinity when the motor is stopped.  That 
resistance is why they get hot.

Unlike that stepper motor every good high performance AC or DC motor 
is designed so as to get that DC resistance as close to zero as possible.

So say you are trying to drag a weight around on the floor while at 
all times controlling its position and velocity.
A stepper motor is like pulling on that weight with bungee cords, it 
will always be in the wrong place and/or moving in the wrong direction.
The servo is more like a steel bar.

While steppers have their place, but if you want precision motion 
control of a machine with unknown and variable factors (part mass and 
cutting forces) they are not the best choice.  And from what I have 
seen by the time you add all the extra stuff to make up for their 
defects you would have been much farther ahead to have just went with 
servos in the first place.

__
Andre' B.


--
Check out the new SourceForge.net Marketplace.
It is the best place to buy or sell services for
just about anything Open Source.
http://p.sf.net/sfu/Xq1LFB
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-06 Thread Jon Elson
Stuart Stevenson wrote:
> Gentlemen,
>My suggestion was to use a stepper of a type built like an
> alternator. If that concept would be useful. Just throwing out ideas.
> It may not be feasible but who knows? Definitely not me. :)
>   
Even an 8-pole alternator would only have 32 full steps/rev.  Since it 
wasn't designed as a stepper, who knows if it would even give properly 
spaced full steps, or what would happen if you tried to microstep it.  
One could try it and see.  Of course, it is a 3-phase motor, so it would 
not work with any standard step motor driver.

On the other hand, using it as a brushless servo motor (except for the 
field brushes, of course) has some promise.  The encoder would at least 
try to solve any problems with position error.  One would have to add 
Hal sensors or use an encoder with commutation tracks.

Jon

--
Check out the new SourceForge.net Marketplace.
It is the best place to buy or sell services for
just about anything Open Source.
http://p.sf.net/sfu/Xq1LFB
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-06 Thread Stuart Stevenson
Gentlemen,
   My suggestion was to use a stepper of a type built like an
alternator. If that concept would be useful. Just throwing out ideas.
It may not be feasible but who knows? Definitely not me. :)
thanks
Stuart

On Tue, Jan 6, 2009 at 11:23 AM, Jon Elson  wrote:
> Stuart Stevenson wrote:
>> Gentlemen,
>>I have seen (youtube) the conversion of an automotive alternator to
>> a stepper motor. The fields are pulsed and no motion occurs until the
>> rotor has dc voltage applied. Would it be possible to use this type of
>> stepper to overcome some of the speed and torque limitations of a PM
>> stepper?
> The problem/advantage of the alternator is it has much lower pole
> count.  I suspect the pole count is WAY too low for it to be much use as
> a step motor.  I think most of them are around 4-8 poles.  What you can
> do with them is use them as brushless motors.  Whether the torque ripple
> and velocity ripple makes them useful as a servo motor can be debated.
> My guess is the ripple is pretty bad, but a tight control loop could
> make them work.  I know some people have done it.
>>  Could you reduce the voltage at faster speeds and get better
>> performance. Maybe you could size it so more voltage to the rotor
>> could give more torque during the cut?
>> Just thoughts of someone who knows NOTHING about stepper motors. :)
>>
> The step driver is basically a current source, and everything it does to
> the motor is based on current, not voltage.
> You need enough supply voltage to overcome the motors generated voltage
> (back EMF) at any particular speed.
>
> Jon
>
> --
> Check out the new SourceForge.net Marketplace.
> It is the best place to buy or sell services for
> just about anything Open Source.
> http://p.sf.net/sfu/Xq1LFB
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
>

--
Check out the new SourceForge.net Marketplace.
It is the best place to buy or sell services for
just about anything Open Source.
http://p.sf.net/sfu/Xq1LFB
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-06 Thread Jon Elson
Stuart Stevenson wrote:
> Gentlemen,
>I have seen (youtube) the conversion of an automotive alternator to
> a stepper motor. The fields are pulsed and no motion occurs until the
> rotor has dc voltage applied. Would it be possible to use this type of
> stepper to overcome some of the speed and torque limitations of a PM
> stepper?
The problem/advantage of the alternator is it has much lower pole 
count.  I suspect the pole count is WAY too low for it to be much use as 
a step motor.  I think most of them are around 4-8 poles.  What you can 
do with them is use them as brushless motors.  Whether the torque ripple 
and velocity ripple makes them useful as a servo motor can be debated.  
My guess is the ripple is pretty bad, but a tight control loop could 
make them work.  I know some people have done it.
>  Could you reduce the voltage at faster speeds and get better
> performance. Maybe you could size it so more voltage to the rotor
> could give more torque during the cut?
> Just thoughts of someone who knows NOTHING about stepper motors. :)
>   
The step driver is basically a current source, and everything it does to 
the motor is based on current, not voltage.
You need enough supply voltage to overcome the motors generated voltage 
(back EMF) at any particular speed.

Jon

--
Check out the new SourceForge.net Marketplace.
It is the best place to buy or sell services for
just about anything Open Source.
http://p.sf.net/sfu/Xq1LFB
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-05 Thread Dave Engvall

On Jan 5, 2009, at 7:51 PM, Stephen Wille Padnos wrote:

> Dave Engvall wrote:
>
>> [snip]
>>
>> If my memory serves me correctly then there might be an intermediate
>> position.
>> I think code exist by JMK to use an rotary encoder plus a linear  
>> scale.
>>
>>
> Yes, we did this on Stuart's G&L servo machine.
>
>> Could this be extended to separate the I from PD in steppers and use
>> an encoder on I to drive final position.
>>
>>
> Since steppers don't use PID, and would fail miserably if they did
> (since PID generally increases requested effort when the motor  
> starts to
> lose position, which (a) is too late and (b) is the exact opposite of
> what you want to do with a stepper), I don't think this would help  
> much.

OK, no PID ... no workee.

D
>
>> Maybe I've been smoking the wrong stuff  who knows.
>> More caffeine certainly won't fix things. :-)
>>
>>
> You never know :)
>
> - Steve
>
>
> -- 
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


--
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-05 Thread Steve Stallings
The rotor current controls the strength of the magnetic
field of the rotor. This will vary the torque, but maximum
torque is still determined by magnetic saturation and by
the amount of current in the field. The rate of change of
the field current  and thus the torque at speed is
limited by the inductance of the field winding. This is 
what limits the torque at speed of stepper motors and
varying the rotor current will not correct this limitation. 

It is a cruel world. Torque is related to amperes of
coil current times the number of turns, while inductance
is also related to the number of turns and fights the
rate of change in the current that is needed to generate
the torque at speed.

don't shoot the messenger...
Steve Stallings

> -Original Message-
> From: Stuart Stevenson [mailto:stus...@gmail.com] 
> Sent: Monday, January 05, 2009 10:06 PM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Steppers with Encoders
> 
> Gentlemen,
>I have seen (youtube) the conversion of an automotive 
> alternator to a stepper motor. The fields are pulsed and no 
> motion occurs until the rotor has dc voltage applied. Would 
> it be possible to use this type of stepper to overcome some 
> of the speed and torque limitations of a PM stepper? Could 
> you reduce the voltage at faster speeds and get better 
> performance. Maybe you could size it so more voltage to the 
> rotor could give more torque during the cut?
> Just thoughts of someone who knows NOTHING about stepper 
> motors. :) Just more smoke.
> thanks
> Stuart
> 
> On Mon, Jan 5, 2009 at 8:24 PM, Greg Bentzinger 
>  wrote:
> > and a voice spoke out from the one lurking in the shadows.
> >
> > I may be just blowing smoke here - but there might be a functional 
> > compromise.
> >
> > I honestly have not been under the hood of EMC (interp or trajectory
> > planner) so I don't know if what I'm proposing is even 
> possible with 
> > the existing code structure.
> >
> > A steppers weakest point is at its peak velocity, or maybe 
> depending 
> > on the accell settings the beginning of decell/breaking 
> from peak vel. 
> > So basically Rapid G00 moves are the Achilles heal.
> >
> > I am not proposing using an encoder for coordinated 
> movement feedback 
> > like a servo would require, that would still be handled by counting 
> > the stepgen output. What I propose would be having an aux input for 
> > the encoders and a separate DRO display on the GUI like 
> XA/YA/ZA. With 
> > the proper ini file setting an "in position check" could be 
> done (with 
> > a acceptable tolerance factor) after each G00 or fixed 
> cycle position 
> > move. If an out of tolerance position is detected an alarm 
> could occur 
> > (the easy way) or a correction move could be applied (much more 
> > difficult). Normally if a G00 is issued the tool is free of 
> the work 
> > so applying a correction should be as safe, if the tool failed to 
> > clear the work, then the damage was all ready done.
> >
> > I'm guessing this would be very resource intensive. So a 
> alternative 
> > might be to use a non-modal user defined M or G code to 
> compare and/or 
> > reset position. This option would be handy for people using 
> Step/dir 
> > servo drives where they are unable to adjust the in-drive following 
> > error such as Gecko 320/340 drives. Geckos allow 128 count error 
> > before tripping a servo fault.
> >
> > This won't help a machine fighting mid-band resonance, or one 
> > overloaded in a cut. That is a hardware/software issue where the 
> > builder needs to know the weakness and limits of the 
> machine. However 
> > these comparisons if logged could help the builder tweak 
> accel & max 
> > vel settings to an acceptable range that will run error 
> free 95+% of 
> > the time.
> >
> > I could see how a machine which ran great all summer start losing 
> > steps in a cold garage in January, Vactra #2 (Way oil) can get like 
> > honey due to age and very cold temps.
> >
> > Greg Bentzinger
> >
> > 
> --
> >  ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> >
> 
> --
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
> 


--
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-05 Thread Stephen Wille Padnos
Dave Engvall wrote:

>[snip]
>
>If my memory serves me correctly then there might be an intermediate  
>position.
>I think code exist by JMK to use an rotary encoder plus a linear scale.
>  
>
Yes, we did this on Stuart's G&L servo machine.

>Could this be extended to separate the I from PD in steppers and use  
>an encoder on I to drive final position.
>  
>
Since steppers don't use PID, and would fail miserably if they did 
(since PID generally increases requested effort when the motor starts to 
lose position, which (a) is too late and (b) is the exact opposite of 
what you want to do with a stepper), I don't think this would help much.

>Maybe I've been smoking the wrong stuff  who knows.
>More caffeine certainly won't fix things. :-)
>  
>
You never know :)

- Steve


--
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-05 Thread Dave Engvall

On Jan 5, 2009, at 7:12 PM, Stephen Wille Padnos wrote:

> Greg Bentzinger wrote:
>
>> [snip]
>> I am not proposing using an encoder for coordinated movement feedback
>> like a servo would require, that would still be handled by  
>> counting the
>> stepgen output. What I propose would be having an aux input for the
>> encoders and a separate DRO display on the GUI like XA/YA/ZA. With  
>> the
>> proper ini file setting an "in position check" could be done (with a
>> acceptable tolerance factor) after each G00 or fixed cycle position
>> move. If an out of tolerance position is detected an alarm could  
>> occur
>> (the easy way) or a correction move could be applied (much more
>> difficult). Normally if a G00 is issued the tool is free of the  
>> work so
>> applying a correction should be as safe, if the tool failed to clear
>> the work, then the damage was all ready done.
>>
>>
> EMC2 already supports using an ecoder for feedback, and will stop if a
> following error is detected.  This happens during moves and while
> stopped.  It is trivial to connect an encoder to appropriate hardware
> (parallel port and software counting for low pulse rates, more  
> advanced
> devices for high step rates).  The motion controller already compares
> actual position to expected position, so if you connect an encoder,  
> this
> will work with steppers.  The only difference between stepper systems
> and servo systems is that with stepper systems, the feedback is  
> usually
> synthesized by the step generator - the motion controller basically  
> sees
> how many steps were output instead of where the motor actually is.  To
> use real feedback, just use the encoder input to the motion controller
> feedback input instead of the faked feedback from the step generator.
>
>> I'm guessing this would be very resource intensive. So a alternative
>> might be to use a non-modal user defined M or G code to compare  
>> and/or
>> reset position. This option would be handy for people using Step/dir
>> servo drives where they are unable to adjust the in-drive following
>> error such as Gecko 320/340 drives. Geckos allow 128 count error  
>> before
>> tripping a servo fault.
>>
>>
> It's not so resource intensive, it's already done ;)
> I think all you need to do to reset the commanded/expected  
> positions is
> to hit F2/F2 - machine off, machine on.  When the machine is in the  
> off
> state, command position is set to feedback position continuously,  
> so you
> can do things like jog and not get a following error as soon as you go
> back to machine on.  To match a gecko, you'd want to set the EMC2
> following error tolerance a little less than the gecko I think (so  
> EMC2
> will detect a problem before the drive faults and has to be reset).
>
>> This won't help a machine fighting mid-band resonance, or one
>> overloaded in a cut. That is a hardware/software issue where the
>> builder needs to know the weakness and limits of the machine. However
>> these comparisons if logged could help the builder tweak accel & max
>> vel settings to an acceptable range that will run error free 95+% of
>> the time.
>>
>>
> Right, you can't fix mechanical issues this way.  You can plot the
> difference between commanded and actual position using halscope.
>
> - Steve

If my memory serves me correctly then there might be an intermediate  
position.
I think code exist by JMK to use an rotary encoder plus a linear scale.
Could this be extended to separate the I from PD in steppers and use  
an encoder on
I to drive final position.
Maybe I've been smoking the wrong stuff  who knows.
More caffeine certainly won't fix things. :-)

Dvae
>
>
> -- 
> 
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


--
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-05 Thread Stephen Wille Padnos
Greg Bentzinger wrote:

>[snip]
>I am not proposing using an encoder for coordinated movement feedback
>like a servo would require, that would still be handled by counting the
>stepgen output. What I propose would be having an aux input for the
>encoders and a separate DRO display on the GUI like XA/YA/ZA. With the
>proper ini file setting an "in position check" could be done (with a
>acceptable tolerance factor) after each G00 or fixed cycle position
>move. If an out of tolerance position is detected an alarm could occur
>(the easy way) or a correction move could be applied (much more
>difficult). Normally if a G00 is issued the tool is free of the work so
>applying a correction should be as safe, if the tool failed to clear
>the work, then the damage was all ready done.
>  
>
EMC2 already supports using an ecoder for feedback, and will stop if a 
following error is detected.  This happens during moves and while 
stopped.  It is trivial to connect an encoder to appropriate hardware 
(parallel port and software counting for low pulse rates, more advanced 
devices for high step rates).  The motion controller already compares 
actual position to expected position, so if you connect an encoder, this 
will work with steppers.  The only difference between stepper systems 
and servo systems is that with stepper systems, the feedback is usually 
synthesized by the step generator - the motion controller basically sees 
how many steps were output instead of where the motor actually is.  To 
use real feedback, just use the encoder input to the motion controller 
feedback input instead of the faked feedback from the step generator.

>I'm guessing this would be very resource intensive. So a alternative
>might be to use a non-modal user defined M or G code to compare and/or
>reset position. This option would be handy for people using Step/dir
>servo drives where they are unable to adjust the in-drive following
>error such as Gecko 320/340 drives. Geckos allow 128 count error before
>tripping a servo fault.
>  
>
It's not so resource intensive, it's already done ;)
I think all you need to do to reset the commanded/expected positions is 
to hit F2/F2 - machine off, machine on.  When the machine is in the off 
state, command position is set to feedback position continuously, so you 
can do things like jog and not get a following error as soon as you go 
back to machine on.  To match a gecko, you'd want to set the EMC2 
following error tolerance a little less than the gecko I think (so EMC2 
will detect a problem before the drive faults and has to be reset).

>This won't help a machine fighting mid-band resonance, or one
>overloaded in a cut. That is a hardware/software issue where the
>builder needs to know the weakness and limits of the machine. However
>these comparisons if logged could help the builder tweak accel & max
>vel settings to an acceptable range that will run error free 95+% of
>the time.
>  
>
Right, you can't fix mechanical issues this way.  You can plot the 
difference between commanded and actual position using halscope.

- Steve


--
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers with Encoders

2009-01-05 Thread Stuart Stevenson
Gentlemen,
   I have seen (youtube) the conversion of an automotive alternator to
a stepper motor. The fields are pulsed and no motion occurs until the
rotor has dc voltage applied. Would it be possible to use this type of
stepper to overcome some of the speed and torque limitations of a PM
stepper? Could you reduce the voltage at faster speeds and get better
performance. Maybe you could size it so more voltage to the rotor
could give more torque during the cut?
Just thoughts of someone who knows NOTHING about stepper motors. :)
Just more smoke.
thanks
Stuart

On Mon, Jan 5, 2009 at 8:24 PM, Greg Bentzinger  wrote:
> and a voice spoke out from the one lurking in the shadows.
>
> I may be just blowing smoke here - but there might be a functional
> compromise.
>
> I honestly have not been under the hood of EMC (interp or trajectory
> planner) so I don't know if what I'm proposing is even possible with
> the existing code structure.
>
> A steppers weakest point is at its peak velocity, or maybe depending on
> the accell settings the beginning of decell/breaking from peak vel. So
> basically Rapid G00 moves are the Achilles heal.
>
> I am not proposing using an encoder for coordinated movement feedback
> like a servo would require, that would still be handled by counting the
> stepgen output. What I propose would be having an aux input for the
> encoders and a separate DRO display on the GUI like XA/YA/ZA. With the
> proper ini file setting an "in position check" could be done (with a
> acceptable tolerance factor) after each G00 or fixed cycle position
> move. If an out of tolerance position is detected an alarm could occur
> (the easy way) or a correction move could be applied (much more
> difficult). Normally if a G00 is issued the tool is free of the work so
> applying a correction should be as safe, if the tool failed to clear
> the work, then the damage was all ready done.
>
> I'm guessing this would be very resource intensive. So a alternative
> might be to use a non-modal user defined M or G code to compare and/or
> reset position. This option would be handy for people using Step/dir
> servo drives where they are unable to adjust the in-drive following
> error such as Gecko 320/340 drives. Geckos allow 128 count error before
> tripping a servo fault.
>
> This won't help a machine fighting mid-band resonance, or one
> overloaded in a cut. That is a hardware/software issue where the
> builder needs to know the weakness and limits of the machine. However
> these comparisons if logged could help the builder tweak accel & max
> vel settings to an acceptable range that will run error free 95+% of
> the time.
>
> I could see how a machine which ran great all summer start losing steps
> in a cold garage in January, Vactra #2 (Way oil) can get like honey due
> to age and very cold temps.
>
> Greg Bentzinger
>
> --
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
>

--
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


[Emc-users] Steppers with Encoders

2009-01-05 Thread Greg Bentzinger
and a voice spoke out from the one lurking in the shadows.

I may be just blowing smoke here - but there might be a functional
compromise.

I honestly have not been under the hood of EMC (interp or trajectory
planner) so I don't know if what I'm proposing is even possible with
the existing code structure.

A steppers weakest point is at its peak velocity, or maybe depending on
the accell settings the beginning of decell/breaking from peak vel. So
basically Rapid G00 moves are the Achilles heal.

I am not proposing using an encoder for coordinated movement feedback
like a servo would require, that would still be handled by counting the
stepgen output. What I propose would be having an aux input for the
encoders and a separate DRO display on the GUI like XA/YA/ZA. With the
proper ini file setting an "in position check" could be done (with a
acceptable tolerance factor) after each G00 or fixed cycle position
move. If an out of tolerance position is detected an alarm could occur
(the easy way) or a correction move could be applied (much more
difficult). Normally if a G00 is issued the tool is free of the work so
applying a correction should be as safe, if the tool failed to clear
the work, then the damage was all ready done.

I'm guessing this would be very resource intensive. So a alternative
might be to use a non-modal user defined M or G code to compare and/or
reset position. This option would be handy for people using Step/dir
servo drives where they are unable to adjust the in-drive following
error such as Gecko 320/340 drives. Geckos allow 128 count error before
tripping a servo fault.

This won't help a machine fighting mid-band resonance, or one
overloaded in a cut. That is a hardware/software issue where the
builder needs to know the weakness and limits of the machine. However
these comparisons if logged could help the builder tweak accel & max
vel settings to an acceptable range that will run error free 95+% of
the time.

I could see how a machine which ran great all summer start losing steps
in a cold garage in January, Vactra #2 (Way oil) can get like honey due
to age and very cold temps.

Greg Bentzinger

--
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-30 Thread Leslie Newell
It does depend on the drive. My mill uses 320s and my biggest gripe is 
that they don't keep track of the position with the power off. My lathe 
has Rutex drives and they do remember the position even during EStop. 
They have separate logic and motor supplies. The rutex drives also have 
a very large following error limit (actually too large in my opinion) so 
it is virtually impossible to make them fault by stopping quickly. I use 
the EStop much more on the lathe because I know I won't lose position.

Les

Jon Elson wrote:
>
> That's only true in a servo system where the encoders feed back 
> to the computer, and the encoder power is not interrupted by the 
> E-stop.  So, the simple Gecko 320 scheme doesn't qualify, for 
> instance.  If you power the Geckos off, or if they fault from a 
> sudden stop, then the position reference is lost.
>
> Jon
>   


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-30 Thread Jon Elson
Leslie Newell wrote:
> I was actually commenting as more of a stepper/servo argument. With a 
> stepper system you hesitate to hit EStop because you know you will have 
> to re-reference. With servos you know you can hit estop then quite 
> happily continue without problems.
That's only true in a servo system where the encoders feed back 
to the computer, and the encoder power is not interrupted by the 
E-stop.  So, the simple Gecko 320 scheme doesn't qualify, for 
instance.  If you power the Geckos off, or if they fault from a 
sudden stop, then the position reference is lost.

Jon

-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-30 Thread Leslie Newell
I was actually commenting as more of a stepper/servo argument. With a 
stepper system you hesitate to hit EStop because you know you will have 
to re-reference. With servos you know you can hit estop then quite 
happily continue without problems.

Les

John Thornton wrote:
> I didn't mean that when things start to go wrong not to use the e-stop. It's 
> kind of like 
> using a circuit breaker to shut off the lights at night... when the light 
> switch is near 
> by. I guess it just depends on the results of using the e-stop vs the stop 
> switch. And 
> by all means you should have your hand on the e-stop when testing things 
> out... so 
> you don't have to look at all.
>
> John
>   


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-30 Thread John Thornton
I didn't mean that when things start to go wrong not to use the e-stop. It's 
kind of like 
using a circuit breaker to shut off the lights at night... when the light 
switch is near 
by. I guess it just depends on the results of using the e-stop vs the stop 
switch. And 
by all means you should have your hand on the e-stop when testing things out... 
so 
you don't have to look at all.

John


On 29 Jul 2008 at 18:23, Leslie Newell wrote:

> IMHO, to a certain extent using the Estop as a stop is a good thing.
> It helps build in an instinct to hit Estop as soon as anything starts
> going wrong, rather than wasting a couple of seconds deciding if the
> problem is basd enough to warrant hitting Estop.
> 
> Les
> 
> John Thornton wrote:
> > Sounds like you are getting some good training to use the e-stop for
> > emergencies and not as a stop button...
> >
> > John
> >   
> 
> 
> --
> --- This SF.Net email is sponsored by the Moblin Your Move Developer's
> challenge Build the coolest Linux based applications with Moblin SDK &
> win great prizes Grand prize is a trip for two to an Open Source event
> anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> ___ Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
> 



-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-29 Thread Kirk Wallace
On Tue, 2008-07-29 at 21:03 -0400, Sergey Izvoztchikov wrote:
... snip
> After all, CNC supposed to be the way to 
> produce parts for my projects, not another project by itself.

I did let that point get away.

> Beside this all there are other learning curves in front of me -
> CNC programming, CAM systems  and CAD to CAM conversion. DIY CNC would 
> add a lot of learning to already big pile I have in front of me.
> 
> PS: Support from the group in my case was basically reassurance that
> steppers would do just fine for my needs.

Cool. Keep us informed on how things go.

-- 
Kirk Wallace (California, USA
http://www.wallacecompany.com/machine_shop/ 
Hardinge HNC/EMC CNC lathe,
Bridgeport mill conversion, doing XY now,
Zubal lathe conversion pending
Craftsman AA 109 restoration
Shizuoka ST-N/EMC CNC)


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-29 Thread Sergey Izvoztchikov
I have my reasoning and 2 main factors lead me to decision you
may not like. I'm going to go with steppers. Main reason is cost.
Second main reason is that I want to start making parts quickly,
and don't want to spend a lot of time on building CNC system itself. 
2 main obstacles beside cost for DIY CNC are lack of knowledge of 
electronics and virtually no tools and skills for producing other 
required mechanical bits. After all, CNC supposed to be the way to 
produce parts for my projects, not another project by itself.

Beside this all there are other learning curves in front of me -
CNC programming, CAM systems  and CAD to CAM conversion. DIY CNC would 
add a lot of learning to already big pile I have in front of me.

PS: Support from the group in my case was basically reassurance that
steppers would do just fine for my needs.

On Tue, 2008-07-29 at 10:52 -0700, Kirk Wallace wrote:
> On Mon, 2008-07-28 at 14:52 -0400, Sergey Izvoztchikov wrote:
> > Thanks for all replays. I definitely didn't mean to sparkle any
> > flame wars, sorry. It's reckless noob question, I probably shouldn't
> > have asked. If others still want to voice their opinions, go ahead, 
> > but I absolutely not want any flame wars over my post.
> > 
> > I guess I just needed some support to deal with my struggle. I
> > think I've got it. Thanks again to all replays.
> 
> I think the choice is so unclear (either solution can work well) that
> you might want to let fate decide. In other words, what do you have
> currently in hand that you could use to get closer to your goal? If you
> have an old printer or piece of surplus equipment with adequate motors,
> start with that. With this you should have a power supply, motor driver,
> motor, sensors, wire, etc. It shouldn't matter if the motor is a stepper
> or servo. I have a pile of surplus I dig into regularly to test ideas
> that come to mind. I think getting EMC to control bits of a surplus
> printer would be a good project that should cost nearly nothing. Follow
> the force, Luke.
> 


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-29 Thread Kirk Wallace
On Mon, 2008-07-28 at 14:52 -0400, Sergey Izvoztchikov wrote:
> Thanks for all replays. I definitely didn't mean to sparkle any
> flame wars, sorry. It's reckless noob question, I probably shouldn't
> have asked. If others still want to voice their opinions, go ahead, 
> but I absolutely not want any flame wars over my post.
> 
> I guess I just needed some support to deal with my struggle. I
> think I've got it. Thanks again to all replays.

I think the choice is so unclear (either solution can work well) that
you might want to let fate decide. In other words, what do you have
currently in hand that you could use to get closer to your goal? If you
have an old printer or piece of surplus equipment with adequate motors,
start with that. With this you should have a power supply, motor driver,
motor, sensors, wire, etc. It shouldn't matter if the motor is a stepper
or servo. I have a pile of surplus I dig into regularly to test ideas
that come to mind. I think getting EMC to control bits of a surplus
printer would be a good project that should cost nearly nothing. Follow
the force, Luke.

-- 
Kirk Wallace (California, USA
http://www.wallacecompany.com/machine_shop/ 
Hardinge HNC/EMC CNC lathe,
Bridgeport mill conversion, doing XY now,
Zubal lathe conversion pending
Craftsman AA 109 restoration
Shizuoka ST-N/EMC CNC)


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-29 Thread Leslie Newell
IMHO, to a certain extent using the Estop as a stop is a good thing. It 
helps build in an instinct to hit Estop as soon as anything starts going 
wrong, rather than wasting a couple of seconds deciding if the problem 
is basd enough to warrant hitting Estop.

Les

John Thornton wrote:
> Sounds like you are getting some good training to use the e-stop for 
> emergencies 
> and not as a stop button...
>
> John
>   


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-29 Thread John Thornton
Sounds like you are getting some good training to use the e-stop for 
emergencies 
and not as a stop button...

John

On 29 Jul 2008 at 0:13, Kirk Wallace wrote:

> On Mon, 2008-07-28 at 23:10 -0500, Jon Elson wrote:
> ... snip
> > 
> > Another thing is that axis alignment is preserved when you hit Estop
> > or crash.  That generally isn't the case with a stepper system.
> > 
> > Jon
> 
> On my stepper mill, I find that I am much less willing to press the
> e-stop for this reason. I suppose home switches with a screw index
> would solve that, but typical stepper machines don't have these.
> 
> -- 
> Kirk Wallace (California, USA
> http://www.wallacecompany.com/machine_shop/ 
> Hardinge HNC/EMC CNC lathe,
> Bridgeport mill conversion, doing XY now,
> Zubal lathe conversion pending
> Craftsman AA 109 restoration
> Shizuoka ST-N/EMC CNC)
> 
> 
> --
> --- This SF.Net email is sponsored by the Moblin Your Move Developer's
> challenge Build the coolest Linux based applications with Moblin SDK &
> win great prizes Grand prize is a trip for two to an Open Source event
> anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> ___ Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
> 



-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-29 Thread Kirk Wallace
On Mon, 2008-07-28 at 23:10 -0500, Jon Elson wrote:
... snip
> 
> Another thing is that axis alignment is preserved when you hit 
> Estop or crash.  That generally isn't the case with a stepper 
> system.
> 
> Jon

On my stepper mill, I find that I am much less willing to press the
e-stop for this reason. I suppose home switches with a screw index would
solve that, but typical stepper machines don't have these.

-- 
Kirk Wallace (California, USA
http://www.wallacecompany.com/machine_shop/ 
Hardinge HNC/EMC CNC lathe,
Bridgeport mill conversion, doing XY now,
Zubal lathe conversion pending
Craftsman AA 109 restoration
Shizuoka ST-N/EMC CNC)


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-28 Thread Jon Elson
Ron Ginger wrote:
>>I am a "servo bigot", and just don't want to do anything like 
>>machining metal while "flying blind", which is how I think of 
>>stepper systems.
>>
>>Jon
> 
> 
> I cant let this pass without a comment. As someone said earlier this is 
> 'holy war #1' in the CNC hobby.
> 
> It is a fact, not disputable, that thousands, maybe 10's of thousands, 
> of large, even Bridgeport machines use steppers. They make parts every 
> day, day after day and never loose a step.
Yup, that's why I specifically CHOSE the word "bigot", to imply 
an element of non-rationality to it.

But, losing steps is not the ONLY reason for servos.  There is 
also the speed range vs. resolution dilemma.  If you want more 
resolution, you need to gear down the stepper.  But, steppers 
are strongest at lower speeds, so gearing down cuts the high end 
speed.  I have encoder resolution of 50 uInch on my Bridgeport, 
but can go to 120 IPM if needed.  (I usually don't, as I tend to 
cause crashes.)  This would be hard to do with stepper motors.

Another thing is that axis alignment is preserved when you hit 
Estop or crash.  That generally isn't the case with a stepper 
system.

Jon

-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-28 Thread Ray Henry

M2CW  Nothing wrong with your question.  No foul in the replies.  We
need a little heat once in a while.  It tends to clarify things and you
asked for clarification.  Many other in the list are looking for the
same info.  We are really fortunate that we have as many choices as we
do.

Rayh



On Mon, 2008-07-28 at 14:52 -0400, Sergey Izvoztchikov wrote:
> Thanks for all replays. I definitely didn't mean to sparkle any
> flame wars, sorry. It's reckless noob question, I probably shouldn't
> have asked. If others still want to voice their opinions, go ahead, 
> but I absolutely not want any flame wars over my post.
> 
> I guess I just needed some support to deal with my struggle. I
> think I've got it. Thanks again to all replays.


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline Mill ?

2008-07-28 Thread Andre' Blanchard
At 11:21 AM 7/28/2008, you wrote:
>I am a "servo bigot", and just don't want to do anything like
>machining metal while "flying blind", which is how I think of
>stepper systems.
>
>Jon

Personally I would go one step farther. I want torque or velocity mode 
system and not a position mode (step/dir) motion control system.  With the 
position mode system be it a stepper or a servo with a step/dir driver the 
motion control loop is just assuming that the hardware is keeping up.  Even 
if the driver outputs a following error signal and it is connected back to 
the motion controller it is generally just a digital signal so it cannot 
know when it is getting close, it only knows after the error has been tripped.

Steppers have there place, but if you have to put a bunch of stuff 
(anti-resonance circuits, micro stepping, no motion power down etc.) into 
the controller to get one to work like a servo motor why not just use a motor.

__
Andre' B.  Clear Lake, Wi.



-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-28 Thread Sergey Izvoztchikov
Thanks for all replays. I definitely didn't mean to sparkle any
flame wars, sorry. It's reckless noob question, I probably shouldn't
have asked. If others still want to voice their opinions, go ahead, 
but I absolutely not want any flame wars over my post.

I guess I just needed some support to deal with my struggle. I
think I've got it. Thanks again to all replays.



-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline

2008-07-28 Thread Ron Ginger
> I am a "servo bigot", and just don't want to do anything like 
> machining metal while "flying blind", which is how I think of 
> stepper systems.
> 
> Jon

I cant let this pass without a comment. As someone said earlier this is 
'holy war #1' in the CNC hobby.

It is a fact, not disputable, that thousands, maybe 10's of thousands, 
of large, even Bridgeport machines use steppers. They make parts every 
day, day after day and never loose a step.

It is clear that a stepper system will always cost less- assume the 
motors could be built for the same cost- they are similar lumps of wire, 
magnetic material and bearings. Assume the drive module could be built 
for the same cost, the servos will always require an encoder and extra 
logic for it. Servos always cost more- the IMserv kit for Sherline is 
over $1000, a Xylotex kit is about $400.

A stepper motor operated within its torque rating will never loose a 
step. If you overload it by trying to go to fast, or take to big a cut 
it could loose steps. I don't do that to my machines.

Servos are sensitive to failures of the encoder and its logic. The 
result of that is often a runaway motor crashing at full speed into its 
limit. Id rather have a machine loose a step or two than crash at high 
speed.

For a Sherline size machine steppers will work just fine. Use the rest 
of the money to buy a lathe or tooling for the mill.

clearly for large machines where the table motion needs over 300-400 
watts then servos are the only choice. Below that use steppers, simplify 
the machine and save your money.

ron ginger

-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline Mill ?

2008-07-28 Thread Jon Elson
Sergey Izvoztchikov wrote:
> I'm faced with dilemma, which has no obvious answer for me at the 
> moment. I was set to buy Xylotex steppers based kit for my CNC Sherline 
> Mill. After reading more about servo based systems I'm divided, I could 
> appreciate number of advantages of servo based systems 
> 
> - no missed steps, corrections via closed loop
> - faster movement speeds, more IPS
> - positions display (DRO)
> 
> However, stepper systems are cheaper and basically ready out of the box
> compare to DIY servo based system, which would require significant 
> build and setup time. Note, I don't have funds for commercial out of the
> box servo based kit. So, DIY is preferred option.
> 
> I don't know exactly what kind of work I will do on my CNC Mill in the 
> future, so it's also hard to target setup to future work. I guess I'm 
> trying to decide is it worth the effort and money to build a "better" 
> system (servo based that is) or should I not bother for such a small 
> Mill as Sherline and go with steppers just fine ?
> 
> Any pros and cons of both type of systems are welcome, especially in 
> relation to usage on Sherline Mills/Lathes.
I wish my source of the Japan Servo servo motors still had 
stock, but they are all gone.  I sold a bunch of them for 
retrofits of Sherline and Taig machines, and have them on my 
minimill, as well.  If you can find some Pittman motors with 
encoders, those would also work.  (I got some Pittman 4443 
brushless servos that are REALLY nice, but at $200 each, I don't 
think I'll be selling these in the hobbyist market.)
You can see what turns up on eBay.  A size 16 or 23 motor with a 
4:1 belt reduction will do great.

I am a "servo bigot", and just don't want to do anything like 
machining metal while "flying blind", which is how I think of 
stepper systems.

Jon

-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline Mill ?

2008-07-28 Thread Ray Henry

Hi Sergey

I've set up both here for testing and have gotten a Sherline to rapid at
125 IPM.  The little leadscrews become a problem with whipping and
rather fast wearout.  For my money I'd set up steppers.  That will get
you into the world of CNC.  You shouldn't loose steps as long as you
keep the speeds below 80% of the speed at which you first see lost
steps.

I'm with you about wanting servos so if you've got the space look for an
older cnc machine with a dead control or retrofit one of the available
benchtop machines.

Rayh


On Mon, 2008-07-28 at 01:14 -0400, Sergey Izvoztchikov wrote:
> I'm faced with dilemma, which has no obvious answer for me at the 
> moment. I was set to buy Xylotex steppers based kit for my CNC Sherline 
> Mill. After reading more about servo based systems I'm divided, I could 
> appreciate number of advantages of servo based systems 
> 
> - no missed steps, corrections via closed loop
> - faster movement speeds, more IPS
> - positions display (DRO)
> 
> However, stepper systems are cheaper and basically ready out of the box
> compare to DIY servo based system, which would require significant 
> build and setup time. Note, I don't have funds for commercial out of the
> box servo based kit. So, DIY is preferred option.
> 
> I don't know exactly what kind of work I will do on my CNC Mill in the 
> future, so it's also hard to target setup to future work. I guess I'm 
> trying to decide is it worth the effort and money to build a "better" 
> system (servo based that is) or should I not bother for such a small 
> Mill as Sherline and go with steppers just fine ?
> 
> Any pros and cons of both type of systems are welcome, especially in 
> relation to usage on Sherline Mills/Lathes.
> 
> 
> 
> -
> This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
> Build the coolest Linux based applications with Moblin SDK & win great prizes
> Grand prize is a trip for two to an Open Source event anywhere in the world
> http://moblin-contest.org/redirect.php?banner_id=100&url=/
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline Mill ?

2008-07-28 Thread Leslie Newell
Hi Sergey,

IM Service do some nice servos that are ideally suited to  a Sherline 


They also do some nice  servo drivers though they are step/direction so 
you can't use the encoders as a DRO.

Steppers do work and can be reliable but they are slow. Basically you 
need to decide if the extra speed is worth the extra cost. I personally 
don't like steppers so I would go the servo route.

Les


Sergey Izvoztchikov wrote:
> I'm faced with dilemma, which has no obvious answer for me at the 
> moment. I was set to buy Xylotex steppers based kit for my CNC Sherline 
> Mill. After reading more about servo based systems I'm divided, I could 
> appreciate number of advantages of servo based systems 
>
> - no missed steps, corrections via closed loop
> - faster movement speeds, more IPS
> - positions display (DRO)
>
> However, stepper systems are cheaper and basically ready out of the box
> compare to DIY servo based system, which would require significant 
> build and setup time. Note, I don't have funds for commercial out of the
> box servo based kit. So, DIY is preferred option.
>
> I don't know exactly what kind of work I will do on my CNC Mill in the 
> future, so it's also hard to target setup to future work. I guess I'm 
> trying to decide is it worth the effort and money to build a "better" 
> system (servo based that is) or should I not bother for such a small 
> Mill as Sherline and go with steppers just fine ?
>
> Any pros and cons of both type of systems are welcome, especially in 
> relation to usage on Sherline Mills/Lathes.
>   


-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers vs Servo based CNC kit for Sherline Mill ?

2008-07-27 Thread Terry
You have asked the age old question servo vs stepper
I wont tell you what to spend your money on I will just tell
you what I have learned.
I own 3 servo machines and one stepper.
The servos are faster, period.
As far as setting them up there are people here
who know how and are willing to help.
The other things you mentioned are relative.
I have made thousands and thousands of parts
on my Bridgeport stepper and only missed steps when I had a crash.
Pepole will tell you that you cant trust the microsteps
between the full steps.All I know is that mine dont miss
steps.
As far as the speed goes how much time will 50 ipm more
rapid save on a machine that has 12 in or so total travel?
Unless you are planning on going into some kind of production
with your Sherline I dont think servos will do you any good.
Some encoders on your motors for manual work is nice though
but you could add them to the steppers.
Im sure this didnt help with your choice Its really about the cost.

Terry


On Mon Jul 28  1:14 , Sergey Izvoztchikov <[EMAIL PROTECTED]> sent:

>I'm faced with dilemma, which has no obvious answer for me at the 
>moment. I was set to buy Xylotex steppers based kit for my CNC Sherline 
>Mill. After reading more about servo based systems I'm divided, I could 
>appreciate number of advantages of servo based systems 
>
>- no missed steps, corrections via closed loop
>- faster movement speeds, more IPS
>- positions display (DRO)
>
>However, stepper systems are cheaper and basically ready out of the box
>compare to DIY servo based system, which would require significant 
>build and setup time. Note, I don't have funds for commercial out of the
>box servo based kit. So, DIY is preferred option.
>
>I don't know exactly what kind of work I will do on my CNC Mill in the 
>future, so it's also hard to target setup to future work. I guess I'm 
>trying to decide is it worth the effort and money to build a "better" 
>system (servo based that is) or should I not bother for such a small 
>Mill as Sherline and go with steppers just fine ?
>
>Any pros and cons of both type of systems are welcome, especially in 
>relation to usage on Sherline Mills/Lathes.
>
>
>
>-
>This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
>Build the coolest Linux based applications with Moblin SDK & win great prizes
>Grand prize is a trip for two to an Open Source event anywhere in the world
>http://moblin-contest.org/redirect.php\?banner_id=100&url=/
>___
>Emc-users mailing list
>Emc-users@lists.sourceforge.net
>https://lists.sourceforge.net/lists/listinfo/emc-users


 Msg sent via CableONE.net MyMail - http://www.cableone.net
-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


[Emc-users] Steppers vs Servo based CNC kit for Sherline Mill ?

2008-07-27 Thread Sergey Izvoztchikov
I'm faced with dilemma, which has no obvious answer for me at the 
moment. I was set to buy Xylotex steppers based kit for my CNC Sherline 
Mill. After reading more about servo based systems I'm divided, I could 
appreciate number of advantages of servo based systems 

- no missed steps, corrections via closed loop
- faster movement speeds, more IPS
- positions display (DRO)

However, stepper systems are cheaper and basically ready out of the box
compare to DIY servo based system, which would require significant 
build and setup time. Note, I don't have funds for commercial out of the
box servo based kit. So, DIY is preferred option.

I don't know exactly what kind of work I will do on my CNC Mill in the 
future, so it's also hard to target setup to future work. I guess I'm 
trying to decide is it worth the effort and money to build a "better" 
system (servo based that is) or should I not bother for such a small 
Mill as Sherline and go with steppers just fine ?

Any pros and cons of both type of systems are welcome, especially in 
relation to usage on Sherline Mills/Lathes.



-
This SF.Net email is sponsored by the Moblin Your Move Developer's challenge
Build the coolest Linux based applications with Moblin SDK & win great prizes
Grand prize is a trip for two to an Open Source event anywhere in the world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers and INI file

2007-03-01 Thread Glenn R. Edwards
Thanks Chris.

The G0 answer makes sense.

I am running EMC 2.1.1

I'll post the INI file as soon as I get it off the machine.

Best regards,
-- --
Glenn

On Thu, Mar 01, 2007 at 04:04:16PM -0800, Glenn R. Edwards wrote:
> 
> I have noticed that when I do a fast-move command with all axes going,
> such as G0 X50 Y30 Z20 A90 (from home), the angular axis will move
> faster than when I do a single axis move such as G0 A90.  

Please post your ini (attach it here, or use www.pastebin.ca and
include just a link here) and also say which version of EMC you are
running.  

> And I noticed
> that a G0 command behaves like a G1 command in that all the axes
arrive
> at the same time.  For example, in the multi-axis move listed above, I
> would expect a trapezoid move profile (the axes with shorter distances
> arrive first) but I am getting a straight-line move profile from home
to
> the end-point.  Any suggestions or comments?

This is the correct behavior; the axes should start and stop together,
according to the rs274ngc spec:

http://www.linuxcnc.org/handbook/RS274NGC_3/RS274NGC_32a.html#1012110

Since you would have to wait for the slowest axis (making the longest
move) anyway, this costs you no extra time, and a straight move is a
lot less "surprising" in a lot of situations.

Chris


-
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share
your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDE
V
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users




-
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


Re: [Emc-users] Steppers and INI file

2007-03-01 Thread Chris Radek
On Thu, Mar 01, 2007 at 04:04:16PM -0800, Glenn R. Edwards wrote:
> 
> I have noticed that when I do a fast-move command with all axes going,
> such as G0 X50 Y30 Z20 A90 (from home), the angular axis will move
> faster than when I do a single axis move such as G0 A90.  

Please post your ini (attach it here, or use www.pastebin.ca and
include just a link here) and also say which version of EMC you are
running.  

> And I noticed
> that a G0 command behaves like a G1 command in that all the axes arrive
> at the same time.  For example, in the multi-axis move listed above, I
> would expect a trapezoid move profile (the axes with shorter distances
> arrive first) but I am getting a straight-line move profile from home to
> the end-point.  Any suggestions or comments?

This is the correct behavior; the axes should start and stop together,
according to the rs274ngc spec:

http://www.linuxcnc.org/handbook/RS274NGC_3/RS274NGC_32a.html#1012110

Since you would have to wait for the slowest axis (making the longest
move) anyway, this costs you no extra time, and a straight move is a
lot less "surprising" in a lot of situations.

Chris

-
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users


[Emc-users] Steppers and INI file

2007-03-01 Thread Glenn R. Edwards
I am running a four-axis mini-type mill with a xylotec board and stepper
motors throughout.  Everything runs fine (pretty much) except for the
4th axis which is an angular axis.  All the linear axes have the same
settings in the INI file and are mechanically the same.

 

I have noticed that when I do a fast-move command with all axes going,
such as G0 X50 Y30 Z20 A90 (from home), the angular axis will move
faster than when I do a single axis move such as G0 A90.  And I noticed
that a G0 command behaves like a G1 command in that all the axes arrive
at the same time.  For example, in the multi-axis move listed above, I
would expect a trapezoid move profile (the axes with shorter distances
arrive first) but I am getting a straight-line move profile from home to
the end-point.  Any suggestions or comments?

 

Best regards,

-- --

Glenn 

 

-
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users