Re: [Emc-users] Bldc commutatation

[jeremy youngs]

Bldc cfg=qi built , I don't get how to assign the Pins to the mesa card .
I found nothing in the 30 odd printed pages of hall tutorial that I have
will go to website and see if I can find clarification.
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Re: [Emc-users] Bldc commutatation

[jeremy youngs]

At 4.2 hal tutorial, connect pins to signals , the bldc docs don't give any
signals , are there none to be net commanded ?


>
>
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Re: [Emc-users] Bldc commutatation

[jeremy youngs]

On Sun, Aug 12, 2018, 7:13 PM andy pugh  wrote:

> On 12 August 2018 at 23:47, jeremy youngs  wrote:
>
> > There are a few other questions I have . I would like to loadrt cfg=ngiiq
>
> ngiiq makes no sense. You can't have gray-coded quadrature. And why
> two indexes?
>

Motors without Hall sensors may be homed in synchronous/direct mode. The
better of these options is to home to the encoder zero using the *iq* config
parameter. When the *init* pin goes high the motor will rotate (in a
direction determined by the *rev* pin) until the encoder indicates an
index-latch (the servo thread runs too slowly to rely on detecting an
encoder index directly). If there is no encoder index or its location
relative to motor zero can not be found, then an alternative is to use
*magnetic* homing using the *q*config. In this mode the motor

>
> > but it won't do that but I think adding this thread is my current hurdle.
>
> You don't need to add any threads, they will already be there
>
Addf for bldc , the function and syntax finally occurred to me , and I have
the bldc component on a 100 thread .

>
> >  and will it be able to align with only 2 sinewaves
> > being controlled . And what to do with the extra pin
>
> You can just ignore the extra pin.
>
> I am very glad to hear that


>
> But you do need some way to convert the numerical value from the bldc
> component into a variable voltage on a hardware pin.
>
>
> https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F171992353893
>
I have 2 of these

Gone to get something to eat , then to step 4

> atp
>



"A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1916
>
>
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Re: [Emc-users] Bldc commutatation

[andy pugh]

On 12 August 2018 at 23:47, jeremy youngs  wrote:

> There are a few other questions I have . I would like to loadrt cfg=ngiiq

ngiiq makes no sense. You can't have gray-coded quadrature. And why
two indexes?

> but it won't do that but I think adding this thread is my current hurdle.

You don't need to add any threads, they will already be there.

>  and will it be able to align with only 2 sinewaves
> being controlled . And what to do with the extra pin

You can just ignore the extra pin.

But you do need some way to convert the numerical value from the bldc
component into a variable voltage on a hardware pin.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916

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Re: [Emc-users] Bldc commutatation

[jeremy youngs]

>
> For driving a bare H-bridge
>
Thank you Andy.

I am here

Let’s see if that worked:
Show Threads

halcmd: show thread

Realtime Threads:
 Period  FP Name   ( Time, Max-Time )
 999855  YES   test-thread (0,0 )

It did. The period is not exactly 1,000,000 ns because of hardware
limitations, but we have a thread that runs at approximately the correct
rate, and which can handle floating point functions. The next step is to
connect the function to the thread:
Add Function

halcmd: addf siggen.0.update test-thread

Up till now, we’ve been using *halcmd* only to look at the HAL. However,
this time we used the *addf* (add function) command to actually change
something in the HAL. We told *halcmd* to add the function *siggen.0.update* to
the
  ngi/iq.jpg

It will run at cfg=nqi , when I addf I get this.
There are a few other questions I have . I would like to loadrt cfg=ngiiq
but it won't do that but I think adding this thread is my current hurdle. I
also will need to edit poles count and I'm curious as to what the reversing
scheme looks like , and will it be able to align with only 2 sinewaves
being controlled . And what to do with the extra pin
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Re: [Emc-users] Bldc commutatation

[andy pugh]

On 12 August 2018 at 20:52, jeremy youngs  wrote:
> *B* Bit level outputs. Either 3 or 6 logic-level outputs indicating which
> high or low gate drivers on an external drive should be used
>
> I don't quite follow this , define please

For driving a bare H-bridge.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916

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Re: [Emc-users] Bldc commutatation

[Gene Heskett]

On Saturday 11 August 2018 23:40:37 Jon Elson wrote:

> On 08/11/2018 08:03 PM, Gene Heskett wrote:
> > On Saturday 11 August 2018 20:14:46 Jon Elson wrote:
> >> On 08/11/2018 03:37 PM, Gene Heskett wrote:
> >>> On Saturday 11 August 2018 15:29:43 andy pugh wrote:
>  On 11 August 2018 at 20:11, Gene Heskett
> 
>   wrote:
> > Where can I find a tut on how the resolver works?
> 
>  https://en.wikipedia.org/wiki/Resolver_(electrical)
> >>>
> >>> Quite simplified, covers the basics but makes little or no
> >>> mention of the
> >>> resolvers speed limits. So in both cases, the encoder is
> >>> king, and much
> >>> cheaper to implement.
> >>>
> >>> Thanks Andy.
> >>
> >> Analog Devices 2S1200 will track a two-pole resolver to
> >> 60,000 RPM (1000 RPS).
> >>
> >> Jon
> >
> > And the heat sink and fans are how big?
>
> The 2S1200 chip is CMOS, and runs completely cold.  Don't
> know about the 60K RPM motor.
> We have a thing that spins a sample in an MRI magnet field
> at work at 300K RPM (5000 RPS).
> it is a tiny ceramic thing with notches in it, it forms an
> air bearing and an air jet shoots at the notches to spin in
> like a turbine.  CRAZY technology.

Air bearings are nice. Run forever with no wear, if the air is truly 
clean.

> Jon

Dentists have been doing that at 150k revs for what, 30 years? :)

-- 
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 

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Re: [Emc-users] Bldc commutatation

[Gene Heskett]

On Sunday 12 August 2018 05:08:37 andy pugh wrote:

> On 12 August 2018 at 02:01, Gene Heskett  wrote:
> >> Resolvers are absolute and much tougher.
> >
> > It appears that Omron's use of precision bearings seems to
> > addressing the toughness aspect.
>
> Now fill your optical encoder with coolant and see how it goes.
>
> I may be sounding like a bit of a resolver fanboi, but that is because
> I am. I have even taken off an encoder to fit a resolver on one of my
> lathe servos.
>
> With a resolver that perfectly matches the motor it makes BLDC
> commutation very easy too. On the Z servo of my lathe absolutely all
> that is needed is:
>
> net z-angle hm2_5i24.0.resover.01.angle => hm2_5i24.0.8i20.0.1.angle
> net z-pid pid.1.out => hm2_5i25.0.8i20.0.1.current

I am probably a poor judge of that as my servo experience is not in the 
machine shop. I've quite some experience tuning servo's in broadcast 
gear, intending to play a tape while keeping the output within 5 ns of 
house time. Ampex, in the VR-1200, was the only maker that "got it 
right" so that could be done in about half an hour on a totalled diddled 
with machine. But they only tried for about 2 u-sec mechanical accuracy 
at the video out, the rest was done electronicly with varactor 
controlled delay lines which could get the off tape color burst to 
within 5ns by the 3rd of 8 cycles of color burst. There were still some 
mechanical residual errors that could cause the colors to shift in phase 
from the just corrected left side of the screen to the right side of the 
screen 50 some u-secs later, but that was eventually solved on later 
machines by servoing the shoe height based on the initial error of the 
next color burst. The shoe is a vacuum pumped tape holder that brought 
to tape to presumably the exact same radius of the head tips as they 
wore in service. A rate of wear highly determined by the environment, 
cooler and drier were better. Heads could wear about 1.75 thou, and head 
hardness determined how much they charged an hour.

Nebraska ETV, (where I spent about 8 years of my broadcasting time) since 
they have 2 time zones, built their delay center with 3 such machines 
(sold for about $125k/ea in those days, late 60's) in a clean room whose 
air was both dried and cooled to about 50F and precipitron cleaned, and 
a roll of blank tape went in and was continually reused until trimming 
the damaged ends made it too short to use anymore. Those machines were 
initially setup with soft heads rated for 500 hours use, so the 
projected cost/hour was around $1.50 US. But with cold dry clean air, 
the first head failure was at just over 7000 hours, and was a solder 
joint in the internal rotary transformer, (the head wheel has 4 tips, 
and is spun at 14400 rpms) which was fixed N.C. and returned as there 
was still a nearly a thou of tip left. So a 500 hour head actually ran 
for just under 10k hours. Over the life of those machines that saved 3x 
the cost of the clean room including the energy bill.  There's a lesson 
in that.

No, I don't know much about servo's in dirty shops.

-- 
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 

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Re: [Emc-users] Bldc commutatation

[jeremy youngs]

*B* Bit level outputs. Either 3 or 6 logic-level outputs indicating which
high or low gate drivers on an external drive should be used

I don't quite follow this , define please
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Re: [Emc-users] Bldc commutatation

[andy pugh]

On 12 August 2018 at 02:01, Gene Heskett  wrote:

>> Resolvers are absolute and much tougher.
>
> It appears that Omron's use of precision bearings seems to addressing the
> toughness aspect.

Now fill your optical encoder with coolant and see how it goes.

I may be sounding like a bit of a resolver fanboi, but that is because
I am. I have even taken off an encoder to fit a resolver on one of my
lathe servos.

With a resolver that perfectly matches the motor it makes BLDC
commutation very easy too. On the Z servo of my lathe absolutely all
that is needed is:

net z-angle hm2_5i24.0.resover.01.angle => hm2_5i24.0.8i20.0.1.angle
net z-pid pid.1.out => hm2_5i25.0.8i20.0.1.current

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1916

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