Re: [Emc-users] very low speed motion

[Gregg Eshelman]

On 1/19/2016 11:55 AM, John Dammeyer wrote:
>> into the rotor.  Microstepping also increases resolution by
>> a small amount.  But, I am convinced Mariss Freimanis is
>> correct that microstepping more than about 10:1 really
>> provides no benefit.  A stepper motor can be modeled as a
>> mass (the rotor and external load) controlled by a spring
>> (the magnetic force on the rotor).  Changing the motor coil
>> currents moves the point where the spring is pulling from.
>> Thus, a stepper does NOT have some hard mechanical detents
>> in it.  Apply a torque, and the position of the rotor
>> shifts.  If you have encoder feedback, the PID system can
>> send a slight shift in position to compensate for this.
>> But, you really don't get a lot of control over it.
>>
>> Jon
>>
> Hi Jon,
> Everything you say is correct.  In a pure open loop system I also agree with
> Mariss that micro-stepping is really more about dealing with resonance
> issues rather than positioning.  Where things have changed is the with the
> capabilities of the high speed DSP processors to monitor phase current and
> encoder position.

Closed loop stepper controls like this
https://www.youtube.com/watch?v=2SozZ7af3wg

and this
https://www.youtube.com/watch?v=M_IuG20PIPQ

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] camview-emc?

[Jon Elson]

On 01/19/2016 09:30 PM, Gene Heskett wrote:
> On Tuesday 19 January 2016 22:02:13 Jon Elson wrote:
>
>>
>> UGH!  Camview is a TOTAL can of worms.
>
> Burns a huge hunk of cpu time when its running, so you have to creep up
> on the target at about 5 thou a minute because its so slow at getting
> you an onscreen picture of where it was at least 5 seconds back.  But it
> did work, as did the align functions in that extra kit of utils.
Well, I DID update my computer to one that had USB 2 ports 
on it. if you are using a camera on a USB 1.x port, that 
WILL be slow.  My camera is of relatively low resolution 
(maybe about 640 x 480 or so) and it is quite snappy, a 
total blur when jogging the table into position.  I think I 
CAN see the individual frames, but it must be at least 10-15 
frames a second.
>> If you run into a specific problem, let me know, but the guy
>> in France who wrote the crop and grafted it onto Axis is
>> really the only person that understands it.
>>
>> Jon
> France?  I thought Nick (psha.org.ru) was a Russian...  The address is
> an .ru.
Well, many people may have worked on  it, but Frederic Rible 
is the guy I had in mind.  He posted some info a LONG time 
ago on the LinuxCNC forum.  Maybe I shouldn't post his email 
here, but if you send me a direct email I can give it to 
you.  Or, you can probably get it off the forum.
> Ok, where to get the latest sources?  I am moderately familiar with the
> various make's and auto-this and ./configure that's. I am willing to
> give it a shot just to see what it reports as it dies.  Maybe this time
> the error might be fixable if I face east as I do the ./configure?
>
> I'll google for a git server in france tomorrow, but if you have a url
> google doesn't, please share.
>
> Cheers, Gene Heskett


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] camview-emc?

[Jon Elson]

On 01/19/2016 10:25 PM, Jon Elson wrote:
> On 01/19/2016 09:30 PM, Gene Heskett wrote:
>> On Tuesday 19 January 2016 22:02:13 Jon Elson wrote:
>>
>>>
>>> UGH!  Camview is a TOTAL can of worms.
>> Burns a huge hunk of cpu time when its running, so you have to creep up
>> on the target at about 5 thou a minute because its so slow at getting
>> you an onscreen picture of where it was at least 5 seconds back.  But it
>> did work, as did the align functions in that extra kit of utils.
> Well, I DID update my computer to one that had USB 2 ports 
> on it. if you are using a camera on a USB 1.x port, that 
> WILL be slow. My camera is of relatively low resolution 
> (maybe about 640 x 480 or so) and it is quite snappy, a 
> total blur when jogging the table into position.  I think 
> I CAN see the individual frames, but it must be at least 
> 10-15 frames a second.
>>> If you run into a specific problem, let me know, but the guy
>>> in France who wrote the crop and grafted it onto Axis is
>>> really the only person that understands it.
>>>
>>> Jon
>> France?  I thought Nick (psha.org.ru) was a Russian...  The address is
>> an .ru.
> Well, many people may have worked on  it, but Frederic 
> Rible is the guy I had in mind.  He posted some info a 
> LONG time ago on the LinuxCNC forum.  Maybe I shouldn't 
> post his email here, but if you send me a direct email I 
> can give it to you.  Or, you can probably get it off the 
> forum.
>> Ok, where to get the latest sources?  I am moderately familiar with the
>> various make's and auto-this and ./configure that's. I am willing to
>> give it a shot just to see what it reports as it dies.  Maybe this time
>> the error might be fixable if I face east as I do the ./configure?
>>
>> I'll google for a git server in france tomorrow, but if you have a url
>> google doesn't, please share.
>>
>> Cheers, Gene Heskett
>

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] camview-emc?

[Gene Heskett]

On Tuesday 19 January 2016 22:02:13 Jon Elson wrote:

> On 01/19/2016 06:37 PM, Gene Heskett wrote:
>
> (Darn, hit the wrong button again...)
>
> > the next step is to make camview-emc work
> > again as it stopped working when I update to the hybrid.iso, which
> > is mostly wheezy.
>
> UGH!  Camview is a TOTAL can of worms.

And quite lively too, should catch some hungry fish. :)

Burns a huge hunk of cpu time when its running, so you have to creep up 
on the target at about 5 thou a minute because its so slow at getting 
you an onscreen picture of where it was at least 5 seconds back.  But it 
did work, as did the align functions in that extra kit of utils.

> I DID manage to get 
> it working on two systems, but it was pure HELL!  It
> requires adding a crop function to camview to zoom in on the
> image, and then recompiling the whole works for your
> kernel.  And, that never goes right the first time, all
> sorts of library problems.
>
> If you run into a specific problem, let me know, but the guy
> in France who wrote the crop and grafted it onto Axis is
> really the only person that understands it.
>
> Jon

France?  I thought Nick (psha.org.ru) was a Russian...  The address is 
an .ru.

Ok, where to get the latest sources?  I am moderately familiar with the 
various make's and auto-this and ./configure that's. I am willing to 
give it a shot just to see what it reports as it dies.  Maybe this time 
the error might be fixable if I face east as I do the ./configure?

I'll google for a git server in france tomorrow, but if you have a url 
google doesn't, please share.

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 

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] camview-emc?

[Jon Elson]

On 01/19/2016 06:37 PM, Gene Heskett wrote:

(Darn, hit the wrong button again...)
> the next step is to make camview-emc work
> again as it stopped working when I update to the hybrid.iso, which is
> mostly wheezy.
>
UGH!  Camview is a TOTAL can of worms.  I DID manage to get 
it working on two systems, but it was pure HELL!  It 
requires adding a crop function to camview to zoom in on the 
image, and then recompiling the whole works for your 
kernel.  And, that never goes right the first time, all 
sorts of library problems.

If you run into a specific problem, let me know, but the guy 
in France who wrote the crop and grafted it onto Axis is 
really the only person that understands it.

Jon


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] camview-emc?

[Jon Elson]

On 01/19/2016 06:37 PM, Gene Heskett wrote:
> Greetings;
>
>
> I sent an email to the address in the README, asking if a fix for wheezy
> had been done, this about 24 hours ago, but no reply has been received
> yet.
>
> Is anybody else any smarter about this than I am?
>
> I have 2 ea 13watt daylight led lamps in the ceiling, but I feel like I
> an sitting here in the dark about camview-emc.
>
> That, and the "align" utility, make registering the two sides of a pcb an
> absolute piece of cake.
>
> Thanks for any info the rest of you have.
>
> Cheers, Gene Heskett


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] camview-emc?

[Gene Heskett]

On Tuesday 19 January 2016 20:41:50 Chris Morley wrote:

> > From: ghesk...@wdtv.com
> > To: emc-users@lists.sourceforge.net
> > Date: Tue, 19 Jan 2016 19:37:01 -0500
> > Subject: [Emc-users] camview-emc?
> >
> > Greetings;
>
> Gene would this be any use to you?
> https://forum.linuxcnc.org/forum/show-your-stuff/30006-spindle-cam?lim
>itstart=0
>
> It may be easier to keep working as it uses a common library - CV
>
> Chris M

My back is about done for the day, so I'll hard copy this and go see if 
it will run on the mill tomorrow.

Thank you Chris Morely.

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 

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] View buttons and views in Axis menu gone in lathe mode

[Tom Easterday]

Mainly I want a button that brings the back plot to the center after touching 
off.  Currently the view is looking down the Y axis at the ZX plane of the 
lathe.  When you touch off the view disappears off screen.  Then we roll the 
center button (usually initially in the wrong direction) until we see the back 
plot and the click and drag and zoom once again.  It's a PIA, frankly.  I want 
to click a view button like I do on the mill or plasma machine and the view 
pops back to center.
-Tom

> On Jan 19, 2016, at 8:37 PM, Chris Morley  wrote:
> 
>> From: tom-...@bgp.nu
>> Date: Tue, 19 Jan 2016 20:17:55 -0500
>> To: emc-users@lists.sourceforge.net
>> Subject: Re: [Emc-users] View buttons and views in Axis menu gone in lathe   
>>  mode
>> 
>> Is there a way to bring them back in Lathe mode?  It is a lathe I am using 
>> it on so want to keep that mode, but want the buttons so I can get the view 
>> back on the screen after touching off.
>> -Tom
>> 
>> 
> 
> What views are you referring to? Axis has always had less view options on 
> lathes.
> Are you saying you want all the mill view options on lathe too?
> 
> Chris M
> 
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] View buttons and views in Axis menu gone in lathe mode

[Chris Radek]

On Tue, Jan 19, 2016 at 08:17:55PM -0500, tom-...@bgp.nu wrote:
> Is there a way to bring them back in Lathe mode?  It is a lathe I
> am using it on so want to keep that mode, but want the buttons so
> I can get the view back on the screen after touching off.

Hit `v'?


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] camview-emc?

[Chris Morley]

> From: ghesk...@wdtv.com
> To: emc-users@lists.sourceforge.net
> Date: Tue, 19 Jan 2016 19:37:01 -0500
> Subject: [Emc-users] camview-emc?
> 
> Greetings;
> 

Gene would this be any use to you?
https://forum.linuxcnc.org/forum/show-your-stuff/30006-spindle-cam?limitstart=0

It may be easier to keep working as it uses a common library - CV

Chris M
  
--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] View buttons and views in Axis menu gone in lathe mode

[Chris Morley]

> From: tom-...@bgp.nu
> Date: Tue, 19 Jan 2016 20:17:55 -0500
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] View buttons and views in Axis menu gone in lathe
> mode
> 
> Is there a way to bring them back in Lathe mode?  It is a lathe I am using it 
> on so want to keep that mode, but want the buttons so I can get the view back 
> on the screen after touching off.
> -Tom
> 
> 

What views are you referring to? Axis has always had less view options on 
lathes.
Are you saying you want all the mill view options on lathe too?

Chris M
  
--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] View buttons and views in Axis menu gone in lathe mode

[tom-emc]

Is there a way to bring them back in Lathe mode?  It is a lathe I am using it 
on so want to keep that mode, but want the buttons so I can get the view back 
on the screen after touching off.
-Tom


> On Jan 19, 2016, at 6:22 PM, John Thornton  wrote:
> 
> Change the mode back to mill.
> 
> JT
> 
> On 1/19/2016 5:11 PM, tom-...@bgp.nu wrote:
>> I am using Axis in lathe mode and the view buttons that are normally there, 
>> at least on my mill and plasma machine, are missing in Axis’ tool bar and 
>> View Menu (2.7.3) .  Is there a way to get them to show up?
>> -Tom
>> 
>> 
>> --
>> Site24x7 APM Insight: Get Deep Visibility into Application Performance
>> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
>> Monitor end-to-end web transactions and take corrective actions now
>> Troubleshoot faster and improve end-user experience. Signup Now!
>> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
> 
> 
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

[Emc-users] camview-emc?

[Gene Heskett]

Greetings;

Finally making the tach, Sp PWR (was the on-led), the fwd and reverse 
leds talling what going on, the next step is to make camview-emc work 
again as it stopped working when I update to the hybrid.iso, which is 
mostly wheezy.

I sent an email to the address in the README, asking if a fix for wheezy 
had been done, this about 24 hours ago, but no reply has been received 
yet.

Is anybody else any smarter about this than I am?

I have 2 ea 13watt daylight led lamps in the ceiling, but I feel like I 
an sitting here in the dark about camview-emc.

That, and the "align" utility, make registering the two sides of a pcb an 
absolute piece of cake.

Thanks for any info the rest of you have.

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 

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] View buttons and views in Axis menu gone in lathe mode

[John Thornton]

Change the mode back to mill.

JT

On 1/19/2016 5:11 PM, tom-...@bgp.nu wrote:
> I am using Axis in lathe mode and the view buttons that are normally there, 
> at least on my mill and plasma machine, are missing in Axis’ tool bar and 
> View Menu (2.7.3) .  Is there a way to get them to show up?
> -Tom
>
>
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

[Emc-users] View buttons and views in Axis menu gone in lathe mode

[tom-emc]

I am using Axis in lathe mode and the view buttons that are normally there, at 
least on my mill and plasma machine, are missing in Axis’ tool bar and View 
Menu (2.7.3) .  Is there a way to get them to show up?
-Tom


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] very low speed motion

[John Dammeyer]

> into the rotor.  Microstepping also increases resolution by
> a small amount.  But, I am convinced Mariss Freimanis is
> correct that microstepping more than about 10:1 really
> provides no benefit.  A stepper motor can be modeled as a
> mass (the rotor and external load) controlled by a spring
> (the magnetic force on the rotor).  Changing the motor coil
> currents moves the point where the spring is pulling from.
> Thus, a stepper does NOT have some hard mechanical detents
> in it.  Apply a torque, and the position of the rotor
> shifts.  If you have encoder feedback, the PID system can
> send a slight shift in position to compensate for this.
> But, you really don't get a lot of control over it.
> 
> Jon
> 
Hi Jon,
Everything you say is correct.  In a pure open loop system I also agree with
Mariss that micro-stepping is really more about dealing with resonance
issues rather than positioning.  Where things have changed is the with the
capabilities of the high speed DSP processors to monitor phase current and
encoder position.  

The TXM24C-1G (Size 23, 117 oz-in) with a 28V supply I have running on my
bench is amazing to watch.  And like a servo it needs a certain amount of
tuning of the PI variables in order to make it work right.  I'm using it in
a constant velocity mode with CANOpen control so I can't compare to the
step/dir versions.  But with a 5000 line encoder built in there is no doubt
they are doing some pretty special software especially since they claim
quadrature performance of 20,000 lines per rev.

The reason my client is looking at this rather than a brushless servo is the
length of the entire motor/encoder is less than the half the power DC servo.
So a 60 oz-in motor w/o encoder won't fit.  A 120 oz-in step/servo does.
The motor is rated up to 3600 RPM.  And without anything on the 10mm shaft
I've spun it up to 3600 RPM.  And then almost burned my fingers trying to
stop it spinning.  And this puppy is expensive with the CANOpen interface.

John Dammeyer



--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] very low speed motion

[Jon Elson]

On 01/19/2016 10:24 AM, Peter C. Wallace wrote:
>
> What I think happens in a step /dir system is this:
>
> Linuxcnc uses floating point numbers for positions and velocities and these
> vary in a stepwise manner at the the servo thread period. If you command a
> move with a .001 mm/sec velocity and a distance of .001 mm the position will
> be incremented by 10^-6 mm every 1 ms servo thread tic until it reaches .0005
> mm (at 500 ms) at which point a step will be generated. Thats is the (nearly)
> continuous linuxcnc position command is quantized to the output device
> resolution at the last stage.
>
> The exact details may vary depending on the actual hardware/driver
>
> For example, the Mesa hardware stepgen has a 16 bit fractional step resolution
> so the actual quantization/rounding to the physical step level occurs in
> hardware.
>
>
But, a stepper motor cannot be expected to move in nm units 
(or, if it was geared to that level, it would not be able to 
move at a perceptible rate).  So, whatever the microstepping 
level permits, and whatever the magnetic-spring effects 
allow, is how small it can move at any time.  Microstepping 
improves smoothness and avoids resonance problems by 
preventing square wave drive from pumping resonant energy 
into the rotor.  Microstepping also increases resolution by 
a small amount.  But, I am convinced Mariss Freimanis is 
correct that microstepping more than about 10:1 really 
provides no benefit.  A stepper motor can be modeled as a 
mass (the rotor and external load) controlled by a spring 
(the magnetic force on the rotor).  Changing the motor coil 
currents moves the point where the spring is pulling from.  
Thus, a stepper does NOT have some hard mechanical detents 
in it.  Apply a torque, and the position of the rotor 
shifts.  If you have encoder feedback, the PID system can 
send a slight shift in position to compensate for this.  
But, you really don't get a lot of control over it.

Jon

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] very low speed motion

[Jon Elson]

On 01/19/2016 09:45 AM, TJoseph Powderly wrote:
>
> clear me up on in this...
> about very slow motion with steppers and servos
>
> assuming the minimum position change is .001mm
> ( commanded step or feedback unit
> so:  a single step moves .001"
>  and any feedback has .001 resolution )
>
> when the system gets a command to move another .001mm,
> what happens when the velocity requested is .001mm per second?
>
> in a stepper system, does it go clunk and wait 999millisecss?
> (or wait 999 then go clunk, or at 500mSec etc.)?
Yes.
> in a servo system does it crawl towards the destination over the whole
> second?
>
>
When I first converted my Bridgeport over to using velocity 
servo amps with tachometer feedback, I wanted to measure 
this.  I hooked a scope up to the current sensing for the 
motor, and moved at slower and slower velocities until the 
motor current got "lumpy", indicating some stick-slip 
friction.  This showed up at about .01 IPM!  I did some 
calculation to figure the tach was producing 7 uV at that 
speed.  Just to see what would happen, I shorted the tach 
out with a screwdriver.  The servo amp immediately faulted.
That proved that is was still closing the velocity loop, 
even at 7 uV.  The encoder was producing 3.33 quadrature 
counts/second.  I verified that the stick-slip was NOT 
harmonically related to that frequency.  So, the velocity 
servo system WAS maintaining the steady motion velocity 
until the slide just got too sticky to keep it steady any 
slower.

So, with a properly tuned velocity servo system, it WILL 
maintain smooth motion down to insanely low speeds.  Without 
tach feedback, such as on my PWM systems, the only way to 
know velocity is from the encoder counts.  If you have a 
high resolution encoder, it can give a steady stream of 
counts at low speed.  With a low res encoder, there are long 
periods between counts, where the position and velocity are 
unknown to the PID, and so it has to ASSUME that the 
velocity has not changed.

Jon

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Jon Elson]

On 01/19/2016 01:04 AM, Chris Albertson wrote:
> I've read that it is hard to use steppers for closed loop CNC.  If this is
> still true could some one explain the theory.
Stepper drivers have fixed current settings for the 
windings.  When the load increases, the voltage applied by 
the driver may increase to maintain the current.  But, this 
gives a maximum torque, above which the stepper will lose 
steps or stall.  A stepper with encoders will allow you to 
detect loss of position or stall, but it WON'T prevent it 
from happening.

A servo drive gives the minimum current to the motor to keep 
at the commanded position.  When load increases, the current 
is increased to maintain position and velocity.  Since the 
minimum current required is used, the motors stay cooler, 
and therefore are available to deliver greater than 
continuous torque when the load demands it.  Generally, 
servos can deliver a peak torque about 4 X the continuous 
rating.
Steppers are good up to a few hundred Watts of mechanical 
power. Remarkably small servos can deliver this much power, 
and modest ones can deliver a KW or more.  Of course, it is 
still possible to stall a beefy servo, but it is a LOT less 
likely.

Another advantage of the servo is that you can go to E-stop 
and back on-line without losing the position alignment.  
(Yes, steppers with encoders can do this, too.)
> I have a small mill with DRO scales that are good to about .001 inch and
> I'd like to put them to use with my planned CNC conversion.   I understand
> software.  I've worked in the field for 30 years and have experience with
> Linux (and other OS) device drivers, embedded real time code and so on.
> If the problem is simply that no one has bothered to write the code, I can
> fix that.   But if there is something of a mechanical nature I'm not
> thinking of maybe some one can point me at what I need to read up on.
>
> At least I think I might be able too automatically measure backlash using
> the DRO scale data.  But my goal is to go closed loop if I can
>
Many low-cost DRO scales are NOT quadrature encoders 
reporting position in real time, but some kind of 
interpolated sensor that gives several position reports a 
second.  These cannot be used for closed-loop servo 
operation.  So, check what sort of scale you have.

See  http://pico-systems.com/minimill.html  for some pics 
and discussion of my minimill servo conversion.
This is not a machine I use for general machining, (I have a 
CNC Bridgeport that is a lot more capable) but is portable 
for demos, and I also use if to experiment with motion control.

I (Pico Systems) have all the hardware you need for such a 
conversion, using either brush or brushless motors.

Jon

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Dave Cole]

On 1/19/2016 5:19 AM, andy pugh wrote:
> On 19 January 2016 at 07:04, Chris Albertson  
> wrote:
>> I've read that it is hard to use steppers for closed loop CNC.  If this is
>> still true could some one explain the theory.
> This may be a misunderstanding.
> It is hard to do anything useful with an encoder attached to a stepper
> motor. You can tell that the motor is out of position, but unlike with
> a DC or AC servo there is no way to "step harder" to recover the
> error. You can step _faster_ but that will reduce rather than increase
> torque.
>
> (Recently a family of stepper motors with integrated encoders and
> drivers to suit have appeared, but they can me more clearly understood
> as very high pole-count 2-phase brushless motors and are not
> immediately relevant to the question)
>
>> I have a small mill with DRO scales that are good to about .001 inch and
>> I'd like to put them to use with my planned CNC conversion.
> In this case you definitely can do closed-loop CNC with steppers.
>
> What you need to do is to run the step-generators in velocity mode.
> Then, just like any other servo system, you compare the linear scale
> position with the commanded position, and the further you are from
> commanded position the faster you drive the motor.
>
> You do this with the normal LinuxCNC PID controller. The controller
> will need to be tuned just like any other PID loop, but the stepper
> motors behave like almost perfect velocity-mode servos in this
> configuration.

I've done what is being discussed on an actual machine except that I 
used a servo motor in step and direction mode, instead of a stepper.

The application was a material feeder, that feeds a strip into a cutoff 
shear.   I used an encoder to track material movement via a contact 
wheel.   The motor was a servo motor (for more power) setup in step and 
direction mode connected to a LinuxCNC stepgen component and the 
component has a velocity input.   So as Andy says it works just like a 
velocity servo motor-drive except step and direction signals are output 
from the component. A traditional position control loop component 
(same as the typical LinuxCNC servo setup) is used to control the 
stepgen which drives the motor.  The feedback for the position loop came 
from the wheel encoder that was tracking the material. The setup 
works fine and the tuning was not difficult.   The machine has been 
running and cutting off strips of material to a programmed length for 4+ 
years now.   If I could have used a stepper motor instead of a servo 
motor I could have lowered the cost considerably.   However we used a 1 
KW servo motor with a gearbox to drive the strip feed rollers.
Actually I forgot, we actually used two servo motor to drive the strip, 
one driving a top "caterpillar drive" and the second driving a bottom 
"caterpillar drive" to squeeze the strip and move it into the cutoff 
shear. Bottom motor simply spun in the opposite direction via the 
stepgen components.   (Invert the direction signal in HAL. ) Its a 
very nice machine.  Very well made.

Not much I did on that control system was "new".   Several other guys at 
the time made suggestions (thanks guys!) and they obviously had 
experience controlling step and dir drives in closed loop.So closed 
loop steppers have been done for a long time.LinuxCNC is super 
flexible for things like this.

The machine runs two shifts - 5 days per week.  That machine paid 
for itself in only a few months.I thought we would make more 
machines but the company that made it has no ability to sell/market 
anything.

Dave
Cole Controls Inc.


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] very low speed motion

[Peter C. Wallace]

On Tue, 19 Jan 2016, TJoseph Powderly wrote:

> Date: Tue, 19 Jan 2016 07:45:02 -0800
> From: TJoseph Powderly 
> Reply-To: "Enhanced Machine Controller (EMC)"
> 
> To: "Enhanced Machine Controller (EMC)" 
> Subject: [Emc-users] very low speed motion
> 
> i was reading the step/servo thread
> ... this is related but OT
>
> clear me up on in this...
> about very slow motion with steppers and servos
>
> assuming the minimum position change is .001mm
> ( commanded step or feedback unit
>   so:  a single step moves .001"
>and any feedback has .001 resolution )
>
> when the system gets a command to move another .001mm,
> what happens when the velocity requested is .001mm per second?
>
> in a stepper system, does it go clunk and wait 999millisecss?
> (or wait 999 then go clunk, or at 500mSec etc.)?
>
> in a servo system does it crawl towards the destination over the whole
> second?
>
> do we see important differences if the velocity is reduced by say 10?
> or increased by 10?
>  ( is the motion jerky?
>  and
>  does motion stay jerky till velocity and the machine frame dampen it)
>
> i think any sudden jerks are bad for machining and process control.
>
> any of the above?
>
> thx
> TomP tjtr33
>

What I think happens in a step /dir system is this:

Linuxcnc uses floating point numbers for positions and velocities and these 
vary in a stepwise manner at the the servo thread period. If you command a 
move with a .001 mm/sec velocity and a distance of .001 mm the position will 
be incremented by 10^-6 mm every 1 ms servo thread tic until it reaches .0005 
mm (at 500 ms) at which point a step will be generated. Thats is the (nearly) 
continuous linuxcnc position command is quantized to the output device 
resolution at the last stage.

The exact details may vary depending on the actual hardware/driver

For example, the Mesa hardware stepgen has a 16 bit fractional step resolution
so the actual quantization/rounding to the physical step level occurs in 
hardware.

>
>
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> 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.


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

[Emc-users] very low speed motion

[TJoseph Powderly]

i was reading the step/servo thread
... this is related but OT

clear me up on in this...
about very slow motion with steppers and servos

assuming the minimum position change is .001mm
( commanded step or feedback unit
   so:  a single step moves .001"
and any feedback has .001 resolution )

when the system gets a command to move another .001mm,
what happens when the velocity requested is .001mm per second?

in a stepper system, does it go clunk and wait 999millisecss?
(or wait 999 then go clunk, or at 500mSec etc.)?

in a servo system does it crawl towards the destination over the whole 
second?

do we see important differences if the velocity is reduced by say 10?
or increased by 10?
  ( is the motion jerky?
  and
  does motion stay jerky till velocity and the machine frame dampen it)

i think any sudden jerks are bad for machining and process control.

any of the above?

thx
TomP tjtr33



--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Gene Heskett]

On Tuesday 19 January 2016 06:31:10 andy pugh wrote:

> On 19 January 2016 at 11:14, Lester Caine  wrote:
> > The newer 'closed loop' motors are essentially using the same
> > approach, but rather than simply applying the same power for longer
>
> I don't think that this is what the original poster was asking. I
> think he was just wanting to close a position loop with linear scales
> on the axes of his stepper-driven machine.

ISTR there's some discussion re that in the wiki.
See:

  

and



Author unk on this last one.

I thought there were some examples in the documentation on linuxcnc.org, 
but they do not seem to exist in the newest development version's html 
menu.  In any event, those wiki notes could be helpful to the O.P.  The 
second link discusses using two PID modules with an output summing 
function driving the step generator as one means of gaining accuracy.  
No mention of the summing gain for that input however. But pid gains 
could negate the need for other than the default gain of 1.000.

I'd note that in my paranoia, I would probably run both pid.n.error 
outputs together thru an abs module each, and sum them to feed them back 
to motion to serve as an error stop of the machine if either pid's error 
was excessive, indicating a problem that could endanger the part or 
machine. The .ini and .hal files were at one time, perhaps 5 years ago, 
present and viewable but I can't find them now.  They might also be 
helpfull to the O.P. if they can be relocated and made viewable.

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 

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Lester Caine]

On 19/01/16 11:31, andy pugh wrote:
>> The newer 'closed loop' motors are essentially using the same approach,
>> > but rather than simply applying the same power for longer
> I don't think that this is what the original poster was asking. I
> think he was just wanting to close a position loop with linear scales
> on the axes of his stepper-driven machine.

I was answering the first question ...

-- 
Lester Caine - G8HFL
-
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk
Rainbow Digital Media - http://rainbowdigitalmedia.co.uk

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Stuart Stevenson]

Gentlemen,
  Having no experience with steppers I will still offer my opinion. Take it
as you will. :)

The case for steppers seems to hinge on cost ie: steppers are less
expensive than servos.

Steppers cannot maintain position like servos because of the aforementioned
lack of increased power if the power need increases. The answer is then
install steppers with more power so you never encounter the power need in
excess of stepper ability.

When you design to this parameter the cost then approaches servo cost hence
the 'need' for steppers is reduced and servos become the appropriate answer.

Until someone is able to design a cheap stepper with the ability to
increase power like a servo then the argument for closed loop steppers is
not as strong. You still may be able to keep cost down depending on how the
steppers are mounted and the room you have on the machine and in the
electrical cabinet and the wiring requirements.

Just my thoughts.

thanks
Stuart


On Tue, Jan 19, 2016 at 5:31 AM, andy pugh  wrote:

> On 19 January 2016 at 11:14, Lester Caine  wrote:
> >
> > The newer 'closed loop' motors are essentially using the same approach,
> > but rather than simply applying the same power for longer
>
> I don't think that this is what the original poster was asking. I
> think he was just wanting to close a position loop with linear scales
> on the axes of his stepper-driven machine.
>
> --
> atp
> If you can't fix it, you don't own it.
> http://www.ifixit.com/Manifesto
>
>
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>



-- 
Addressee is the intended audience.
If you are not the addressee then my consent is not given for you to read
this email furthermore it is my wish you would close this without saving or
reading, and cease and desist from saving or opening my private
correspondence.
Thank you for honoring my wish.
--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[andy pugh]

On 19 January 2016 at 11:14, Lester Caine  wrote:
>
> The newer 'closed loop' motors are essentially using the same approach,
> but rather than simply applying the same power for longer

I don't think that this is what the original poster was asking. I
think he was just wanting to close a position loop with linear scales
on the axes of his stepper-driven machine.

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

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Lester Caine]

On 19/01/16 10:33, Gene Heskett wrote:
> Something that has not been mentioned here is that a real error because 
> the stepper has lost a full step or more because it is being asked for 
> step movement faster than it can maintain lock.
> 
> When that occurs, generally the motor stops/locks, and thestepper 
> generator must be stopped and re-started from a low speed and the 
> controlled acceleration re-applied.  But if its a multiaxis move, there 
> will be a jog in whats supposed to be a straight line unless the whole 
> machine is stopped while the errored axis is getting back into position.  
> It would be a good idea to stop the errored axis at the caught up 
> position, then restart the whole move so that it can proceed along the 
> selected co-ordinate path, but because it errored at the selected speed, 
> the new speed ought to be 10% slower until that move is completed.

I'll cut the other comments and just concentrate on the basic problem
with a couple of older closed loop options. The Microproto DSLS3000 is
sold as a closed loop stepper driver, which works because the driver is
only half stepping, and the 'closed loop' simply continues to apply
power until it detects that the motor has moved. The problem with that
is that if each step takes longer you have to have an interface back to
the 'pulse generator' to slow it down. The Microproto 'fix' for that is
simply to remember how many steps it needs and keep moving until the the
right number have happened ... how ever long it takes ... you see the
problem, and the axies can be up to 200 steps adrift before the fault
signal fires. In theory LinuxCNC could be configured to monitor the
buffering and slow down pulses, but I don't think anybody has added that
as yet. On Mach3 it ends up with rounded corners as the change of
direction happens before the first move finishes.

The newer 'closed loop' motors are essentially using the same approach,
but rather than simply applying the same power for longer, they apply a
lot more power so as to try and avoid having to wait for the motor to
catch up. What I am not sure about as yet is just how effective that is
and just what the lag can be between a step pulse and the final
positioning. The DSLS3000 approach is sold as a speed improvement with
security that the axis has moved, but once the mill is actually cutting
one has to drop below the open loop speeds anyway. Yes in free air one
can move between cuts quicker, but the characteristics of the closed
loop process have to be taken care of when setting feed rates.

-- 
Lester Caine - G8HFL
-
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk
Rainbow Digital Media - http://rainbowdigitalmedia.co.uk

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Gregg Eshelman]

On 1/19/2016 3:33 AM, Gene Heskett wrote:

> 2 optos in series because the BoB you bought is also an isolated version,
> _will_ hurt you. Particularly if using a PWM output for spindle speed
> control, you _WILL_ have to get rid of it if you want anything that even
> resembles linear speeds so the PID can control it right.
> Cheers, Gene Heskett

That's what the Pico stepper control board I bought is for. Still 
sitting on the big box bolted to the side of my Acra mill.

It has linear scales on X and Y and a 127 count rotary encoder on the Z 
ball screw. I do have 1600 oz/in steppers mounted in place of the more 
massive 14 volt DC motors that had tachometers. According to the specs 
for both, the steppers have higher torque than the DC motors did at 
their peak RPM, and the steppers are rated to run at even higher RPM 
than the DC motors. On paper the steppers appear stronger. I did a test 
hookup on the X axis and fiddled around jogging it back and forth In 
Mach 3. It moved plenty quick, faster than I've seen on Youtube demos of 
old Anilam Crusader M systems. The proof will be in the pudding 
milling.

Anilam had no problems 26 years ago doing closed loop with linear scales 
and DC motors only reporting back their RPM. Don't see why it should be 
difficult to do with steppers. I kept the 2:1 belt reduction on all axes.

Spent yesterday shifting stuff around in the shop to be able to get back 
to work on the 13" LeBlond lathe.

I also now have to take apart and inspect the Z-axis servo on my 
PLM2000. Buying an old space saver Hyster with some brake issues. I said 
let's check out the brakes first. Nooo. Dad wants to use the new toy to 
move heavy stuff, right now, including my CNC mill. Well it got knocked 
over and the Z motor housing now resembles a crumple zone on one corner. :(

However it IS on the sturdy table I have been wanting to move it to so I 
could actually use it to Do Stuff.

Turns out the "brake issue" was no brake fluid, at all. Zilch. Zero.

Also got to have fun with rollers and large steel prybars to move a B&S 
#2 surface grinder and a Hardinge DV59 split bed lathe. Two more fix up 
projects.

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Gene Heskett]

On Tuesday 19 January 2016 03:35:32 John Dammeyer wrote:

> Hi Chris,
> Wiki defines Servo Motor as a motor that has closed the loop so it
> knows the position of the motor.
>
> Years ago there were discussions about closed loop with linear scales.
>  The trouble there is the amount the motor has to turn before the
> scales report data.  That can cause oscillations that are hard to
> damp.
>
> There is no reason a stepper cannot be the drive part of the motor
> with an encoder feedback.  Google TXM24C-1CG for example.  And there
> are others. The current name for that type of drive is step-servo.
>
> The UHU Servo driver http://www.uhu-servo.de/servo_en/ explains how to
> use a DC motor with either a 0 to +/- 10V or PWM and DIR.
>
> One of the first electronic lead screws also used a DC motor on the
> lathe lead screw.  Using counters connected to the spindle motor and
> the lead screw motor the difference between the counters is an error
> value that adjusts the DC voltage out to the motor.
>
> In each of these examples a varying DC voltage or PWM to a DC motor is
> the control.  A brushless DC motor still essentially works the same
> way too. Supply a voltage or PWM and the motor turns.
>
> Not so with stepper motors.  You essentially need to first create a
> driver that effectively turns the motor at a specific RPM based on a
> voltage input. Then you can close the loop with the desired number of
> steps in verses the encoder counts as an error that moves the motor in
> the correct direction for the required distance.
>
> John Dammeyer
> .
>
> > -Original Message-
> > From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> > Sent: January-18-16 11:04 PM
> > To: Enhanced Machine Controller (EMC)
> > Subject: [Emc-users] Question about closed loop CNC
> >
> >
> > I've read that it is hard to use steppers for closed loop CNC.  If
> > this is still true could some one explain the theory.
> >
> > I have a small mill with DRO scales that are good to about .001 inch
> > and I'd like to put them to use with my planned CNC conversion.   I
> > understand software.  I've worked in the field for 30 years and have
> > experience with Linux (and other OS) device drivers, embedded real
> > time code and so on. If the problem is simply that no one has
> > bothered to write the code, I can fix that.   But if there is
> > something of a mechanical nature I'm not thinking of maybe some one
> > can point me at what I need to read up on.
> >
> > At least I think I might be able too automatically measure backlash
> > using the DRO scale data.  But my goal is to go closed loop if I can
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California

Something that has not been mentioned here is that a real error because 
the stepper has lost a full step or more because it is being asked for 
step movement faster than it can maintain lock.

When that occurs, generally the motor stops/locks, and thestepper 
generator must be stopped and re-started from a low speed and the 
controlled acceleration re-applied.  But if its a multiaxis move, there 
will be a jog in whats supposed to be a straight line unless the whole 
machine is stopped while the errored axis is getting back into position.  
It would be a good idea to stop the errored axis at the caught up 
position, then restart the whole move so that it can proceed along the 
selected co-ordinate path, but because it errored at the selected speed, 
the new speed ought to be 10% slower until that move is completed.

Hopefully the part will still be usable, but you can only determine that 
after the finishing cuts.

Steppers can be persnickity. 2 things can help if the motor loses steps.
First is the signal path. Going thru 2 or 3 sets of opto-isolators can 
and will play hell with the step timings. So I, once I had identified 
that as a contributing factor, got rid of the isolators except for the 
ones actually in the input circuit to the driver module.

Second is the supply voltage to the motor. Example:
My toy mill, a small HF with bigger tables and ball screws on the XY, 
8mmx2.5 screws, is apt to act up at just above 10 ipm as it only has a 
28 volt supply for the motors.  A highly regulated 300 watt switcher 
with a 5 volt output to power the BoB.

When I did my toy lathe, I made a un-regulated supply of about 38 volts 
when loaded  but used the same motors and 2m542 drivers.  Its Z has a 
16x5 screw, with a 40 tooth gear on the motor turning an 80 tooth on the 
z screw. So as far as the motor is concerned, its turning a 2.5 pitch 
screw.

Where the toy mill can have trouble at 10 ipm,  the lathe, with its 
nominally 10 volt higher motor supply, can move the z at better than 60 
ipm!  I have a bigger supply made for the toy mill, some 50 volt 
supplies reset for 42 volts that will be installed when warmer weather 
comes back as that building isn't insulated, and I only keep it warm 
enough to stay above the dew point with electric heaters.

To my way of thinking,

Re: [Emc-users] Question about closed loop CNC

[andy pugh]

On 19 January 2016 at 07:04, Chris Albertson  wrote:
> I've read that it is hard to use steppers for closed loop CNC.  If this is
> still true could some one explain the theory.

This may be a misunderstanding.
It is hard to do anything useful with an encoder attached to a stepper
motor. You can tell that the motor is out of position, but unlike with
a DC or AC servo there is no way to "step harder" to recover the
error. You can step _faster_ but that will reduce rather than increase
torque.

(Recently a family of stepper motors with integrated encoders and
drivers to suit have appeared, but they can me more clearly understood
as very high pole-count 2-phase brushless motors and are not
immediately relevant to the question)

> I have a small mill with DRO scales that are good to about .001 inch and
> I'd like to put them to use with my planned CNC conversion.

In this case you definitely can do closed-loop CNC with steppers.

What you need to do is to run the step-generators in velocity mode.
Then, just like any other servo system, you compare the linear scale
position with the commanded position, and the further you are from
commanded position the faster you drive the motor.

You do this with the normal LinuxCNC PID controller. The controller
will need to be tuned just like any other PID loop, but the stepper
motors behave like almost perfect velocity-mode servos in this
configuration.

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

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Andrew]

Hi Chris! 
How about that: 
http://catalog.orientalmotor.com/item/all-categories/ories-legacy-products-stepper-motor-drivers-legacy/asd16a-c?cid=1002&prodid=3001170&itemid=63126&backtoname=Item+%23+ASM98ACE&pane=sb&bc=100%7C3001136%7C3001170xx
I use it for a long time.
Regards,
Andrew






Вторник, 19 января 2016 г., 10:04 +0300 от albertson.ch...@gmail.com  
:
>I've read that it is hard to use steppers for closed loop CNC.  If this is
>still true could some one explain the theory.
>
>I have a small mill with DRO scales that are good to about .001 inch and
>I'd like to put them to use with my planned CNC conversion.   I understand
>software.  I've worked in the field for 30 years and have experience with
>Linux (and other OS) device drivers, embedded real time code and so on.
>If the problem is simply that no one has bothered to write the code, I can
>fix that.   But if there is something of a mechanical nature I'm not
>thinking of maybe some one can point me at what I need to read up on.
>
>At least I think I might be able too automatically measure backlash using
>the DRO scale data.  But my goal is to go closed loop if I can
>
>-- 
>
>Chris Albertson
>Redondo Beach, California
>--
>Site24x7 APM Insight: Get Deep Visibility into Application Performance
>APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
>Monitor end-to-end web transactions and take corrective actions now
>Troubleshoot faster and improve end-user experience. Signup Now!
>http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
>___
>Emc-users mailing list
>Emc-users@lists.sourceforge.net
>https://lists.sourceforge.net/lists/listinfo/emc-users
--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[John Dammeyer]

Hi Chris,
Wiki defines Servo Motor as a motor that has closed the loop so it knows the
position of the motor.

Years ago there were discussions about closed loop with linear scales.  The
trouble there is the amount the motor has to turn before the scales report
data.  That can cause oscillations that are hard to damp.

There is no reason a stepper cannot be the drive part of the motor with an
encoder feedback.  Google TXM24C-1CG for example.  And there are others.
The current name for that type of drive is step-servo.

The UHU Servo driver http://www.uhu-servo.de/servo_en/ explains how to use a
DC motor with either a 0 to +/- 10V or PWM and DIR.

One of the first electronic lead screws also used a DC motor on the lathe
lead screw.  Using counters connected to the spindle motor and the lead
screw motor the difference between the counters is an error value that
adjusts the DC voltage out to the motor.

In each of these examples a varying DC voltage or PWM to a DC motor is the
control.  A brushless DC motor still essentially works the same way too.
Supply a voltage or PWM and the motor turns.

Not so with stepper motors.  You essentially need to first create a driver
that effectively turns the motor at a specific RPM based on a voltage input.
Then you can close the loop with the desired number of steps in verses the
encoder counts as an error that moves the motor in the correct direction for
the required distance.

John Dammeyer
.




> -Original Message-
> From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> Sent: January-18-16 11:04 PM
> To: Enhanced Machine Controller (EMC)
> Subject: [Emc-users] Question about closed loop CNC
> 
> 
> I've read that it is hard to use steppers for closed loop CNC.  If this is
> still true could some one explain the theory.
> 
> I have a small mill with DRO scales that are good to about .001 inch and
> I'd like to put them to use with my planned CNC conversion.   I understand
> software.  I've worked in the field for 30 years and have experience with
> Linux (and other OS) device drivers, embedded real time code and so on.
> If the problem is simply that no one has bothered to write the code, I can
> fix that.   But if there is something of a mechanical nature I'm not
> thinking of maybe some one can point me at what I need to read up on.
> 
> At least I think I might be able too automatically measure backlash using
> the DRO scale data.  But my goal is to go closed loop if I can
> 
> --
> 
> Chris Albertson
> Redondo Beach, California
>

--
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Yves Watier]

Hi Chris,

At my work place, closed loop systems with steppers has been in use for years.
It is a scientific institute and the controller has been developed inhouse.
The controller is doing the step generation based on a demanded position.
Encoder feedback on the real axis is giving the error.
Without a doubt it can be done in linuxcnc.
On the daily basis it is not more complicated to tune than another pid
system with servos.

So far as I've seen in linuxcnc for a closed loop system with stepper,
you only have code for controlling if you don't have a following error
too big. I haven't check recently but I haven't seen code for stepper
close loops.

Linuxcnc guru's advices would be interesting here.

Cheers,
Yves


2016-01-19 8:04 GMT+01:00 Chris Albertson :
> I've read that it is hard to use steppers for closed loop CNC.  If this is
> still true could some one explain the theory.
>
> I have a small mill with DRO scales that are good to about .001 inch and
> I'd like to put them to use with my planned CNC conversion.   I understand
> software.  I've worked in the field for 30 years and have experience with
> Linux (and other OS) device drivers, embedded real time code and so on.
> If the problem is simply that no one has bothered to write the code, I can
> fix that.   But if there is something of a mechanical nature I'm not
> thinking of maybe some one can point me at what I need to read up on.
>
> At least I think I might be able too automatically measure backlash using
> the DRO scale data.  But my goal is to go closed loop if I can
>
> --
>
> Chris Albertson
> Redondo Beach, California
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users



-- 
Watier Yves

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] G2/G3 is eating my lunch again

[Kyle Kerr]

Re: OSHPark and gEDA/PCB
I have sent artwork from PCB to OSHPark and received exactly what I sent
them. Problem being exactly what I sent was ... wrong. There were no
circuits on the back side due to me not paying attention to the files I was
renaming. As to OSHPark vs some of the Chinese fab houses (iTead, Seeed),
it really depends on board size. If the best you can do is 2" square, go
with the overseas fab houses. If you are after dainty boards and don't need
a boatload, go with OSHPark.
I am not thrilled about linking to this info, but,
http://letsmakerobots.com/node/37591 and
http://letsmakerobots.com/node/38709
might be of some interest. I scanned the first link and found the mention
of the bottom file not being what you want to rename, but rather, the
group1 file actually holds the image of the bottom traces. The second link
is a quick post about custom silk screen on the bottom of a board using PCB.

On Mon, Jan 18, 2016 at 7:55 PM, Gene Heskett  wrote:

> On Monday 18 January 2016 11:36:47 andy pugh wrote:
>
> > On 18 January 2016 at 16:07, Gene Heskett  wrote:
> > >> http://www.ebay.com/itm/252240794914
> > >
> > > But it says 0-400 hz.
> >
> > No it doesn't, it says
> >
> > "Range:0.1~2500.0Hz"
>
> I'll look again, brb.  Humm, way down the page.  Yeah, I could
> (theoretically) go to 150,000 rpms if I could buy a suitable motor, but
> I don't believe that puppy has been invented yet.
>
> In any event, I bought it. But despite its showing a row of motor
> selections, I couldn't find one at that "store".  So I'll have to go
> back to trolling.
>
> I did find an air cooled motor and a bracket and bought them too. But its
> 80mm in diameter, so might be a bit difficult to mount anywhere near
> permanently. Getting it configured as a 2nd spindle might be "fun", but
> that bridge is not in sight yet.
>
> Now, to go email Nick at psha.org.ru and see if he can be cajoled into
> assembling some camview-emc packages for wheezy.
>
> I just came in from testing the charge-pump detector, and it appears it
> might just barely work in a 3.3 volt circuit, but works great on
> anything above 3.75V p-p input.  So I think I am in business for that
> function since all my I/O is 5 volts at the BoB screw terminal.
>
> Thanks for the pointer on that Andy.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page 
>
>
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] Question about closed loop CNC

[Karlsson & Wang]

In a closed loop their is feed back, read about control theory. Stepper motors 
are usually run open loop and no feedback is needed although they may loose 
steps if not correctly tuned.

Nicklas Karlsson


On Mon, 18 Jan 2016 23:04:05 -0800
Chris Albertson  wrote:

> I've read that it is hard to use steppers for closed loop CNC.  If this is
> still true could some one explain the theory.
> 
> I have a small mill with DRO scales that are good to about .001 inch and
> I'd like to put them to use with my planned CNC conversion.   I understand
> software.  I've worked in the field for 30 years and have experience with
> Linux (and other OS) device drivers, embedded real time code and so on.
> If the problem is simply that no one has bothered to write the code, I can
> fix that.   But if there is something of a mechanical nature I'm not
> thinking of maybe some one can point me at what I need to read up on.
> 
> At least I think I might be able too automatically measure backlash using
> the DRO scale data.  But my goal is to go closed loop if I can
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> --
> Site24x7 APM Insight: Get Deep Visibility into Application Performance
> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
> Monitor end-to-end web transactions and take corrective actions now
> Troubleshoot faster and improve end-user experience. Signup Now!
> http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users

--
Site24x7 APM Insight: Get Deep Visibility into Application Performance
APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month
Monitor end-to-end web transactions and take corrective actions now
Troubleshoot faster and improve end-user experience. Signup Now!
http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users