Re: [Emc-users] Rough motion with servos

On 06/30/2017 11:45 AM, Peter C. Wallace wrote: This does show that a relatively small quadrature error causes a large velocity modulation is the relative time between edge changes so much Good encoders have very close to 50% duty cycle on the individual A and B outputs, at least when new.

Re: [Emc-users] Rough motion with servos

users@lists.sourceforge.net> > > To: emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Rough motion with servos > > > > On Friday 30 June 2017 12:45:55 Peter C. Wallace wrote: > >> On Fri, 30 Jun 2017, Gene Heskett wrote: > >>> Dat

Re: [Emc-users] Rough motion with servos

Dammit, for some reason when I reply to messages on this list they often end up going to the author of the message rather than to the list. Sorry Gene, you'll probably end up receiving two copies of this. Les, when I have something like that, I often ask myself if it was worth chewing thru

Re: [Emc-users] Rough motion with servos

On Fri, 30 Jun 2017, Gene Heskett wrote: Date: Fri, 30 Jun 2017 16:59:19 -0400 From: Gene Heskett <ghesk...@shentel.net> Reply-To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Ro

Re: [Emc-users] Rough motion with servos

users@lists.sourceforge.net> > > To: emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Rough motion with servos > > > > On Friday 30 June 2017 09:27:29 Peter C. Wallace wrote: > >> On Fri, 30 Jun 2017, Les Newell wrote: > >>> Date:

Re: [Emc-users] Rough motion with servos

it the same even though it Just Works(TM) now? > > On 29/06/2017 22:29, Peter C. Wallace wrote: > > On Thu, 29 Jun 2017, Les Newell wrote: > >> Date: Thu, 29 Jun 2017 21:59:46 +0100 > >> From: Les Newell <les.new...@fastmail.co.uk> > >> Reply-To: &quo

Re: [Emc-users] Rough motion with servos

Years ago Jon Elson convinced me you almost could not too many counts/rev. Going from 5000 c/in (glass scale) to 40K c/in made a huge difference in how easy it was to tune. I agree with Jon but changing the encoder is a pain and once I got past the noise issues, tuning it was pretty

Re: [Emc-users] Rough motion with servos

On 06/30/2017 04:11 AM, Les Newell wrote: I think it is time to put a scope on the encoder. it sounds like there may be a big duty cycle or phase angle error in that encoder. In other words, at constant speed, the 4 quadrature transitions are not evenly spaced, but at least one of them is

Re: [Emc-users] Rough motion with servos

On Fri, 30 Jun 2017, Gene Heskett wrote: Date: Fri, 30 Jun 2017 12:22:24 -0400 From: Gene Heskett <ghesk...@shentel.net> Reply-To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Ro

Re: [Emc-users] Rough motion with servos

On 06/29/2017 06:42 AM, Les Newell wrote: I tried using Buildbot on a fresh install of Stretch amd64 and got a bunch of missing dependencies: python-gst0.10 (Stretch has python-gst1.0) gstreamer0.10-plugins-base hostmot2-firmware-all Thanks for reporting this problem. We've removed the

Re: [Emc-users] Rough motion with servos

users@lists.sourceforge.net> > > To: emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Rough motion with servos > > > >> I think it is time to put a scope on the encoder. it sounds like > >> there may be a big duty cycle or phase angle error

Re: [Emc-users] Rough motion with servos

r (EMC)" <emc-users@lists.sourceforge.net> To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Rough motion with servos Do you have and raw-write encoder filter tweaking stuff in the hal file: No. For testing purposes I am running the barest minimum needed to achieve motion u

Re: [Emc-users] Rough motion with servos

On Fri, 30 Jun 2017, Les Newell wrote: Date: Fri, 30 Jun 2017 12:11:09 +0100 From: Les Newell <les.new...@fastmail.co.uk> Reply-To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Ro

Re: [Emc-users] Rough motion with servos

May I opine that noise on one of the encoder lines may cause a zero speed estimation. If you get two of the same channel edges in a row the encoder logically must have reversed direction. It must go through zero speed to change direction. Since a third edge (one on the other channel) is not yet

Re: [Emc-users] Rough motion with servos

On Friday 30 June 2017 07:11:09 Les Newell wrote: > > I think it is time to put a scope on the encoder. it sounds like > > there may be a big duty cycle or phase angle error in that encoder. > > In other words, at constant speed, the 4 quadrature transitions are > > not evenly spaced, but at

Re: [Emc-users] Rough motion with servos

I think it is time to put a scope on the encoder. it sounds like there may be a big duty cycle or phase angle error in that encoder. In other words, at constant speed, the 4 quadrature transitions are not evenly spaced, but at least one of them is out of time. I can see the phase angle

Re: [Emc-users] Rough motion with servos

On 06/29/2017 03:59 PM, Les Newell wrote: Do you have and raw-write encoder filter tweaking stuff in the hal file: No. For testing purposes I am running the barest minimum needed to achieve motion using a config generated by pncconf. After spending a lot of time playing with halscope I

Re: [Emc-users] Rough motion with servos

On Thu, 29 Jun 2017, Les Newell wrote: Date: Thu, 29 Jun 2017 21:59:46 +0100 From: Les Newell <les.new...@fastmail.co.uk> Reply-To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Ro

Re: [Emc-users] Rough motion with servos

Do you have and raw-write encoder filter tweaking stuff in the hal file: No. For testing purposes I am running the barest minimum needed to achieve motion using a config generated by pncconf. After spending a lot of time playing with halscope I have some interesting findings. Most of what

Re: [Emc-users] Rough motion with servos

On 06/29/2017 10:20 AM, Les Newell wrote: Well, some progress figuring out what is going on. I just ran some more tests using Ubuntu 16.04 with a freshly built preempt-rt kernel and freshly built Git master. No surprise, it still shows the fault. I took a Halscope log from the original

Re: [Emc-users] Rough motion with servos

@lists.sourceforge.net> Subject: Re: [Emc-users] Rough motion with servos Well, some progress figuring out what is going on. I just ran some more tests using Ubuntu 16.04 with a freshly built preempt-rt kernel and freshly built Git master. No surprise, it still shows the fault. I took

Re: [Emc-users] Rough motion with servos

Well, some progress figuring out what is going on. I just ran some more tests using Ubuntu 16.04 with a freshly built preempt-rt kernel and freshly built Git master. No surprise, it still shows the fault. I took a Halscope log from the original setup. The encoder velocity is rather noisy but

Re: [Emc-users] Rough motion with servos

I tried using Buildbot on a fresh install of Stretch amd64 and got a bunch of missing dependencies: python-gst0.10 (Stretch has python-gst1.0) gstreamer0.10-plugins-base hostmot2-firmware-all Les On 28/06/2017 19:37, Todd Zuercher wrote: If you install from buildbot, both linuxcnc and

Re: [Emc-users] Rough motion with servos

; <les.new...@fastmail.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, June 28, 2017 2:52:03 PM Subject: Re: [Emc-users] Rough motion with servos Hi Todd, Does buildbot go back to 10.04 times? I though

Re: [Emc-users] Rough motion with servos

Hi Peter, As far as I can tell the spikes are in the feedback velocity. It can be a little difficult to tell cause and effect. Are you using identical hal files for the system with the spikes/without spikes? When I built the 2.6.13 branch on the 2.7.9 ISO I only had to make some very

Re: [Emc-users] Rough motion with servos

to build all of Linuxcnc from source. - Original Message - From: "Les Newell" <les.new...@fastmail.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, June 28, 2017 2:26:52 PM Subject: Re: [Emc-users] Rough mo

Re: [Emc-users] Rough motion with servos

Did you trace the source of the PID output spikes? that is, are there glitches in feedback position of feedback velocity? The whole thing sounds very strange Are you using identical hal files for the system with the spikes/without spikes? Peter Wallace Mesa Electronics

Re: [Emc-users] Rough motion with servos

PS. Thanks for your contributions that became MB2HAL. I'm using it. - Original Message - From: "Les Newell" <les.new...@fastmail.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, June 28, 2017 2:26:52 P

Re: [Emc-users] Rough motion with servos

; <les.new...@fastmail.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, June 28, 2017 2:26:52 PM Subject: Re: [Emc-users] Rough motion with servos Hi Todd, I am building from source. I have tried several distros: Debian - some

Re: [Emc-users] Rough motion with servos

Hi Todd, I am building from source. I have tried several distros: Debian - something old, I can't remember what. This has been running fine for about 8 years but it lacks driver support for modern hardware. Ubuntu 10.04 LinuxCNC ISO - appears to run smoothly but I can't test properly until I

Re: [Emc-users] Rough motion with servos

- From: "Les Newell" <les.new...@fastmail.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, June 28, 2017 12:51:51 PM Subject: Re: [Emc-users] Rough motion with servos Hi Todd, I did that but I can't build because i

Re: [Emc-users] Rough motion with servos

s Newell" <les.new...@fastmail.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, June 28, 2017 4:50:38 AM Subject: Re: [Emc-users] Rough motion with servos Is there any way to

Re: [Emc-users] Rough motion with servos

On 06/28/2017 03:50 AM, Les Newell wrote: OK, Tried the usual reseating components etc and that PC does not want to play. I found a Dell SFF PC in the junk pile. After hacking it to take a full size PCI card I fired it up. Running my old Debian + LinuxCNC 2.6.0 it runs smooth. Latency jitter

Re: [Emc-users] Rough motion with servos

multiverse - Original Message - From: "Les Newell" <les.new...@fastmail.co.uk> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Wednesday, June 28, 2017 4:50:38 AM Subject: Re: [Emc-users] Rough motion with servos Is there

Re: [Emc-users] Rough motion with servos

net> Sent: Wednesday, June 28, 2017 4:50:38 AM Subject: Re: [Emc-users] Rough motion with servos OK, Tried the usual reseating components etc and that PC does not want to play. I found a Dell SFF PC in the junk pile. After hacking it to take a full size PCI card I fired it up. Running my old

Re: [Emc-users] Rough motion with servos

OK, Tried the usual reseating components etc and that PC does not want to play. I found a Dell SFF PC in the junk pile. After hacking it to take a full size PCI card I fired it up. Running my old Debian + LinuxCNC 2.6.0 it runs smooth. Latency jitter is 7us,10us. Running the latest LinuxCNC

Re: [Emc-users] Rough motion with servos

On 06/27/2017 03:06 PM, Les Newell wrote: Hmm, looks like that was a red herring. The problem is back. I can't do any more testing because the pixies inside the old computer finally abandoned ship and it now no longer boots. Doesn't even post. My priority now is going to be to find a box that

Re: [Emc-users] Rough motion with servos

Hmm, looks like that was a red herring. The problem is back. I can't do any more testing because the pixies inside the old computer finally abandoned ship and it now no longer boots. Doesn't even post. My priority now is going to be to find a box that will run my old EMC. Les On 27/06/17

Re: [Emc-users] Rough motion with servos

150 uS?? YIKES! That is not generally good enough for even a servo system I have done a lot of work with PID loops in various non LinuxCNC systems and in my general experience they generally seem to be very tolerant to timing variation. After all we are dealing with motors that have a

Re: [Emc-users] Rough motion with servos

What version of Linuxcnc (EMC2) were you running before the upgrade? I think there were some changes in how PIDs were handled between v2.5 and 2.7 that usually require a little servo returning. - Original Message - > From: "Les Newell" > To:

Re: [Emc-users] Rough motion with servos

Even though latency run well then I user computer for others at the same time I sometimes get a latency delay and are on the path to give up ordinary computer for servo threads. I think a small simpler computer will be more than enough and then I am free to move display. On Tue, 27 Jun 2017

Re: [Emc-users] Rough motion with servos

On 06/27/2017 10:31 AM, Les Newell wrote: Same PC, same hardware, same settings. The only difference between the two setups is the hard drive. Changing the PC (AMD processor VS Intel on the original) had no effect on the symptoms. I checked latency on the new PC and if I remember correctly

Re: [Emc-users] Rough motion with servos

Hi Dave, Just ran latency test on the old computer with LinuxCNC 32us servo 54us base. I moved some windows, opened a few programs etc. As I mentioned before I had checked on the new computer and although it wasn't great it was good enough. The fact that the fault is identical on two very

Re: [Emc-users] Rough motion with servos

"The computer I am using is showing it's age and the ancient version of Debian I have been running won't even boot properly on my new computer." implies some change to us, what?, changing OS will change the latency too Dave

Re: [Emc-users] Rough motion with servos

Same PC, same hardware, same settings. The only difference between the two setups is the hard drive. Changing the PC (AMD processor VS Intel on the original) had no effect on the symptoms. I checked latency on the new PC and if I remember correctly worst case after a couple of hours was

Re: [Emc-users] Rough motion with servos

On 06/27/2017 09:01 AM, Les Newell wrote: I have been running my lathe using EMC for many years and decided to upgrade to the latest LinuxCNC. The computer I am using is showing it's age and the ancient version of Debian I have been running won't even boot properly on my new computer. The

Re: [Emc-users] Rough motion with servos

New PC new possible latency problems? Dave Caroline -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot

Re: [Emc-users] Rough motion with servos

On Tue, 27 Jun 2017, Les Newell wrote: Date: Tue, 27 Jun 2017 15:01:34 +0100 From: Les Newell Reply-To: "Enhanced Machine Controller (EMC)" To: emc-users@lists.sourceforge.net Subject: [Emc-users] Rough motion with servos I have