On Tuesday 03 March 2020 21:54:55 Jon Elson wrote: > On 03/03/2020 10:54 AM, andy pugh wrote: > > On Tue, 3 Mar 2020 at 16:50, Jon Elson <el...@pico-systems.com> wrote: > >> Does anybody have a more specific case of how it is failing? > > > > https://forum.linuxcnc.org/38-general-linuxcnc-questions/38367-2-7-1 > >5?start=0 > > So, the pid command-deriv was not used in the past? Geez, > that could explain a LOT of issues with > servo tuning before the change. > > I use feedback-deriv in my servo systems, would a > non-functioning command-deriv make that not > work right? > > Jon > It sure screwed up my stepper systems that used it, following errors galore. From my TLM's *.hal file:
net x-vel-cmd <= joint.0.vel-cmd # => pid.x.command-deriv It turns out there is no such signal source as a joint.n.vel-cmd from motion. So one could break the noise injection path as above or put a # in front of the net command that constructs it, either way fixes it. The symptoms were needing to use 1/2" or more FERROR settings. I have one axis still set at .50000 for FERROR, but it is NOT even present in the hal file so its not even used! Obviously I need to fix that before I do anything critical on TLM. And on the GO704 too probably. But that can wait till I have working spindle encoders on both the GO704, and the Sheldon. The GO704 should be done tomorrow as I've about got it converted from opto indexing to ATS-667 watching a short piece of nail glued to the spindle for an index pulse. Major delay is waiting for jbkwik to set, which takes about a day. The optical I had built years ago, the disk came unbolted and sawed the opto's in 2. Since all I needed was the index to trigger rigid tapping, that is all I'm putting back in. The A/B stuff is on the rear of the motor, and around 100x more accurate. Based on what I found in my configs just now, I am guessing several we's have work to do to optimize that again. Is there a procedure to do that? Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
