Because steps/machine unit and volts/unit are not the same scale. Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031
-----Original Message----- From: Gene Heskett <ghesk...@shentel.net> Sent: Thursday, February 11, 2021 10:42 PM To: emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Dealing with Servo Faults [EXTERNAL EMAIL] Be sure links are safe. On Thursday 11 February 2021 18:31:31 Jon Elson wrote: > On 02/11/2021 04:37 PM, Gene Heskett wrote: > > So, looking at pid.error with a 100mv/div scale, 1 div would be .1 > > degree? > > If you look closely at the Halscope screen, you will see that it does > NOT show a "v". > So, you would get a 100m/div scale, 100 milli-somethings. > If the INPUT_SCALE or SCALE in > the ini file is set right so that the DRO on the Axis screen reads in > degrees, then one division would be .1 degree, at the 100m Halscope > scale. > > > I think my gain is quite a bit higher than that, but I just ran it > > from here and that is what the pid.error channel is showing for > > gain, 100m. Only the leading edge of a g0 mdi move shows more than > > .1 degree of error, and slowing the max_accel would probably lower > > that, currantly at 1000.. cruizing noise is perhaps +- .20 division > > worst case. > > A little bit of FF2 can help with spikes at the beginning and end of a > move. But, VERY small amounts are required, in the 0.001 range. > Well, it takes FF1 = 20.5 to get a cruise at about null, And I did have FF2 = .5, but .35 cancels the stop spike. So my question is why are these so far out of the normal range where for a stepgen FF1=1.0 and FF2 = .001 is about right. Something else must be seriously out of whack. But what? pid_A.output is almost straight to the pwmgen.A.value, with that pwmgen in mode 2. An idb in the middle of the link seems to be without measurable effect, but maybe I've not tried a high enough idb.amount. That is currantly at 10, a value I would think would make it overshoot and oscillate but does not. Thanks Jon > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
