On Wednesday, February 2, 2022 2:39:29 AM EST Thaddeus Waldner wrote: > Hi, > > I have a pi4 running the 2.8.2 iso. I have it connected to a Mesa 7i96 > and from there I’m driving small stepper motors with tmc2209 > “stepstick” drivers. I think my step rate at max speed is around 8khz > > I get around +-70us? Max latency. > > I’ve been having an issue with what I think is latency which makes the > steppers sound like they have bad bearings. Raising the servo period > to 2ms made it worse. So I tried a faster servo thread and discovered > the issue pretty much goes away with the servo period at 250us. At > that rate I start running into joint following issues. > > I then learned that with the servo period at 1ms, if I lower the > stepper PID P parameter to 100 instead of the 1000 set by the > configuration wizard, the noise goes away completely and the steppers > run buttery smooth. > > I have a few questions: > 1) what are the implications of running the PID stepper with p=100? > 2) why is servo thread jitter even making into the stepper pulse train > with a Mesa Ethernet card and no communication errors? Do I have > anything misconfigured? > > Thanks
What kernel does that iso use on an rpi4? See with a uname -aENTER And post it plz. > > > > _______________________________________________ > 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, 1940) 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
