Maybe it's a MESA issue? It's set up as output type 1 which is 0-100% which means either the Out2 should invert when pwmgen gets negative? Or the output should clip to 0 when the calculation determines a negative output. http://linuxcnc.org/docs/html/man/man9/hostmot2.9.html#pwmgen
BTW this is commented out. setp pid.s.maxerror .0005 If I set it to 0.05 then the spindle does stop but now the PID isn't very responsive. I have to add large amounts of P and I to get it to stabilize quickly and at 100RPM it then surges Set it to 0.5 and it goes wonky with the negative error again. Any smaller than 0.05 and response is so poor that it's really not a manageable system. I could just switch over to using step/dir and do away with the PWM but that likely won't solve the closed loop problem. The AC Servo by itself is responsive and stable. But the pulley ratio means what I tell it isn't what it's doing and that's an issue for tapping. John > -----Original Message----- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: July-08-21 4:25 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Runaway PID spindle. > > On Fri, 9 Jul 2021 at 00:21, John Dammeyer <jo...@autoartisans.com> wrote: > > > > Oh and I was using this series of postings as a guide. > > https://forum.linuxcnc.org/49-basic-configuration/32553-spindle-pid-control > > but he never ran into this issue. Same with the other postings where they > > have problems achieving the speed. Not running away > with a negative correction. > > I have had exactly your problem in the past, but I can't remember how > I fixed it, as it was years ago. > > But it was definitely caused by the PID going negative, but negative > output giving positive speed/ > > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is > designed for the especial use of mechanical geniuses, daredevils and > lunatics." > � George Fitch, Atlanta Constitution Newspaper, 1912 > > > _______________________________________________ > 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
