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.
> -----Original Message----- > From: andy pugh [mailto:bodge...@gmail.com] > Sent: July-08-21 3:57 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Runaway PID spindle. > > On Thu, 8 Jul 2021 at 23:19, John Dammeyer <jo...@autoartisans.com> wrote: > > > When I click the '-' with the RPM at 501 it drops to 401. Again and so on > > down to 101. The last click should take it down to 1 or 0 > RPM. However that last click sends it to max speed of 3000 RPM. > > This happens when the PID goes negative. Imagine that the PID output > is 0, but the speed is still positive, so the PID reduces the output > to -10. This becomes an absolute speed ot 10, which is still too high, > so the PID goes down to -100.... > > The best way round this is probably to pass the pid output through an > abs block (I think that you do that) but then control the spindle > direction using the abs.0.is-positive / is-negative outputs rather > than the spindle direction pins. > > -- > 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
