> From: andy pugh [mailto:bodge...@gmail.com] > On Fri, 9 Jul 2021 at 18:43, John Dammeyer <jo...@autoartisans.com> wrote: > > > Although if I understand the G31.1 correctly the Z axis tracks the encoder > > reported speed right? > > No, that would be silly. It tracks the actual spindle position. > > G74 / G84 work on open-loop velocity, but assume a tension/compression head. > > > So the spindle speed before the tapping starts and for reversing is really > > more of a guide than an actual written in stone value? > > > > In other words, is the PID even needed? > > No, you can, in fact, turn the spindle off and rotate it by hand and > LinuxCNC will still track. > Haven't tried that as the spindle servo enable is tied to the general system enable so it's locked when not turning. Handy since I can loosen and tighten the drawbar without a second wrench.
At some point I want to add a few switches and a control so I can manually switch on the spindle and set the speed without touching the mouse. I can do that from my pendant but it's not as convenient was what I'd really like to do. Plus still want to get into Modbus using the modio I have lying around here. At the moment I can consider the PWM to 0V-10V with 60 slot encoder project complete. The PID works well enough to bring the spindle to the target speed and hold it there. I believe that if you are running PWM to voltage with the encoder back to LCNC with PID that the +/- output is perfectly reasonable since the closed loop control is only being done my LCNC and a minus voltage to the windings would cause hard braking to slow down the spindle (or whatever). But running a high end servo with internal PID that has the capability of decelerating and spinning in the other direction rather than just braking to slow down with a minus PID output from the LCNC PID is dangerous. I'd suggest rather than having to add a limit block, that the PID module have the same sort of min/max parameters added. Doing it outside the PID seems slower. Thanks for everyone's help. Time to rewire for step/dir and change the BIT file in the 7i92H. John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
