Hi Matt, I'm running the XYZ with a P1000 and FF1=1. But the Servo Drives do the rest. Even the spindle is an AC Servo Drive with step/dir interface but for it I'm running P=0 and FF1=0. When I first started I had issues with P=0 and FF1=1 and I had no motion at all. Setting FF1=0 solved that problem.
So try FF1=0 and P=0 and then only the drive should be involved in tuning. John [AXIS_X] MIN_LIMIT = -0.04 MAX_LIMIT = 13.5 MAX_VELOCITY = 3.0 MAX_ACCELERATION = 12 [JOINT_0] TYPE = LINEAR HOME = 0.0 FERROR = 0.5 MIN_FERROR = 0.1 MAX_VELOCITY = 3.0 #MAX_ACCELERATION = 7.5 MAX_ACCELERATION = 12 # The values below should be 25% larger than MAX_VELOCITY and MAX_ACCELERATION # If using BACKLASH compensation STEPGEN_MAXACCEL should be 100% larger. STEPGEN_MAXVEL = 3.75 #STEPGEN_MAXVEL = 3.75 #STEPGEN_MAXACCEL = 15.0 STEPGEN_MAXACCEL = 24 P = 1000.0 I = 0.0 D = 0.0 FF0 = 0.0 FF1 = 1.0 FF2 = 0.0 BIAS = 0.0 DEADBAND = 0.0 MAX_OUTPUT = 0.0 # these are in nanoseconds DIRSETUP = 1000 DIRHOLD = 1000 STEPLEN = 2000 STEPSPACE = 1000 STEP_SCALE = 15000.0 MIN_LIMIT = -0.04 MAX_LIMIT = 13.5 # tested backlash at 4.2" from home 14MAR2020 BACKLASH = 0.0189 HOME_OFFSET = -0.1 #HOME_SEARCH_VEL = -0.8 #HOME_LATCH_VEL = 0.01 HOME_FINAL_VEL = 0.2 HOME_IGNORE_LIMITS = YES HOME_VOLATILE = 1 #HOME_SEQUENCE = 1 > -----Original Message----- > From: Matthew Herd [mailto:[email protected]] > Sent: June-29-21 7:32 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Advice on Tuning Servo System > > I fiddled with the X axis servo drive and tuned the parameters with P=1 and > jog speed set to 60 IPM. The ferror always returned to > zero but did so at an exceedingly slow pace. I tuned the drive to the limits > of stability (or a little over) and the movement was always > so slow you couldn�t detect it. I then went to LinuxCNC and turned up the P > values until I saw instability. The machine moved much > more quickly, but still lagged the commanded value. As P increased the lag > was lessened, but always increased with constant > jogging. The velocity command to the USC board was a clean acceleration > ramp, constant velocity, and deceleration ramp. I cannot > explain why my results are so poor, but I�m hoping that someone might have > some suggestions on how to determine whether it�s a > problem with my settings in LinuxCNC or a problem with the drives. > > Matt > > > > On Jun 29, 2021, at 8:55 AM, Matthew Herd <[email protected]> wrote: > > > > Ok I thought so. I just want to confirm that setting all PID parameters to > > 0 will allow the velocity commands to pass through. I�d > think I�d need P=1 or something along those lines? > > > > I hope to try this one evening this week if I can get to the shop. > > > > Thanks again! > > > > Matthew Herd > > [email protected] > > 610-608-8930 > > > >> On Jun 29, 2021, at 8:31 AM, Les Newell <[email protected]> wrote: > >> > >> ?I just checked the docs and you are correct. I assumed you were using a > >> standard stepgen. I didn't realize Pico USC works > differently. > >> > >> Les > >> > >>> On 29/06/2021 13:18, Matthew Herd wrote: > >>> Hi Les, > >>> > >>> I�m not sure if that will work with the Pico USC board. If I�m not > >>> mistaken LinuxCNC treats the motors as servos and the board > handles the step generation. > >>> > >>> Matt > >>> > >>> > >> > >> > >> > >> _______________________________________________ > >> Emc-users mailing list > >> [email protected] > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
