Hi John, I’m just confused, since I’m not clear on how the signal would then be communicated if both parameters are set to 0. I did try both with zero initially and didn’t observe any movement so I went to P=1. Then I saw very slow movement. That prompted me to tune for the limit of stability per some instructions I found. But at the end of the day the steady state jog ferror just increases for all reasonable P values in LinuxCNC regardless of the drive tune. I was planning to try P=0 and FF1=1 next.
Matt > On Jun 29, 2021, at 10:48 PM, John Dammeyer <jo...@autoartisans.com> wrote: > > 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:herd.m...@gmail.com] >> 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 <herd.m...@gmail.com> 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 >>> herd.m...@gmail.com >>> 610-608-8930 >>> >>>> On Jun 29, 2021, at 8:31 AM, Les Newell <les.new...@fastmail.co.uk> 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 >>>> 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 > > > > _______________________________________________ > 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
