Thanks Todd, your suggestion lead me to the issue. Turns out PNConfig sets the P term to 1000 (and Deadband to 0.0) at which point I got a terrible nose from the motors. Setting the P term down to 10, and setting Deadband to 0.0005 has it running quite smoothly. Now to run Halscope and get the tuning right…
-Tom > On Jun 26, 2017, at 10:28 AM, Todd Zuercher <zuerc...@embarqmail.com> wrote: > > Maybe you've already tried this, but I would think the easiest way is to use > PNCcofig to create an ordinary stepper configuration. It will set up a > velocity mode config with the hardware stepgen sending the feedback to close > the pid loop. Get that working. Then modify that config by adding the > encoder reading, and replace the stepgen's feed back with the encoder's > feedback to the pid loop and to the axis.N.pos-fb (or joint.N.pos-fb in > Master) Then adjust the P tuning till it "works". I have such a setup on a > machine using step/dir servos, and using it with step motors would be exactly > the same (except for the PID tuning.) > > The trick is to only try making one major modification at a time. So first > get a velocity mode stepgen config working (without encoder feedback), Then > add encoder feedback (do it one axis at a time.) First get the DRO's working > with the encoder feedback. Then connect the encoders to the PID loops. > > ----- Original Message ----- > From: "Tom Easterday" <tom-...@bgp.nu> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Sent: Monday, June 26, 2017 8:37:47 AM > Subject: Re: [Emc-users] steppers with encoders in closed loop > > Exactly, and any help in getting my stall detection and position tracking > working using velocity mode would be greatly appreciated 😀 > > -Tom > >> On Jun 26, 2017, at 6:52 AM, Rene Hopf <reneh...@mac.com> wrote: >> >> there is no benefit in using them in linuxcnc, apart from stall detection or >> position tracking. >> > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
