On Mon, 13 Jan 2014, Viesturs L?cis wrote: > Date: Mon, 13 Jan 2014 21:50:51 +0200 > From: "[UTF-8] Viesturs L?cis" <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Subject: [Emc-users] Servo questions > > Hello! > > I am trying to set the machine up. It has 5i23+7i48 cards, 3 Kinco servo > drives and 3 linear scales, so I am aiming at trying 2 feedback devices for > each joint. > I have following questions: > > 1) I tried autotuning of these Kinco drives; currently motors are stable > and as it seems fine as much as I can tell at the moment. > Does anybody have experience with Kinco servo drives and their autotuning > feature? Is there anything specific to take into account, anything specific > to adjust? > > 2) to test feedback loop in servo drive, I would like temporarily not to > use pid modules in LinuxCNC, but it seems that I can't figure out correct > HAL connections. > In HAL file I have: > axis.0.motor-pos-cmd => hm2_5i23.0.pwmgen.00.value > axis.0.motor-pos-fb <= hm2_5i23.0.encoder.00.position > But it seems that there is something wrong - if I try to jog motor, it just > moves until ferror is triggered. Everything is fine, if I drive pwmgen > value from pyvcp widget - motor moves smoothly and encoder velocity seems > correct, it smoothly changes as I adjust pwmgen value. > > 3) currently my servo tuning experience includes exclusively 7i39 drives, > so now I do not understand, how am I supposed to close position loop in > LinuxCNC, when velocity loop is closed in servo drives (they are running in > velocity mode). Is it correct that I should use only P and I parameters? > If yes, does it mean that with 2 feedback devices I would use only P > parameter in pid controller that receives position feedback from motor and > and I parameter in pid controller that receives position feedback from > linear scales?
For a velocity mode drive you tune mainly with P and FF1: http://gnipsel.com/linuxcnc/tuning/servo.html Note that I would first scale the PID output so the the velocity command (the output of the PID loop) is scaled in machine units per second at full scale (10V) This makes FF1 be close to 1 (so the PID comp just passes the velocity command directly to the drive) I think that dual loop systems tend to use mainly I for the slow (linear scale) portion > > Thanks in advance! > > Viesturs > ------------------------------------------------------------------------------ > CenturyLink Cloud: The Leader in Enterprise Cloud Services. > Learn Why More Businesses Are Choosing CenturyLink Cloud For > Critical Workloads, Development Environments & Everything In Between. > Get a Quote or Start a Free Trial Today. > http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
