On Sat, 17 Sep 2011, Viesturs L?cis wrote: > Date: Sat, 17 Sep 2011 19:02:48 +0300 > From: "[UTF-8] Viesturs L?cis" <viesturs.la...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Encoders on 7i48 > > 2011/9/17 Peter C. Wallace <p...@mesanet.com>: >> >> Since you have no feedback until you get your encoders working, I would just >> try getting +- 10V out of the 7I48 by setting the output scale to 10, >> disconnecting the PWM .value from the PID loop and setting it >> manually in volts with setp ) try +10, -10, +5 ,-5 ,0 etc > > Thank You for the suggestion! > EMC does receive encoder signal from servo drive (motors have > resolvers, servodrive emulates encoder signal and outputs it on a > 9-pin serial port connector, from where the signal is wired to 7i48). > I am watching "position" pins of encoders from servo drive and they > either increase to very high values or decrease to very low values. > Actually EMC receives all 6 encoder signals, also 3 from linear scales > - I also checked their "position" pins, when pushing machine by hand > (motors are detached) and it seems that the increase/decrease in the > value of linear scales' position pin matches the actual travel. > > I have 2 questions: > 1) I have managed to get 2 joints oscillate around zero, (which tells > me that they need have PID parameters adjusted). There is a problem > with a third joint, which just runs away. When I try to change > something for that third joint, it affects also some of first two. Why > is that so? For example, if I set Output_scale for third joint from 1 > to -1, second joint will not oscillate around zero, but run away.
There should be no interaction of the axis I would do as I has suggested and verify that all DAC channels work as expected before proceeding. interaction suggests a grounding/ analog input problem (do the drives have differential inputs ( most do) If so the IN+ sould go to 7I48 AOUT and the IN- to 7I48 ground > > 2) How do I solve the situation, when PWM value is +1, but encoder > position increases in negative direction? That is for the third joint. > As I mentioned, changing output scale to -1 for third joint will make > second joint to misbehave. What else can cause that? Should I change A > and B wires from encoder signal cable? I would first set up the encoders so they count in the correct direction for your axis, and then change the output scale to reverse the PID feedback if need be. But first you need to find out where the interaction is coming from (could also be HAL file error) > > Viesturs > > ------------------------------------------------------------------------------ > BlackBerry® DevCon Americas, Oct. 18-20, San Francisco, CA > http://p.sf.net/sfu/rim-devcon-copy2 > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > 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. ------------------------------------------------------------------------------ BlackBerry® DevCon Americas, Oct. 18-20, San Francisco, CA http://p.sf.net/sfu/rim-devcon-copy2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
