On Wed, 17 Aug 2011, Scott Hasse wrote: > Date: Wed, 17 Aug 2011 14:32:20 -0500 > From: Scott Hasse <scott.ha...@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] Mesa 5i23/7i33TA servo instability question > > I'm in the shop working on this right now and am wondering how to verify the > PID loop is providing feedback to each axis. I've been using pncconf to > generate the configuration, and assumed since it allows you to set PID that > it would configure it to feedback automatically. However, since I've been > using pncconf as a crutch, I'm not sure off-hand how to config PID feedback > is working. I see P, I, D values in the ini file for each axis, but I am > still seeing small amounts of servo instability. > > I see the instability even with the servo signal grounded. > > I have followed this page: > > http://wiki.linuxcnc.org/emcinfo.pl?Tuning_EMC2/HAL_PID_Loops > > and verified that the output voltages are correct, but get stumped at the: > > Set up PID loop add the loop and interconnect step. > > Thanks in advance for any advice, > > Scott
Did you set your FERROR larger so you can see whats going on? Normally for a velocity mode servo what I would do is this: First FERROR and min FERROR to 1 inch or so set I and D to 0 and set a small P term (say .1) Jog around to verify that the PID loop is controlling the servo Then slowly increase P until you have oscillation (jog around while adjusting P to make sure that stiction is not preventing oscillation) Once you have P adjusted to the point of oscillation, start adding D term until the oscillation stops. Then I would set up halscope to trigger on commanded position, view commanded position, actual position, and FERROR and then do some long slewing back and forth motions. Adjust the FF1 for minimum FERROR during motion. > > On Wed, Aug 17, 2011 at 7:55 AM, John Thornton <bjt...@gmail.com> wrote: > >> The 1100M came both ways with glass scales (earlier model) then with >> encoder feedback. Mine is the encoder variety of 1100M. >> >> John >> >> On 8/17/2011 7:28 AM, andy pugh wrote: >>> On 17 August 2011 04:15, Scott Hasse<scott.ha...@gmail.com> wrote: >>> >>>> To the point, though, I am having one not-so-minor problem. When I >> enable >>>> the servos, they are not completely stable, and I'll get following error >>>> almost immediately after enabling them. They don't run away, but the >>>> encoders show them moving ever so slightly, and physically the motors >>>> actually are moving. >>> Are you retaining the velocity feedback to the amps, so that they run >>> an internal velocity loop, and then you use velocity commands to close >>> your position loop based on the encoders? >>> >>> The previous Anilam system I chatted to someone about had velocity >>> tachs on the motors and linear scales, no rotary encoders. >>> >>> So, in Anilam control is the feedback from linear scales, and encoders >>> in EMC2 mode? >>> >> >> >> ------------------------------------------------------------------------------ >> Get a FREE DOWNLOAD! and learn more about uberSVN rich system, >> user administration capabilities and model configuration. Take >> the hassle out of deploying and managing Subversion and the >> tools developers use with it. http://p.sf.net/sfu/wandisco-d2d-2 >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > ------------------------------------------------------------------------------ > Get a FREE DOWNLOAD! and learn more about uberSVN rich system, > user administration capabilities and model configuration. Take > the hassle out of deploying and managing Subversion and the > tools developers use with it. http://p.sf.net/sfu/wandisco-d2d-2 > _______________________________________________ > 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. ------------------------------------------------------------------------------ Get a FREE DOWNLOAD! and learn more about uberSVN rich system, user administration capabilities and model configuration. Take the hassle out of deploying and managing Subversion and the tools developers use with it. http://p.sf.net/sfu/wandisco-d2d-2 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
