On Monday 10 December 2012 23:07:29 noel did opine: > For a little information on tuning see this > http://support.motioneng.com/Downloads-Notes/Tuning/default.htm
Some neat stuff here, thanks. > And on the right near the bottom > http://support.motioneng.com/Utilities/Bode/default.htm > > Body Plot would be great to have. > How about an FFT too? > > Noel R. > 'Roguish" > > > -----Original Message----- > From: Gene Heskett [mailto:[email protected]] > Sent: Sunday, December 09, 2012 4:40 PM > To: EMC developers > Subject: [Emc-developers] PID tuning, Zeigler-Nichols method > > Greetings; > > I haven't tried this method yet, primarily because when it says its > supposed to oscillate, I would assume it is meaning a runaway, and will > be limited by the rail to rail range of the control at pid.N.out. > > I can't make Pgain cause more than about a 10% of that range cyclic > wibble, not near enough to hear it with the spindle at say 6 rps > commanded. At least at Pgains up to 150 or so, with FF0 = 100, FF1 = > 20 and FF2 = 10. > > Should I be able to induce a rail to rail oscillation with Pgain? > > Also, the sheet I've printed > > <http:www.linuxcnc.org/2.5/html/motion/pid_tuning> > > for guidance make no mention of the FF0, FF1 & FF2, whereas the man 9 > pid does. But it does make this statement in the man page that I just > now noticed: > > pid.N.feedback-deriv float in > The derivative of the actual (feedback) value for the control loop. > If no signal is connected then the derivative will be estimated > numerically. When the feedback is from a quantized position source > (e.g., encoder feedback position), behavior of the D term can be > improved by using a better velocity estimate here, such as the velocity > output of encoder(9) or hostmot2(9). > > I hadn't noticed this before, so encoder.0.velocity only feeds the > pid.N.feedback pin. > > It sounds as if I should feed both pins with encoder.0.velocity. Done, > but not tested yet. > > Comments anyone? > > Thanks. > > > Cheers, Gene > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! > Fairy Tale, n.: > A horror story to prepare children for the newspapers. > I was taught to respect my elders, but its getting harder and harder to > find any... > > ------------------------------------------------------------------------ > ---- -- > LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial > Remotely access PCs and mobile devices and provide instant support > Improve your efficiency, and focus on delivering more value-add > services Discover what IT Professionals Know. Rescue delivers > http://p.sf.net/sfu/logmein_12329d2d > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > > > ------------------------------------------------------------------------ > ------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free > Trial Remotely access PCs and mobile devices and provide instant > support Improve your efficiency, and focus on delivering more value-add > services Discover what IT Professionals Know. Rescue delivers > http://p.sf.net/sfu/logmein_12329d2d > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! Hedonist for hire... no job too easy! I was taught to respect my elders, but its getting harder and harder to find any... ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
