Hi, run away is the typical behaviour when the PID loop is on wrong polarity (try changing INPUT_SCALE or output scale with negative number)
also, D term is really important, having P only may easily behave in vibration. I personally prefer starting with quite a lot of D (upon it start to vibrate, then decrease by a factor of 2..), then only increase P. Le 20.12.2012 12:54, Viesturs Lācis a écrit : > Hello! > > I am trying to tune servo PID loop. > I am starting with: > P = 5 > I = 0 > D = 0 > > FF0 = 0 > FF1 = 0 > FF2 = 0 > > INPUT_SCALE = 2000 > OUTPUT_SCALE = 1 > > FERROR = 100 > MIN_FERROR = 100 > > I am trying to jog the motor by hand and what happens is that most of > the times the servo motor just runs away. > But when it does not, it turns really slow with even slower > acceleration which seems like just a pure lack of tuning. > LinuxCNC receives encoder signal and reports the actual position of > the motor - it stops the run, when ferror is exceeded. > > I did not have this with my previous servo machine so I am totally out > of ideas, what could possibly be wrong here. Any advice will be > appreciated a lot. > ------------------------------------------------------------------------------ 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-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
