Dear Jon, Thanks you give me some suggest. Today I try to use small value of the P. But there are an error when I click 'F2'. http://myweb.polyu.edu.hk/~icwfchan/error.png Would you mind telling me what has happen?
http://myweb.polyu.edu.hk/~icwfchan/x.png I would like to ask you is it the accel/decel too high and how can I find the best value of DEFAULT_ACCELERATION My setting: [TRAJ] DEFAULT_VELOCITY = 10.0 MAX_VELOCITY = 37.6 DEFAULT_ACCELERATION = 112.8 MAX_ACCELERATION = 138.0 [AXIS_0] MAX_VELOCITY = 56.4 MAX_ACCELERATION = 112.8 P = 4.000 I = 100.000 D = 0.00 FF0 = 0.000 FF1 = 0.089 FF2 = 0.0019 Thanks Howard > OK, you may need more P, I seems VERY high, I would expect a value more > like 2 with your P of 25. > D may need more or less, depending on the drive. Those spikes at the > beginning and end are the worst error, and are not caused by EMC, in my > experience. You may need to check the tuning within the drive to see if > you can eliminate that. The error during the accel/decel can be helped > with a VERY SMALL amount of FF2. Sometimes just .001 to .005 is > sufficient. If your machine is set up in mm units, then the error trace > there is .002mm per vertical division, so that isn't too bad. > > Even though you are not using my servo controller system, the page I > wrote on PID tuning might be helpful > http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?PWM_Servo_Amplifiers > The specific hal pins will have different names, and not all encoder > interfaces provide the "delta" pin, which is change in raw encoder > counts per servo sample cycle, which I find to be useful both for > triggering halscope and for seeing where in the move (accel, coast, > decel) we are. > > Jon > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ SF.Net email is Sponsored by MIX09, March 18-20, 2009 in Las Vegas, Nevada. The future of the web can't happen without you. Join us at MIX09 to help pave the way to the Next Web now. Learn more and register at http://ad.doubleclick.net/clk;208669438;13503038;i?http://2009.visitmix.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
