drifting servo position

[ScottW 134]

I am trying to control a tolomatic DV20 servo drive with a PCI-7344 Motion controller. If I use the 1-D Interactive section of MAX to make a large move, the servo seems to be drifting. I am only moving the servo at about 10,000 counts/sec. After ten revolutions, the position seems to be off by about 10 degrees. The drive is connected to the motion card with a UMI-7764.

[Jim Laudie]

To whom it may concern:

I'm not quite sure what you mean by "drifting." Are you able to have the motor move one revolution and stop at or near the destination point? If it is getting the close to the destination point, but never quite reaching it and the move is never complete (per the LED in the 1D Interactive screen that signals "Move Complete"), you might want to look at tuning your servo motor. Use either the Auto Tune under the Calibration hierarch under your 7344 in MAX or you can manually input PID parameters for tuning your motor. Refer to http://zone.ni.com/devzone/conceptd.nsf/webmain/4B7775373E4AE64986256B6000691505?opendocument for more information on Servo Tune.

Best of luck to you in getting things together...

Jim Laudie
Applications Eng
ineer, National Instruments