WOOHOO chips in pan, Galil servo tune?

[Karl_T]

First of all; WOOHOO, YEEHAW, ALL RIGHT ALL RIGHT ALL RIGHT!!!!!

The CHNC lathe that's I've been refitting made its first chips today. I've got codes G0 G1 M3 M4 M5 tested and working. Soooo, I just had to face a part. Still a long ways to go, but we'll just call the rest fine tuning and optimizing.

I feel I gotta ask one question. One of the Galil brush type PWM servo amps, model MSA-12-80, sent the axis all the way to one end of travel on Estop reset. I just replaced that amp to get past the trouble, but I would like to know what's wrong. I note pots for loop gain, curr limit, ref in gain, and test/offset

Karl

[Al_The_Man]

I trust you had the dip switches set OK for torque mode? If the Offset was way off it can do it.
Al.

[Karl_T]

dip switches are good.

I haven't found any instructions for adjustment of pots. There's nothing on it in the manual for the servo amps.

Just a guess here, should I put a voltmeter on the servo motor leads and adjust offset until I have 0 volts? Any checks for the other pots?

Karl

[Al_The_Man]

The Galil drives are re-packaged A-M-C drives (25A8), the pots should be adjusted so P1, loop gain is fully CCW in current mode.
P2, Current limit should be adjusted fully CCW, then clockwise to the appropriate value, If the servo amp peak is 20 amps but the desired limit is 10amps then turn to 50% point.
P3 should be adjusted fully CW or back it off if the motor oscillates or is unstable.
P4 Offset, I normally hook power up to the drive with a motor attached and the analogue signal input shorted so it is equal to zero, the motor should not move, adjust until no motion.
Al.