I'm having a strange behavior on a servo system.. perhaps someone can offer some advice or point me in the correct (or some) direction.
Baldor Microflex.. Baldor BSM63N motor.. encoder feedback with halls...
Servo operates in Position Mode (Step/Dir).. been working for about 15years.. not my design or fabrication.. recently client had an issue that the Servo was not repeating position.. only has two positions.. 11 rotations in one direction.. and then 11 direction back to the original direction. Problem was traced to abnormal pulses being generated into the Microflex and appeared to be remedied by adding grounding to the drive.. now the drive holds position (moves are relatively slow for a servo.. it will take 3-4 seconds for the motor to do 11 revs.. without any problem.. operation is smooth on both accel, decel and movement.. then after roughly 15-20 minutes, servo appears to start positioning differently.. accel and movement still appear smooth, but decel starts to get jerky.. motor starts to overshoot slightly and recover.. its still maintaining both internal count position and machine position.. this effect continues to get worse until the motor starts to oscillate until the drive trips.. I can reset it.. change the speed kp or ki a bit.. and then the preceding operation repeats. It does not appear to be a bad encoder or hall sensor (at least as far as I can determine).. and I can't imagine any type of failure that gets worse like this.. then continues and repeats the identical process.
Any possible hints?
Thanks, Bob
Baldor Microflex.. Baldor BSM63N motor.. encoder feedback with halls...
Servo operates in Position Mode (Step/Dir).. been working for about 15years.. not my design or fabrication.. recently client had an issue that the Servo was not repeating position.. only has two positions.. 11 rotations in one direction.. and then 11 direction back to the original direction. Problem was traced to abnormal pulses being generated into the Microflex and appeared to be remedied by adding grounding to the drive.. now the drive holds position (moves are relatively slow for a servo.. it will take 3-4 seconds for the motor to do 11 revs.. without any problem.. operation is smooth on both accel, decel and movement.. then after roughly 15-20 minutes, servo appears to start positioning differently.. accel and movement still appear smooth, but decel starts to get jerky.. motor starts to overshoot slightly and recover.. its still maintaining both internal count position and machine position.. this effect continues to get worse until the motor starts to oscillate until the drive trips.. I can reset it.. change the speed kp or ki a bit.. and then the preceding operation repeats. It does not appear to be a bad encoder or hall sensor (at least as far as I can determine).. and I can't imagine any type of failure that gets worse like this.. then continues and repeats the identical process.
Any possible hints?
Thanks, Bob
