Galil DMC-3425 user manual Communication, Stability, Operation, 156 • Troubleshooting

Communication

Symptom	Cause
Using terminal emulator, cannot	Selected comport incorrect
communicate with controller.
Same as above	Selected baud rate incorrect

Remedy

Try another comport

Check to be sure that baud rate same as dip switch settings on controller, change as necessary.

Stability

Symptom	Cause
Motor runs away when the loop is closed.	Wrong feedback polarity.
Motor oscillates.	Too high gain or too little
	damping.

Remedy

Invert the polarity of the loop by inverting the motor leads (brush type) or the encoder.

Decrease KI and KP. Increase KD.

Operation

Symptom	Cause	Remedy
Controller rejects command. Responded	Anything.	Interrogate the cause with TC or
with a ?		TC1.
Motor does not complete move.	Noise on limit switches	To verify cause, check the stop
	stops the motor.	code (SC). If caused by limit
		switch noise, reduce noise.
During a periodic operation, motor drifts	Encoder noise	Interrogate the position
slowly.		periodically. If controller states
		that the position is the same at
		different locations it implies
		encoder noise. Reduce noise. Use
		differential encoder inputs.
Same as above.	Programming error.	Avoid resetting position error at
		end of move with SH command.

156 • Chapter 9 Troubleshooting DMC-3425