Yaskawa LEGEND-MC - Manual (Page 353)

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LEGEND-MC User’s Manual
11 Troubleshooting
Overview
The following discussion may help you get your system running if a problem is encountered.
Potential problems have been divided into groups as follows:
1. Installation
2. Stability and Compensation
3. Operation
The various symptoms along with the cause and the remedy are described in the following tables.
Installation
Stability
Symptom Cause Remedy
Motor runs away when connected to amplifier
with no additional inputs. Amplifier offset
too large. Adjust amplifier offset
Same as above, but offset adjustment does not
stop motor. Damaged
amplifier. Replace amplifier.
Controller does not read changes in encoder
position. Wrong encoder
connections. Check encoder wiring.
Same as above Bad encoder Check the encoder
signals. Replace encoder
if necessary.
Same as above Bad controller Connect the encoder to
different axis input. If it
works, controller failure.
Repair or replace.
Symptom Cause Remedy
Motor runs away when the
loop is closed. Wrong feedback polarity.
(Positive Feedback)
Invert the polarity of the loop by
inverting the motor leads (brush
type) or the encoder (channel A+,
B+ if single ended; channel A+, A-
and B+, B- if differential)
Motor oscillates. Too high gain or too little
damping. Decrease KI and KP. Increase KD.