YASKAWA UAK series User Manual page 282

11 Inspection, Maintenance, and Troubleshooting
11.2.3 Troubleshooting of the Servo Drive Alarms
Alarm:
Alarm Name
A.C91:
Encoder
Communications
Position Data Error
A.C92:
Encoder
Communications
Timer Error
A.CA0:
Encoder Parameter
Error
A.CB0:
Encoder Echoback
Error
11-28
Cause
The noise interference occurred
on the input/output signal line
because the encoder cable is bent
and the sheath is damaged.
The encoder cable is bundled
with a high-current line or near a
high-current line.
The FG potential varies because
of influence from machines on
the servomotor side, such as the
welder.
Noise interference occurred on
the input/output signal line from
the encoder.
Excessive vibration and shocks
were applied to the encoder.
Encoder failure
SERVOPACK failure
Encoder failure
SERVOPACK failure
The encoder wiring and contact
are incorrect.
Noise interference occurred due
to incorrect encoder cable specifi-
cations.
Noise interference occurred
because the wiring distance for
the encoder cable is too long.
The FG potential varies because
of influence from machines on
the servomotor side, such as the
welder.
Excessive vibration and shocks
were applied to the encoder.
Encoder failure
SERVOPACK failure
Investigative Actions
Check the encoder cable and con-
nector.
Check the encoder cable layout.
Check the encoder cable layout.
−
Check the operating environment.
−
−
−
−
Check the encoder wiring.
−
−
Check the encoder cable and con-
nector.
Check the operating environment.
−
−
(cont'd)
Corrective Actions
Confirm that there is no problem
with the encoder cable layout.
Confirm that there is no surge volt-
age on the encoder cable.
Properly ground the device to sepa-
rate from the encoder FG.
Take countermeasures against
noise.
Reduce the machine vibration, or
correctly install the servomotor.
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the SERVOPACK may be
faulty. Replace the SERVOPACK.
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the SERVOPACK may be
faulty. Replace the SERVOPACK.
Correct the encoder wiring.
Use tinned annealed copper twisted-
pair or shielded twisted-pair cable
with a core of at least 0.12 mm
The wiring distance must be 20 m
max.
Make the grounding for the
machine separately from encoder
side FG.
Reduce the machine vibration or
correctly install the servomotor.
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the SERVOPACK may be
faulty. Replace the SERVOPACK.
2
.