8.1 Alarm Displays
8-17
8
Trou
blesh
ooting
A.C90:
Encoder
Communications Error
Contact fault of connector or
incorrect wiring for encoder
cable.
Check the connector contact status
for encoder cable.
Re-insert the connector and confirm
that the encoder is correctly wired.
Cable disconnection for encoder
cable or short-circuit.
Or, incorrect cable impedance.
Check the encoder cable.
Use the cable with the specified rat-
ing.
Corrosion caused by improper
temperature, humidity, or gas,
short-circuit caused by intrusion
of water drops or cutting oil, or
connector contact fault caused by
vibration.
Check the operating environment.
Improve the operating environmen-
tal conditions, and replace the cable.
If the alarm still occurs, replace the
multi-winding drive unit.
Malfunction caused by noise
interference.
−
Correct the wiring around the
encoder by separating the encoder
cable from the servomotor main cir-
cuit cable or by checking the
grounding and other wiring.
A fault occurred in the multi-
winding drive unit.
−
Connect the servomotor to another
SERVOPACK, and turn ON the
control power supply. If no alarm
occurs, the multi-winding drive unit
may be faulty. Replace the multi-
winding drive unit.
A.C91:
Encoder
Communications
Position Data Error
Noise interference occurred on
the I/O signal line because the
encoder cable is bent and the
sheath is damaged.
Check the encoder cable and con-
nector.
Confirm that there is no problem
with the cable layout.
The encoder cable is bundled
with a high-current line or near a
high-current line.
Check the cable layout for encoder
cable.
Confirm that there is no surge volt-
age on the cable.
The FG potential varies because
of influence from machines on
the servomotor side, such as the
welder.
Check the cable layout for encoder
cable.
Properly ground the machines to
separate from the encoder FG.
A.C92:
Encoder
Communications
Timer Error
Noise interference occurred on
the I/O signal line from the
encoder.
−
Take countermeasures against noise
for the encoder wiring.
Excessive vibration and shocks
were applied to the encoder.
Check the operating environment.
Reduce the machine vibration or
correctly install the servomotor.
An encoder fault occurred.
−
Turn the control power supply OFF
and ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
A fault occurred in the multi-
winding drive unit.
−
Turn the control power supply OFF
and ON again. If the alarm still
occurs, the multi-winding drive unit
may be faulty. Replace the multi-
winding drive unit.
A.CA0:
Encoder Parameter
Error
An encoder fault occurred.
−
Turn the control power supply OFF
and ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
A fault occurred in the multi-
winding drive unit.
−
Turn the control power supply OFF
and ON again. If the alarm still
occurs, the multi-winding drive unit
may be faulty. Replace the multi-
winding drive unit.
(cont’d)
Alarm Number:
Alarm Name
(Alarm Description)
Cause
Investigative Actions
Corrective Actions
