8.1 Alarm Displays
8-11
8
Trou
blesh
ooting
A.bF4:
System Alarm 4
A SERVOPACK fault occurred.
−
Restart the SERVOPACK. If the
alarm still occurs, the SERVO-
PACK may be faulty. Replace the
SERVOPACK.
A.C10:
Servo Overrun
Detected
(Detected when the
servomotor power is
ON.)
The order of phases U, V, and W
in the servomotor wiring is incor-
rect.
Check the motor wiring.
Confirm that the servomotor is cor-
rectly wired.
An encoder fault occurred.
−
If the alarm still occurs after restart-
ing the SERVOPACK, even though
the servomotor is correctly wired,
the servomotor may be faulty.
Replace the servomotor.
A SERVOPACK fault occurred.
−
Restart the SERVOPACK. If the
alarm still occurs, the SERVO-
PACK may be faulty. Replace the
SERVOPACK.
A.C80:
Absolute Encoder
Clear Error and Multi-
turn Limit Setting Error
An encoder fault occurred.
−
Restart the SERVOPACK. If the
alarm still occurs, the servomotor
may be faulty. Replace the servo-
motor.
A SERVOPACK fault occurred.
−
Restart the SERVOPACK. If the
alarm still occurs, the SERVO-
PACK may be faulty. Replace the
SERVOPACK.
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 connectors and con-
firm that the encoder is correctly
wired.
Cable disconnection for encoder
cable or short-circuit.
Or, incorrect cable impedance.
Check the encoder cable.
Use the cables with the specified
rating.
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
SERVOPACK.
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 SERVOPACK fault occurred.
−
Connect the servomotor to another
SERVOPACK, and turn ON the
control power. If no alarm occurs,
the SERVOPACK may be faulty.
Replace the SERVOPACK.
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 cables.
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.
(cont’d)
Alarm Number:
Alarm Name
(Alarm Description)
Cause
Investigative Actions
Corrective Actions