8 Troubleshooting
8.1.2 Troubleshooting of Alarms
8-14
A.810:
Encoder Backup Error
(Only when an absolute
encoder is connected.)
(Detected on the encoder
side.)
Alarm occurred when the power
to the absolute encoder was ini-
tially turned ON.
Check to see if the power was
turned ON initially.
Set up the encoder (Fn008).
The encoder cable disconnected,
and connected again.
Check to see if the power was
turned ON initially.
Confirm the connection and set up
the encoder (Fn008).
The power from both the control
power supply (+5 V) from the
multi-winding drive unit and the
battery power supply is not being
supplied.
Check the encoder connector bat-
tery or the connector contact status.
Replace the battery or take similar
measures to supply power to the
encoder, and set up the encoder
(Fn008).
An absolute encoder fault
occurred.
−
If the alarm cannot be reset by set-
ting up the encoder again, replace
the servomotor.
A fault occurred in the multi-
winding drive unit.
−
The multi-winding drive unit may
be faulty. Replace the multi-wind-
ing drive unit.
A.820:
Encoder Checksum
Error
(Detected on the encoder
side.)
An encoder fault occurred.
−
• Absolute encoder
Set up the encoder again using
Fn008. If the alarm still occurs,
the servomotor may be faulty.
Replace the servomotor.
• Absolute encoder that shows val-
ues for a single rotation or incre-
mental encoder
The servomotor may be faulty.
Replace the servomotor.
A fault occurred in the multi-
winding drive unit.
−
The multi-winding drive unit may
be faulty. Replace the multi-wind-
ing drive unit.
A.830:
Absolute Encoder
Battery Error
(The absolute encoder
battery voltage is lower
than the specified value.)
The battery connection is incor-
rect.
Check the battery connection.
Reconnect the battery.
The battery voltage is lower than
the specified value 2.7 V.
Measure the battery voltage.
Replace the battery.
A fault occurred in the multi-
winding drive unit.
−
The multi-winding drive unit may
be faulty. Replace the multi-wind-
ing drive unit.
A.840:
Encoder Data Error
(Detected on the encoder
side.)
An encoder malfunctioned.
−
Turn the control power supply OFF
and ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
Malfunction of encoder because
of noise interference, etc.
−
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.850:
Encoder Overspeed
(Detected when the con-
trol power supply was
turned ON.)
(Detected on the encoder
side.)
The servomotor speed is higher
than 200 min
-1
when the control
power supply was turned ON.
Check the motor rotating speed
(Un000) to confirm the servomotor
speed when the power is turned ON.
Reduce the servomotor speed to a
value less than 200 min
-1
, and turn
ON the control power supply.
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
