YASKAWA UAK series User Manual page 278

11 Inspection, Maintenance, and Troubleshooting
11.2.3 Troubleshooting of the Servo Drive Alarms
Alarm:
Alarm Name
A.840:
Encoder Data Error
(Detected on the
encoder.)
A.850:
Encoder Overspeed
(Detected when the con-
trol power supply was
turned ON.)
(Detected on the
encoder.)
A.860:
Encoder Overheated
(Only when an absolute
encoder is connected.)
(Detected on the
encoder.)
A.8A0:
External Encoder
Error of Scale
A.8A1:
External Encoder
Error of Module
A.8A2:
External Encoder
Error of Sensor
(Incremental)
A.8A3:
External Encoder
Error of Position
(Absolute)
A.8A5:
External Encoder
Overspeed
A.8A6:
External Encoder
Overheated
11-24
Cause
Encoder failure
Malfunction of encoder because
of noise interference, etc.
The servomotor was running at
-1
200 min or higher when the
control power supply was turned
ON.
Encoder failure
SERVOPACK failure
The ambient temperature around
the servomotor is too high.
The servomotor load is greater
than the rated load.
Encoder failure
SERVOPACK failure
Setting of the zero point position
of absolute external scale failed
because the servomotor rotated.
External encoder failure
External encoder failure
Serial converter unit failure
External encoder failure
Absolute external encoder failure −
The overspeed from the external
encoder occurred.
The overheat from the external
encoder occurred.
Investigative Actions
−
−
Check the speed monitor in
SigmaWin for the Σ-V-SD (MT)
to see the servomotor speed
when the power is turned ON.
−
−
Measure the ambient temperature
around the servomotor.
Check the accumulated load ratio
monitor in SigmaWin for the Σ-V-
SD (MT) to see the load.
−
−
Before setting the zero point posi-
tion, use the fully-closed feedback
counter monitor in SigmaWin for
the Σ-V-SD (MT) to confirm that
the servomotor is not rotating.
−
−
−
−
−
−
(cont'd)
Corrective Actions
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
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.
Reduce the servomotor speed to a
-1
value less than 200 min , and turn
ON the control power supply.
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.
The ambient temperature must be
40°C or less.
Set the servomotor load within the
specified range.
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.
Make the settings so that the servo-
motor will be stopped while setting
the zero point position.
Replace the external encoder.
Replace the external encoder.
Replace the serial converter unit.
Replace the external encoder.
The absolute external encoder may
be faulty. Refer to the encoder man-
ufacture's instruction manual for
corrective actions.
Repair or replace the external
encoder.
Repair or replace the external
encoder.