YASKAWA UAK series User Manual

11 Inspection, Maintenance, and Troubleshooting
11.2.3 Troubleshooting of the Servo Drive Alarms
11-24
A.840:
Encoder Data Error
(Detected on the
encoder.)
Encoder failure −
Turn the power supply OFF and
then 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.)
The servomotor was running at
200 min
-1
or higher when the
control power supply was turned
ON.
Check the speed monitor in
SigmaWin for the Σ-V-SD (MT)
to see 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.
Encoder failure −
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
SERVOPACK failure −
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the SERVOPACK may be
faulty. Replace the SERVOPACK.
A.860:
Encoder Overheated
(Only when an absolute
encoder is connected.)
(Detected on the
encoder.)
The ambient temperature around
the servomotor is too high.
Measure the ambient temperature
around the servomotor.
The ambient temperature must be
40°C or less.
The servomotor load is greater
than the rated load.
Check the accumulated load ratio
monitor in SigmaWin for the Σ-V-
SD (MT) to see the load.
Set the servomotor load within the
specified range.
Encoder failure −
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the servomotor may be
faulty. Replace the servomotor.
SERVOPACK failure −
Turn the power supply OFF and
then ON again. If the alarm still
occurs, the SERVOPACK may be
faulty. Replace the SERVOPACK.
A.8A0:
External Encoder
Error of Scale
Setting of the zero point position
of absolute external scale failed
because the servomotor rotated.
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.
Make the settings so that the servo-
motor will be stopped while setting
the zero point position.
External encoder failure − Replace the external encoder.
A.8A1:
External Encoder
Error of Module
External encoder failure − Replace the external encoder.
Serial converter unit failure − Replace the serial converter unit.
A.8A2:
External Encoder
Error of Sensor
(Incremental)
External encoder failure − Replace the external encoder.
A.8A3:
External Encoder
Error of Position
(Absolute)
Absolute external encoder failure −
The absolute external encoder may
be faulty. Refer to the encoder man-
ufacture’s instruction manual for
corrective actions.
A.8A5:
External Encoder
Overspeed
The overspeed from the external
encoder occurred.
−
Repair or replace the external
encoder.
A.8A6:
External Encoder
Overheated
The overheat from the external
encoder occurred.
−
Repair or replace the
external
encoder.
(cont’d)
Alarm:
Alarm Name
Cause Investigative Actions Corrective Actions

YASKAWA UAK series Specifications

General

Brand	YASKAWA
Model	UAK series
Category	Servo Drives
Language	English