Troubleshooting Of Warnings - YASKAWA UAK series User Manual

11.3.2 Troubleshooting of Warnings

Refer to the following table to identity the cause of a warning and the action to be taken. Contact your
Yaskawa representative if the problem cannot be solved by the described corrective action.
Warning
Number:
Warning Name
(Warning
Description)
The servomotor U, V,
and W wirings is faulty.
The SERVOPACK gain
is too low.
The position reference
acceleration is too fast.
A.900:
Position Error
Setting of the excessive
Overflow
position error alarm
level (Pn520) is low
against the operating
condition.
SERVOPACK failure
When the servomotor
A.901:
power turns ON, the
Position Error
position error exceeded
Overflow Alarm
the parameter setting
at Servo ON
(Pn526×Pn528/100).
Incorrect wiring or con-
tact fault of servomotor
and encoder.
Operation beyond the
overload protection
A.910:
characteristics.
Overload
Excessive load was
(Warning before
applied during opera-
alarm A.710 or
tion because the servo-
A.720 occurs)
motor was not driven
due to mechanical prob-
lems.
SERVOPACK failure
Abnormal vibration was
detected while the ser-
vomotor is rotating.
A.911:
The moment of inertia
Vibration
ratio (Pn103) value is
greater than the actual
value or is greatly
changed.
Cause Investigative Actions
Check the servomotor main circuit
cable connection.
Check the SERVOPACK gain.
Reduce the reference acceleration, and
operate the SERVOPACK.
Check the alarm level (Pn520) to see
if it is set to an appropriate value.
−
−
Check the wiring.
Check the servomotor overload char-
acteristics and executed run com-
mand.
Check the executed operation refer-
ence and servomotor speed.
−
Check for abnormal noise from the
servomotor, and check the speed and
torque waveforms during operation.
Check the moment of inertia ratio.
11.3 Warning Displays
Corrective Actions
Confirm that there is no contact fault
in the motor wiring or encoder wiring.
Increase the servo gain by using the
function such as advanced autotuning.
Reduce the reference acceleration.
Set the Pn520 to proper value.
Turn the power supply OFF and then
ON again. If the warning still occurs,
the SERVOPACK may be faulty.
Replace the SERVOPACK.
Correct the excessive position error
warning level at servo ON (Pn528).
Confirm that the servomotor and
encoder are correctly wired.
Reconsider the load conditions and
operating conditions. Or, increase the
servomotor capacity.
Remove the mechanical problems.
The SERVOPACK may be faulty.
Replace the SERVOPACK.
Reduce the servomotor speed or
reduce the servo gain by using the
function such as one-parameter tun-
ing.
Set the moment of inertia ratio
(Pn103) to an appropriate value.
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