9 Troubleshooting
9.2.2 Troubleshooting of Warnings
9-22
9.2.2
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 Num-
ber: Warning
Name (Warning
Description)
Cause
Investigative Actions
Corrective Actions
A.900:
Position Error
Overflow
The servomotor U, V,
and W wirings is faulty.
Check the servomotor main circuit
cable connection.
Confirm that there is no contact fault
in the motor wiring or encoder wiring.
The multi-winding
drive unit gain is too
low.
Check the multi-winding drive unit
gain to see if it is low.
Increase the servo gain by using the
function such as advanced autotuning.
The frequency of the
position reference pulse
is too high.
Reduce the reference pulse frequency,
and operate the multi-winding drive
unit.
Reduce the position reference pulse
frequency or acceleration of position
reference. Or, reconsider the elec-
tronic gear ratio.
The acceleration of the
position reference is too
high.
Reduce the reference acceleration, and
operate the multi-winding drive unit.
Apply the smoothing function, such as
using the position reference accelera-
tion/deceleration time constant
(Pn216).
Setting of the excessive
position error alarm
level (Pn520) is low
against the operating
condition.
Check the alarm level (Pn520) to see
if it is set to an appropriate value.
Set the Pn520 to proper value.
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.
A.901:
Position Error
Overflow Alarm
at Servo ON
When the servomotor
power is ON, the posi-
tion error exceeded the
parameter setting
(Pn526
×
Pn528/100).
−
Set Pn200.2 to 0 to clear the number
of position error while the servomotor
power is OFF. Or set an appropriate
value for the excessive position error
warning level at servo ON (Pn528).
A.910:
Overload
(Warning before
alarm A.710 or
A.720 occurs)
Incorrect wiring or con-
tact fault of servomotor
and encoder.
Check the wiring.
Confirm that the servomotor and
encoder are correctly wired.
Operation beyond the
overload protection
characteristics.
Check the motor overload characteris-
tics and executed run command.
Reconsider the load conditions and
operating conditions. Or, increase the
motor capacity.
Excessive load was
applied during opera-
tion because the servo-
motor was not driven
due to mechanical prob-
lems.
Check the executed operation refer-
ence and motor speed.
Remove the mechanical problems.
A fault occurred in the
multi-winding drive
unit.
−
The multi-winding drive unit may be
faulty. Replace the multi-winding
drive unit.
