
2 ALARM DISPLAY AND
CORRESPONDING
COUNTERMEASURES
B--65245EN/02
TROUBLESHOOTING AND
COUNTERMEASURES
140
No. CountermeasureDescriptionLED display
351
The battery voltage of the absolute pulse coder
is low. (warning)
Replace the battery.
401
A communication error was detected in the seri-
al pulse coder.
Check the continuity of the pulse coder signal
cable. If the cable is normal, the pulse coder or
servo amplifier unit may be defective. This error
can also be caused by external noise. See the
chapter on noise reduction in “Descriptions.”
Servo ala rms
No. LED display Description Countermeasure
400
The servo motor has overheated (estimated
value).
The motor operation condition may be too se-
vere. Check the operation condition.
SVU--12 The cooling fins have overheated.
SVU--20 (hardware detection)
The load on the motor may be too high. Re --ex-
amine the load conditions.
403
SVU--40 This alarm will not be issued.
SVU--80
The regenerative discharge unit has over-
heated.
This alarm is issued when the average regen-
erative discharge energy is too high (when the
acceleration/deceleration frequency is too high,
for example).
404
(1) When the separate regenerative discharge resistor is not used: For the SVU --12 and the
SVU--20, check whether the CX11--6 connector is short--circuited with a dummy connector; for
the SVU--40 and the SVU--80, check whether the CX20 and CX23 connectors are short--cir-
cuited with a dummy connector.
(2) The average regenerative discharge energy may be too high. Decrease the acceleration/de-
celeration frequency.
(3) The separate regenerative discharge unit may not be connected properly. Check the connec-
tion.
(4) The thermostat of the separate regenerative discharge unit may be defective. Disconnect the
separate regenerative discharge unit, then check the thermostat. Ifthe thermostatis open even
through the separate regenerativ e discharge unit is cool, replace the separate regenerative
discharge unit.
(5) The resistor of the separate regenerative discharge unit may be defective. Disconnectthe sep-
arate regenerative discharge unit, then check the resistance. If it does not fall in the range of
the predetermined resistance 20%, replace the separate regenerative discharge unit.
(6) If (1) to (5) are not the cause of the alarm, replace the servo amplifier unit.
Reference position return could not be
executed correctly.
Re--execute reference position return.
If a value in the range of 4 to 96 is set for parameter No. 032 (CMR), an alarm may be issued. In
this case, prevent an alarm from being issued by setting N405 (bit 4 of parameter No. 001) to “1”.
410
The servo position error in the stop state is
larger than the value specified in parameter
No.110.
Determine the mechanical cause of the large
position error. If no mechanical cause is found,
specify a larger value for the parameter.
411
The s ervo position error during movement is
larger than the value specified in parameter
No.182.
Determine the mechanical cause of the large
position error. If no mechanical cause is found,
apply any of the following countermeasures:
S Specify a larger value for the parameter.
S Specify a lower feedrate.
S Increase the time constants.