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9. TROUBLESHOOTING
Display
IFU DRU
Name Definition Cause Action
1. Drive unit having large load is
adjacent.
1. Change the slot of the drive
unit whose load is large.
2. Reduce the load.
3. Reexamine the operation
pattern.
4. Use a servo motor whose
output is large.
2. Servo system is instable and
hunting.
1. Repeat acceleration/
deceleration and perform auto
tuning.
2. Change the response setting of
auto tuning.
3. Turn off auto tuning and make
gain adjustment manually.
FA.53 Multiple axis
overload
Drive unit whose
effective load factor is
85% or more is
adjacent.
3. Encoder cable and power cable (U,
V, W) coming out of one drive unit
are connected to the incorrect servo
motor.
Make correct connection.
FA.54 Drive unit
alarm
Alarm occurred in one
or more axes of drive
units installed to the
base unit.
Alarm occurred in one or more axes of
drive units installed to the base unit.
Remove the alarm causes of all
drive units where alarm has
occurred.
1. Extension IO unit is not inserted
properly.
Insert correctly.
2. Incompatibility with the extension
IO unit.
Change the interface unit for the
one compatible with the
extension IO unit.
3. Extension IO unit is faulty. Change the extension IO unit.
FA.78 Option slot fault Extension IO unit is
faulty.
4. Base unit is faulty. Change the base unit.
FA.79 Option slot
loading error
Extension IO unit is
connected improperly.
Extension IO unit is disconnected. Switch power off and reinsert the
extension IO unit.
1. Communication cable fault.
(Wire break or short circuit)
Repair or change the cable.
2. Communication cycle is longer than
the IFU parameter No. 1 setting.
Set the IFU parameter value
correctly.
FA.8A Serial
communication
time-out
Serial communication
stopped for longer
than the time set in
IFU parameter No. 1.
3. Protocol is incorrect. Correct the protocol.
1. Communication cable fault.
(Open cable or short circuit)
Repair or change the cable.FA.8E Serial
communication
error
Serial communication
error occurred
between interface unit
and communication
device (e.g. personal
computer).
2. Communication device (e.g. personal
computer) faulty.
Change the communication
device (e.g. personal computer).
88888 Watchdog CPU, parts faulty Fault of parts in interface unit.
Checking method
Alarm (8888) occurs if power is
switched on after disconnection
of all cables but the control
circuit power supply cables.
Change interface unit.