Mitsubishi Electric MR-J2M-P8B Instruction Manual page 133

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