Mitsubishi Electric Melservo-J2-SUPER series Instruction Manual page 235

11. TROUBLESHOOTING
Display Name
AL.63 Home position
return
incomplete
AL.64 Home position
setting error
AL.8A Serial
communication
time-out error
AL.8E Serial
communication
error
88888 Watchdog
Definition
In incremental 1. Positioning operation was
system: performed without home position
1. Positioning return.
operation was 2. Home position return speed could
performed without not be decreased to creep speed.
home position 3. Limit switch was actuated during
return. home position return starting at
2. Home position other than position beyond dog.
return ended
abnormally.
In absolute position 1. Positioning operation was
detection system: performed without home position
1. Positioning setting.
operation was 2. Home position setting speed could
performed without not be decreased to creep speed.
home position 3. Limit switch was actuated during
setting. home position setting starting at
2. Home position other than position beyond dog.
setting ended
abnormally.
Home position 1. Droop pulses remaining are
setting could not be greater than the in-position range
made. setting.
2. Command pulse entered after
clearing of droop pulses.
3. Creep speed high.
RS-232C or RS-422 1. Communication cable breakage.
communication
2. Communication cycle longer than
stopped for longer
parameter No. 23 setting.
than the time set in
3. Wrong protocol.
parameter No.23.
Serial 1. Communication cable fault
communication error (Open cable or short circuit)
occurred between
2. Communication device (e.g.
servo amplifier and
personal computer) faulty
communication
device (e.g. personal
computer).
CPU, parts faulty Fault of parts in servo amplifier
Alarm (88888) occurs if power is
switched on after disconnection
of all cables but the control
circuit power supply cables.
Cause
Checking method
11 - 8
Action
1. Perform home position return.
2. Review home position return speed/creep
speed/moving distance after proximity
dog.
1. Perform home position setting.
2. Review home position setting speed/creep
speed/moving distance after proximity
dog.
Remove the cause of droop pulse
occurrence
Do not enter command pulse after clearing
of droop pulses.
Reduce creep speed.
Repair or change communication cable
Set correct value in parameter.
Correct protocol.
Repair or change the cable.
Change the communication device (e.g.
personal computer).
Change servo amplifier.