Mitsubishi Electric MELSERVO-J3 Series Manual page 629

16. INDEXER POSITIONING OPERATION
Display Name
(Note) Watchdog
888
Note. At power-on, "888" appears instantaneously, but it is not an error.
(3) Remedies for warnings
CAUTION
Definition
CPU, parts faulty. Fault of parts in servo amplifier.
Alarm (888) occurs if power is
switched on after disconnection of
all cables but the control circuit
power supply cable.
If an absolute position counter warning (AE3) occurred, always make home
position setting again. Not doing so may cause unexpected operation.
POINT
When any of the following alarms has occurred, do not resume operation by
switching power of the servo amplifier OFF/ON repeatedly. The servo
amplifier and servo motor may become faulty. If the power of the servo
amplifier is switched OFF/ON during the alarms, allow more than 30 minutes
for cooling before resuming operation.
Excessive regenerative warning (AE0)
Overload warning 1 (AE1)
Always execute a home position return when the forward rotation stroke end
(LSP) or the reverse rotation stroke end (LSN) turns off.
Cause
Checking method
16 - 108
Action
Change the servo amplifier.