Mitsubishi Electric MELSERVO-J4 Instruction Manual page 40

1. TROUBLESHOOTING FOR SERVO AMPLIFIER (DRIVE UNIT)
Alarm No.: 21 Name: Encoder normal communication error 2
Alarm content
Detail
Detail name
No.
21.5 Encoder Check it with the check method for [AL. 21.2].
hardware error
1
21.6 Encoder
hardware error
2
21.9 Encoder data Check it with the check method for [AL. 21.1].
error 2
Alarm No.: 24 Name: Main circuit error
Alarm content
Detail
Detail name
No.
24.1 Ground fault (1) The servo amplifier is
detected by
hardware
detection circuit
(2) A ground fault or short
(3) A ground fault occurred
(4) The main circuit power
(5) Something near the
The encoder detected an error signal.
Cause
A ground fault occurred on the servo motor power lines.
A ground fault occurred at the servo motor.
Power supply voltage for inverter circuit control is low. (Only for MR-J4W2-0303B6)
Cause
Disconnect the servo
malfunctioning. motor power cables
(U/V/W) and check if
the alarm occurs.
Check if only the
occurred at the servo servo motor power
motor power cable. cable is shorted.
Disconnect the servo
at the servo motor. motor power cables
on motor side, and
check insulation of
the motor (between
U/V/W/ ).
Shut off the power,
supply cable and servo and check if the main
motor power cable circuit power supply
were shorted. cable and servo
motor power cable
are in contact.
Check the noise,
device caused it. ambient temperature,
etc.
Check method Check result
Check method Check result
It occurs.
It does not occur.
It is shorted.
It is not shorted.
It is shorted.
It is not shorted.
They are in contact.
They are not in
contact.
It has a failure.
1 - 33
Action Target
Action Target
Replace the servo [A]
amplifier. [B]
[WB]
Check (2).
[RJ010]
[GF]
Replace the servo
motor power cable.
Check (3).
Replace the servo
motor.
Check (4).
Correct the wiring.
Check (5).
Take
countermeasures
against its cause.