Mitsubishi Electric Melservo-J4 Instruction Manual page 45

Alarm No.: 21 Name: Encoder normal communication error 2
 The encoder detected an error signal.
Alarm content
Detail Detail name Cause
No.
21.1 Encoder data (1) The encoder detected a
error 1 high speed/
acceleration rate due to
an oscillation or other
factors.
(2) The external conductor
of the encoder cable is
not connected to the
ground plate of the
connector.
(3) An encoder is
malfunctioning.
(4)
device caused it.
21.2 Encoder data (1) An encoder is
update error malfunctioning.
(2) The external conductor
of the encoder cable is
not connected to the
ground plate of the
connector.
(3)
device caused it.
21.3 Encoder data Check it with the check method for [AL. 21.2].
waveform error
21.4 Encoder non- (1)
signal error has not been inputted.
(2) The external conductor
of the encoder cable is
not connected to the
ground plate of the
connector.
(3)
device caused it.
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
Check method
Decrease the loop gain,
and then check the
repeatability.
Check if it is connected.
Replace the servo motor,
and then check the
repeatability.
Something near the Check the noise, ambient
temperature, vibration,
etc.
Replace the servo motor,
and then check the
repeatability.
Check if it is connected.
Something near the Check the noise, ambient
temperature, etc.
A signal of the encoder Check if the encoder
cable is wired correctly.
Check if it is connected.
Something near the Check the noise, ambient
temperature, etc.
Check result
It is not repeatable.
It is repeatable.
It is not connected.
It is connected.
It is not repeatable.
It is repeatable.
There is a problem in the
surrounding.
It is not repeatable.
It is repeatable.
It is not connected.
It is connected.
There is a problem in the
surrounding.
It has a failure.
It has no failure.
It is not connected.
It is connected.
There is a problem in the
surrounding.
1 TROUBLESHOOTING FOR SERVO AMPLIFIER (DRIVE UNIT)
Action Target
Use the encoder with low [A]
loop gain. [B]
[WB]
Check (2).
[RJ010]
[GF]
Connect it correctly.
Check (3).
Replace the servo motor.
Check (4).
Take countermeasures
against its cause.
Replace the servo motor. [A]
[B]
Check (2).
[WB]
[RJ010]
Connect it correctly.
[GF]
Check (3).
Take countermeasures
against its cause.
Review the wiring. [A]
[B]
Check (2).
[WB]
Connect it correctly.
[GF]
Check (3).
Take countermeasures
against its cause.
1.4 Remedies for alarms
1
43