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Troubleshooting – MITSUBISHI ELECTRIC MELSERVO MR-J2S- A User Manual

Page 205

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10. TROUBLESHOOTING

Display

Name

Definition

Cause

Action

1. Acceleration/deceleration time

constant is too small.

Increase the acceleration/deceleration
time constant.

2. Torque limit value (parameter

No.28) is too small.

Increase the torque limit value.

3. Motor cannot be started due to

torque shortage caused by power
supply voltage drop.

1. Review the power supply capacity.
2. Use servo motor which provides larger

output.

4. Position control gain 1 (parameter

No.6) value is small.

Increase set value and adjust to ensure
proper operation.

5. Servo motor shaft was rotated by

external force.

1. When torque is limited, increase the

limit value.

2. Reduce load.
3. Use servo motor that provides larger

output.

6. Machine struck something.

1. Review operation pattern.
2. Install limit switches.

7. Encoder faulty

Change the servo motor.

AL.52

Error excessive
(Note)

The difference
between the model
position and the
actual servomotor
position exceeds 2.5
rotations.
(Refer to the
function block
diagram in Section
1.2.)

8. Wrong connection of servo motor.

Servo amplifier's output terminals
U, V, W do not match servo
motor's input terminals U, V, W.

Connect correctly.

1. Communication cable breakage.

Repair or change communication cable

2. Communication cycle longer than

parameter No. 56 setting.

Set correct value in parameter.

AL.8A

Serial
communication
time-out error

RS-232C or RS-422
communication
stopped for longer
than the time set in
parameter No.56.

3. Wrong protocol.

Correct protocol.

1. Communication cable fault

(Open cable or short circuit)

Repair or change the cable.

AL.8E

Serial
communication
error

Serial
communication
error occurred
between servo
amplifier and
communication
device (e.g. personal
computer).

2. Communication device (e.g.

personal computer) faulty

Change the communication device (e.g.
personal computer).

88888 Watchdog

CPU, parts faulty

Fault of parts in servo amplifier

Checking method

Alarm (88888) occurs if power
is switched on after disconnection
of all cables but the control circuit
power supply cable.

Change servo amplifier.

Note. The error excessive detection for 2.5 revolutions is available only when the servo amplifier of software version B0 or later is used.

For the servo amplifier of software version older than B0, an error excessive alarm occurs when the deviation (deviation counter
value) between the instructed position and the actual servo motor position exceeds 10 revolutions.