Mitsubishi Electric GENERAL PURPOSE AC SERVO MR-E- A/AG Instruction Manual page 161

10. TROUBLESHOOTING
Display Name
AL.51 Overload 2
AL.52 Error excessive The droop pulse
AL.8A Serial
communication
time-out error
AL.8E Serial
communication
error
88888 Watchdog
Definition
Machine collision or 1. Machine struck something.
the like caused max.
output current to
2. Wrong connection of servo motor.
flow successively for
Servo amplifier's output terminals
several seconds.
U, V, W do not match servo
Servo motor locked:
motor's input terminals U, V, W.
1s or more
3. Servo system is instable and
During rotation:
hunting.
2.5s or more
4. Encoder faulty.
When the servo motor shaft is
rotated with the servo off, the
cumulative feedback pulses do
not vary in proportion to the
rotary angle of the shaft but the
indication skips or returns
midway.
1. Acceleration/deceleration time
value of the constant is too small.
deviation counter
2. Torque limit value (parameter
exceeded 2.5
No.28) is too small.
rotations.
3. Motor cannot be started due to
torque shortage caused by power
supply voltage drop.
4. Position control gain 1 (parameter
No.6) value is small.
5. Servo motor shaft was rotated by
external force.
6. Machine struck something.
7. Encoder faulty
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.
RS-232C or RS-422 1. Communication cable breakage.
communication
2. Communication cycle longer than
stopped for longer
parameter No. 56 setting.
than the time set in
3. Wrong protocol.
parameter No.56.
Serial
1. Communication cable fault
communication
(Open cable or short circuit)
error occurred
2. Communication device (e.g.
between servo
personal computer) faulty
amplifier and
communication
device (e.g. personal
computer).
CPU, parts faulty Fault of parts in servo amplifier
Cause
Checking method
10 - 10
Action
1. Review operation pattern.
2. Install limit switches.
Connect correctly.
1. Repeat acceleration/deceleration to
execute auto tuning.
2. Change auto tuning response setting.
3. Set auto tuning to OFF and make gain
adjustment manually.
Change the servo motor.
Increase the acceleration/deceleration
time constant.
Increase the torque limit value.
1. Review the power supply capacity.
2. Use servo motor which provides larger
output.
Increase set value and adjust to ensure
proper operation.
1. When torque is limited, increase the
limit value.
2. Reduce load.
3. Use servo motor that provides larger
output.
1. Review operation pattern.
2. Install limit switches.
Change the servo motor.
Connect correctly.
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.