Mitsubishi Electric Melservo-J4 Instruction Manual page 71

Alarm No.: 52 Name: Error excessive
 Droop pulses have exceeded the alarm occurrence level.
Alarm content
Detail Detail name Cause
No.
52.1 Excess droop (1) The servo motor power
pulse 1 cable was
disconnected.
(2) The connection of the
servo motor is incorrect.
(3) The connection of the
encoder cable is
incorrect.
(4) The torque limit has
been enabled.
(5) A moving part collided
against the machine.
(6) The electromagnetic
brake has not released.
(The electromagnetic
brake has been
activated.)
(7) The torque is
insufficient.
(8) Power supply voltage
dropped.
(9) Acceleration/
deceleration time
constant is too short.
(10) The position loop gain is
small.
(11) The error excessive
alarm level was not set
correctly.
(12) Servo motor shaft was
rotated by external
force./ The moving part
of the linear servo motor
was moved by external
force.
Check method Check result
Check the servo motor It is disconnected.
power cable.
It is not disconnected.
Check the wiring of U/V/ It is incorrect.
W.
It is correct.
Check if the encoder It is incorrect.
cable is connected
It is correct.
correctly.
Check if the limiting The limiting torque is in
torque is in progress. progress.
The limiting torque is not
in progress.
Check if it collided. It collided.
It did not collide.
Check if electromagnetic It is not released.
brake is released.
It is released.
Check the peak load The torque is saturated.
ratio.
The torque is not
saturated.
Check the bus voltage The bus voltage is low.
value.
The bus voltage is high.
Set a longer deceleration It is not repeatable.
time constant, and then
check the repeatability.
It is repeatable.
Increase the position It is not repeatable.
loop gain, and then
check the repeatability.
It is repeatable.
Check the setting of the It is not set correctly.
error excessive alarm
level.
[A]: [Pr. PC24], [Pr.
It is set correctly.
PC43]
[B] [WB] [RJ010] [GF]:
[Pr. PC01], [Pr. PC06]
Measure the actual It is rotated by external
position under the servo- force./ It was moved by
lock status. external force.
It is not rotated by
external force./ It was not
moved by external force.
1 TROUBLESHOOTING FOR SERVO AMPLIFIER (DRIVE UNIT)
Action Target
Repair or replace the [A]
servo motor power cable. [B]
[WB]
Check (2).
[RJ010]
Connect it correctly.
[GF]
Check (3).
Connect it correctly.
Check (4).
Increase the torque limit
value.
Check (5).
Check operation pattern.
Check (6).
Release the
electromagnetic brake.
Check (7).
Reduce the load or
review the operation
pattern. Or use a larger
capacity motor.
Check (8).
Check the power supply
voltage and power
supply capacity.
Check (9).
Increase the
acceleration/deceleration
time constant.
Check (10).
Increase the position
loop gain ([Pr. PB08]).
Check (11).
Set it correctly.
Check (12).
Review the machine.
Check (13).
1.4 Remedies for alarms
1
69