Filter
Top Products
7 - 26
7 Troubleshooting
MITSUBISHI CNC
Alarm No.
51
Overload 2
Current command of more than 95% of the unit's max. current was being continuously given for longer than 1 second in a servo
system. In a spindle system, current command of more than 95% of the motor's max. current was being continuously given for
longer than 1 second.
Investigation details Investigation results Remedies SV SP
1 Did the alarm occur immediately after READY ON?
The alarm occurred after ready ON before
operation starts.
Investigate item 2.
◯
The alarm occurred after normal operation. Investigate item 5.
2
Check that the PN voltage is supplied to the drive
unit.
MDS-DJ Series is not connected to the power
supply unit, so investigate item 3 for MDS-DJ.
[1] Is the CHARGE lamp ON?
The CHARGE lamp becomes dark.
L+ or L- screw was loosened.
Increase the capacity of power supply.
Tighten the L+ and L- screws.
◯
Approx. 300V is correctly supplied. Investigate item 3.
3
Check the motor power cable (U, V, W phases).
[1] The power cable is not connected.
[2] Is the cable connected to the motor for another
axis?
The connections are incorrect.
Connected to the incorrect axis.
Connect correctly.
◯
The connections are correct. Investigate item 4.
4
Check the encoder cable connection.
[1] Is the cable connected to the motor for another
axis?
The connections are incorrect. Connect correctly.
◯
The connections are correct. Investigate item 5.
5 Check whether the machine has collided.
The machine has collided.
Check the machining program and soft limit
settings.
◯
The machine has not collided. Investigate item 6.
6
Check whether the current value on the NC Servo
Monitor screen is saturated during acceleration/
deceleration.
The current is saturated during acceleration/
deceleration.
Increase the acceleration/ deceleration time
constant.
◯
The current value during acceleration/
deceleration is appropriate.
Investigate item 7.
7 Check the encoder Feedback.
The Feedback signal is abnormal.
- The droop does not stabilize.
Replace the encoder.
(With the absolute position system, the zero
point must be established.)
◯
The Feedback signal is normal. Replace the drive unit.
8 Check the load meter value.
The value is large. Lower the load.
◯
The value is normal. Investigate item 9.
9
Check the PLG output waveform.
For TS5690, waveform cannot be checked.
There is a problem. Adjust the PLG output waveform.
◯
Normal Replace the drive unit.
Alarm No.
52
Excessive error 1
A difference between the actual and theoretical motor positions during servo ON exceeded the setting value.
Investigation details Investigation results Remedies SV SP
1
The load inertia is large.
The unbalance torque in the Z (gravity) direction is
high.
An excessive workpiece or tool is mounted on the
spindle.
The load inertia is excessive.
[1] Lower the machine weight applied to the
servo motors (by the unbalance torque).
[2] Lower the weight of the workpiece.
◯◯
The load inertia is normal. Investigate item 2.
2
Check the excessive error detection width.
Servo
SV053
Spindle
SP023 (Interpolation, spindle
synchronization)SP053 (Non-interpolation)
The excessive error detection width is too
small.
Servo standard value:
SV053 ={RAPID/(60*PGN1)}/2
Spindle standard value:
No alarm is set at SP023 =120:0
SP053 =motor max. speed×6/PGV/2
Set appropriate values.
◯◯
Appropriate values are set. Investigate item 3.
3
Check the position encoder polarity.
SV017/bit4 (Servo)
SP017/bit4 (Spindle: position FB)
SP017/bit0 (Spindle: speed FB)
#3106/bit7 (Synchronous tap control)
The polarity is reversed. Correctly set the parameters.
◯◯
Normal. Investigate item 4.
4 Check the alarm No. "51" items.
◯◯