Mitsubishi Electric C70 Setup Manual page 592

Alarm No.
Excessive error 2
53
A difference between the actual and theoretical motor positions during servo OFF exceeded the setting value.
Investigation details
Check the follow-up function while the NC is
1
in the servo OFF state.
Check whether the axis has moved during
servo OFF (either by visual inspection or
monitor the position droop waveform).
[1] Check if the motor brake is released in
2
the middle.
[2] Check if the axis moves because the
servo OFF is applied during the C axis
mode.
Check the excessive error detection width.
3 SV026 (Servo)
(Note) Set the same value to SV023.
Alarm No.
Excessive error 3
54
When an excessive error 1 occurred, detection of the motor current failed.
Investigation details
Check that the PN voltage is supplied to the
1 drive unit.
[1] Is the CHARGE lamp ON?
Check the motor power cable (U, V, W
phases).
2 [1] The power cable is not connected.
[2] Is the cable connected to the motor for
another axis?
Supplement (servo)
Depending on the ideal machine position in respect to the command position, the actual machine
position could enter the actual shaded section shown below, which is separated more than the
distance set in OD1.
Position
Servo OFF
Investigation results
The axis detachment function (NC
parameter) is invalid.
(Note) For the axis detachment function,
refer to the NC manual.
The axis detachment function (NC
parameter) is valid.
(Note) For the axis detachment function,
refer to the NC manual.
[1] The axis has moved.
[2] The servo OFF is applied during the
mode.
The axis has not moved.
The excessive error detection width is too
small.
SV026 ={RAPID/(60*PGN1)}/2
An appropriate value is set.
Investigation results
The voltage is not supplied.
It is correctly supplied (DC300V).
The connections are incorrect.
The connections are correct.
Command position
OD1
OD2
OD2
OD1
Servo ON
Appendix 2.16 Troubleshooting
Remedies
Check the investigation item No. 2.
Check the investigation item No. 3.
[1] Adjust the brakes, etc. so that the axis
does not move.
[2] Avoid the servo OFF from being applied
during position control.
Check the investigation item No. 3.
Set an appropriate value.
Check for problems on the NC side, such as
the position FB follow-up control.
Remedies
Correctly supply the PN voltage.
Investigate item 2.
Connect correctly.
Replace the drive unit.
Ideal machine position
Time
C70 Setup Manual
SV SP
SV SP
575