6.1  Alarm Displays
 6.1.2  Troubleshooting Alarms
6-15
A.50D:
Position Devia-
tion Between 
Axes Overflow
Alarm
Twisting of mechani-
cal parts has occurred 
between axes A and 
B.
Check the position 
deviation between the 
axes. 
Resolve the twisting of 
mechanical parts between 
the axes.
–
Set the Position Correc-
tion Table to appropriate 
values.
page 3-7
Axis A and axis B are 
not synchronized with 
the reference.
Check the reference 
position for axis A and 
axis B.
The host controller should 
command the system to 
synchronize operation of 
axis A and axis B.
–
Pn66A (Position Devi-
ation Between Axes 
Overflow Alarm Level) 
is low for the operat-
ing conditions.
Check if Pn66A (Posi-
tion Deviation Between 
Axes Overflow Alarm 
Level) is appropriate.
Set Pn66A to an appropri-
ate value.
page 5-3
A.510:
Overspeed 
(The motor 
exceeded the 
maximum speed.)
The order of phases 
U, V, and W in the 
motor wiring is not 
correct.
Check the wiring of the 
Servomotor.
Make sure that the Servo-
motor is correctly wired.
–
A reference value that 
exceeded the over-
speed detection level 
was input.
Check the input refer-
ence.
Reduce the reference 
value. Or, adjust the gain.
−
The motor exceeded 
the maximum speed.
Check the waveform of 
the motor speed.
Reduce the speed refer-
ence input gain and 
adjust the servo gain. Or, 
reconsider the operating 
conditions.
A failure occurred in 
the SERVOPACK.
–
The SERVOPACK may be 
faulty. Replace the 
SERVOPACK.
–
A.51A:
Synchronized 
Stopping Over-
speed Alarm
The axis undergoing 
synchronized stop-
ping was accelerating.
Check the feedback 
speed of the axis under-
going synchronized 
stopping.
Remove the cause of 
acceleration for the axis 
undergoing synchronized 
stopping.
–
A.520:
Vibration Alarm
Abnormal oscillation 
was detected in the 
motor speed.
Check for abnormal 
motor noise, and check 
the speed and torque 
waveforms during oper-
ation.
Reduce the motor speed. 
Or, reduce the setting of 
Pn100 (Speed Loop 
Gain).
*1
The setting of Pn103 
(Moment of Inertia 
Ratio) is greater than 
the actual moment of 
inertia or was greatly 
changed.
Check the moment of 
inertia ratio or mass 
ratio.
Set Pn103 (Moment of 
Inertia Ratio) to an appro-
priate value.
*1
The vibration detec-
tion level (Pn312 or 
Pn384) is not suitable.
Check that the vibra-
tion detection level 
(Pn312 or Pn384) is 
suitable.
Set a suitable vibration 
detection level (Pn312 or 
Pn384).
*1
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Continued from previous page.
Alarm Number: 
Alarm Name
Possible Cause Confirmation Correction Reference