11-21
11-4 Troubleshooting
OMNUC G5-SERIES AC SERVOMOTOR AND SERVO DRIVE USER'S MANUAL
  11
Troubleshooting and Maintenance
*1. This alarm may occur due to the timing between safety input 1/2 and alarm clear input. For details, 
refer to  Alarm No. 99.0 on page 11-22.
*2. For the alarm reset input timing, refer to  Operation Timings to a Safety Status on page 7-4.
55
0
Phase-A connection 
error
An error such as broken wiring was 
detected in the external encoder 
phase-A connection.
Check the external encoder phase-A 
connection.
1
Phase-B connection 
error
An error such as broken wiring was 
detected in the external encoder 
phase-B connection.
Check the external encoder phase-B 
connection.
2
Phase-Z connection 
error
An error such as broken wiring was 
detected in the external encoder 
phase-Z connection.
Check the external encoder phase-Z 
connection.
87 0
Emergency stop input 
error
An emergency stop input (STOP) was 
input.
Check the emergency stop input 
(STOP) wiring.
95
0 to 
4
Motor non-conformity
The Servomotor does not match the 
Servo Drive.
Replace the Servomotor with a 
Servomotor that matches the Servo 
Drive.
99 0
Other errors
· An alarm was reset when safety 
input 1 or 2 was not normal (one of 
the input photocouplers is not 
ON). *1
· The control circuit malfunctioned 
due to excess noise or some other 
problem.
· The self-diagnosis function of the 
Servo Drive was activated, and an 
error occurred in the Servo Drive.
· Reset the alarm when safety 
inputs 1 and 2 are normal (both 
input photocouplers are ON). *2
· Turn OFF the power once, and 
turn it ON again.
· If the alarm is displayed even after 
the power is turned ON again, the 
system may be faulty. Stop using 
the system, and replace the 
Servomotor and/or the Servo 
Drive. Return the Servo Drive to 
the dealer that it was purchased 
from and ask for investigation and 
repair.
Other 
numbers
· The control circuit malfunctioned 
due to excess noise or some other 
problem.
· The self-diagnosis function of the 
Servo Drive was activated, and an 
error occurred in the Servo Drive.
· A voltage of ±11 V or higher was 
applied to analog input 2 or analog 
input 3.
· Turn OFF the power once, and 
turn it ON again.
· If the alarm is displayed even after 
the power is turned ON again, the 
system may be faulty. Stop using 
the system, and replace the 
Servomotor and/or the Servo 
Drive. 
Return the Servo Drive to the 
dealer that it was purchased from 
and ask for investigation and 
repair.
· Adjust the voltage applied to 
analog input 2 or analog input 3 to 
a suitable value.
Alarm 
number
Name Cause Measures
Main Sub