12-25
12-4 Troubleshooting
OMNUC G5-series AC Servomotors and Servo Drives User’s Manual (with Built-in EtherCAT Communications)
  12
Troubleshooting and Maintenance
Troubleshooting Using the Operation State
Symptom Probable cause Items to check Measures
The 7-segment display 
does not light.
The control power is not 
supplied.
Check to see if the power 
supply input is within the 
allowed power supply voltage 
range.
Supply the correct power 
supply voltage.
Check to see if the power 
supply input is wired correctly.
Wire correctly.
The ERR indicator flashes 
or lights.
A communications-related 
error occurred.
Refer to  Troubleshooting Errors Related to EtherCAT 
Communications on page 12-24.
The L/A IN and the L/A 
OUT indicators are OFF.
A link in the EtherCAT 
physical communications 
layer has not been 
established yet.
Check to see if the 
communications cable is 
connected correctly.
Connect the 
communications cable 
correctly.
Check to see if the host 
controller has started.
Start the host controller.
An error occurred. Read the error number and 
the error log.
Check the cause listed in  
Troubleshooting with Error 
Displays on page 12-13.
Take appropriate 
measures against the 
cause of the error that 
are listed in  
Troubleshooting with 
Error Displays on page 
12-13.
The servo does not lock. The power cable is not 
connected correctly.
Check to see if the 
Servomotor power cable is 
connected properly.
Wire the Servomotor 
power cable correctly.
The Servomotor power 
supply is not ON.
Check the main circuit wiring 
and power voltage.
Input the correct power 
and voltage for the main 
circuit.
The Forward or Reverse 
Drive Prohibition Input (POT 
or NOT) is OFF.
• Check to see if the input for 
Forward or Reverse Drive 
Prohibition Input (POT or 
NOT) is OFF.
• Check the input of +24 VIN 
to CN1.
• Turn ON POT and 
NOT. Input +24 VIN to 
CN1.
The torque limit is set to 0. Check to see if the torque 
limits in the Positive torque 
limit value (60E0 hex) and the 
Negative torque limit value 
(60E1 hex) are set to 0.
Set the maximum torque 
to be used for each of 
these objects.
The Servo Drive has broken 
down.
− Replace the Servo Drive.