11-23
11-4 Troubleshooting
OMNUC G5-SERIES AC SERVOMOTOR AND SERVO DRIVE USER'S MANUAL
  11
Troubleshooting and Maintenance
Troubleshooting Using the Operation Status
Symptom Probable cause Items to check Measures
The PWR LED 
indicator does not 
light when the power 
supply is turned ON.
The power supply cable is wired 
incorrectly.
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 motor does not 
rotate even if 
commands are input 
from the controller.
(Continued on next 
page)
The operation command (RUN) 
is OFF.
In Monitor Mode, check whether the RUN 
signal is ON or OFF.
· Turn ON the operation 
command (RUN).
· Wire correctly.
The Forward or Reverse Drive 
Prohibition Input (POT or NOT) 
is OFF.
In Monitor Mode, check whether the POT 
signal and NOT signal are ON or OFF.
· Turn ON the POT and NOT 
signals.
·
Disable them in the settings when the 
POT and NOT signals are not used.
The control mode does not 
conform to the command.
Check the control mode Selection 
(Pn001).
Set the control mode according to 
the command.
The error counter reset 
(ECRST) is ON.
In Monitor Mode, check whether the 
ECRST signal is ON or OFF.
·
Turn OFF the ECRST signal.
· Wire correctly.
Command Pulse Mode 
Selection (Pn007) is selection is 
incorrect.
Check the controller's command pulse 
type and the Servo Drive's command 
pulse type.
Set the Servo Drive's pulse type 
to match the controller's 
command pulse type.
The zero speed designation 
(VZERO) is OFF.
In Monitor Mode, check whether the 
VZERO signal is ON or OFF.
·
Turn ON the VZERO signal.
· Wire correctly.
The internally set speeds are not set.
Check the set value of Pn304 to Pn311.
Set the desired speeds.
The No. 1 Torque Limit (Pn013) 
or No. 2 Torque Limit (Pn522) is 
set to 0.
Check the set value of Pn013 and Pn522. Return the set value to the default 
setting.
The Servomotor power cable is 
wired incorrectly.
Check the wiring. Wire correctly.
The encoder cable is wired 
incorrectly.
The control I/O connector (CN1) 
is wired incorrectly.
Check the command pulse's wiring. Wire correctly.
Check the command pulse type. Set the Servo Drive's pulse type 
to match the controller's 
command pulse type.
Check the command pulse's voltage. Connect a resistor that matches 
the voltage.
Power is not supplied.
Check whether the power supply is ON and 
check the PWR LED indicator.
Turn ON the power supply.
Check the voltage across the power 
supply terminals.
Wire the power-ON circuit 
correctly.
The speed command is 
disabled.
Check if the speed command method is 
correct.
· Set the external analog 
command correctly.
·
Set the internal speed correctly.