Omron OMNUC G5 R88M-K series User Manual page 423

Symptom
The motor rotates without
a command.
The motor rotates in the
reverse direction from the
command.
The holding brake does
not work.
Motor rotation is unstable. The motor power cable or
OMNUC G5-Series AC Servo Drives Users Manual (Built-in MECHATROLINK-II communications type)
Probable cause
There are inputs of small
values in speed control
mode.
There are inputs of small
values in torque control
mode.
The Servo Drive breaks
down.
The value set on the
Rotation Direction Switching
(Pn000) is incorrect.
The command given by the
host controller is incorrect.
Power is supplied to the
holding brake.
encoder cable is wired
incorrectly.
Low rigidity. It causes
vibration.
The load's moment of inertia
exceeds the Servo Drive's
allowable value.
Loose joint and/or large
clearance with the machine
The pulse signal line's
connections are loose.
The load and gain do not
conform.
11-4 Troubleshooting
Items to check
Check if there is any inputs in
speed control mode.
Check if there is any inputs in
torque control mode.

Check the value set on the
Pn000.
• The absolute command is
set improperly in size.
• The incremental command
is set improperly in polarity.
Check whether power is
supplied to the holding brake.
Check the wiring of the motor
power cable's phases U, V,
and W and check the encoder
cable's wiring.
Measure the vibration
frequency of the load.
Calculate the load inertia.
Check the joint with the
machine.
Check the pulse signal line's
wiring at the controller and
Servo Drive.
Check the controller's
command pulse type and the
Servo Drive's commands
pulse type.
Check the response
waveforms for speed and
torque.
Measures
Set the speed command
to 0.
Alternatively, change the
mode to position control.
Change the mode from
torque control to position
control.
Replace the Servo Drive
with a new one.
Chang the setting on the
Pn000.
• Check the present and
target values.
• Check the rotation
direction.
• Check the brake
interlock output (BKIR)
signal and the relay
circuit.
• Check that the holding
brake is not worn
down.
Wire correctly.
Enable the damping
control. Set the damping
filter frequency.
• Check if the manual
tuning can make a
proper adjustment.
• Increase the
Servomotor capacity.
Remove the joint
looseness with the
machine.
Wire correctly.
Set the Servo Drive's
pulse type to match the
controller's command
pulse type.
Adjust the speed loop
gain to stabilize the
rotation.
11-30
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