Omron OMNUC G Series User Manual page 425

Symptom Probable cause
There is a small input for
speed command mode.
The Servomotor
rotates
without a
There is a small input for
command.
torque command mode.
The Operating Direction
Setting (Pn043) setting is
The Servomotor
incorrect.
rotates in the
direction opposite
to the command.
NCF71 command is
incorrect.
The holding
Power is supplied to the
brake does not
holding brake.
work.
The load is too large.
The heat radiation condi-
The Servomotor
tions for the Servomotor
is overheating.
have worsened.
The ambient temperature is
too high.
Load and gain do not
match.
Load inertia exceeds the
specified range.
The Servomotor
rotation is
unstable.
Low rigidity is resulting in
vibration.
Loose coupling with the
machine, and/or large
gaps.
Items to check
Check that there is no input
for speed command mode.
Check that there is no input for
torque command mode.
Check the Operating Direction
Setting (Pn043) value.
 Set values are inappropriate for
an absolute command.
 The polarity is incorrect for an
incremental command.
Check whether power is supplied to
the holding brake.
Measure the torque using the front
panel IM or a tool.
 Check that the specified heat
radiation conditions are satisfied.
 For a Servomotor with a brake,
check the load ratio.
Check that the ambient tempera-
ture has not exceeded 40 C.
Check the response waveforms for
speed and torque.
Calculate the load inertia.
Measure the vibration frequency of
the load.
Check coupling with the machine.
8-3 Troubleshooting
Countermeasure
Set the speed command to
0, or switch to position con-
trol mode.
Switch from torque control
mode to position control
mode.
Change the Operating
Direction Setting (Pn043)
value.
 Check the current and
target values.
 Check the rotation
direction.
 Check the brake interlock
(BKIR) signal and the relay
circuit.
 Check that the holding
brake is not worn down.
 Slow down the
acceleration/deceleration.
 Lower the speed and
measure the load.
 Improve the heat radiation
conditions.
 Reduce the load.
 Improve ventilation.
 Radiate heat and cool.
 Reduce the load ratio.
Adjust the speed loop gain
so that the rotation is
stabilized.
 Check if the adjustments
can be made via manual
tuning.
 Increase the capacity of the
Servomotor.
Enable damping control, and
set the vibration filter fre-
quencies.
Tighten the coupling with the
machine.
8-18
8