Omron OMNUC G User Manual page 403

Symptom Probable cause
Problem with the coupling
between the Servomotor
axis and the machine.
Machine position
is misaligned.
Deceleration stop
command is received from
the host controller.
The Servomotor
Load inertia is too large.
is slow to stop
even if the RUN
command is
turned OFF while
the Servomotor is
Dynamic brake is disabled.
rotating.
The Position Loop Gain
(Pn010) is too large.
Poor balance between the
Speed Loop Integration
Time Constant (Pn012)
Overshoots when
and the Speed Loop Gain
starting or
(Pn011).
stopping.
Inappropriate machine
rigidity setting by realtime
autotuning.
Inertial ratio setting differs
from the load.
Items to check
Check that the coupling of the Ser-
vomotor and the machine is not
misaligned.
Check the control ladder on the
host controller.
Check the load inertia.
Dynamic brake resistor is
disconnected.
Check if the dynamic brake
is disabled or has failed.
Review the Position Loop Gain
(Pn010).
Review the Speed Loop Integration
Time Constant (Pn012) and the
Speed Loop Gain (Pn011).
Review the machine rigidity setting.
Review the Inertial Ratio (Pn020).
8-3 Troubleshooting
Countermeasure
Re-tighten the coupling.
Replace with a tight
coupling.
Review the control on the
host controller.
Review the load inertia.
Replace the Servomotor
and Servo Drive with
appropriate models.
If disabled, enable it.
If there is a failure, or
disconnection of the
resistor, replace the
Servomotor.
Adjust the gain to avoid
overshooting.
Use CX-Drive and analog
monitors (SP, IM) to mea-
sure the response and adjust
the gain.
Match the machine rigidity
setting to the load rigidity.
Match the Inertia Ratio
(Pn020) to the load.
8-18
8