YASKAWA SGMJV User Manual page 358

10 Troubleshooting
Problem
Abnormal Noise
from Servomotor
(cont'd)
Servomotor
Vibrates at
Frequency of
Approx 200 to 400
Hz
High Rotation
Speed Overshoot
on Starting and
Stopping
10-26
Probable Cause
FG potential varies because of
influence of machines such as weld-
ers at the servomotor.
SERVOPACK pulse counting error
due to noise interference
Excessive vibration and shock to
the encoder
An encoder fault occurred.
Unbalanced servo gains
Speed loop gain value (Pn100) too
high.
Position loop gain value (Pn102)
too high.
Incorrect speed loop integral time
constant (Pn101) setting
Incorrect moment of inertia ratio
data (Pn103)
Unbalanced servo gains
Speed loop gain value (Pn100) too
high
Position loop gain value (Pn102)
too high
Incorrect speed loop integral time
constant (Pn101) setting
Incorrect moment of inertia ratio
data (Pn103)
Investigative Actions
Check if the machines are correctly
grounded.
Check if there is noise interference
on the input/output signal line from
the encoder.
Check if vibration from the machine
occurred or servomotor installation
is incorrect (mounting surface accu-
racy, fixing, alignment, etc.).
−
Check to see if the servo gains have
been correctly adjusted.
Check the speed loop gain value
(Pn100).
Factory setting: Kv = 40.0 Hz
Check the position loop gain value
(Pn102).
Factory setting: Kp = 40.0/s
Check the speed loop integral time
constant (Pn101).
Factory setting: Ti = 20.0 ms
Check the moment of inertia ratio
setting (Pn103).
Check to see if the servo gains have
been correctly adjusted.
Check the speed loop gain value
(Pn100).
Factory setting: Kv = 40.0 Hz
Check the position loop gain value
(Pn102).
Factory setting: Kp = 40.0/s
Check the speed loop integral time
constant (Pn101).
Factory setting: Ti = 20.0 ms
Check the moment of inertia ratio
setting (Pn103).
Corrective Actions
Ground machines correctly, and
prevent diversion to the FG at the
PG side.
Take measures against noise in the
encoder wiring.
Reduce vibration from the machine,
or secure the servomotor installa-
tion.
Replace the servomotor.
Execute the advanced autotuning.
Reduce the speed loop gain
(Pn100).
Reduce the position loop gain
(Pn102).
Correct the speed loop integral time
constant (Pn101) setting.
Correct the moment of inertia ratio
(Pn103) setting.
Execute the advanced autotuning.
Reduce the speed loop gain
(Pn100).
Reduce the position loop gain
(Pn102).
Correct the speed loop integral time
constant setting (Pn101).
Correct the moment of inertia ratio
setting (Pn103).