YASKAWA SGM7D-30F Product Manual page 209

3.3 FT82 SERVOPACK with MECHATROLINK-III Communications References
3.3.7 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Abnormal
Noise from
Servomotor
Servomotor
Vibrates at
Frequency
of Approx.
200 to 400
Hz.
3-140
Possible Cause
Noise interference occurred
because the Encoder Cable
is too long.
Noise interference occurred
because the Encoder Cable
is damaged.
The Encoder Cable was sub-
jected to excessive noise
interference.
There is variation in the FG
potential because of the
influence of machines on the
Servomotor side, such as a
welder.
There is a SERVOPACK
pulse counting error due to
noise.
The encoder was subjected
to excessive vibration or
shock.
A failure occurred in the
encoder.
The servo gains are not bal-
anced.
The setting of Pn100 (Speed
Loop Gain) is too high.
The setting of Pn102 (Posi-
tion Loop Gain) is too high.
The setting of Pn101 (Speed
Loop Integral Time Con-
stant) is not appropriate.
The setting of Pn103
(Moment of Inertia Ratio or
Mass Ratio) is not appropri-
ate.
Confirmation
Check the length of the
Encoder Cable.
Check the Encoder Cable
to see if it is pinched or
the sheath is damaged.
Check to see if the
Encoder Cable is bundled
with a high-current line or
installed near a high-cur-
rent line.
Check to see if the
machines are correctly
grounded.
Check to see if there is
noise interference on the
signal line from the
encoder.
Check to see if vibration
from the machine
occurred. Check the Ser-
vomotor installation
(mounting surface preci-
sion, securing state, and
alignment).
–
Check to see if the servo
gains have been cor-
rectly tuned.
Check the setting of
Pn100.
The default setting is Kv =
40.0 Hz.
Check the setting of
Pn102.
The default setting is Kp
= 40.0/s.
Check the setting of
Pn101.
The default setting is Ti =
20.0 ms.
Check the setting of
Pn103.
Continued from previous page.
Correction Reference
Rotary Servomotors:
The Encoder Cable
–
length must be 50 m
max.
Replace the Encoder
Cable and correct the
–
cable installation envi-
ronment.
Correct the cable lay-
out so that no surge is
–
applied by high-current
lines.
Properly ground the
machines to separate
–
them from the FG of
the encoder.
Implement counter-
measures against noise
–
for the encoder wiring.
Reduce machine vibra-
tion. Improve the
–
mounting conditions of
the Servomotor.
Replace the Servomo-
–
tor.
Perform autotuning
*
without a host refer-
ence.
Set Pn100 to an appro-
–
priate value.
Set Pn102 to an appro-
–
priate value.
Set Pn101 to an appro-
–
priate value.
Set Pn103 to an appro-
–
priate value.
Continued on next page.