YASKAWA Sigma-7 Series Product Manual page 138

6.3 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Abnormal
Noise from
Servomotor
6-50
Possible Cause
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.
A failure occurred in the
Serial Converter Unit.
A failure occurred in the linear
encoder.
Confirmation
Turn OFF the power sup-
ply to the servo system.
Check to see if the
Encoder Cable is bundled
with a high-current line or
installed near a high-cur-
rent line.
Turn OFF the power sup-
ply to the servo system.
Check to see if the
machines are correctly
grounded.
Check to see if there is
noise interference on the
signal line from the
encoder.
Turn OFF the power sup-
ply to the servo system.
Check to see if vibration
from the machine
occurred. Check the Ser-
vomotor installation
(mounting surface preci-
sion, securing state, and
alignment).
Check the linear encoder
installation (mounting sur-
face precision and secur-
ing method).
–
–
–
Continued from previous page.
Correction Reference
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.
Turn OFF the power
supply to the servo
system.
–
Implement counter-
measures against noise
for the encoder wiring.
Reduce machine vibra-
tion. Improve the
mounting state of the
–
Servomotor or linear
encoder.
Turn OFF the power
supply to the servo
system.
–
Replace the Servomo-
tor.
Turn OFF the power
supply to the servo
system.
–
Replace the Serial Con-
verter Unit.
Turn OFF the power
supply to the servo
system.
–
Replace the linear
encoder.
Continued on next page.