YASKAWA SGD7S Product Manual page 503

14.4 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Absolute
Encoder
Position
Deviation
Error (The
position
that was
saved in the
host con-
troller when
the power
was turned
OFF is dif-
ferent from
the posi-
tion when
the power
was next
turned ON.)
14-62
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 SER-
VOPACK.
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.
Turn OFF the power sup-
ply to the servo system.
Check to see if there is
noise interference on the
I/O signal line from the
encoder or Serial Con-
verter Unit.
Turn OFF the power sup-
ply to the servo system.
Check to see if vibration
from the machine
occurred.
Check the Servomotor
installation (mounting sur-
face precision, 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.
Implement counter-
measures against noise
−
for the encoder or
Serial Converter Unit
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 or linear encoder.
Turn OFF the power
supply to the servo
−
system.
Replace the SERVO-
PACK.
Continued on next page.