YASKAWA E-7S SERVOPACK SGD7S Product Manual page 586

Problem Possible Cause
Noise interference occurred
because of incorrect Encoder
Cable specifications.
Noise interference occurred
because the Encoder Cable
is too long.
Absolute
Encoder
Position
Deviation
Noise interference occurred
Error (The
because the Encoder Cable
position
is damaged.
that was
saved in the
host con-
troller when
The Encoder Cable was sub-
the power
ject to excessive noise inter-
was turned
ference.
OFF is dif-
ferent from
the posi-
There is variation in the FG
tion when
potential because of the
the power
influence of machines on the
was next
Servomotor side, such as a
turned ON.)
welder.
There is a SERVOPACK
pulse counting error due to
noise.
The encoder was subjected
to excessive vibration or
shock.
15.4 Troubleshooting Based on the Operation and Conditions of the Servomotor
Confirmation
Turn OFF the power sup-
ply to the servo system.
Check the Encoder Cable
to see if it satisfies speci-
fications.
Use a shielded twisted-
pair wire cable or a
screened twisted-pair
cable with conductors of
at least 0.12 mm
Turn OFF the power sup-
ply to the servo system.
Check the length of the
Encoder Cable.
Turn OFF the power sup-
ply to the servo system.
Check the Encoder Cable
to see if it is pinched or
the sheath is damaged.
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
Use cables that satisfy
the specifications.
2
.
• Rotary Servomotors:
The Encoder Cable
length must be 50 m
max.
• Linear Servomotors:
Make sure that the
Serial Converter Unit
cable is no longer
than 20 m and that
the Linear Encoder
Cable and the Sensor
Cable are no longer
than 15 m each.
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 or
Serial Converter Unit
wiring.
Reduce machine vibra-
tion. Improve the
mounting state of the
Servomotor or linear
encoder.
Continued on next page.
Reference
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15
15-75