YASKAWA SGM7D-30F Product Manual page 324

Problem Possible Cause
Noise interference occurred
because of incorrect Encoder
Cable specifications.
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
Position
pulse counting error due to
Deviation
noise.
(without
Alarm)
The encoder was subjected
to excessive vibration or
shock.
The coupling between the
machine and Servomotor is
not suitable.
Noise interference occurred
because of incorrect I/O sig-
nal cable specifications.
Noise interference occurred
because an I/O signal cable
is too long.
An encoder fault occurred.
(The pulse count does not
change.)
A failure occurred in the SER-
VOPACK.
3.5 FT83 SERVOPACKs with Analog Voltage/Pulse Train References
3.5.9 Troubleshooting Based on the Operation and Conditions of the Servomotor
Confirmation
Check the Encoder Cable
to see if is satisfies speci-
fications. Use a shielded
twisted-pair wire cable or
a screened twisted-pair
cable with conductors of
at least 0.12 mm
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
I/O signal line from the
encoder or Serial Con-
verter Unit.
Check to see if vibration
from the machine
occurred.
Check the Servomotor
installation (mounting sur-
face precision, securing
state, and alignment).
Check to see if position
offset occurs at the cou-
pling between machine
and Servomotor.
Check the I/O signal
cables to see if they sat-
isfy specifications. Use a
shielded twisted-pair wire
cable or a screened
twisted-pair cable with
conductors of at least
2
0.12 mm .
Check the lengths of the
I/O signal cables.
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Continued from previous page.
Correction
Use cables that satisfy
the specifications.
2
.
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
or Serial Converter Unit
wiring.
Reduce machine vibra-
tion. Or, improve the
mounting conditions of
the Servomotor.
Correctly secure the
coupling between the
machine and Servomo-
tor.
Use cables that satisfy
the specifications.
The I/O signal cables
must be no longer than
3 m.
Replace the Servomo-
tor.
Replace the SERVO-
PACK.
Continued on next page.
Reference
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