YASKAWA SGM7D-30F Product Manual page 322

Problem Possible Cause
Noise interference occurred
because of incorrect Encoder
Cable specifications.
Noise interference occurred
because the Encoder Cable
is too long.
Absolute
Noise interference occurred
Encoder
because the Encoder Cable
Position
is damaged.
Deviation
Error (The
position
Noise interference occurred
that was
because the Encoder Cable
is damaged.
saved in the
host con-
troller when
There is variation in the FG
the power potential because of the
influence of machines on the
was turned
Servomotor side, such as a
OFF is dif-
welder.
ferent from
the posi-
There is a SERVOPACK
tion when
pulse counting error due to
the power
noise.
was next
turned ON.)
The encoder was subjected
to excessive vibration or
shock.
A failure occurred in the
encoder.
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 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
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).
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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 or
Serial Converter Unit
wiring.
Reduce machine vibra-
tion. Or, improve the
mounting conditions of
the Servomotor.
Replace the Servomo-
tor.
Replace the SERVO-
PACK.
Continued on next page.
Reference
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3-253