YASKAWA SGM7D-30F Product Manual page 212

Problem Possible Cause
The selection of the Servo-
Overtravel
motor stopping method is
Occurred
not correct.
The limit switch position and
Improper
dog length are not appropri-
Stop Posi-
ate.
tion for
The overtravel limit switch
Overtravel
position is too close for the
(OT) Signal
coasting distance.
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
Position
Servomotor side, such as a
Deviation
welder.
(without
Alarm)
There is a SERVOPACK
pulse counting error due to
noise.
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.
3.3 FT82 SERVOPACK with MECHATROLINK-III Communications References
3.3.7 Troubleshooting Based on the Operation and Conditions of the Servomotor
Confirmation
Check the servo OFF
stopping method set in
Pn001 = n.X or
Pn001 = n.X.
Check the torque control
stopping method set in
Pn001 = n.X or
Pn001 = n.X.
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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).
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 .
Continued from previous page.
Correction
Select a Servomotor
stopping method other
than coasting to a stop.
Select a Servomotor
stopping method other
than coasting to a stop.
Install the limit switch at
the appropriate posi-
tion.
Install the overtravel
limit switch at the
appropriate position.
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.
Continued on next page.
Reference
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