YASKAWA SGM7D-30F Product Manual page 117

3.1 FT82 SERVOPACKs with Analog Voltage/Pulse Train References
3.1.7 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Position
Deviation
(without
Alarm)
3-48
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.
The coupling between the
machine and Servomotor is
not suitable.
Noise interference occurred
because of incorrect I/O sig-
nal cable specifications.
If reference pulse input multi-
plication switching is being
used, noise may be causing
the I/O signals used for this
function (/PSEL and /PSELA)
to be falsely detected.
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.
Confirmation
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 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.
–
–
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 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.
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.