YASKAWA Sigma-7 SGD7S Series - Page 657

Problem Possible Cause Confirmation Correction Reference
Noise interference
occurred because the
Encoder Cable is too
long.
Turn OFF the power
supply to the servo
system. Check the
length of the Encoder
Cable.
n Rotary Servomo-
tors: The Encoder
Cable length must
be 50 m max.
n Linear Servomo-
tors: 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.
–
Noise interference
occurred because the
Encoder Cable is
damaged.
Turn OFF the power
supply to the servo
system. Check the
Encoder Cable to see
if it is pinched or the
sheath is damaged.
Replace the Encoder
Cable and correct the
cable installation envi-
ronment.
–
The Encoder Cable
was subjected to
excessive noise inter-
ference.
Turn OFF the power
supply to the servo
system. Check to see
if the Encoder Cable
is bundled with a high-
current line or
installed near a high-
current line.
Correct the cable
layout so that no
surge is applied by
high-current lines.
–
There is variation in
the FG potential
because of the influ-
ence of machines on
the Servomotor side,
such as a welder.
Turn OFF the power
supply to the servo
system. Check to see
if the machines are
correctly grounded.
Properly ground the
machines to separate
them from the FG of
the encoder.
–
There is a SERVO-
PACK pulse counting
error due to noise.
Turn OFF the power
supply to the servo
system. Check to see
if there is noise inter-
ference on the I/O
signal line from the
encoder or Serial
Converter Unit.
Implement counter-
measures against
noise for the encoder
wiring or Serial Con-
verter Unit wiring.
–
Sigma-7 Series SERVOPACKs
Maintenance
Troubleshooting Based on the Operation and Conditions of the Servomotor
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