YASKAWA SGD7S-1R9D Product Manual page 535

Problem Possible Cause
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
pulse counting error due to
noise.
Abnormal
Noise from
Servomotor
The encoder was subjected
to excessive vibration or
shock.
A failure occurred in the
encoder.
A failure occurred in the
Serial Converter Unit.
A failure occurred in the linear
encoder.
The servo gains are not bal-
anced.
The setting of Pn100 (2100
hex) (Speed Loop Gain) is too
high.
Servomotor
Vibrates at
The setting of Pn102 (2102
Frequency
hex) (Position Loop Gain) is
too high.
of Approx.
200 to 400
The setting of Pn101 (2101
Hz.
hex) (Speed Loop Integral
Time Constant) is not appro-
priate.
The setting of Pn103 (2103
hex) (Moment of Inertia Ratio
or Mass Ratio) is not appro-
priate.
15.4 Troubleshooting Based on the Operation and Conditions of the Servomotor
Confirmation
Turn OFF the Servo Sys-
tem. Check the Encoder
Cable to see if it is
pinched or the sheath is
damaged.
Turn OFF the Servo Sys-
tem. Check to see if the
Encoder Cable is bundled
with a high-current line or
installed near a high-cur-
rent line.
Turn OFF the Servo Sys-
tem. Check to see if the
machines are correctly
grounded.
Check to see if there is
noise interference on the
signal line from the
encoder.
Turn OFF the Servo Sys-
tem. Check to see if
vibration from the
machine occurred. Check
the Servomotor installa-
tion (mounting surface
precision, securing state,
and alignment).
Check the linear encoder
installation (mounting sur-
face precision and secur-
ing method).
–
–
–
Check to see if the servo
gains have been cor-
rectly tuned.
Check the setting of
Pn100 (2100 hex).
The default setting is Kv =
40.0 Hz.
Check the setting of
Pn102 (2102 hex).
The default setting is Kp
= 40.0/s.
Check the setting of
Pn101 (2101 hex).
The default setting is Ti =
20.0 ms.
Check the setting of
Pn103 (2103 hex).
Continued from previous page.
Correction Reference
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.
Turn OFF the Servo
System. Implement
countermeasures
–
against noise for the
encoder wiring.
Reduce machine vibra-
tion. Improve the
mounting state of the
–
Servomotor or linear
encoder.
Turn OFF the Servo
System. Replace the –
Servomotor.
Turn OFF the Servo
System. Replace the
–
Serial Converter Unit.
Turn OFF the Servo
System. Replace the –
linear encoder.
Perform autotuning
without a host refer-
page 8-23
ence.
Set Pn100 (2100 hex)
–
to an appropriate value.
Set Pn102 (2102 hex)
–
to an appropriate value.
Set Pn101 (2101 hex)
–
to an appropriate value.
Set Pn103 (2103 hex)
–
to an appropriate value.
Continued on next page.
15
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