YASKAWA SGD7S-R70A Product Manual page 198

8.3 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Absolute
Encoder
Position
Deviation
Error
(The posi-
tion that
was saved
in the host
controller
when the
power was
turned OFF
is different
from the
position
when the
power was
next turned
ON.)
Overtravel
Occurred
Improper
Stop Posi-
tion for
Overtravel
(OT) Signal
8-58
Possible Cause
There is a SERVOPACK
pulse counting error due to
noise.
The encoder was subjected
to excessive vibration or
shock.
A failure occurred in the
encoder.
A failure occurred in the
SERVOPACK.
The P-OT/N-OT (Forward
Drive Prohibit or Reverse
Drive Prohibit) signal was
input.
The P-OT/N-OT (Forward
Drive Prohibit or Reverse
Drive Prohibit) signal
malfunctioned.
The selection of the Servo-
motor stopping method is
not correct.
The limit switch position and
dog length are not appropri-
ate.
The overtravel limit switch
position is too close for the
coasting distance.
Confirmation
Turn OFF the power sup-
ply to the servo system.
Check to see if there is
noise interference on the
I/O signal line from the
encoder or Serial Con-
verter Unit.
Turn OFF the power sup-
ply to the servo system.
Check to see if vibration
from the machine
occurred.
Check the Servomotor
installation (mounting sur-
face precision, securing
state, and alignment).
Check the linear encoder
installation (mounting sur-
face precision and secur-
ing method).
–
–
Check the external power
supply (+24 V) voltage for
the input signals.
Check the operating con-
dition of the overtravel
limit switches.
Check the wiring of the
overtravel limit switches.
Check for fluctuation in
the external power supply
(+24 V) voltage for the
input signals.
Check to see if the opera-
tion of the overtravel limit
switches is unstable.
Check the wiring of the
overtravel limit switches
(e.g., check for cable
damage and loose
screws).
Check the servo OFF
stopping method set in
Pn001 = n.X or
PnB1F.
–
–
Continued from previous page.
Correction Reference
Implement counter-
measures against noise
for the encoder or
–
Serial Converter Unit
wiring.
Reduce machine vibra-
tion. Improve the
mounting state of the
–
Servomotor or linear
encoder.
Turn OFF the power
supply to the servo
system. Replace the
–
Servomotor or linear
encoder.
Turn OFF the power
supply to the servo
–
system. Replace the
SERVOPACK.
Correct the external
power supply (+24 V)
–
voltage for the input
signals.
Make sure that the
overtravel limit switches
–
operate correctly.
Correct the wiring of
the overtravel limit –
switches.
Eliminate fluctuation
from the external power
–
supply (+24 V) voltage
for the input signals.
Stabilize the operating
condition of the over-
–
travel limit switches.
Correct the wiring of
the overtravel limit
–
switches.
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.
Continued on next page.