YASKAWA SGD7S Product Manual page 486

14.4 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Overtravel
Occurred
Improper
Stop Posi-
tion for
Overtravel
(OT) Signal
14-60
Possible Cause
The CCW-OT/CW-OT (CCW
Drive Prohibit or CW Drive
Prohibit) signal was input.
The CCW-OT/CW-OT (CCW
Drive Prohibit or CW Drive
Prohibit) signal malfunc-
tioned.
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
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
Pn001 = n.X.
−
−
Continued from previous page.
Correction Reference
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
page 5-29
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
page 5-30
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.