YASKAWA UAK series User Manual page 299

Problem Probable Cause
Forward or reverse run prohibited
signal is input.
Forward or reverse run prohibited
signal malfunctioning.
Overtravel (OT)
Incorrect forward or reverse run
prohibited signal (P-OT/N-OT)
allocation (parameters Pn50A.3,
Pn50B.0)
Incorrect motor stop method selec-
tion
Improper limit switch position and
Improper Stop
dog length
Position by
The overtravel limit switch position
Overtravel (OT)
is too short for the coasting dis-
Signal
tance.
11.5 Troubleshooting Malfunction Based on Operation and Conditions of the Motor
Investigative Actions
Check the external power supply
(+24 V) voltage for the input signal.
Check if the overtravel limit switch
operates properly.
Check if the overtravel limit switch
is wired correctly.
Check the fluctuation of the exter-
nal power supply (+24 V) voltage
for the input signal.
Check if the overtravel limit switch
operates correctly.
Check if the overtravel limit switch
wiring is correct. (check for dam-
aged cables or loose screws.)
Check if the P-OT signal is allo-
cated in Pn50A.3.
Check if the N-OT signal is allo-
cated in Pn50B.0.
Check the settings for parameters
Pn001.0 and Pn001.1 when the ser-
vomotor power is OFF.
Check the settings for parameters
Pn001.0 and Pn001.1 when in
torque control.
−
−
(cont'd)
Corrective Actions
Correct the external power supply
(+24 V) voltage.
Correct the overtravel limit switch.
Correct the overtravel limit switch
wiring.
Stabilize the external power supply
(+24 V) voltage.
Correct the overtravel limit switch.
Correct the overtravel limit switch
wiring.
If another signal is allocated in
Pn50A.3, allocate P-OT.
If another signal is allocated in
Pn50B.0, allocate N-OT.
Select a servomotor stop method
other than "coast to stop."
Select a servomotor stop method
other than "coast to stop."
Install the limit switch at the appro-
priate position.
Install the overtravel limit switch at
the appropriate position.
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