YASKAWA SGM7D-30F Product Manual page 116

Problem Possible Cause
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 mal-
Overtravel
functioned.
Occurred
There is a mistake in the allo-
cation of the P-OT or N-OT
(Forward Drive Prohibit or
Reverse Drive Prohibit) sig-
nal in Pn50A = n.X or
Pn50B = n.X.
The selection of the Servo-
motor stopping method is
not correct.
The limit switch position and
Improper
dog length are not appropri-
Stop Posi-
ate.
tion for
The overtravel limit switch
Overtravel
position is too close for the
(OT) Signal
coasting distance.
Noise interference occurred
because of incorrect Encoder
Cable specifications.
Position
Deviation
(without
Noise interference occurred
because the Encoder Cable
Alarm)
is too long.
Noise interference occurred
because the Encoder Cable
is damaged.
3.1 FT82 SERVOPACKs with Analog Voltage/Pulse Train References
3.1.7 Troubleshooting Based on the Operation and Conditions of the Servomotor
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 the settings of the
overtravel input signal
allocations (Pn50A/Pn50B).
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 to see if the P-OT
signal is allocated in
Pn50A = n.X.
Check to see if the N-OT
signal is allocated in
Pn50B = n.X.
Check the servo OFF
stopping method set in
Pn001 = n.X or
Pn001 = n.X.
Check the torque control
stopping method set in
Pn001 = n.X or
Pn001 = n.X.
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Check the Encoder Cable
to see if it satisfies speci-
fications. Use a shielded
twisted-pair wire cable or
a screened twisted-pair
cable with conductors of
at least 0.12 mm
Check the length of the
Encoder Cable.
Check the Encoder Cable
to see if it is pinched or
the sheath is damaged.
Continued from previous page.
Correction
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.
Set the parameters to
correct values.
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.
If another signal is allo-
cated in Pn50A
=n.X, allocate the
P-OT signal instead.
If another signal is allo-
cated in Pn50B
=n.X, allocate the
N-OT signal instead.
Select a Servomotor
stopping method other
than coasting to a stop.
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.
Use cables that satisfy
the specifications.
2
.
The Encoder Cable
length must be 50 m
max.
Replace the Encoder
Cable and correct the
cable installation envi-
ronment.
Continued on next page.
Reference
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