YASKAWA SGD7S series Product Manual page 208

Problem Possible Cause
Absolute
Encoder
Position
Deviation
Error (The
position
that was
saved in the
host con-
Host Controller Multiturn
troller when Data or Absolute Encoder
Position Data Reading Error
the power
was turned
OFF is dif-
ferent from
the posi-
tion when
the power
was next
turned ON.)
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
Overtravel
Drive Prohibit) signal mal-
Occurred functioned.
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.
9.3 Troubleshooting Based on the Operation and Conditions of the Servomotor
Confirmation
Check the error detec-
tion section of the host
controller.
Check to see if the host
controller is executing
data parity checks.
Check for noise interfer-
ence in the cable
between the SERVO-
PACK and the host con-
troller.
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.
Continued from previous page.
Correction Reference
Correct the error detec-
tion section of the host
–
controller.
Perform parity checks
for the multiturn data or
–
absolute encoder posi-
tion data.
Implement counter-
measures against noise
and then perform parity
checks again for the
–
multiturn data or abso-
lute encoder position
data.
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.
Continued on next page.
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