YASKAWA E-7S SERVOPACK SGD7S Product Manual page 587

15.4 Troubleshooting Based on the Operation and Conditions of the Servomotor
Problem
Absolute
Encoder
Position
Deviation
Error (The
position
that was
saved in the
host con-
troller when
the power
was turned
OFF is dif-
ferent from
the posi-
tion when
the power
was next
turned ON.)
Overtravel
Occurred
Improper
Stop Posi-
tion for
Overtravel
(OT) Signal
15-76
Possible Cause
A failure occurred in the
encoder.
A failure occurred in the SER-
VOPACK.
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-
functioned.
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 the settings of
PnB0F and PnB10.
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
Turn OFF the power
supply to the servo
system. –
Replace the Servomo-
tor or linear encoder.
Turn OFF the power
supply to the servo
system. –
Replace the SERVO-
PACK.
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 5-27
switches.
Set the parameters to
page 5-27
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.
Select a Servomotor
stopping method other
page 5-28
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.