YASKAWA E-7S SERVOPACK SGD7S - Page 587

15.4 Troubleshooting Based on the Operation and Conditions of the Servomotor
15-76
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.)
A failure occurred in the
encoder.
–
Turn OFF the power
supply to the servo
system.
Replace the Servomo-
tor or linear encoder.
–
A failure occurred in the SER-
VOPACK.
–
Turn OFF the power
supply to the servo
system.
Replace the SERVO-
PACK.
–
Overtravel
Occurred
The P-OT/N-OT (Forward
Drive Prohibit or Reverse
Drive Prohibit) signal was
input.
Check the external power
supply (+24 V) voltage for
the input signals.
Correct the external
power supply (+24 V)
voltage for the input
signals.
–
Check the operating con-
dition of the overtravel
limit switches.
Make sure that the
overtravel limit switches
operate correctly.
–
Check the wiring of the
overtravel limit switches.
Correct the wiring of
the overtravel limit
switches.
page 5-27
Check the settings of
PnB0F and PnB10.
Set the parameters to
correct values.
page 5-27
The P-OT/N-OT (Forward
Drive Prohibit or Reverse
Drive Prohibit) signal mal-
functioned.
Check for fluctuation in
the external power supply
(+24 V) voltage for the
input signals.
Eliminate fluctuation
from 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.
Stabilize the operating
condition of the over-
travel limit switches.
–
Check the wiring of the
overtravel limit switches
(e.g., check for cable
damage and loose
screws).
Correct the wiring of
the overtravel limit
switches.
–
The selection of the Servo-
motor stopping method is
not correct.
Check the servo OFF
stopping method set in
Pn001 = n.X or
PnB1F.
Select a Servomotor
stopping method other
than coasting to a stop.
page 5-28
Improper
Stop Posi-
tion for
Overtravel
(OT) Signal
The limit switch position and
dog length are not appropri-
ate.
–
Install the limit switch at
the appropriate posi-
tion.
–
The overtravel limit switch
position is too close for the
coasting distance.
–
Install the overtravel
limit switch at the
appropriate position.
–
Continued on next page.
Continued from previous page.
Problem Possible Cause Confirmation Correction Reference