YASKAWA SGM7D-30F Product Manual page 211

3.3 FT82 SERVOPACK with MECHATROLINK-III Communications References
3.3.7 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
3-142
Possible Cause
The encoder was subjected
to excessive vibration or
shock.
A failure occurred in the
encoder.
A failure occurred in the SER-
VOPACK.
Host Controller Multiturn
Data or Absolute Encoder
Position Data Reading Error
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.
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.
Confirmation
Check to see if vibration
from the machine
occurred.
Check the Servomotor
installation (mounting sur-
face precision, securing
state, and alignment).
–
–
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.
Continued from previous page.
Correction Reference
Reduce machine vibra-
tion. Or, improve the
–
mounting conditions of
the Servomotor.
Replace the Servomo-
–
tor.
Replace the SERVO-
–
PACK.
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.
Continued on next page.