YASKAWA E-V Series User Manual page 309

9 Troubleshooting
9.1.2 Troubleshooting of Alarms
Alarm:
Alarm Name
A.C50:
Polarity Detection
Error
(cont'd)
A.C51:
Overtravel
Detection at Polarity
Detection
A.C52:
Polarity Detection
Uncompleted
A.C53:
Out of Range for
Polarity Detection
A.C54:
Polarity Detection
Error 2
9-16
Cause
Noise interference occurred on
the scale signal.
An external force was applied to
the motor coil assembly.
The linear scale resolution is too
low.
An overtravel signal was detected
during polarity detection.
The servo has been turned ON
under the following circum-
stances.
• Polarity detection was not yet
complete.
• The /PDET signal was not
input.
The moving distance exceeded
the set value of Pn48E in the mid-
dle of detection.
External force was applied to the
servomotor.
Investigative Actions
Check the wiring to see if:
• Each FG of the serial converter
unit and linear servomotor is con-
nected to the FG of the SERVO-
PACK.
• The FG of the SERVOPACK is
connected to the FG of the power
supply.
• The encoder cable is securely
shielded.
Check to see if the detection refer-
ence is repeatedly output in one
direction.
−
Check the linear scale pitch to see if
it is within 100 μm.
Check the position after overtravel.
−
−
−
Corrective Actions
Take measures to avoid noise inter-
ference by correctly connecting FG
lines, shielding the encoder cable,
etc.
The polarity cannot be properly
detected if the detection reference is
0 (zero), but the speed feedback is
not 0 (zero) because of an external
force, such as cable tension, applied
to the motor coil assembly.
Take measures to reduce the exter-
nal force so that the speed feedback
becomes 0 for a 0 detection refer-
ence.
If external force cannot be reduced,
increase the value of the changes in
the sequence input signal allocation
for each signal (Pn481).
If the linear scale pitch is 100 μm or
longer, the SERVOPACK cannot
detect the correct speed feedback.
Use a scale pitch with higher accu-
racy (a pitch within 40 μm recom-
mended.) Or, increase the value of
the polarity detection reference
speed (Pn485). However, note that
increasing the value of Pn485 will
widen the servomotor movement
range required for polarity detec-
tion.
Perform the wiring for an overtravel
signal. Execute polarity detection at
a position where an overtravel sig-
nal is not detected.
Input the /PDET signal.
Increase the value of the polarity
detection range (Pn48E). Or,
increase the value of the changes in
the sequence input signal allocation
for each signal (Pn481).
Increase the value of the polarity
detection confirmation force refer-
ence (Pn495).
Increase the value of the polarity
detection allowable error range
(Pn498). Note that increasing the
allowable error will also increase
the motor temperature.