Troubleshooting For Polarity Detection Errors - YASKAWA SGLGW User Manual

5.5.3

Troubleshooting for Polarity Detection Errors

Refer to the following table for troubleshooting if polarity detection is not completed
normally.
No. Problem
Polarity detection
1
error (A.C50)
Overtravel
detection at
2
polarity detection
(A.C51)
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Cause
The settings for linear scale pitch (Pn282) and motor
Parameter 
phase selection (Pn080.1) may not be appropriate for
settings are 
the device. Check the linear scale specifications and
incorrect.
feedback signal conditions.
When the detection reference is repeatedly output sev-
eral times in the same direction, noise may occur in the
Noise is present scale signal, resulting in malfunction. Check that the
in the scale 
FG of the serial converter unit and linear servomotor is
signal.
connected to FG of the SERVOPACK, and that FG of
the SERVOPACK is connected to the power supply FG.
Also check that the encoder cable is securely sealed.
If the moving coil is subjected to a gravity or/and an
external force such as cable tension, and the speed feed-
back is not 0 regardless of a 0 detection reference,
polarity detection will be poor. 
The moving coil is
being subjected to
Reduce the external force and make the speed feedback
0. 
an external force.
If the external force can not be reduced, increase the
value of the changes in the sequence input signal allo-
cation for each signal (Pn481).
When the linear scale pitch is 100 m min., the SER-
VOPACK cannot detect correct speed feedback.
Use a linear scale with good scale pitch precision
The linear scale
(within 40 m is recommended).
resolution is
Alternatively, increase the value of the polarity detec-
rough.
tion reference speed (Pn485).
The range of linear servomotor movement at polarity
detection, however, will increase.
The OT signal
The alarm A.C51 occurs when the OT signal is detected
was detected during polarity detection. Before executing the polarity
during polarity detection, place the motor to the position where the OT
detection signal is not detected.
5.5 Polarity Detection
Countermeasure
5
5-21