YASKAWA SGD7S Product Manual page 471

14.2 Alarm Displays
14.2.2 Troubleshooting Alarms
Alarm Number:
Alarm Name
A.C20:
Phase Detection
Error
A.C21:
Polarity Sensor
Error
A.C22:
Phase Informa-
tion Disagree-
ment
14-30
Possible Cause
Check the voltage of
The linear encoder
the linear encoder sig-
signal level is too low.
nal.
Check the setting of
The count-up direc-
Pn080 = n.X
tion of the linear
(Motor Phase Selec-
encoder does not
tion). Check the installa-
match the forward
tion orientation for the
direction of the Mov-
linear encoder and
ing Coil in the motor.
Moving Coil.
The polarity sensor
signal is being –
affected by noise.
The setting of Pn282 Check the setting of
(Linear Encoder Scale Pn282 (Linear Encoder
Pitch) is not correct. Scale Pitch).
The polarity sensor is
protruding from the Check the polarity sen-
Magnetic Way of the sor.
motor.
The polarity sensor is Check the wiring of the
not wired correctly. polarity sensor.
The polarity sensor
–
failed.
The SERVOPACK
phase information is
different from the lin- –
ear encoder phase
information.
Confirmation
Fine-tune the mounting of
the scale head. Or,
replace the linear
encoder.
Change the setting of
Pn080 = n.X.
Correctly reinstall the lin-
ear encoder or Moving
Coil.
Correct the FG wiring.
Implement countermea-
sures against noise for the
polarity sensor wiring.
Check the specifications
of the linear encoder and
set a correct value.
Correctly reinstall the
Moving Coil or Magnetic
Way of the motor.
Correct the wiring of the
polarity sensor.
Replace the polarity sen-
sor.
Perform polarity detec-
tion.
Continued from previous page.
Correction Reference
–
page 5-22
–
page 5-17
–
–
–
page 5-27
Continued on next page.