Yaskawa YASNAC PC NC Maintenance Manual - Manual (Page 84)

Chapter 4: Troubleshooting PC NC Maintenance Manual
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AL-71:The magnetic sensor signal detection is defective.
Error Contents The magnetic sensor signal voltage level does not enter a proper value
(at tuning).
Cause and measures
AL-73:Pulse number error per one rotation
Detection Methods The motor pulse per spindle one rotation exceeded ±6%. (at tuning,
magnetic sensor method ORT)
Cause and measures
AL-74:Magnetic sensor signal disconnection
Error Contents The magnetic sensor signal conductor disconnection/improper connec-
tion.
Detection Methods An alarm sounds when sensor signals are not able to be detected after
waiting 10 seconds.
Cause and measures
Cause Measures
Magnetic sensor signal disconnection and
improper connection Check magnetic sensor signal wiring.
Magnetic sensor and magneto defective Exchange a magnetic sensor and magneto
Cause Measures
Improper setting of transmission gear
ratio Check the control parameter (C1-27, 28, 29)
Encoder signal conductor disconnection
and improper connection Check motor encoder signal conductor wiring.
Improper drive by noise (encoder cable
characteristic defect) Check encoder signal conductor is isolated from the main
circuit wiring and other power lines.
Check encoder cable specification (twisted-pair shield wire)
[recommended cable “KQVV-SW” by Fujikura-Densen Co.]
Cause Measures
Magnetic sensor signal conductor dis-
connection Check wiring for the magnetic sensor reading line.
Magnetic sensor fault Exchange the magnetic sensor,
Perform tuning, again.