Mitsubishi Electric C70 Setup Manual page 487

MITSUBISHI CNC
Appendix 2 Explanation of Alarms
Y20 Output OFF check error (NC side) 0051 (Unit No.)
Details
Although the output OFF check function turned OFF the dual signal module's output signals, there is a
feedback input signal which is staying ON.
Remedy
The NC side output transistor may be broken.
The No. of the error module is displayed.
Replace the dual signal module.
Carry out the output OFF check to confirm there is no problem.
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