Mitsubishi Electric Melsec QJ71LP21 Reference Manual page 402

8 TROUBLESHOOTING
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(2) Error history detail monitoring
Displays the causes of loop switches and the history of the transient transmission
errors.
1)
2)
3)
[Loop switching]
1) Station No. (SW00E0 to 00E7)
Displays the number of the station (not necessarily an adjacent station) that
requested the loop switch and loopback.
2) Factor (SW00D0 to 00DF)
Displays the reason why the loop switch and loop back are executed.
• Normal return
• Forward loop hardware error
• Reverse loop hardware error
3) Switched to (SW00D0 to 00DF)
Displays the data link status after the loop switch.
• Multiplex transmission: Forward loop/reverse loop normal
• Forward loop transmission
• Reverse loop transmission
• Loopback transmission
[Transient transmission errors]
4) Error code, error type (SW00F0 to 00FF)
Displays the error code.
Refer to Section 8.3
(3) Clear of error history
Error history can be cleared for each item by selecting the item from the list.
4)
: Cable or optical module error
: Cable or optical module error
MELSEC-Q
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