Mitsubishi QJ71LP21 Reference Manual page 238

8 TROUBLESHOOTING
Check the codes, history, description, and action of an error of the master module
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(c) For the remote master station, check the code, history, description, and
action of the error that occurred on the network module on the portions of
the module detailed information screen shown below.
For the error code of the transient instruction issued by a PLC program,
check the device data of section (3).
Module detailed information screen for remote master station
For remote I/O stations, check the present error and its history on the PC
diagnosis screen.
PLC diagnosis screen of remote I/O station
When the remote I/O network starts, if the remote master station starts earlier
than the remote I/O station, an error will occur at the remote I/O station and the
time of the error will appear as 2000 year 0 month 00 day 0:0:0. Also, if
communication is interrupted due to a broken cable or other reason, time data
will not be renewed after the communication has been disrupted.
MELSEC-Q
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