Ras Functions; Control Station Switching Function - Mitsubishi Electric MELSEC Q Series Reference Manual

4.4

RAS Functions

This section explains the RAS functions.
4.4.1

Control station switching function

Even if the control station goes down, a normal station (sub-control station) takes over the control to continue data link.
● While the control station status is switched, data link stops for a period of a data link monitoring time (up to two seconds).
( Page 183, Section 6.3)
Data immediately before the stop are held during data link stop.
● While data link is stopped, the own station identifies all other stations as faulty.
● Even if cyclic transmission of the control station is stopped with a programming tool, the control station status is not
switched. (
● The control station status can be switched to a normal station where cyclic transmission has stopped with a programming
tool. (
124
Control station
No.1
Down
Normal station
No.4
Page 91, Section 4.1.12)
Page 91, Section 4.1.12)
Switching
Sub-control station
No.2
Normal station
No.3