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6.5 Precautions for Writing Device Data from Other Station
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REDUNDANT SYSTEM NETWORKS
(b) Checking for system switching by system A and system B identification
flags
Whether system switching occurred or not can be confirmed by checking the
system A and system B identification flags before and after write of device data.
Diagram 6.42 Flowchart for Checking for System Switching with the
system A and system B identification Flags
Specify the control system and read
the following special relays:
System A identification flag (SM1511)
System B identification flag (SM1512)
Specify the control system and read
the following special relays:
System A identification flag (SM1511)
System B identification flag (SM1512)
Specify the control system and write
device data.
Start
End
Can the data be read normally?
Are the SM1511 and
SM1512 contents read in (1)
and (3) consistent?
YES(Communication normal)
NO(Communication failure) System switching occurred
NO(Inconsistent) System switching occurred
YES(Consistent)
Change the connection setup.
(1)
(2)
(3)
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