Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 56)

Publication 1747-UM010B-EN-P - September 2003
4-4 Operating Your SLC 500 Backup System
Secondary Processor Remote Programming
In the 1747 backup system, only the primary processor is connected
to the link. The secondary processor is not physically connected, but
it communicates with the secondary 1747-BSN module making this
processor think that it is on the DH+ network. This separate link
prevents Data Highway faults in the secondary processor.
Primary Secondary
SLC 5/04 1747-BSN
Remote I/0 Link
1747-BSN SLC 5/04
Primary Secondary
SLC 5/04 1747-BSN
DH+ Network
1747-BSN
SLC 5/04
HSSL
1747-SN
emulation
1747-SN
emulation
RIO
HSSL DH+
IMPORTANT
The programming device must be connected through
the DH+ network and must not bypass the relay in
the 1747-BSN module (if the programs in both
processor are identical; e.g., if both DH+ mode
addresses are the same). If you were to connect the
device directly to a processor, it must be connected
to the primary processor. Therefore, if your system
were to switch to the secondary system, you must
then move your device to your new primary
processor.