Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 55)

Publication 1747-UM010B-EN-P - September 2003
Operating Your SLC 500 Backup System 4-3
RIO/DH+ Communication Channel
The RIO/DH+ communication channel has a relay that is closed when
the 1747-BSN module is in the primary mode; otherwise the relay is
open. The communication channel supports the following
configurations (The illustration on the next page shows the channel
block diagram):
1. RIO: Supports the 57.6, 115.2 and 230.4 KBaud configurations.
When the module is in primary mode, it emulates all the
1747-SN Series B functionality. When the module is in secondary
mode, the channel receives the input data from the primary
1747-BSN module and sends it to the SLC 5/0x, emulating the
1747-SN Series B backplane communication. As a result, the
secondary SLC 5/0x “thinks” that it is really connected to the
remote racks.
2. DH+: Works under 57.6, 115.2 and 230.4 KBaud configurations.
The primary 1747-BSN enters into the DH+ network using the
first address that follows the secondary SLC 5/04 network
address. The commands that it receives are sent through the
HSSL to the secondary 1747-BSN and then to the secondary
processor (the secondary 1747-BSN emulates the DH+ network
for the secondary SLC 5/04). The replies come back to the
primary 1747-BSN (again through the HSSL) and are sent to the
DH+ network. This link has a functionality similar to that found
in the 1785-BCM series B and C. The link is designed to make
remote programming possible for the secondary SLC 5/04. The
primary SLC 5/04 is connected to the DH+ network through the
primary 1747-BSN communication channel relays and
sends/receives messages without any intervention of the
1747-BSN module.
3. Disabled: In this mode the RIO/DH+ communication channel is
disabled and is used only as a relay that is closed when the
1747-BSN is in the primary mode and otherwise is open.