Rockwell Automation 1747-BSN Backup Scanner Module - Manual (Page 36)

Publication 1747-UM010B-EN-P - September 2003
1-22 Overview
A Typical SLC 500 Backup Configuration
An SLC 500 backup system contains a minimum of two each of the
following hardware components:
•
SLC 500 processor module
•
1747-BSN module
•
power supply
•
local chassis
How the SLC 500 Backup System Works
In the SLC 500 backup configuration, one system (consisting of one
SLC 500 processor, 1747-BSN module, power supply, and chassis)
controls the operation of the remote I/O. This system is referred to as
the primary system. The other system is ready to take control of the
remote I/O in the event of a fault in the primary system. This is
referred to as the secondary system. The SLC 500 backup system does
not back up local I/O; therefore, do not install I/O in the local chassis.
The system provides high-speed data table transfer from the primary
system to the secondary system. This guarantees that the data tables of
the two processors track each other. To provide the possibility of
backing up a large number of I/O points, a backup system supports
up to eight 1747-BSN modules in each processor chassis linked by a
local status link (LSL).
The high-speed serial link (HSSL) has the following functionality:
•
Sends the network commands from the primary to the
secondary 1747-BSN and the replies from the secondary to the
primary when the communication channel is configured as DH+.
•
Transfers a limited number of SLC 5/0x data table files from
primary to the secondary processor. This data table transfer is
done through an application program in the SLC 5/0x processor.
Processor Catalog Number
SLC 5/02 1747-L524
SLC 5/03 1747-L531, -L532
SLC 5/04 1747-L541, -L542, -L543
SLC 5/05 1747-L551, -L552, -L553