User Manual

1 Publication 1747-UM010B-EN-P - September 2003
Chapter 1
Overview
This chapter contains the following information:
• system overview
• how the backup scanner interacts with the SLC processor
• how the backup scanner interacts with adapter modules
• scanner I/O image concepts
• extended node capability
• complementary I/O
• scanner features
• compatible network devices
• backup concepts for the SLC-500 system
System Overview
The 1747-BSN Backup Scanner provides redundancy for:
• Remote I/O (RIO)
• RS232 channel switchover for communications to devices such
as operator interface
• DH+
The backup scanner also provides a High Speed Serial Link (HSSL) to
write any retentative data from a primary to a secondary processor. In
addition, the module has a Local Serial Link (LSL) to pass status
information between multiple 1747-BSN modules located in the same
chassis (optional).
The 1747-BSN is a complementary set of modules, with one module
residing in the primary system and another module in the secondary
or backup system. The primary module controls the operation of
remote I/O, while the secondary module is available to take over
control in the event of a fault in the primary.
The backup scanner has the capability to switch between two
communication channels. The first channel is configurable as RIO or
DH+. The second channel is used to switch the RS232/485 channel in
order to provide connection for electronic operator interfaces. The
DH+/RIO and the RS232/485 channels can be used simultaneously.
The Remote I/O (RIO) scanner, Catalog Number 1747-SN, enables
communication between an SLC processor (SLC 5/02 or later) and