Allen-Bradley 1747-BSN Backup Scanner Module

Allen-Bradley 1747-BSN Backup Scanner Module

Description

The 1747-BSN Backup Scanner Module provides a high-speed communication channel between two modular SLC 500™ (5/02 or higher) processors. The 1747- BSN backup system uses a set of modules, with one or more 1747-BSN modules residing in the primary system and one or more complementary modules in the secondary or backup system. The primary system controls the operation of remote I/O, while the secondary system monitors communications via the highspeed serial link (HSSL) and is available to take over control in the event of a fault in the primary system.

The backup scanner has the capability to switch between two communication channels. The first channel is configurable as Remote I/O (RIO) or Data Highway Plus™ (DH+). The second channel is used to switch one RS232/485 channel in order to provide connection for electronic operator interfaces.

A backup system using the 1747-BSN modules supports up to eight BSN modules in each processor chassis, connected by a local status link (LSL). Only I/ O residing in remote chassis is backed up. Local I/O is not backed up.

Note:

During the transfer of control from one processor to another (switchover), the output modules in the remote chassis maintain their last state until the secondary processor program takes control. The secondary processor program is not synchronized with the primary program.

The 1747-BSN module provides backup functionality for the following:

DH+ or RIO on a single pair of modules - Both may be backed up when two or more pairs of modules are used.

RS232 - Any RS232 device communicating with channel 0 of the SLC controller may be backed up provided hardware-handshake lines are not required. These ports only allow switchover of the transmit, receive and ground wires for RS232.  

Technical Specifications