1785-BEM Product datasheet  

1785-BEM Functional Description

The Allen-Bradley 1785-BCM is a critical legacy communication module designed for use with the PLC5 controller platform. This single-slot module ensures communication redundancy and switchover capabilities, enabling seamless transition between a primary and a stand-by PLC5 processor. It supports high-speed Data Highway Plus (DH+) and Remote I/O (RIO) communication backup via the high-speed serial link (HSSL), with switchover speeds reaching up to 1.2 Megabaud.

The 1785-BCM communication module can initiate a switchover in various scenarios, including power failure, processor errors, or faults in the partner module. Additionally, it allows switchover during specific modes, such as manual transitions from RUN to PROGRAM, REMOTE RUN to REMOTE PROGRAM, or when REM RUN and REMOTE TEST modes change. The module also features a 4K-word internal buffer for reliable data handling.

Compatible with a range of PLC5 processors, including the PLC-5/15 series B, -5/20, -5/25, -5/30, -5/40, and -5/60, the 1785-BCM communication module  is installed in a 1771 I/O chassis. It's important to note that I/O modules must be installed remotely from the processor and BCM, serving as distributed I/O stations. When setting up the 1785-BCM communication module , the use of a Wiring Arm (catalog number 1771-WG) is required for efficient communication wire termination.

The 1785-BCM communication module’s versatility and reliability make it an essential component for enhancing communication and system uptime in PLC5-based systems.