Description

Technical Specifications for 1785-BCM

Manufacturer	Rockwell Automation
Module Type	Backup Communications Module
Certification	UL – Industrial Control Equipment, E65584 CSA – Class 1, Division 2, LR69960C
Operational Temperature	0 Deg. Celsius to 60 Deg. Celsius (32 Deg. Fahrenheit to 140 Degree Fahrenheit)
HSSL	communicates with 1.2 Megabaud
Customer Relay	.25A @ 24V dc (resistive)
Keying Locations	between 8 and 10 between 34 and 36
Module Location	1771 I/O Chassis (local)
Compatible processors	PLC-5/15 series B, -5/20, -5/25, -5/30, -5/40, and -5/60
Brand	Allen-Bradley
Part Number/Catalog No.	1785-BCM
High Speed Serial Link Interface	1

DH+/RIO Interface	2
Wiring Arm	1771-WG
Bus Communcations	Local PCI 2.3 Compliant
LEDs	1 Diagnosis/Status Per Channel
Max Modules Per System	4
Weight	0.3 lbs (0.1 kg)
Coating	Conformal Coat
Required External Power	None
Typical AC Signal Delay (Off)	29 (+/- 8) ms
Typical DC Signal Delay (Off)	30 (+/- 7) ms
Dimensions	4.5 x 12.4 x 6.3 in (115 x 317 x 160 mm)
UPC	10612598117472

About 1785-BCM

The Allen-Bradley 1785-BCM is a legacy communication module that is used with the PLC5 controller platform. This module is a single-slot chassis that is used to provide communication redundancy and switchover capability from a primary PLC processor to a stand-by PLC5 processor. This module is able to provide high-speed Data Highway Plus (DH+) and Remote I/O (RIO) communication backup via the high-speed serial link (HSSL) with switchover speed up to 1.2 Megabaud.

The 1785-BCM also features an internal buffer amounting up to 4K Words and capable of initiating switchover in different events such as power failure, processor error including 1785-BCM partner module fault. Additionally, switchover may also happen during manual switchover from RUN to PROGRAM mode, REMOTE RUN to REMOTE PROGRAM transition and REM RUN and REMOTE TEST mode changed.

The 1785-BCM is compatible for use with a variety of PLC5 processors such as PLC-5/15 series B, -5/20, -5/25, -5/30, -5/40, and -5/60 processors. It is installed to a 1771 I/O chassis with keying locations between 8 and 10 or between 34 and 36. It requires use of a Wiring Arm with catalog number 1771-WG for fast termination of communication wires to the 1785-BCM.

When using the BCM, input and output modules are not permitted to be installed in the same chassis where the processor and the BCM is installed. The I/O modules must be installed remotely, acting as distributed I/O stations.