Allen-Bradley 1756-RM2K ControlLogix Enhanced Redundancy Module

Product Overview

The Allen-Bradley 1756-RM2K is an Enhanced Redundancy Module from the ControlLogix series, designed by Rockwell Automation to provide high-availability redundancy in critical industrial control systems. This module is the primary redundancy solution for a single ControlLogix chassis, supporting Ethernet network integration. It ensures system uptime by synchronizing two chassis and enabling seamless switchover during faults.

Technical Specifications Breakdown

The 1756-RM2K delivers a transmission speed of 1000 MB per second over a single channel, using a wavelength of 1310 Newton Meters and supporting fiber lengths up to 10 kilometers. It operates within a temperature range of 32-140 Fahrenheit (0-60 Celsius) and draws 1.16 Amps at 5.1 Volts DC, plus 3.4 mA at 24 Volts DC. The module dissipates a maximum of 6 Watts (21 BTU per hour) and has dimensions of 5.51 x 4.41 x 5.71 inches with a shipping weight of 0.64 pounds. It uses 20 AWG wire and comes with an open enclosure.

Industry Applications

In process industries like oil and gas, the 1756-RM2K ensures continuous control by synchronizing primary and backup controllers, preventing costly downtime. In manufacturing, it supports high-speed production lines where even a 10-millisecond switchover delay is acceptable for maintaining throughput. Its fiber-optic communication (1310 nm, 10 km) makes it ideal for distributed systems spanning large facilities.

Installation & Setup Guidance

Install the 1756-RM2K in any slot of a ControlLogix chassis. Use compatible cables: the 1756-RMC1 (1 meter), 1756-RMC3 (3 meter), or 1756-RMC10 (10 meter) for fiber connections. Pair it with 1756-L7x controllers in both chassis for optimal scan performance. Ensure the operating environment stays within 32-140°F (0-60°C) and avoid exposure to conductive contaminants.

Maintenance & Reliability

The 1756-RM2K features enhanced safety features that reduce interference, contributing to long-term reliability. Periodically inspect fiber connections for cleanliness and verify that the module’s current draw remains within specifications (1.16 A at 5.1 VDC). Regular checks of the chassis temperature and power supply help maintain consistent operation. With proper care, this module supports extended service life, reducing total cost of ownership.

Compatibility & Integration

The 1756-RM2K integrates with seven enhanced ControlNet and EtherNet/IP communication modules. It works seamlessly with 1756-L7x controllers and supports redundant fiber ports to eliminate single points of failure. The module is designed for ControlLogix systems and uses standard 20 AWG wiring for power connections.

Selection Guide & Purchasing Advice

When selecting the 1756-RM2K, verify your chassis compatibility and required cable lengths (1, 3, or 10 meters). Confirm that your system uses 1756-L7x controllers for best performance. For current availability and lifecycle status, contact plcmatrix.com — a trusted supplier of new, surplus, and obsolete automation parts. They can help you source this module and provide guidance on replacement options if needed.