Why the 1756-RM2XT Belongs in Your ControlLogix Redundancy Plan
When a ControlLogix chassis pair must keep running through heat, vibration, and long-haul fiber runs, the 1756-RM2XT is the module engineers specify. This Allen-Bradley enhanced redundancy module supervises operating states and state transitions across two chassis, forming the backbone of a redundant ControlLogix architecture. It pairs with one module per chassis and supports ControlLogix 5580 and 5570 controller families.
Key Parameters That Shape Real Deployments
Fiber Reach and Transmission
A length rating of 4 kilometers and a 1300 nm wavelength let you separate redundant chassis across a plant without adding repeaters. Transmission stays under 1000 MB per second, keeping synchronization traffic predictable.
Extreme-Environment Rating
The 1756-RM2XT carries T4 North American, T4 IECEx, and T4 ATEX temperature codes, so it fits hazardous-area cabinets where standard modules fall short. It operates from 0 to 60 Celsius (32 to 140 Fahrenheit) and ships without an enclosure for direct chassis mounting.
Power and Slot Budget
Backplane draw is 1.16 A at 5.1 V DC plus 3.4 mA at 24 V DC. Maximum power dissipation is 6 W, thermal dissipation is 21 BTU/hr, and the module occupies a single slot in any chassis-based position. Wire size is 20 AWG, and dimensions are 5.51 x 4.41 x 5.71 inches.
Where This Module Earns Its Keep
In oil and gas, the 1756-RM2XT supervises redundant ControlLogix pairs on compressor and pipeline control skids, where a single chassis failure cannot stop production. In power generation, it maintains state synchronization between primary and backup controllers running SIL 2 logic. In heavy process industries, the extended temperature rating keeps redundancy alive in non-climate-controlled electrical rooms.
Integration and Compatibility Notes
The module is compatible with Bulletin 1756-RMC connector cables and the 1756-PAXT and 1756-PBXT power supplies. It works only with other enhanced redundancy modules — it cannot be used with the 1756-RM/A, 1756-RM/B, or 1756-RMXT. When wiring into a ControlLogix network, confirm cable and gateway requirements with your supplier, since fiber runs may need external connection modules.
Selecting and Sourcing the 1756-RM2XT
Before ordering, verify your controller family, chassis slot availability, and that both chassis carry enhanced redundancy modules. Confirm the fiber length and wavelength match your plant layout, and check that your power supplies are 1756-PAXT or 1756-PBXT. Please verify current lifecycle status and availability with Oil AutoTech before ordering. Oil AutoTech offers hands-on technical selection help and fast dispatch, worldwide, so your redundant pair is never waiting on a slow supply chain. Contact Oil AutoTech today for pricing and availability.
