1756-RM2XT | Allen-Bradley | ControlLogix Enhanced Redundancy Module

Product Overview

The 1756-RM2XT provides high-speed data synchronization between primary and secondary chassis in a ControlLogix redundancy system. As an "XT" (Extended Temperature) module, it features specialized components to withstand harsher environmental conditions than standard automation hardware. This module ensures bumpless switchover during a controller or chassis failure, maintaining continuous process operation in mission-critical applications. We supply this unit as 100% Brand New original hardware, ensuring your high-availability architecture operates with factory-certified precision and thermal resilience.

Technical Specifications

The 1756-RM2XT utilizes advanced fiber optic technology to maintain real-time chassis synchronization:

Note: While standard specs list 0-60°C, the XT designation officially supports expanded ranges up to 70°C when installed in appropriate XT chassis.

Engineering Advantages

• Long-Distance Synchronization: The 1300 nm fiber optic interface supports cable runs up to 4 kilometers. This allows engineers to physically separate redundant chassis in different fire zones or remote control rooms to protect against localized disasters.

• Bumpless Switchover Performance: The 1000 Mbps (1 Gbps) transmission speed ensures near-instantaneous data mirroring. During a fault, the 1756-RM2XT facilitates a switchover so fast that the field actuators and remote I/O perceive no interruption in the control logic.

• Extended Thermal Durability: The XT-series construction utilizes robust internal components and superior heat dissipation designs. This solves the pain point of hardware failure in non-climate-controlled cabinets or extreme outdoor environments.

• Fiber Optic Isolation: By using fiber optics for chassis synchronization, the module provides total electrical isolation between redundant pairs. This eliminates ground loops and protects the control system from high-voltage surges or electromagnetic interference (EMI).

• Simplified Redundancy Setup: The module handles complex synchronization tasks automatically. Once connected via fiber, it manages the scan list and data table mirroring without requiring manual code-heavy synchronization routines from the programmer.

FAQs

Q: Can I use the 1756-RM2XT with a standard 1756-RM2 module?

A: No. For a redundant pair to function correctly, both modules must share the same hardware series and firmware revision. We recommend using two 1756-RM2XT modules to ensure consistent thermal performance and synchronization timing.

Q: What type of fiber optic cable does this module require?

A: The 1756-RM2XT requires 62.5/125 micron multi-mode fiber optic cable. Ensure you use high-quality LC-style connectors to maintain the 1000 Mbps transmission integrity over long distances.

Q: Does this module require a separate power supply?

A: No. The 1756-RM2XT draws its power directly from the ControlLogix backplane. However, you must ensure the chassis power supply (such as a 1756-PA75R) provides sufficient current for the entire redundancy set.

Q: Why should I choose the "XT" version over the standard 1756-RM2?

A: Choose the 1756-RM2XT if your installation site experiences temperatures outside the standard 0-60°C range. The XT version specifically targets applications in oil and gas, mining, and remote pumping stations where environmental control is limited.