The Allen-Bradley 1757-SRM/B is a ControlLogix System Redundancy Module designed to provide high-availability and fault tolerance for critical control applications. As a key component of a redundant ControlLogix system, this module works in pairs to synchronize the memory of a primary and a secondary controller. It utilizes a high-speed fiber-optic link to ensure constant communication and data integrity between the two chassis. In the event of a fault or failure in the primary controller, the 1757-SRM/B facilitates a seamless, “bumpless” transfer of control to the secondary controller, minimizing downtime and preventing loss of production. This Series B module is essential for applications in process control, manufacturing, and infrastructure where system reliability is paramount.