Allen-Bradley 1756-CN2R ControlNet Redundant Bridge Module

The Allen-Bradley 1756-CN2R ControlNet Redundant Bridge Module is a ControlLogix bridge that adds a redundant path between two ControlNet networks, enabling seamless failover in high-availability automation systems. Installed in a 1756 ControlLogix chassis, it provides two ControlNet ports to connect networks A and B and serves as the redundant media bridge within Rockwell’s Enhanced Redundancy System. The CN2R maintains deterministic communications during switchover and supports network scheduling via RSNetWorx for ControlNet in redundant configurations. It supports up to 100 ControlNet connections, and includes USB interfaces for backplane and ControlNet configuration and diagnostics. Firmware for the CN2R has evolved through the 25.x release family (with documented revisions such as 25.005 and 25.006), reflecting ongoing improvements in redundancy, stability, and interoperability with ControlLogix controllers. The CN2R replaces earlier CN2R/CNBR combinations in newer redundancy architectures and is the standard bridge module when building modern, resilient ControlNet networks around a ControlLogix system, suitable for applications like packaging lines, batch processes, and other manufacturing environments where uninterrupted ControlNet communication is critical.