Allen-Bradley 1756-CN2 ControlNet Communications Bridge

The Allen-Bradley 1756-CN2 ControlNet Communications Bridge is a ControlLogix-compatible bridge module that connects a ControlNet network to a ControlLogix controller, enabling deterministic data exchange with remote ControlNet I/O racks and devices. It serves as the bridge in a ControlNet topology, allowing ControlNet communications to be routed to or from a ControlLogix chassis for distributed I/O and cross-network messaging. The 1756-CN2 supports up to 128 CIP connections over ControlNet, making it suitable for networks with substantial I/O traffic or multiple remote nodes. This module is part of Rockwell’s 1756 CNB/CN2 family of ControlNet bridges and is commonly used when migrating from older CNB/D hardware or expanding ControlNet capacity within a ControlLogix system. Its role within a modular Allen-Bradley control system is to provide a dedicated interface that consolidates ControlNet traffic for the ControlLogix processor, enabling scalable, centralized control without requiring a complete controller replacement. Typical applications include linking remote ControlNet I/O racks to a ControlLogix controller, integrating ControlNet devices into a larger Rockwell Automation architecture, and supporting migration paths from CNB-based networks to CN2 for greater connectivity.