Allen-Bradley 1756-CN2R ControlNet Communication Module

The Allen-Bradley 1756-CN2R acts as a high-capacity bridge between ControlNet networks and ControlLogix backplanes. This module facilitates high-speed data transfer for mission-critical industrial applications. It belongs to the Rockwell Automation 1756 platform. This specific hardware supports redundant media configurations. Consequently, it prevents system failure during cable damage or signal loss. The unit ensures deterministic, repeatable data delivery for distributed I/O and peer-to-peer interlocking.

Technical Specifications

• Brand: Allen-Bradley / Rockwell Automation
• Model Number: 1756-CN2R
• Network Speed: 5 Mbps
• Logix Connections: Up to 128 connections
• Maximum Nodes: 99 nodes per network
• Communication Format: Scheduled and Unscheduled data
• Power Dissipation: 5.1 Watts
• Module Width: Single slot (standard ControlLogix)
• Backplane Current: 1100 mA at 5.1V DC; 3 mA at 24V DC
• Isolation Voltage: 30V (continuous)

Operational Features

This communication bridge provides significant throughput improvements over previous 1756-CNBR models. It manages complex automation tasks across expansive plant architectures. The redundant dual-channel architecture enhances network availability. Therefore, the system automatically switches channels if a fault occurs. This process happens without interrupting the control application. The hardware also supports CIP (Common Industrial Protocol) safety and motion control requirements. Engineers use this module to bridge messages across different network types within the Logix architecture.

Deployment and Compatibility

The 1756-CN2R installs directly into any slot of a standard ControlLogix chassis. It requires a network tap for physical connection to the ControlNet coaxial cable. The module supports a variety of network topologies including trunk-line and drop-line configurations. Its rugged design operates effectively in harsh industrial environments with 0 to 60°C temperature ranges. It carries multiple certifications including UL, CSA, CE, and C-Tick for global industrial compliance.