Allen-Bradley 1756-CNBR ControlLogix ControlNet Bridge Module

Product Description

The 1756-CNBR is a ControlNet communication bridge module designed for the Allen-Bradley ControlLogix platform. It enables deterministic high-speed data exchange between controllers and distributed nodes across a ControlNet network, supporting both simplex and redundant network topologies.

This module is equipped with dual ControlNet ports for network redundancy and a Network Access Port (NAP) for configuration and diagnostic access via RJ-45 interface. It is engineered to maintain stable communication in time-critical control applications requiring synchronized I/O and motion data transfer.

The 1756-CNBR supports high-capacity network connections and is designed for installation in standard ControlLogix chassis systems, integrating seamlessly with system power supplies and backplane architecture.

Key Technical Specifications

Communication Interface

• Network Protocol: ControlNet

• Data Rate: 5 Mbps

• ControlNet Ports: 2 (supports redundant or simplex configuration)

• Network Access Port: RJ-45 (8-pin shielded)

• Maximum Network Nodes: up to 99

• Logical Connections: 40–48 (up to 64 max supported connections)

System Compatibility

• Platform: ControlLogix

• Chassis Compatibility: 1756-A4, A7, A10, A13, A17

• Slot Requirement: 1-slot module

Electrical Characteristics

• Backplane Current:

• 970 mA @ 5.1 VDC

• 1.7 mA @ 24 VDC

• Power Dissipation: max. 5.5 W

• Isolation Voltage: 30 V continuous

Mechanical & Installation

• Mounting: ControlLogix chassis backplane

• Enclosure Type: Open-style module

• Weight: 0.99 lbs

• Communication Cable: 1786-RG6 quad-shield coaxial cable

Environmental Conditions

• Operating Temperature: 0°C to 60°C (32°F to 140°F)

Functional Features

• Dual-port architecture for redundant ControlNet networks

• Deterministic communication for synchronized control systems

• Supports high-density I/O and controller messaging

• Integrated diagnostics and network access capability

Applications

• High-speed motion control systems

• Large-scale distributed control architectures

• Process automation requiring deterministic communication

• Redundant industrial network configurations

FAQ

Q: Does this module support redundant network operation?
A: Yes, it supports both simplex and fully redundant ControlNet configurations using dual communication ports.

Q: What is the purpose of the Network Access Port (NAP)?
A: The NAP provides RJ-45 access for configuration, diagnostics, and network troubleshooting.

Q: How many connections can it handle?
A: It supports up to 64 total connections with 40–48 logical ControlLogix communication links.