Allen-Bradley 1756-CNBR

Product Parameters

• Model: 1756-CNBR

• Product Type: Redundant ControlNet Bridge Module (ControlLogix)

• Network: ControlNet (dual coaxial media for redundancy)

• Communication Rate: 5 Mbps (ControlNet standard)

• Node Capacity: Supports multiple ControlNet nodes per network

• Chassis Compatibility: ControlLogix 1756 chassis

• Configuration Software: Studio 5000 / RSLogix 5000

• Redundancy: Dual-media redundancy supported (primary and secondary channels)

• Operating Environment: Industrial temperature range per datasheet

(Confirm exact series, communication rate, and redundancy behavior from the official Rockwell Automation datasheet for 1756-CNBR.)

Advantages and Features

• Dual-media redundancy — the 1756-CNBR maintains communication through a secondary ControlNet path if the primary media fails.

• Deterministic ControlNet communication — scheduled, repeatable network performance for time-critical I/O.

• Native ControlLogix integration — installs directly into the 1756 chassis and configures through Studio 5000.

• Peer-to-peer messaging — enables controller-to-controller data exchange over ControlNet.

• Remote I/O support — connects distributed I/O racks to the ControlLogix controller.

• Proven reliability — part of Rockwell Automation’s widely deployed ControlLogix communication family.

Application Cases and Fields

• Oil & Gas — mission-critical distributed control and remote I/O networks

• Power Generation — high-availability control network interconnections

• Chemical & Petrochemical — redundant process control network segments

• Water/Wastewater — plant-wide distributed I/O with redundancy

• Manufacturing & Material Handling — ControlNet-connected drive and I/O systems requiring high availability

The 1756-CNBR is commonly deployed where deterministic ControlNet communication with media redundancy is required.

Comparison with Competing Products

Selection Suggestions and Precautions

• Confirm the exact series/revision of 1756-CNBR before ordering — series variants can affect firmware and redundancy behavior.

• Do not substitute the non-redundant 1756-CNB where media redundancy is required.

• Verify redundant ControlNet topology, media (dual coaxial runs, taps, terminators), and node addressing are correctly planned.

• Check firmware compatibility with your ControlLogix controller and Studio 5000 version.

• Consider whether EtherNet/IP (1756-EN2TR) better fits new installations — ControlNet is a mature network.

• Ensure proper network grounding, termination, and shielding for both redundant channels per Rockwell guidelines.

• Source from authorized channels to avoid counterfeit or mismatched revisions of the 1756-CNBR.