1756-CNBR | Allen-Bradley ControlLogix ControlNet Redundant Media Bridge Module
1756-CNBR | Allen-Bradley ControlLogix ControlNet Redundant Media Bridge Module
1756-CNBR | Allen-Bradley ControlLogix ControlNet Redundant Media Bridge Module
    1756-CNBR | Allen-Bradley ControlLogix ControlNet Redundant Media Bridge Module
1756-CNBR | Allen-Bradley ControlLogix ControlNet Redundant Media Bridge Module

1756-CNBR | Allen-Bradley ControlLogix ControlNet Redundant Media Bridge Module

Part #: 1756-CNBR Manufactured by: Allen-Bradley
$689.00
$689.00
11 in Stock
Condition: New – Open box
Shipping calculated at checkout.
Product Overview
The Allen-Bradley ControlLogix 1756-CNBR is a Redundant Bridge Module with 5.1 Watts, 5 Mbps, and 40-48 Logix Communicatio...  Read more
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Product Description P/N: 1756-CNBR

Description / Specifications

Description 

The Allen-Bradley 1756-CNBR is a redundant ControlNet bridge module engineered for reliable communication within ControlLogix systems. It manages data exchange between ControlNet networks and Logix controllers while supporting dual media paths for uninterrupted operation. This module is commonly applied in high-speed industrial automation, including manufacturing, processing, and motion-control environments.

 

 

Technical Specifications 

Condition New/Never Used Surplus
Brand Allen-Bradley
Category Industrial Communication Modules
Part Number 1756-CNBR
Subcategory Redundant ControlNet Bridge Module
Type Parallel communication module
Series / Platform ControlLogix
Function Redundant communication bridging between ControlNet and Logix systems
Ports 2x BNC ControlNet (redundant), 1x RJ45 ControlNet
Communication Speed 5 Mbps
Power Consumption 5.1 W
Input Current 970 mA at 5.1 VDC; 1.7 mA at 24 VDC
Communication Connections 40–48 Logix connections
Message Buffers Up to 20 for unconnected messaging
Supported Nodes Up to 99
Protocol CIP (Common Industrial Protocol)
Mounting ControlLogix chassis slot
Operating Temperature 0 to 60 °C
Isolation Voltage 30 V continuous
Certifications CE, CSA, cUL, KC, Marine, NRTL, RCM, UL
Application ControlNet networks, real-time automation, redundant architectures
Display Type Digital status indicators

  

 

Information About 1756-CNBR

The 1756-CNBR is part of the ControlLogix communication family from Allen-Bradley, designed specifically for redundant ControlNet architectures. It incorporates two BNC ports to support dual-media operation, offering improved resilience compared to the single-port 1756-CNB. The module handles scheduled and unscheduled messaging, enabling smooth traffic flow between ControlNet devices and Logix controllers. It supports CIP messaging, high-throughput data exchange, and up to 48 communication connections for complex automation systems. With its chassis-based installation, isolation rating, and compatibility with standard or redundant power supplies, the 1756-CNBR is an essential component for applications requiring continuous uptime and precise network coordination.

Key Features:

  • Redundant Media Support: Dual BNC ports allow primary and secondary ControlNet paths for fault-tolerant network operation.
  • High Throughput: Supports 5 Mbps communication speed for real-time industrial data exchange.
  • Connectivity: Includes one ControlNet RJ45 port for additional network integration.
  • Performance Capacity: Handles 40–48 Logix communication connections and up to 20 unconnected message buffers.
  • CIP Protocol: Utilizes Common Industrial Protocol for combined I/O and peer-to-peer communication.
  • Isolation Rating: Provides 30 V continuous isolation for enhanced electrical protection.
  • System Compatibility: Works with ControlLogix chassis, Logix5550 and other Logix controllers, and redundant power configurations.
  • Industrial Durability: Rated for 0–60°C operation and meets global certifications including UL, CE, CSA, and Marine approvals.

The 1756-CNBR delivers the reliability and precision required for demanding ControlNet automation systems.

Frequently Asked Questions about 1756-CNBR
Question: What is the main function of the Allen-Bradley 1756-CNBR module?
Date Update:05/06/2025
Answer:

The 1756-CNBR is a ControlNet bridge communication module used in ControlLogix systems. Its primary function is to facilitate data exchange between the ControlLogix backplane and ControlNet network devices. It supports both scheduled and unscheduled messaging, providing real-time data exchange capabilities. Additionally, this module allows for redundant media connections, ensuring higher network reliability. It is often used in applications requiring deterministic communication across multiple control nodes.

Question: What is the difference between the 1756-CN2R and 1756-CNBR modules?
Date Update:05/06/2025
Answer:

The main difference between the 1756-CN2R and 1756-CNBR lies in their network media type and capabilities. The 1756-CNBR uses coaxial media and is equipped with BNC connectors for connection to traditional coaxial-based ControlNet networks. It supports redundant ControlNet topologies through its two BNC ports. In contrast, the 1756-CN2R uses fiber optics or twisted-pair cables through SC or RJ-type connectors, depending on the model. The CN2R is part of the newer generation of ControlNet modules, supporting higher channel density and improved diagnostics. Therefore, while both modules provide redundancy and ControlNet connectivity, they differ in media type, connector format, and intended applications.

Question: What is the maximum number of Logix communication connections the module supports?
Date Update:05/06/2025
Answer:

The 1756-CNBR supports up to 48 Logix communication connections per module. These connections are used to exchange data with Logix controllers and I/O devices over ControlNet. It can manage both scheduled (cyclical) and unscheduled (event-driven) traffic. This capacity allows the module to serve large systems with many controllers and nodes. Applications requiring high-speed control benefit from this robust communication capability.

Question: Which ControlLogix chassis are compatible with the 1756-CNBR?
Date Update:05/06/2025
Answer:

The 1756-CNBR is compatible with ControlLogix chassis models including 1756-A4, A7, A10, A13, and A17. It can be installed in any available slot within the chassis. The module uses one slot and interfaces with the backplane for power and communication. It can be located near the controller or in remote I/O racks for flexible system architecture. The versatility in chassis compatibility makes integration into existing systems straightforward.

Question: Is the 1756-CNBR still available or actively manufactured?
Date Update:05/06/2025
Answer:

No, the Allen-Bradley 1756-CNBR has been officially discontinued by Rockwell Automation. According to the manufacturer, this module will no longer be available for sale starting December 31, 2024. Users are advised to begin migration planning and remove this module from future designs. The recommended engineering replacement for the 1756-CNBR is the 1756-CN2R, which supports newer ControlNet capabilities and improved performance. Customers should consult Rockwell’s migration guides for a smooth transition.

IQElectro is not an authorized distributor.
IQElectro LLC (IQElectro) is NOT an Authorized Distributor or in any way affiliated with Rockwell Automation, Siemens, or any other Manufacturers. IQElectro is NOT an Authorized Dealer of this product. The product may be of older version, date codes, or design than that available from authorized dealers. As IQElectro is not an authorized dealer of this product, the Original Manufacturer's Warranty and Support DO NOT apply. IQElectro sells SURPLUS only and DOES NOT SELL SOFTWARE or FIRMWARE licenses For more detailed information, please refer to the full version of our disclaimer policy Disclaimer Policy.
Description / Specifications

Description 

The Allen-Bradley 1756-CNBR is a redundant ControlNet bridge module engineered for reliable communication within ControlLogix systems. It manages data exchange between ControlNet networks and Logix controllers while supporting dual media paths for uninterrupted operation. This module is commonly applied in high-speed industrial automation, including manufacturing, processing, and motion-control environments.

 

 

Technical Specifications 

Condition New/Never Used Surplus
Brand Allen-Bradley
Category Industrial Communication Modules
Part Number 1756-CNBR
Subcategory Redundant ControlNet Bridge Module
Type Parallel communication module
Series / Platform ControlLogix
Function Redundant communication bridging between ControlNet and Logix systems
Ports 2x BNC ControlNet (redundant), 1x RJ45 ControlNet
Communication Speed 5 Mbps
Power Consumption 5.1 W
Input Current 970 mA at 5.1 VDC; 1.7 mA at 24 VDC
Communication Connections 40–48 Logix connections
Message Buffers Up to 20 for unconnected messaging
Supported Nodes Up to 99
Protocol CIP (Common Industrial Protocol)
Mounting ControlLogix chassis slot
Operating Temperature 0 to 60 °C
Isolation Voltage 30 V continuous
Certifications CE, CSA, cUL, KC, Marine, NRTL, RCM, UL
Application ControlNet networks, real-time automation, redundant architectures
Display Type Digital status indicators

  

 

Information About 1756-CNBR

The 1756-CNBR is part of the ControlLogix communication family from Allen-Bradley, designed specifically for redundant ControlNet architectures. It incorporates two BNC ports to support dual-media operation, offering improved resilience compared to the single-port 1756-CNB. The module handles scheduled and unscheduled messaging, enabling smooth traffic flow between ControlNet devices and Logix controllers. It supports CIP messaging, high-throughput data exchange, and up to 48 communication connections for complex automation systems. With its chassis-based installation, isolation rating, and compatibility with standard or redundant power supplies, the 1756-CNBR is an essential component for applications requiring continuous uptime and precise network coordination.

Key Features:

  • Redundant Media Support: Dual BNC ports allow primary and secondary ControlNet paths for fault-tolerant network operation.
  • High Throughput: Supports 5 Mbps communication speed for real-time industrial data exchange.
  • Connectivity: Includes one ControlNet RJ45 port for additional network integration.
  • Performance Capacity: Handles 40–48 Logix communication connections and up to 20 unconnected message buffers.
  • CIP Protocol: Utilizes Common Industrial Protocol for combined I/O and peer-to-peer communication.
  • Isolation Rating: Provides 30 V continuous isolation for enhanced electrical protection.
  • System Compatibility: Works with ControlLogix chassis, Logix5550 and other Logix controllers, and redundant power configurations.
  • Industrial Durability: Rated for 0–60°C operation and meets global certifications including UL, CE, CSA, and Marine approvals.

The 1756-CNBR delivers the reliability and precision required for demanding ControlNet automation systems.

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