1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
    1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
    1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module
1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module

1756-CNB | Allen-Bradley ControlLogix ControlNet Bridge Module

Part #: 1756-CNB Manufactured by: Allen-Bradley
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$963.00
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$963.00
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Condition: New-Surplus Original Box
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Product Overview
Allen Bradley 1756-CNB ControlLogix Bridge Module with 99 Maximum Nodes
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Product Description P/N: 1756-CNB

Description / Specifications

Description 

The 1756-CNB is an Allen-Bradley communication adapter that functions as a ControlNet Bridge. It is provided with an integrated ControlNet interface such as One (1) BNC connector for non-redundant media operation and One (1) NAP (RJ-45 8-pin with shield).

 

Technical Specifications 

Brand Allen-Bradley
Series ControlLogix
Part Number 1756-CNB
Manufacturer Rockwell Automation
Module Type Bridge Module
Maximum Nodes 99
Maximum Connections 64
ControlNet Communication Rate 5 megabits-second
Configuration Standard
Input Current 970 milliamps at 5.1 Volts DC, 1.7 milliamps at 24 Volts DC
Thermal Dissipation 17.4 BTU per Hour
Power Dissipation 5.1 Watts
Slot width 1

  

 

Information About 1756-CNB

The Allen-Bradley 1756-CNB or ControlNet Bridge module is an interface module used for interfacing a ControlLogix rack to ControlNet network. Compared to the Allen-Bradley 1756-CNBR module, the 1756-CNB is used in standard, non-redundant configuration. This module is perfect if the user applications have 40 to 48 Logix communication connections per communication module. It has a communication rate of 5 megabytes per second and it has 99 nodes available. The 1756-CNB module handles 2 things, namely the control of I/O data when it is used with a Logix5550 controller for scheduled data and for unscheduled data, bridging data between the ControlLogix backplane and the ControlNet Network. Make sure that the path information is correct in order to properly route the messages it receives.

Up to 64 bidirectional connections with other ControlNet devices can be supported by the 1756-CNB module. It can be a mix of both scheduled and unscheduled connections. However, the number of supported connections also depends on the network configuration. If an application needs more connections, the users can add another 1756-CNB module, but they must make sure to do it in the same chassis and on the same network as the first module. It can also support up to 20 buffers for unconnected messages. It also has 2 ports - 1 ControlNet BNC port and 1 ControlNet RJ45 port. The users need to set the module’s node address switches first when installing the 1756-CNB module. They can select a unique node address from 01 to 99. The users can then use the module as a standalone control module by using 1 set of modules or as a redundant control setup by using identical pairs of modules (partners). Note that when using redundant control, the node address switches should have the same node address. The 1756-CNB current draw at 5.1 Volts DC is 970 milliamps and 1.7 milliamps if the current draw is at 24 Volts DC. Its power dissipation is rated at 5.14 Watts.

The 1756-CNB is a ControlLogix Communication adapter used for interfacing any ControlLogix rack to a ControlNet data Highway. This module a single slot module with integrated communication ports of One (1) BNC connector for non-redundant media operation and One (1) NAP (RJ-45 8-pin with shield).

This ControlNet bridge is compatible with ControlNet modules from Allen-Bradley platforms such as Flex IO system, POINT IO, SLC and PLC5 ControlNet, ControlNet interface cards, encompass partner modules.

It may be used to implement Distributed I/O application where a large number of rack containing ControlLogix I/O modules are installed. It may also be used to bridge across networks of different protocols and Exchange information over ControlNet network. In a ControlNet system, connection to a single ControlNet bridge module allows a direct path to the main controller in the network where program modifications and tests may be executed. Also, this protocol may also be used to interface with Human Machine Interface (HMI) and Supervisory Control and Data Acquisition (SCADA) applications.

It is also capable of implementing self-diagnostics by accessing the module’s online backplane connection which displays connection properties and error counters. The module’s front panel is also provides with a textual display that cyclically changes to display the module name, connection status, node address and other parameters.



Manufacturer information

Allen-Bradley, a brand of Rockwell Automation, specializes in manufacturing industrial automation equipment. The product range includes programmable logic controllers (PLCs), motion control systems, safety devices, motor control equipment, automation software, and HMI panels. Allen-Bradley products are known for their reliability and integration with other systems.

Frequently Asked Questions about 1756-CNB
Question: What is the function of the 1756-CNB module?
Date Update:28/05/2025
Answer:

The Allen-Bradley 1756-CNB is a ControlNet bridge module that connects a ControlLogix chassis to a ControlNet network. It facilitates communication between the controller and distributed I/O, other ControlNet nodes, or HMI/SCADA systems. The module supports both scheduled and unscheduled messaging and can route control and diagnostic data efficiently. It plays a vital role in large, distributed automation systems where real-time control is needed.

Question: How many devices or nodes can be connected using the 1756-CNB?
Date Update:28/05/2025
Answer:

The 1756-CNB module supports up to 99 nodes on the ControlNet network. It can manage up to 64 bidirectional communication connections, including both scheduled and unscheduled traffic. Additional modules can be used in the same chassis if more connections are needed. These capabilities make it ideal for complex network architectures.

Question: What diagnostic features are built into the 1756-CNB?
Date Update:28/05/2025
Answer:

The module supports both software and hardware diagnostics. It displays connection status, node address, and module name on its front panel. Users can also view error counters and network status through the programming software to aid in troubleshooting and performance monitoring.

Question: How is the module configured and installed?
Date Update:28/05/2025
Answer:

The 1756-CNB is a single-slot module that fits into any ControlLogix chassis. Configuration includes setting the node address via DIP switches and defining communication parameters using Studio 5000 or RSNetWorx software. It is important to verify path routing for accurate communication between devices.

Question: Is the 1756-CNB still in production?
Date Update:28/05/2025
Answer:

No, according to Rockwell Automation, the 1756-CNB will be discontinued on December 31, 2024. Customers are advised to migrate to the 1756-CN2, which is the recommended engineering replacement and offers enhanced capabilities.

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QElectro 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 1756-CNB is an Allen-Bradley communication adapter that functions as a ControlNet Bridge. It is provided with an integrated ControlNet interface such as One (1) BNC connector for non-redundant media operation and One (1) NAP (RJ-45 8-pin with shield).

 

Technical Specifications 

Brand Allen-Bradley
Series ControlLogix
Part Number 1756-CNB
Manufacturer Rockwell Automation
Module Type Bridge Module
Maximum Nodes 99
Maximum Connections 64
ControlNet Communication Rate 5 megabits-second
Configuration Standard
Input Current 970 milliamps at 5.1 Volts DC, 1.7 milliamps at 24 Volts DC
Thermal Dissipation 17.4 BTU per Hour
Power Dissipation 5.1 Watts
Slot width 1

  

 

Information About 1756-CNB

The Allen-Bradley 1756-CNB or ControlNet Bridge module is an interface module used for interfacing a ControlLogix rack to ControlNet network. Compared to the Allen-Bradley 1756-CNBR module, the 1756-CNB is used in standard, non-redundant configuration. This module is perfect if the user applications have 40 to 48 Logix communication connections per communication module. It has a communication rate of 5 megabytes per second and it has 99 nodes available. The 1756-CNB module handles 2 things, namely the control of I/O data when it is used with a Logix5550 controller for scheduled data and for unscheduled data, bridging data between the ControlLogix backplane and the ControlNet Network. Make sure that the path information is correct in order to properly route the messages it receives.

Up to 64 bidirectional connections with other ControlNet devices can be supported by the 1756-CNB module. It can be a mix of both scheduled and unscheduled connections. However, the number of supported connections also depends on the network configuration. If an application needs more connections, the users can add another 1756-CNB module, but they must make sure to do it in the same chassis and on the same network as the first module. It can also support up to 20 buffers for unconnected messages. It also has 2 ports - 1 ControlNet BNC port and 1 ControlNet RJ45 port. The users need to set the module’s node address switches first when installing the 1756-CNB module. They can select a unique node address from 01 to 99. The users can then use the module as a standalone control module by using 1 set of modules or as a redundant control setup by using identical pairs of modules (partners). Note that when using redundant control, the node address switches should have the same node address. The 1756-CNB current draw at 5.1 Volts DC is 970 milliamps and 1.7 milliamps if the current draw is at 24 Volts DC. Its power dissipation is rated at 5.14 Watts.

The 1756-CNB is a ControlLogix Communication adapter used for interfacing any ControlLogix rack to a ControlNet data Highway. This module a single slot module with integrated communication ports of One (1) BNC connector for non-redundant media operation and One (1) NAP (RJ-45 8-pin with shield).

This ControlNet bridge is compatible with ControlNet modules from Allen-Bradley platforms such as Flex IO system, POINT IO, SLC and PLC5 ControlNet, ControlNet interface cards, encompass partner modules.

It may be used to implement Distributed I/O application where a large number of rack containing ControlLogix I/O modules are installed. It may also be used to bridge across networks of different protocols and Exchange information over ControlNet network. In a ControlNet system, connection to a single ControlNet bridge module allows a direct path to the main controller in the network where program modifications and tests may be executed. Also, this protocol may also be used to interface with Human Machine Interface (HMI) and Supervisory Control and Data Acquisition (SCADA) applications.

It is also capable of implementing self-diagnostics by accessing the module’s online backplane connection which displays connection properties and error counters. The module’s front panel is also provides with a textual display that cyclically changes to display the module name, connection status, node address and other parameters.



Manufacturer information

Allen-Bradley, a brand of Rockwell Automation, specializes in manufacturing industrial automation equipment. The product range includes programmable logic controllers (PLCs), motion control systems, safety devices, motor control equipment, automation software, and HMI panels. Allen-Bradley products are known for their reliability and integration with other systems.

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