Description
The Allen-Bradley 1756-CNB is a high-performance ControlLogix communication module that facilitates high-speed ControlNet networking. This bridge module allows a ControlLogix controller to communicate with other controllers, I/O modules, and devices across a ControlNet link. It is designed for mission-critical applications that require deterministic, repeatable data transfers and scheduled messaging. The 1756-CNB operates as a gateway, bridging the ControlLogix backplane to the ControlNet media, ensuring seamless integration of distributed I/O and peer-to-peer interlocking in complex automation architectures.
Technical Specifications and Datasheet
Model Number: 1756-CNB Product Series: ControlLogix Communication Network: ControlNet Data Rate: 5 Mbps Number of Nodes: Up to 99 nodes per network ControlNet Connections: 40 to 64 (dependent on hardware revision/firmware) Backplane Current: 970 mA @ 5.1V DC; 1.7 mA @ 24V DC Power Dissipation: 5.1 Watts Dimensions: 145 mm x 35 mm x 132 mm (Single-slot) Weight: 0.29 kg Country of Origin: USA Isolation Voltage: 30V (continuous), Basic Insulation Type, ControlNet to Backplane
Application Fields
The 1756-CNB is a staple in large-scale industrial environments, including:
- Automotive Manufacturing: Coordinating synchronized motion and I/O across assembly lines.
- Food and Beverage: Managing high-speed packaging and bottling processes.
- Water/Wastewater: Communicating between remote pump stations and centralized control rooms.
- Material Handling: Real-time control of conveyor systems and automated sorting facilities.
ALLEN BRADLEY 1756-CNBR
ALLEN BRADLEY 1756-CNBR
ALLEN BRADLEY 1756-CNB
Product Instructions and Usage
Installation of the 1756-CNB must be done in a ControlLogix chassis (1756-A4, A7, A10, etc.). Before inserting the module, set the unique node address using the dual rotary switches located on the side of the module (range 01-99). Use standard RG-6 coaxial cable with BNC connectors for physical media connection. Once installed, the module must be configured within the RSLogix 5000 or Studio 5000 Logix Designer software. For scheduled traffic, the RSNetWorx for ControlNet software is required to perform a network “schedule” to ensure deterministic communication. Always verify that the firmware revision of the module is compatible with your controller’s CPU version.
Common Questions and Answers (Q&A)
What is the difference between the 1756-CNB and 1756-CN2? The 1756-CN2 is an enhanced version that supports a higher number of connections (up to 128) and improved processing speed compared to the standard 1756-CNB.
Can this module be used for Redundant Media? While the 1756-CNB has a single BNC port, the 1756-CNBR (Redundant version) should be used if dual-media redundancy is required for the application.
How do I check the status of the module? The front panel features several status indicators: “OK” (Module health), “NET” (Network status), and an alphanumeric display that provides specific error codes or the current node address.
Is the 1756-CNB hot-swappable? Yes, it supports Removal and Insertion Under Power (RIUP), allowing you to replace the module without shutting down the entire chassis, provided safety protocols are followed.
Does it support fiber optic media? The module has a BNC interface for coaxial cable. To use fiber optics, you must use a 1786-RPFM (Fiber Repeater Adapter) to convert the signal.
Explore Related Components
For technical manuals and to order the 1756-CNB and other Allen-Bradley communication adapters, please browse our online inventory.
Recommended Similar Models
- Allen-Bradley 1756-CNBR (ControlNet Bridge, Redundant)
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- Allen-Bradley 1756-CN2 (High-Capacity ControlNet Bridge)
- Allen-Bradley 1756-DHRIO (Data Highway Plus/Remote I/O Module)
- Allen-Bradley 1756-PA72 (ControlLogix Power Supply 120/240V AC)
