Features:
- Supports deterministic CIP-based ControlNet communication for real-time industrial control
- Handles up to 99 network nodes with structured high-speed data exchange at 5000 kbps
- Built for industrial environments with strong electrical immunity and chassis-based flexibility
1756-CNB is widely deployed in industrial automation systems where deterministic communication between controllers and distributed I/O is required. In production lines and process control environments, the module ensures synchronized data transfer between ControlLogix controllers and remote devices. The single-channel ControlNet interface enables stable communication in structured automation networks. Its design supports both real-time I/O and peer-to-peer messaging under a unified protocol framework. This makes 1756-CNB suitable for legacy ControlNet-based infrastructures still operating in critical industries.
In operation, 1756-CNB prioritizes time-sensitive control tasks such as I/O updates and controller interlocking. Non-critical tasks like program uploads and downloads are deprioritized to maintain deterministic performance. The module also supports diagnostic buffer monitoring, including client and server buffer usage indicators (U c x x and U s x x). These diagnostic tools help engineers monitor network load and optimize communication performance. As a result, 1756-CNB provides predictable and stable network behavior under industrial workloads.
From a deployment perspective, 1756-CNB integrates into any ControlLogix chassis slot and works with RG6 quad-shield coaxial cabling (1786-RG6) and NAP connections via 1786-CP. However, system design must consider connection limitations, as rack optimization supports up to five controllers per remote module. Exceeding this limit may result in connection faults and communication errors. The module is optimized for redundancy systems when used with compatible CNBR configurations. These considerations make 1756-CNB a structured yet legacy-focused communication solution.
The 1756-CNB Allen-Bradley ControlLogix Communication Module may still be available for purchase and support from Apter Power beyond End-Of-Life (EOL) by the manufacturer (OEM).
Allen-Bradley 1756-CNB ControlLogix Communication Module Manuals,Datasheets,Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
Allen-Bradley 1756-CNB ControlLogix Communication Module Specs
General
- Manufacturer Allen-Bradley
- Model 1756-CNB
- Condition New Original ready stock
- Product Family 1756-CNBR,1756-CNBK,1756-CNBRK
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
- Coaxial cable redundancy backup: Supports synchronous transmission of A/B dual control network channels, enabling seamless and safe switching when a single physical link is damaged.
- Rack ESD and surge protection: Built-in industrial-grade anti-interference electronic circuitry withstands high-voltage ESD surges from the backplane bus or external networks.
- Node logic isolation protection: When a remote I/O station experiences a hardware short circuit, the module automatically isolates the node, ensuring the main network remains unaffected.
- Control key lock synchronization: The module's communication status is deeply linked to the controller's physical key switch, locking unauthorized remote modification commands from the underlying layer.
- Remote I/O Station Control: Connects the central ControlLogix controller to multiple remote 1756 or 1794 Flex I/O racks via ControlNet network.
- Inter-Controller Interlocking: Enables highly deterministic production line data interlocking between multiple ControlLogix, CompactLogix, and PLC-5C controllers.
- Redundant Hot Standby System Bridging: Serves as a network communication switching bridge between master and slave racks in a dual-rack redundant control system (1756-RM2).
- SCADA and HMI Data Acquisition: Acts as a high-speed deterministic data transmission channel between the underlying workshop control network and the upper-level RSLinx communication server.
- Fully automatic network parameter bridging: Automatically acquires I/O attributes via the backplane, eliminating the need to manually write complex communication mapping code for each channel.
- RSNetWorx configuration support: Quickly plan network nodes, set refresh times, and generate scheduling files using graphical industrial software.
- Intelligent node address addressing: Directly set network node station numbers using hardware knobs on the module surface or software; the configuration process is intuitive and easy to maintain.
- Integrated Dynamic Tag Synchronization: Production/consumption tags can be created directly within the Studio 5000 environment, enabling automatic data alignment across controllers.