Allen‑Bradley 1756‑CNB/D ControlNet Bridge Module

The Allen‑Bradley 1756‑CNB/D is a ControlNet communication bridge module built for the ControlLogix automation platform. It connects ControlLogix controllers to ControlNet field networks, realizing real-time data exchange between the local rack and remote I/O nodes, HMI and other automation devices.

This single-slot module supports 5 Mbps deterministic ControlNet communication, equipped with a BNC network port and NAP diagnostic RJ45 port. Widely used as spare replacement parts for upgrading and maintenance of Rockwell ControlLogix systems in manufacturing and process industries.

Main Specifications

• Brand: Allen‑Bradley (Rockwell Automation)
• Model: 1756‑CNB/D
• Product Type: ControlNet Bridge Communication Module
• Compatible Platform: ControlLogix 1756 chassis system
• Communication Rate: 5 Mbps ControlNet
• Interfaces: 1 × BNC port, 1 × NAP RJ45 diagnostic port
• Max supported network nodes: 99; Max connections: 40~48
• Backplane power: 970mA @ 5.1VDC, 1.7mA @ 24VDC
• Operating Temperature: 0°C ~ +60°C
• Single slot mounting, support hot swap under specified conditions

Core Functions

• Serve as communication gateway between ControlLogix controller and ControlNet field network
• Transmit scheduled real-time I/O data and unscheduled message instructions
• Support remote ControlNet I/O scanning, tag data exchange and peer-to-peer communication
• NAP RJ45 port enables convenient on-site network diagnosis and temporary programming access
• Front panel LED indicators display module status, network communication and fault alarms
• Deterministic communication ensures stable cycle time for closed-loop process control
• Plug-in modular design allows quick disassembly and replacement during equipment maintenance
• Cooperate with other ControlNet modules to build multi-layer distributed control architecture
• Support system expansion to connect more remote field devices and operator terminals
• Industrial circuit design provides stable operation under vibration and electromagnetic interference

Application Scenarios

• Automobile assembly line welding, painting and conveyor automation control systems
• Petrochemical plant continuous process distributed control and monitoring racks
• Food & beverage, pharmaceutical production line process control equipment
• Water treatment plant pump stations and valve group automatic control platforms
• Material handling, packaging machinery and automated warehouse control systems
• Power plant auxiliary equipment sequential control and data acquisition cabinets
• Tire, rubber and plastic manufacturing production line automation systems
• Mining machinery and bulk material conveying control equipment
• Retrofit, maintenance and spare parts replacement of legacy ControlLogix projects
• ControlNet communication module spare parts inventory and field emergency replacement