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Overview
The Allen-Bradley 1756-CNBR Series D is a redundant ControlNet bridge communication module designed for ControlLogix control systems. This module is a ControlLogix redundant bridge module with 40-48 connections. It features two ControlNet ports supporting simplex and redundant ControlNet network configurations, enabling robust data exchange between ControlLogix controllers and ControlNet devices.
Key Features
- 5 Mbps communication rate supporting 40-48 ControlNet logical connections
- Redundant coaxial media with two ControlNet BNC connectors for dual-path operation
- Network Access Protocol (NAP) with RJ-45 8-pin shielded connector
- Handles up to 64 bidirectional scheduled and unscheduled connections with other ControlNet devices
- Supports up to 20 buffers for unconnected messages
- Bulletin 1756 ControlLogix communications modules offer security to encrypt information between controllers and servers to prevent tampering
- 99 operational nodes supported on the network
Technical Specifications
- Current draw: 970 milliamperes at 5.1 Volts DC and 1.7 milliamperes at 24 Volts DC
- Dimensions: 6 inches x 7 inches x 2 inches; Weight: 1 lb
- Communication rate: 5 Mbps; Configuration: Redundant
- Mounting: Single-slot ControlLogix chassis module
- Network media: Coaxial ControlNet (redundant dual-port)
- Message handling: Scheduled and unscheduled CIP messaging
Typical Applications
This module is commonly applied in high-speed industrial automation, including manufacturing, processing, and motion-control environments. The 1756-CNBR excels in applications requiring:
- High-availability control systems with redundant communication paths
- Integration of ControlLogix platforms with ControlNet I/O networks
- Real-time messaging between distributed control devices
- Systems requiring 40-48+ logical communication connections
- Motion control and synchronized multi-axis automation
Compatibility & Replacements
Compatible With
- ControlLogix 1756 chassis (5570, 1756-A7, 1756-A10, 1756-A13, 1756-A16, 1756-A19, 1756-A22)
- Studio 5000 Logix Designer programming environment
- ControlNet protocol networks (redundant and simplex configurations)
- Allen-Bradley ControlNet I/O modules (1756-IF16, 1756-OF4, 1756-OF8, etc.)
- Legacy PLC-5 and SLC-500 systems via ControlNet bridge
- Network security and message encryption features
Replaces / Drop-In Replacement For
The 1756-CNBR is the designated module for applications requiring redundant ControlNet bridging. The only module you can use for such connections is the 1756-CNBR. For non-redundant ControlNet applications, the single-port 1756-CNB may be considered, though technical specifications differ.
Works With
- Studio 5000 Logix Designer (all versions supporting 1756-CNBR)
- ControlLogix communications firmware and controller modules
- EtherNet/IP gateway devices and Ethernet communications modules
- CIP (Common Industrial Protocol) messaging
- RSNetWorx configuration and network management software
- ControlNet media with BNC connectors (coaxial tap or drop-line configurations)
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