Allen-Bradley 1756-CNBR/E ControlNet Redundant Bridge Module

The Allen-Bradley 1756-CNBR/E is a Series E ControlNet Bridge Redundancy module designed for the ControlLogix architecture. This single-slot interface module provides a deterministic connection between ControlLogix controllers and the ControlNet network. By utilizing dual communication channels, this module ensures high availability for scheduled I/O data and unscheduled messaging, effectively mitigating the risk of network downtime caused by physical media failures.

Features

• Dual-Channel Media Redundancy: Monitors signal integrity across two coaxial lines. In the event of a cable break or tap disconnection, the module automatically switches to the secondary channel to maintain continuous communication.
• Deterministic Performance: Maintains a consistent 5 Mbps transmission speed, suitable for time-critical control applications.
• High Capacity: Supports up to 99 nodes on a single network and manages up to 64 concurrent system connections.
• Flexible Configuration: Compatible with standard ControlLogix chassis and power supplies, facilitating integration into existing control systems.

Applications

This module is intended for use in industrial environments requiring high-reliability networking, such as distributed I/O systems, multi-controller synchronization, and critical process control where network redundancy is a requirement to prevent production interruptions.

Technical Specifications

Installation Guidelines

• ESD Protection: Always use a grounded wrist strap when handling the module to prevent electrostatic discharge damage to internal components.
• Chassis Insertion: Ensure the ControlLogix chassis is powered down before inserting or removing the module. Align the module with the chassis guides and seat it firmly into the backplane connector.
• Cabling: Use 1786-RG6 quad-shield coaxial cable for all ControlNet connections. Ensure all BNC connections are secure and properly terminated according to ControlNet network standards.
• Grounding: Maintain proper chassis grounding to ensure noise immunity and compliance with electromagnetic compatibility requirements.
• Environment: Install in an environment free from excessive dust, corrosive gases, and moisture, ensuring adequate ventilation to stay within the 60 deg C operating limit.

FAQ

Q: Is the 1756-CNBR/E compatible with all ControlLogix chassis?
A: Yes, it is designed for use in standard 1756 chassis including 1756-A4, A7, A10, A13, and A17 models.

Q: Does this module support redundant power supplies?
A: Yes, the module is compatible with various redundant power supply configurations, including the 1756-PA75R and 1756-PSCA2 systems.