Allen-Bradley 1756-CN2R – ControlLogix ControlNet Redundant Communication Module

Description

1. Product Title

Allen-Bradley 1756-CN2R – ControlLogix ControlNet Redundant Communication Module

2. Product Overview

The 1756-CN2R is a redundant ControlNet communication module from Allen-Bradley, designed for the ControlLogix platform. It enables high-speed, deterministic data exchange over ControlNet networks while supporting redundant media for enhanced system reliability.

The 1756-CN2R is specifically engineered for mission-critical industrial applications where network uptime is essential. With dual coaxial ports, it provides media redundancy to ensure continuous communication even in the event of cable or network failure. This module acts as a bridge between the ControlLogix backplane and ControlNet network, facilitating real-time control, synchronized data transfer, and system-wide coordination.

3. Technical Specifications

• Brand: Allen-Bradley (Rockwell Automation)
• Model: 1756-CN2R
• Warranty: One Year
• Condition: 100% New & Original

Detailed Specifications:

• Product Type: ControlNet Redundant Communication Module
• Network Protocol: ControlNet (scheduled and unscheduled messaging)
• Ports: 2 × ControlNet BNC coaxial ports (for redundant media)
• Network Speed: 5 Mbps (ControlNet standard)
• Backplane Interface: ControlLogix high-speed backplane
• Node Capacity: Up to 99 nodes per ControlNet network
• Update Time (NUT): Configurable network update time (typically 2–100 ms)
• Communication Mode: Deterministic and time-scheduled data transfer
• Power Consumption: Approx. 5 W
• Current Draw:
  • 5V DC: ~1 A
  • 24V DC: ~3 mA
• Operating Temperature: 0°C to +60°C
• Storage Temperature: -40°C to +85°C
• Humidity: 5–95% non-condensing
• Isolation Voltage: 30 V continuous
• Dimensions: Standard 1756 module form factor
• Weight: Approx. 0.3 kg
• Certifications: CE, UL, CSA, FM

4. Key Features & Benefits

• Redundant ControlNet Communication:
  Dual coaxial ports provide media redundancy, ensuring continuous operation even in case of network failure.
• Deterministic Data Transfer:
  Supports scheduled communication, enabling precise and predictable control in time-critical applications.
• High System Availability:
  Designed for mission-critical processes, minimizing downtime and enhancing system reliability.
• Seamless ControlLogix Integration:
  Directly interfaces with the ControlLogix chassis, enabling efficient data exchange with controllers and I/O modules.
• Flexible Network Configuration:
  Supports both scheduled and unscheduled messaging for control and diagnostics data.

5. Application Scenarios

• Process Industries (Oil & Gas, Chemical):
  Ensures reliable communication in distributed control systems where network redundancy is essential.
• Power Generation:
  Used in turbine and plant control systems requiring deterministic and fault-tolerant communication.
• Manufacturing Automation:
  Supports synchronized control across multiple PLCs and I/O systems in large-scale production environments.

6. Frequently Asked Questions (FAQ)

Q: What is the primary function of the 1756-CN2R?
A: It provides redundant ControlNet communication, enabling reliable and deterministic data exchange between ControlLogix systems and network devices.

Q: Is 1756-CN2R compatible with legacy systems?
A: Yes, it is compatible with ControlLogix platforms and existing ControlNet networks, supporting integration with legacy automation systems that use ControlNet communication.