Allen Bradley 1756-CNBR ControlNet Bridge Module

The AB 1756-CNBR is a high-speed ControlNet bridge module designed for use within ControlLogix systems. Offering redundant media support for mission-critical applications, it enables real-time control and information sharing over ControlNet at a fixed rate of 5 Mbps.

This module supports up to 48 total connections (scheduled and unscheduled) and is ideal for applications that require deterministic communication, network redundancy, and high availability in distributed I/O and controller-to-controller networks.

Technical Specifications

Model: 1756CNBR
Series: ControlLogix Communication Modules
Type: ControlNet Bridge Module
Media Support: Redundant Coaxial
Communication Rate: 5 Mbps (fixed)
Maximum Connections: 40–48 (any mix of scheduled/unscheduled)
Redundancy Mode: Dual BNC ports for redundant trunk lines
Backplane Interface: ControlLogix 1756 chassis (via backplane)

Electrical Specifications

Power Supply: Supplied via ControlLogix chassis backplane
Backplane Current (5.1V): 800 mA
Backplane Current (24V): 3 mA
Power Dissipation: 4.1 W typical
Isolation Voltage: 30V (continuous), basic insulation
Power Protection: Reverse polarity and overvoltage protection via chassis

Network & Interface Specifications

Supported Protocol: ControlNet
Media Type: Coaxial (RG-6 quad-shield)
Connector Type: 2 x BNC (for redundant or single trunk)
Connection Capacity:

• 40 connections for ControlLogix controller
• 48 connections when used in remote I/O chassis
  Scheduling: Supports scheduled and unscheduled traffic
  Node Addressing: Rotary switch configurable
  Network Diagnostics: Status LEDs for module health, activity, and redundancy

Mechanical Specifications

Enclosure Type: Open module, designed for chassis installation
Mounting Type: Chassis-mounted (ControlLogix 1756 series)
Width: 35 mm (1 slot)
Height: 185 mm
Depth: 140 mm
Weight: Approx. 300 g
Installation Orientation: Vertical, in ControlLogix rack
Locking Mechanism: Chassis latching with backplane connector

Environmental Specifications

Operating Temperature: 0…60 °C
Storage Temperature: –40…85 °C
Relative Humidity: 5% to 95% non-condensing
Shock Rating: 30 g operating, 50 g non-operating
Vibration Resistance: 2 g @ 10–500 Hz
Pollution Degree: 2
Application Suitability: Indoor use, control cabinet installation
Altitude Limit: Up to 2000 m

Compliance & Certifications

Certifications: UL, c-UL, CE, ATEX, RoHS
Standards Met: EN 61131-2, IEC 61010-1, IEC 60068
EMC Compliance: EN 61000-6-2 / 6-4
Use with: ControlLogix 1756 chassis and modules
Safety Category: General industrial use

Key Features & Benefits

✅ Redundant Media Support – Ensures high availability with dual BNC trunk ports for ControlNet redundancy

✅ Deterministic Communication – Fixed 5 Mbps rate for precise timing and real-time control data transmission

✅ Scalable Connectivity – Supports up to 48 total connections for high-density network topologies

✅ Diagnostic Feedback – Built-in status LEDs provide fast feedback on module and network health

✅ Flexible Deployment – Use as a bridge or I/O scanner in distributed ControlNet networks

📦 Order the Allen Bradley 1756-CNBR from Drive Outlet Megastore

At Drive Outlet Megastore we offer unbeatable Allen Bradley 1756-CNBR prices. This ControlNet redundant bridge module is ideal for high-availability automation systems—ready to support complex, time-sensitive industrial networks with guaranteed performance.

Click here to request a quote or check availability

Drive Outlet Megastore – your trusted source for Allen Bradley ControlLogix communication modules and industrial networking solutions.