ControlNet Bridge Module 1756-CNBR | Allen-Bradley Redundant

Allen-Bradley ControlLogix ControlNet Redundant Bridge Module 1756-CNBR

The Allen-Bradley 1756-CNBR is a high-availability communication bridge for ControlNet networks. It provides dual media ports for simplex or redundant network configurations, ensuring robust data transfer. 

Core Specifications

• Brand & Model: Allen-Bradley 1756-CNBR
• Series: ControlLogix ControlNet Communication Module
• Function: Redundant Media Bridge
• ControlNet Ports: 2 BNC Connectors (for redundant/simplex media)
• Network Access Port (NAP): 1 RJ-45 (8-pin) for local programming
• Data Rate: 5 Mbps
• Max Connections: 64 total (supports 40-48 Logix connections)
• Max Nodes: 99 per network
• Backplane Current: 970 mA @ 5.1V DC, 1.7 mA @ 24V DC

Installation & Compatibility

• Compatible Chassis: 1756-A4, A7, A10, A13, A17 ControlLogix racks.
• Power Supplies: Works with standard (e.g., 1756-PA75) and redundant (e.g., 1756-PA75R) supplies.
• Slot Requirement: Occupies 1 slot in the chassis.
• Communication Cable: Requires 1786-RG6 quad-shield coaxial cable and ControlNet taps.
• Important: Correctly label tap drop cables to prevent segment reversal and network issues.

Physical & Environmental

• Dimensions: 5.51" x 4.41" x 5.71" (140 x 112 x 145 mm approx.)
• Weight: 0.64 lbs (0.293 kg)
• Operating Temperature: 32° to 140°F (0° to 60°C)
• Power Dissipation: 5.5 Watts Max (17.4 BTU/hour)
• Isolation Voltage: 30V Continuous
• Enclosure: Open Type (for chassis mounting)

Packaging & Shipping

• One Allen-Bradley 1756-CNBR bridge module.
• Standard protective packaging.
• Shipped via FedEx, UPS, or DHL.

FAQ

• What is the difference between 1756-CNB and 1756-CNBR?
  The 1756-CNBR has two ControlNet BNC ports to support redundant media, while the 1756-CNB has only one port for simplex networks.
• What is the Network Access Port (NAP) used for?
  The RJ-45 NAP port is used for local programming, configuration, and diagnostics of the module using a laptop or programming device.
• Can this module be used in a non-redundant network?
  Yes, it can be used in a standard simplex ControlNet network using just one of its two BNC ports.