The Allen-Bradley 1756-CNB is a ControlLogix ControlNet Communication Bridge module designed to facilitate high-speed data exchange between a ControlLogix controller and a ControlNet network. As a critical component in the ControlLogix architecture, this module manages the transfer of I/O data and messaging across the network, supporting up to 99 nodes and 64 connections. It provides a reliable interface for distributed control systems requiring deterministic communication performance.
Features
Supports ControlNet communication at a rate of 5 Mbps.
Provides a single ControlNet port for network connectivity.
Designed for seamless integration into the ControlLogix chassis.
Supports up to 99 nodes and 64 connections for scalable network configurations.
Efficient power management with low thermal dissipation.
Technical Specifications
Product Model
1756-CNB
Module Type
ControlNet Bridge Module
Communication Rate
5 Mbps
Maximum Nodes
99
Maximum Connections
64
Input Current
970 mA at 5.1 VDC; 1.7 mA at 24 VDC
Power Dissipation
5.1 Watts
Thermal Dissipation
17.4 BTU/hr
Installation Guidelines
Ensure the ControlLogix chassis is powered down before inserting or removing the module.
Slide the module into the designated slot in the chassis and ensure it is fully seated before tightening the mounting screws.
Use appropriate ControlNet cabling and ensure proper termination at both ends of the network segment to maintain signal integrity.
Maintain adequate clearance around the chassis to ensure proper airflow and cooling.
Avoid routing communication cables near high-voltage lines or sources of electromagnetic interference (EMI).
Follow standard ESD (Electrostatic Discharge) precautions when handling the module.
FAQ
What is the primary function of the 1756-CNB?
The 1756-CNB acts as a bridge between the ControlLogix backplane and the ControlNet network, allowing the controller to communicate with remote I/O and other controllers on the network.
Does this module require external power?
No, the 1756-CNB draws its required power directly from the ControlLogix chassis backplane.
What is the maximum data rate for this module?
The 1756-CNB supports a fixed ControlNet communication rate of 5 Mbps.
