1756-CN2RXT Allen Bradley 1756 ControlLogix Communication Modules Specifications

A ControlLogix system uses connections to establish communication links between devices. The types of connections 

include the following:

• Controller-to-local I/O modules or local communication modules

• Controller-to-remote I/O or remote communication modules

• Controller-to-remote I/O (rack-optimized) modules

• Produced and consumed tags

• Messages

• Controller access with the Studio 5000 environment

• Controller access with RSLinx® software for HMI or other applications

You indirectly determine the number of connections the controller uses by configuring the controller to communicate with 

other devices in the system. The limit of connections may ultimately reside in the communication module you use for the 

connection. If a message path routes through a communication module, the connection related to the message also counts 

towards the connection limit of that communication module.

Stratix Switches

To effectively manage real-time control and information flow throughout the manufacturing and IT enterprise, Rockwell 

Automation offers a full portfolio of industrial Ethernet switches and media, including a line of Stratix switches integrated 

with Cisco technology. The Stratix line of switches includes modular managed, fixed managed, and unmanaged switches.

The ControlNet network is an open, control network for real-time, high-throughput applications. The 

ControlNet network uses the Common Industrial Protocol (CIP) to combine the functionality of an I/O network 

and a peer-to-peer network providing high-speed performance for both functions. The ControlNet network gives 

you deterministic, repeatable transfers of all mission-critical control data in addition to supporting transfers of 

non-time-critical data. I/O updates and controller-to-controller interlocking always take precedence over program 

uploads and downloads, and messaging.