Allen-Bradley ControlLogix User Manual

1756-6.5.3 - December 1999
ControlNet Communication Basics 1-9
Assume you have set up a system that contains 10 discrete I/O modules in a
remote ControlNet chassis. If you used direct connections to transfer data to
each of the these I/O modules, you would need 11 connections to transfer all
of the data (one connection to the communication module and 1 connection
to each of the ten I/O modules). If you used a rack-optimized connection to
transfer the data, you would only need a single connection – the connection
to the communication module. Since the 1756-CNB module is limited to 64
connections, using rack-optimized connections can save valuable resources.
Important:Although rack optimized connections offer an efficient way to
use resources, there are a few limitations on their use:
• You can only use rack optimized connections to send data
to and from discrete digital I/O modules. Analog I/O
requires direct connections.
• Rack optimized connections can contain I/O data and status
information only. Additional module information, such as
diagnostics, is not available through a rack-optimized
connection.
• You must use a consistent RPI for all data in a single
rack-optimized connection. Since you are using a single
connection to send the data, all of the data will be
transferred in the same message at a uniform rate.
Mixing Communication Formats
When multiple I/O modules exist in the same chassis, the user can mix
Comm Formats for the different I/O modules. I/O modules set up to use
Rack Optimization will communicate at the rate of the RPI configured for
the 1756-CNB module. I/O modules configured for direct communication
will communicate at their set RPI and ignore the CNB RPI.
Important:After the proper I/O configuration is set up in RSLogix5000,
I/O communication on ControlNet is not established until
RSNetWorx for ControlNet software is run. RSNetWorx is used
to set up the network parameters of a ControlNet network.
See Appendix A for more information on connections.

Allen-Bradley ControlLogix Specifications

General

Communication	EtherNet/IP, ControlNet, DeviceNet, DH+
I/O Capacity	Up to 128, 000 I/O points (varies by configuration)
Redundancy	Supported (with specific modules)
Programming Software	Rockwell Automation Studio 5000 Logix Designer
Operating Temperature	0°C to 60°C (32°F to 140°F)
Programming Languages	Ladder Logic, Function Block Diagram, Structured Text, Sequential Function Chart
Modularity	Yes
Certifications	UL, CE
Processor Type	Multiple options available, including standard, safety, and extreme environment processors
Power Supply	Multiple options available, including standard and redundant power supplies with various voltage ranges (e.g., 24V DC, 120/240V AC)

Summary

Chapter 1: ControlNet Communication Basics

Communication Models and Protocols

Chapter 2: Installing the ControlNet Network

Installing and Configuring Interface Card

Installing ControlLogix and PLC-5C Modules

Connecting the ControlNet Network

Chapter 3: Logix5550 to Logix5550 Unscheduled Messaging

Chapter 4: Logix5550 to Logix5550 Scheduled Communication

Producer and Consumer Application Setup

Network Configuration and Communication Testing

Covers scheduling the network, verifying properties, and testing communication.

Chapter 5: Logix5550 Controller to PLC-5C Unscheduled Messaging

Chapter 6: Logix5550 Controller to PLC-5C Scheduled Communications

Producer Application Setup and Network Scheduling

PLC-5C Configuration and Communication Testing

Details configuring the PLC-5C to receive data and testing the communication.

Chapter 7: PLC-5C to Logix5550 Controller Unscheduled Messaging

Example Setup and PLC-5C Program Creation

Program Download and Message Verification

Chapter 8: PLC-5C to Logix5550 Controller Scheduled Communications

Network and Controller Configuration

Guides configuring the ControlNet network, PLC-5C, and Logix5550 consumer.

Producer Setup and Network Scheduling

Details creating the PLC-5C producer application and scheduling the network.

Communication Verification

Chapter 9: PLC-5C to PLC-5C Unscheduled Messaging Over Two ControlNet Networks

Example Setup and Program Creation

Guides system setup, application creation, and ladder program development.

Program Download and Communication Testing

Details downloading the program and testing the message bridging.

Chapter 10: Controlling I/O Over a ControlNet Network

I/O Configuration and Setup

Guides adding local and remote CNB modules and I/O modules to the configuration.

Ladder Logic, Download, and Network Scheduling

Details editing tags, creating ladder logic, downloading, and scheduling the network.

Testing Remote I/O Operation

Chapter 11: Adding an I/O Chassis to an Existing ControlNet Network

Network Expansion Configuration

Guides adding a second remote CNB module and analog I/O to the network.

Logic, Download, and Network Scheduling

Details editing tags, modifying logic, downloading, and scheduling the expanded network.

Testing Analog Output Operation

Chapter 12: Troubleshooting

Module Status Indicators and Causes

ControlNet Network Status Indicators

Appendix B: Creating Produced and Consumed Tags

Tag Creation Fundamentals