Rockwell Automation Publication 842E-UM001B-EN-P—April 2015
17
EtherNet/IP overview
Chapter 3
Device level ring topology
A DLR network is a single-fault-tolerant ring network intended for the
interconnection of automation devices. DLR topology is advantageous as it can
tolerate a a break in the network. If a break is detected, the signals are sent out in
both directions. With this topology, use both the Link 1 and Link 2 ethernet
connections on the 842E encoder.
CIP object model
EtherNet/IP uses an object model for network communication wherein all
functions and data of a device are defined. The important terms are as follows:
Class:
A class contains related objects of a device, organized in instances.
Instance:
An instance consists of different attributes that describe the properties
of the instance. Different instances of a class have the same services, the same
behavior, and the same attributes. They can, however, have different values.
Attribute:
The attributes represent the data a device provides over EtherNet/IP.
These include the current values of, for example, a configuration or an input.
Typical attributes are configuration and status information.
Service:
Services are used to access classes or the attributes of a class or to
generate specific events. These services execute defined actions such as reading
the attributes.
The following table shows an example of the object model for the 842E encoders.
Class
Instance
Attribute
Value
842E
Basic
Resolution per revolution
15 bit
Revolutions, total
12 bit
Advanced
Resolution per revolution
18 bit
Revolutions, total
12 bit
Summary of Contents for Rockwell Automation 842E-MIP Series
Page 1: ...842E EtherNet IP Absolute Encoder 842E SIP xxx 842E MIP xxx User Manual ...
Page 6: ...iv Rockwell Automation Publication 842E UM001B EN P April 2015 About this document Notes ...
Page 34: ...28 Rockwell Automation Publication 842E UM001B EN P April 2015 Chapter 4 Installation Notes ...
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