Rockwell Automation 842E EtherNet/IP Absolute Encoder User Manual - Manual (Page 20)

12 Rockwell Automation Publication 842E-UM001A-EN-P May 2012
Chapter 3 EtherNet/IP overview
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.
The 842E EtherNet/IP encoder supports the following classes of the encoder
profile:
Supported classes
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
Class code Object class Description
Number of
instances
0x01 Identity object Contains information on the node within the network 1
0x02
Message router object
Processes all messages and routes them to the
appropriate objects 1
0x04
Assembly object
(I/O-assembly class)
Assembles attributes (data) of various objects to a
single object
Used for I/O messages 7
0x06
Connection manager object
Contains connection specific attributes for triggering,
transport, and connection type 1
0x23
Position sensor object
Administrates device specific data like position and
counting direction 1
0x47
Device level ring (DLR) object
Contains the configuration and status information of
the DLR protocol 1
0x48
QoS object
Contains mechanisms used to treat traffic streams with
different relative priorities 1
0xF4
Port object
Contains implemented port types port numbers and
port names 1
0xF5
TCP/IP interface object
Contains all attributes for configuring the TCP/IP
interface
1
0xF6
Ethernet link object
Contains connection-specific attributes like
transmission rate, MAC address, or duplex mode 3