Chapter 9 Ethernet  Specification and Operation 
 
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9.8 CIP Object 
9.8.1 Object List 
CIP requires objects (groups of related data and behaviors associated with this data) to describe a device, how it 
functions, communicates, and to define its unique identity. Objects can be further defined by Class (a set of objects 
representing the same type of system), Instance (a copy of an object), and Attribute (data values). An object’s instance 
and class have attributes, providing services and implementing behaviors. Instance 0 contains the basic information for 
every object, that is: version and length. Instance 1–N contains parameters for creating connections. You can get product 
parameters from the supported service code through objects.   
 
You can use API 2208 EIPRW instruction or explicit messages to read / write objects. The supported EtherNet/IP objects 
are listed in the following table. Refer to Section 9.8.2 for the data type definitions. Refer to Section 9.8.3 ~ 9.8.19 for 
object contents.   
Object Name  Function  Class ID 
Identity Object  Provides identification of general information about the device.    1 (H’01) 
Message Router Object 
Provides a messaging connection point through which a client 
can address a service to any object class or instance residing in 
the physical device. 
2 (H’02) 
Assembly Object 
Binds attributes of multiple objects, which allows data to or from 
each object to be sent or received over a single connection and 
can be used to bind input data or output data.   
4 (H’04) 
Connection Manager 
Object 
Provides connection and connectionless communications, 
including establishing connections across multiple subnets. 
6 (H’06) 
Port Object 
Describes the communication interfaces that are present on the 
device and visible to CIP, including USB, Ethernet/IP and more. 
244 (H’F4)