10-4
Specifying Request Path
The CIP object is specified in the request path.
In CIP, the EPATH data type is used for the request path.
With this method, the request path is divided into segments and a value is assigned to each segment.
The request path notation shows the path to the final destination when the data segments are joined
together.
Each segment includes the segment type information and the segment data.
Segment 1 Segment 2 Segment 3 Segment 4
The first byte gives the interpretation method for the segment. It consists of two parts; a 3-bit segment
type and a 5-bit segment format.
Segment Type Segment Format
7 6 5 4 3 2 1 0
The segment type specifications are defined as follows in the CIP specifications.
Segment Type
Meaning
7 6 5
0 0 0 Port Segment
0 0 1 Logical Segment
0 1 0 Network Segment
0 1 1 Symbolic Segment
1 0 0 Data Segment
1 0 1 Data Type
1 1 0 Data Type
1 1 1 Reserved
The specifications for the segment format are different for each segment type. Use the segment format
to request a service from a particular object of a particular device.
Logical segments and data segments, which are needed to specify variables in CIP message commu-
nications, are described below.
10-4-1
Examples of CIP Object Specifications
Logical Segments are joined to form the request path that specifies the object to access.
Logical Segment
(Attribute ID)
Logical Segment
(Instance ID)
Logical Segment
(Class ID)
Specify the Class ID. Specify the Instance ID. Specify the Attribute ID.
10 CIP Message Communications
10-26
NX-series EtherNet/IP Unit User's Manual (W627)
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