Cip Message Structure For Accessing Variables - Omron NX-series User Manual

8 CIP Message Communications
8-2-2

CIP Message Structure for Accessing Variables

This section shows how to specify messages to access variables.
The variables to access are given by connecting the segments that are defined in the CIP Common
specifications so that explicit message can be set in the request path field.
The following elements are combined to make the specification.
Specifying the variable to access: The elements are stored in the CIP segments and then joined to
make the message.
Example: Reading the Present Value of One Member of the VarAA.MemB[1.2] Structure Variable
Example for Using the CIP Read Data Service for a Variable Object
CIP Explicit Message for a Request
Service
Code
(4C hex)
Specify the service code to perform
reading and writing variables. (*1)
*1. Refer to 8-5 Read and Write Services for Variables on page 8 - 39 for information about the service codes.
*2. Refer to 8-3-5 Specifying Variable Names in Request Paths on page 8 - 7 for information about how to
specify variables names.
*3. Refer to 8-6 Variable Data Types on page 8 - 43 for details about how to specify data formats.
8 - 4
Request
"VarAA"
Path Length
(91 05 45 61 72 41 41 00)
(09)
ANSI Extended Symbol Segment
Specify the variable name and
range to access. (*2)
NX-series Communication Control Unit Built-in Function User's Manual (Z396)
Request Path
"MemB" [1]
(91 04 4D 65 6D 42) (28 01)
Logical Segment
(Member ID)
Specify the data format to read
and write. (*3)
Request
Service
Data
[2]
(28 02)
(num of
elem)