Omron NX Series User Manual page 242

10 CIP Message Communications
These are called IOI (Internal Object Identifier) because they identify the Class ID, Instance ID, and
Attribute ID within the device.
Refer to 10-5 CIP Object Services on page 10-28 for the class ID, instance ID, attribute ID, and serv-
ice code for each object.
Providing the Structure Variables to Input Request Paths
For a CIP communications instruction, you prepare a variable to store the request path. In this varia-
ble, you specify the object to access with the user program.
A structure in which the Class ID, Instance ID, and Attribute ID are specified is provided for the data
type of a variable for a request path.
There are two types of structures: standard structure (_sREQUEST_PATH) and extension structure
(_sREQUEST_PATH_EX). When you use an extension structure, it is possible to specify the size ac-
cording to the size of values of the Class ID, Instance ID, and Attribute ID of the object that you ac-
cess. When you use a standard structure, the size is always set to 16 bits.
l When a Standard Structure Variable Is Used
Example: Using a standard structure variable to input values into RqPath (Request Path) for the
CIPSend instruction
Create variable A with a variable with
the standard structure (_sREQUEST_PATH).
Variable A
1
Create a standard structure variable.
To use a standard structure variable to input values into RqPath (Request Path) for a CIP com-
munications instruction, first you need to create a standard structure user-defined variable.
When you create a variable in a variable table, select the pre-registered standard structure
(_sREQUEST_PATH) for a CIP communications instruction.
Variable table
Name
A
Select a standard structure for the data type of variable A.
2
Input a value for each standard structure variable member.
10-14
CIP communications instruction
CIPSend
RqPath
(Request Path)
Data type
_sREQUEST_PATH
RqPath data type
Member
ClassID
(Class ID)
InstanceID
(Instance ID)
isAttributeID
(Attribute usage)
AttributeID
(Attribute ID)
NX-series EtherNet/IP Unit User's Manual (W627)
Value
2
3
TRUE
1