Read And Write Services For Variables; Read Service For Variables - Omron NX-series User Manual

8-5

Read and Write Services for Variables

This section shows services that specify the variables in the Request Path and access the CIP mes-
sage server function of the CIP Safety-compliant Communication Control Unit.
8-5-1

Read Service for Variables

Specify service code 4C hex to read the value of the variable that is specified by the request path.
Service code: 4C hex
l Request Data Format
Variable name specification
Request Service Data
+0 Num of Element
+1
Response Service Data
Data Type
AddInfo Length
*1. The actual data is stored in little-endian format.
Data Type
AddInfoLength
AddInfo
Actual data
Response Codes
CIP
status
00
02
04
05
NX-series Communication Control Unit Built-in Function User's Manual (Z396)
Request Path Data
(L)
(H)
(AddInfo)
Actual data*
Code for data type of variable to read. Refer to 8-6-1 Data Type Codes on page
8 - 43.
The size of the AddInfo area is stored only when accessing a structure variable.
Set 02 hex for a structure variable. Otherwise, set 00 hex.
The CRC code of the structure definition is stored only when accessing a structure vari-
able. In this case, the size of AddInfo will be 2 bytes.
The actual data is stored in little-endian format.
If 0001 hex is specified for an array, the actual data is stored in the same format as
when you access a variable with the data type of the elements of the array.
Meaning
SUCCESS
RESOURCE_UNAVAILABLE
PATH_SEGMENT_ERROR
PATH_DESTINATION_UNKNOWN
8 CIP Message Communications
UINT Specify the number of elements to read for an array variable.
USINT Data type of variable to read
USINT Additional information: Field length in bytes
Additional information: CRC value of structure
Add
status
--- The service ended normally.
--- The internal processing buffer is not
available.
--- The request path specification is not cor-
rect.
--- The variable specification is not correct.
Cause
8 - 39
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