Prosoft-technology MVI56E-LDM Manual de usuario descargar pdf (Pagina 116)

CIP API Functions ControlLogix Platform ♦ "C" Programmable

Developer's Manual Linux Application Development Module

Page 110 of 264 ProSoft Technology, Inc.

March 12, 2014

5.6 Tag Access Functions

The API functions in this section can be used to access tag data withing

ControlLogix controllers. The prototypes for most of these functions and their

associated data structure definitions can be found in the header file

OCXTagDb.h.

The tag access functions that include "Db" in the name are for use with a valid

tag database (see OCXcip_BuildTagDb).

OCXcip_AccessTagData

Syntax

int OCXcip_AccessTagData (OCXHANDLE apihandle,

char * pPathStr,

WORD rspTimeout,

OCXCIPTAGACCESS * pTagAccArr,

WORD numTagAcc );

Parameters

apihandle

handle returned by previous call to OCXcip_Open

pPathStr

Pointer to NULL terminated device path string

rspTimeout

CIP response timeout in milliseconds

pTagAccArr

Pointer to array of pointers to tag access definitions

numTagAcc

Number of tag access definitions to process

Description

This function efficiently reads and/or writes a number of tags. As may operations

as will fit will be combined into a single CIP packet. Multiple packets may be

required to process all of the access requests

pTagAccArr is a pointer to an array of pointers to OCXCIPTAGACCESS structures.

numTagAcc is the number of pointers in the array.

The OCTCIPTAGACCESS structure is show in the following example:

typedef struct tagOCXCIPTAGACCESS

{

char * tagName; //tag name (symName[x,y,z].mbr.mbr [x].etc)

WORD daType; //Data type code

WORD eleSize; //Size of one data element

WORD opType; //Read/Write operation type

WORD numEle; //Number of elements to read or write

void * data; //Read/Write data pointer

void * wrMask; //Pointer to write bit mask data, NULL if none

int result; // Read/Write operation result

} OCXCIPTAGACCESS

tagName

Pointer to tag name string (symName[x,y,z].mbr[x].etc). All

array indices must be specified except the last set of

brackets. If the last set is omitted, the indices are assumed

to be zero.

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