Agilent Technologies FS2010 Podręcznik Użytkownika Pobierz pdf (Strona 21)

Building a VISA Application in Windows 2

Agilent VISA User’s Guide 21

Dim flt_array(50) As Double

status = viVPrintf(id, "%,50f", dbl_array(0))

Strings

When reading in a string value with viVScanf or

viVQueryf, you must pass a fixed length string as the

params parameter. To declare a fixed length string, instead

of using the normal variable length declaration:

Dim strVal as String

use the following declaration, where 40 is the fixed length.

Dim strVal as String * 40

Sample VISA Program (Visual Basic)

This section lists a sample program called idn that queries a

GPIB instrument for its identification string. This sample

builds a standard .exe application for WIN32 programs

using the Visual Basic 6.0 programming language.

Assuming default installation directories, the idn sample files

are in

C:\Program Files\Agilent\IO Libraries Suite\

ProgrammingSamples\VB6\VISA\IDN

Steps to Running the Program

The steps to building and running the idn sample program

follow.

1 Connect an instrument to a GPIB interface that is

compatible with IEEE 488.2.

2 Start the Visual Basic 6.0 application.

NOTE

This example assumes you are building a new project (no .vbp file exists

for the project). If you do not want to build the project from scratch, from

the menu select File > Open Project... and select and open the idn.vbp

file. Then skip to Step 7.

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Agilent Technologies FS2010 Podręcznik Użytkownika Strona 21