National Instruments 374318A-01 用户手册

' convert the string to a double

Dim D As Double = Convert.ToDouble(S.Replace(NlChar, NullChar))

'Plot the point

WaveformGraph1.PlotYAppend(D, 1)

Next

System.Runtime.InteropServices.Marshal.FreeHGlobal(Buffer)

[C#]

stringwrtString = "val?";

int

rdBufSize = 100;

char

nlChar = '\n';

char

nullChar = '\0';

addressprimaryAddress = new Address(2);

int

boardNum = 0;

// open a gpib device

Device device = new Device(boardNum, primaryAddress);

// allocate a buffer to hold the data

IntPtr buffer = 

System.Runtime.InteropServices.Marshal.AllocHGlobal(rdBufSize);

// read and plot 100 samples

for (int i=0; i<100; i++)

{

// write the string (val?) to the Fluke45

device.Write(wrtString);

// read the response from the Fluke45

string s = device.ReadString(rdBufSize);

// replace the newline character with a null and

// convert the string to a double

double d = Convert.ToDouble(s.Replace(nlChar, nullChar));

// plot the point

waveformGraph1.PlotYAppend(d, 1);

}

System.Runtime.InteropServices.Marshal.FreeHGlobal(buffer);

3.

Select File»Save Form1.cs to save your application.

4.

Select Debug»Start Without Debugging to run the application.

5.

After your program builds and runs, click Run. Notice each time you 
click the Run button, the graph shows the acquired value.