Extract data from CNiReal64Vector

[tuanbui]

I'm using MFC Visual C++ to read 3 thermo couple channels.  My partial code to read the data look like the following

CNiReal64Vector Data;

CNI_MFC_DAQmx_App_UserCode userCode;

userCode.GetData(Data);

How do I extract data out from Data variable to store into a file?  How does the data store in Data variable for all three channels?

Thanks,

Tuan Bui

[Manooch_H]

Hello Tuan,

I'm not too familiar with the CNiReal64Vector data type however, I suggest looking at one of our C++ Thermocouple examples that ships with Measurement Studio. This example can be found in the following directory:

C:\Documents and Settings\All Users\Documents\National Instruments\NI-DAQ\Examples\MStudioVC2005\Analog In\Measure Temperature\ContAcqThermocoupleSamples_IntClk

Please take a look at this example to get an idea of how you would go about programming your own application. If you still run into problems please post back to this thread.

[angelmcdoggie]

 

/* Create a file to save your datalog*/

try { m_fileWrite.exceptions(ifstream::failbit | ifstream::badbit);

      m_fileWrite.open("YourDatalog.txt");

}

catch (ofstream::failure e) {   AfxMessageBox("Error opening text file.");

if (m_fileWrite.is_open()) {  m_fileWrite.close();

                                                 m_fileWrite.clear();

                                      return;

} }

 /*your CNiReal64Matrix data is processed into CNiReal64Vector, that is if you used these data types.  The matrix type caters to multiple signals, thermo1, thermo2 & thermo3, in your case.  The output is tabulated in column form.  Open it in excel for readability*/

int channelCount = m_data.GetRows();  int dataCount = m_data.GetCols();

// Write header

for (unsigned int j = 0; j < m_task->AIChannels.Count; j++) { m_fileWrite << m_task->AIChannels[j].PhysicalName << "\t";

}

m_fileWrite << endl;

m_outStream.str("");

CNiReal64Vector v;

// Write data

for (int i = 0; i < dataCount; i++) {  m_data.CopyColumn(i, v);

for (int j = 0; j < 1; j++) {  m_outStream << dec << v[j] << "\t";  }

m_outStream << endl;  }

m_lTotalSamples += dataCount;

if (m_fileWrite.is_open()) {  m_fileWrite << m_outStream.str();

m_fileWrite.close();  }

This is a snippet from an analog voltage program with file I/O with few modifications.