Error while running program in qt to read from DAQ

Question

I have a simple data acquisition system to read analog dc voltage from the NI USB 6009. I have also created a qt console application to use the NIDAQmxbase functionality.

The .pro file is as follows

QT += core
QT -= gui

TARGET = untitled4
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp
LIBS += "C:\Users\nikhilmurthy161229\Documents\untitled3\nidaqmxbase.lib"
HEADERS += "C:\Users\nikhilmurthy161229\Documents\untitled3\NIDAQmxBase.h"

I have included the .lib file and the .h file in the project folder.

MY main.cpp file looks as follows

#include <QCoreApplication>
#include <stdio.h>
#include <NIDAQmxBase.h>


#define DAQmxErrChk(functionCall) { if( DAQmxFailed(error=(functionCall)) ) { goto Error; } }

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    // Task parameters
        int32       error = 0;
        TaskHandle  taskHandle = 0;
        char        errBuff[2048]={'\0'};

        // Channel parameters
        char        chan[] = "nikhil\ai0";
        float64     min = 0;
        float64     max = 5;

        // Timing parameters
        uInt64      samplesPerChan = 1;

        // Data read parameters
        float64     data;
        int32       pointsToRead = 1;
        int32       pointsRead;
        float64     timeout = 5;


        DAQmxErrChk (DAQmxBaseCreateTask("",&taskHandle));
        DAQmxErrChk (DAQmxBaseCreateAIVoltageChan(taskHandle,chan,"",DAQmx_Val_Cfg_Default,min,max,DAQmx_Val_Volts,NULL));
        DAQmxErrChk (DAQmxBaseStartTask(taskHandle));
        DAQmxErrChk (DAQmxBaseReadAnalogF64(taskHandle,pointsToRead,timeout,DAQmx_Val_GroupByChannel,&data,samplesPerChan,&pointsRead,NULL));
        DAQmxErrChk (DAQmxBaseStopTask(taskHandle));
        DAQmxErrChk (DAQmxBaseClearTask(taskHandle));

        printf ("Acquired reading: %f\n", data);

    Error:
        if( DAQmxFailed(error) )
            DAQmxBaseGetExtendedErrorInfo(errBuff,2048);
        if( taskHandle!=0 ) {
            DAQmxBaseStopTask(taskHandle);
            DAQmxBaseClearTask(taskHandle);
        }
        if( DAQmxFailed(error) )
        printf ("DAQmxBase Error %ld: %s\n", error, errBuff);
        return a.exec();
}

However when i run the program I am getting the following error "DAQmxBase Error -200428: Value passed to the Task/channels In contril is invalid"

I have verified that the device name is same as in NI MAX but the problem still persists.

PLEASE HELP

Answer 1

As a quick guess I would make your chan variable

char        chan[] = "nikhil\\ai0";

The char array is probably interpreting the backslash

Answer 2

The DAQ device name is incorrect.

Even though you used MAX to rename the device to nikhil, DAQmx Base enumerates devices differently. Use the lsdaq utility to find your device name (likely Dev1) and change your chan variable to use the discovered name.