Continuous output of any waveform

Note

Steps:
1.Create task. VkDaqCreateTask
2.Create analog output channel VkDaqCreateAIAccelChan
3.Set sampling clock VkDaqCfgSampClkTiming
4.Start task VkDaqStartTask
5.Continuously set task data for any waveform VkDaqSetTaskStreamData
6.Stop task VkDaqStopTask
7.Clear task VkDaqClearTask



Note:
1. When setting waveform data in a loop, the number of waveform points set should be consistent with the clock frequency. Please refer to the SAMPLING-FREQUEncy parameter in the C Language Reference below. When setting waveform data continuously in a loop, the return value should be ≥ 0. Otherwise, it needs to be re uploaded until ≥ 0

Example of Continuous output of any waveform Process Diagram

C language reference

#include <iostream>
#include <stdio.h>
#include <thread>
#include "libvkdaq.h"
 
#define CH_NAME                     "dev1/AOUT1"
#define PI                          3.14159265358979323846
 
#define SAMPLING_FREQUENCY          10000   //1~99200               
#define WAVE_AMPLITUDE              1       //0~9
#define WAVE_FREQUENCY              10
#define WAVE_PHASE                  0       //0~360
#define WAVE_OFFSET                 0
 
#define DAQmxFailed(error)              ((error)<0)
#define VkDaqErrChk(functionCall)       if( DAQmxFailed(error=(functionCall)) ) goto Error; else
 
int main(int argc, char* argv[])
{
    int             i = 0;
    int             ret = 0;
    int32_t         error = 0;
    const char* taskHandle = "VkDaqTaskHandledac";
    // Sin Wave
    double* data = new double[SAMPLING_FREQUENCY];
    double phase_rad = WAVE_PHASE * PI / 180.0;
    double step = 2.0 * PI * WAVE_FREQUENCY / SAMPLING_FREQUENCY; 
    int value = WAVE_AMPLITUDE; 
 
    for (int i = 0; i < SAMPLING_FREQUENCY; ++i)
    {
        double theta = step * i + phase_rad;
        double sin_v = WAVE_AMPLITUDE * sin(theta) + WAVE_OFFSET;
        data[i] = sin_v; 
    }
 
    // VkDaq Configure Code
    VkDaqErrChk(VkDaqCreateTask(taskHandle));
    VkDaqErrChk(VkDaqCreateAOVoltageChan(taskHandle, CH_NAME, "", -9, 9, VkDaq_Val_Volts, ""));
    VkDaqErrChk(VkDaqCfgSampClkTiming(taskHandle, VkDaq_Val_ClkSrc_OnBoardClk,SAMPLING_FREQUENCY, 0,VkDaq_Val_ContSamps, SAMPLING_FREQUENCY));
    VkDaqErrChk(VkDaqStartTask(taskHandle));
    printf("StartTask success.\n");
    printf("Start continuous DAC output...\n");
    while (true)
    {
        // VkDaq Write Code
        ret = VkDaqSetTaskStreamData(taskHandle,data,SAMPLING_FREQUENCY,0,1,0,1);
        // The return value of the function is less than 0, and the data needs to be uploaded again. 
        // Until there is space in the buffer, the upload is successful, and the function returns a value greater than 0
        while (ret < 0) {
            ret = VkDaqSetTaskStreamData(taskHandle, data, SAMPLING_FREQUENCY, 0, 1, 0, 1); 
        }
 
        //change Sin Wave 
        value++;
        if (value == 4) {
            value = 1;
        }
        for (int i = 0; i < SAMPLING_FREQUENCY; ++i)
        {
            double theta = step * i + phase_rad;
            double sin_v = value * sin(theta) + WAVE_OFFSET; 
            data[i] = sin_v;  
        }
 
    }
 
    printf("Generate success\n");
Error:
    if (DAQmxFailed(error))
        printf("VkDaq Error: %s\n", VkDaqGetLastErrorInfo());
    if (taskHandle != 0) {
        VkDaqStopTask(taskHandle);
        VkDaqClearTask(taskHandle);
    }
    delete[] data;
    printf("End of program, press Enter key to quit\n");
    getchar();
    return 0;
}