Hi. I'm getting pretty far with my code now to read an analog voltage input, display it and then save the data to a file. I've hit an issue though, as soon as it gets to my writting code block, it comes up with
VC_Acq_IntClk.exe has triggered a breakpoint.
When I click continue, it pumps a load of garbage to the specified text document name (May not be garbage, but it looks like that to me. For example
- Visual Studio Error:
Unhandled exception at 0x7728A208 (ntdll.dll) in VC_Acq_IntClk.exe: 0xC0000005: Access violation reading location 0x658B26FD.
File data:
*Huú… $@WêÄ/ $@
WêÄ/ $@WêÄ/ $@
WêÄ/ $@ÄϯßZ $@
ÄϯßZ $@*Huú… $@
*Huú… $@í&‹e2 $@
í&‹e2 $@GÀ:± $@
GÀ:± $@GÀ:± $@
GÀ:± $@ 8 0Ü $@
8 0Ü $@ 8 0Ü $@
8 0Ü $@êP€] $@
This is the code:
/*********************************************************************
*
* ANSI C Example program:
* Acq-IntClk.c
*
* Example Category:
* AI
*
* Description:
* This example demonstrates how to acquire a finite amount of data
* using the DAQ device's internal clock.
*
* Instructions for Running:
* 1. Select the physical channel to correspond to where your
* signal is input on the DAQ device.
* 2. Enter the minimum and maximum voltages.
* Note: For better accuracy try to match the input range to the
* expected voltage level of the measured signal.
* 3. Select the number of samples to acquire.
* 4. Set the rate of the acquisition.
* Note: The rate should be AT LEAST twice as fast as the maximum
* frequency component of the signal being acquired.
*
* Steps:
* 1. Create a task.
* 2. Create an analog input voltage channel.
* 3. Set the rate for the sample clock. Additionally, define the
* sample mode to be finite and set the number of samples to be
* acquired per channel.
* 4. Call the Start function to start the acquisition.
* 5. Read all of the waveform data.
* 6. Call the Clear Task function to clear the task.
* 7. Display an error if any.
*
* I/O Connections Overview:
* Make sure your signal input terminal matches the Physical
* Channel I/O Control. For further connection information, refer
* to your hardware reference manual.
*
*********************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <NIDAQmx.h>
#include <string.h>
#include <windows.h>
#define DAQmxErrChk(functionCall) if( DAQmxFailed(error=(functionCall)) ) goto Error; else
FILE *save_file = NULL;
int main(void)
{
int32 error=0;
int32 counter[2]={'0'};
TaskHandle taskHandle=0;
int32 read=0;
int32 amount=0;
float64 *i_array=0;
int j=0;
char errBuff[2048]={'\0'};
char c = 64;
char filename[256];
/*********************************************/
// DAQmx Configure Code
/*********************************************/
printf("Please enter the amount of voltage checks you wish to run.\n");
while(scanf_s("%d%c", &amount, &c) !=2) // This is where the user inputs his data. If it isn't a number, it returns false and goes into the while loop.
{
getchar();
puts("Please enter a number.");
}
i_array = malloc(j * sizeof *i_array);
for (j = 0; j < amount; j++) // Loops through the specified amount
{
DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0","",DAQmx_Val_Cfg_Default,1.0,10.0,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",10000.0,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,1000));
/*********************************************/
// DAQmx Start Code
/*********************************************/
DAQmxErrChk (DAQmxStartTask(taskHandle));
/*********************************************/
// DAQmx Read Code
/*********************************************/
DAQmxErrChk (DAQmxReadAnalogF64(taskHandle,1000,10.0,DAQmx_Val_GroupByChannel,i_array,1000,&read,NULL));
printf("Updating... ");
printf("Data point %d has %f",j, i_array[j]); // Displays the voltage set number of times
printf(" volts\n");
Sleep(200); // ms pause between each reading
if( taskHandle!=0 )
{
/*********************************************/
// DAQmx Stop Code
/*********************************************/
DAQmxStopTask(taskHandle);
DAQmxClearTask(taskHandle);
}
}
if(j==amount)
{
printf("\nVoltage readings aquired. Please specify a filename so the data can be saved.\n");
goto Save;
}
Save:
printf("\nPlease enter a filename...\n");
gets (filename);
printf("Name is: ");
puts(filename);
save_file = fopen(filename,"w+");
printf("File made\n");
for (j = 0; j < amount; j++)
{
fwrite(&i_array[j], sizeof(j), sizeof(amount), save_file);
fputc('\n',save_file);
printf("Data point %d read",j, i_array[amount]); // Displays the voltage set number of times
printf("\n");
}
printf("Saving...\nSaved.");
free(i_array);
Error:
if( DAQmxFailed(error) )
DAQmxGetExtendedErrorInfo(errBuff,2048);
if( DAQmxFailed(error) )
printf("DAQmx Error: %s\n",errBuff);
return 0;
}
Any ideas what is going on here? The file is being made and the data is being inputted, but it just seems to be inputting a garbage loads of ASCII characters instead of the voltage readings.
