Hello? My system is using a double buffer based code and I have to use them. I tested a stand alone DAQmx program dealing with a double buffer technique and it is working pretty much fine with my system. Since I am not only one wrote my system c++ code since 1980s, I'm not sure how to manipulate the DAQmx double buffer system.
Here is my old c++ code dealing with a double buffer code to display on a graph.
I attached these codes and the last one is DAQmx code and there are error points; //<******************** Error occurs here.
The rest of them is old c++ and EvenBank and OddBank are representing double buffers. Their types are
double* EvenBank;
double* OddBank;
and these are manipulated/initialized in this way later
EvenBank = new double[ iTotalSize ]; //iTotalSize = 7200
OddBank = new double[ iTotalSize ];
int i;
for( i= 0; i< iTotalSize; i++ )
EvenBank[ i ] = OddBank[ i ] = 0;
Then the thread function attached in here. I don't have any idea how to assign the acquired sample to even and odd bank to display them in the graph.
Thanks for help.
1.Thread display:
unsigned int ThreadDisplay( LPVOID pParams )
{
static unsigned long count = 1;
static unsigned long traceNum = 1;
CNatAcqView* ptr = (CNatAcqView*) pParams;
if( traceNum %2 )
{
traceNum = 1; //reset counter
ptr->StartEvenIntScanATD();
if( ptr->WriteEnable )
ptr->WriteToDisplayBuffer( FALSE ); // ODD, Calling startScan()
}
else
{
ptr->StartOddIntScanATD();
if( ptr->WriteEnable )
ptr->WriteToDisplayBuffer( TRUE ); // EVEN, Calling startScan()
}
ptr->WriteEnable = TRUE;
Check_Daq( ptr, ptr->iTotalSize ); // wait till end of signal window
traceNum++;
Sleep( 50 ); //minimum for checking keys and menu bars
ptr->PostMessage( WM_DISPLAY_BUFFER, count, (long)0 ); // if done exit ,else restart...
AfxEndThread( 0 );
return 0;
}
2. Display data on the screen:
int CNatAcqView::WriteToDisplayBuffer( bool even )
{
int i,j;
for( i= 0; i< iChannel_Acq; i++ ) //display buffer depends on IRIS model
{
for( j= 0; j< fdat.trace_size; j++)
{
if( even )
{
if( gd.ch[i].active == 1 )
gd.ch[ i ].iatd[ j ] = EvenBank[ i + j*iChannel_Acq ]; //iChannel_Acq = 6
else
gd.ch[i].iatd[j] = 0;
}
else
{
if( gd.ch[i].active == 1 )
gd.ch[ i ].iatd[ j ] = OddBank[ i + j*iChannel_Acq ];
else
gd.ch[i].iatd[j] = 0;
}
}
}
//PreProcessing
for ( i= 0; i< MAX_RADARS; i++ )
{
//if( i < 4 ) //for BatteryLevel
//{
if( processFlag == 1 && gd.ch[i].active == 1 )
AcqPoll_ProcessSignal( i );
//}
}
for( i= 0; i< iChannel_Acq; i++ ) //MAX_CHANN
{
if( gd.ch[i].active == 1 )
{
for( j= 0; j< fdat.trace_size; j++ )
iAveBuffer[i][j] = iAveBuffer[i][j] + gd.ch[i].iatd[j]; //average calculation, not important
}
}
if( SampleTimeFlag != 1 )
{
for( i= 0; i< MAX_RADARS; i++ )
{
gd.ch[i].blength = fdat.trace_size;
gd.ch[i].sampleTime = .000001 * fdat.period * fdat.its[i]; // display text info on a screen
if( i >= IRIS_SYSTEM )
gd.ch[i].sampleTime = fdat.period;
}
}
else //if( SampleTimeFlag == 1 )
{
for( i= 0; i< MAX_RADARS; i++ )
{
gd.ch[i].sampleTime = fdat.period;
gd.ch[i].blength = fdat.trace_size;
}
}
return 1;
}
3. Check_Daq:
BOOL Check_Daq( LPVOID pParams, int expect) // int expect is a total size of the sample buffer.
{
short done;
unsigned long number = 0;
int status;
status = DAQ_Check( 1, &done, &number );
CNatAcqView* ptr = (CNatAcqView*)pParams;
AfxMessageBox("Check_Daq is called", MB_OK, 0);
ptr->bAbortAcquire = FALSE;
ptr->bRadarTrigger = TRUE;
ptr->iTriggerLED = 1; //Trigger On
int i=0;
while( done != 1 )
{
status = DAQ_Check( 1, &done, &number );
ptr->bRadarTrigger = FALSE;
ptr->uiTriggerCheck++;
//protect overflow data type
if( ptr->uiTriggerCheck >= MAX_DMI_COUNT )
ptr->uiTriggerCheck = 0;
if( ptr->bAbortAcquire ) //from OnAcquire Mode
done = 1;
}
ptr->uiTriggerCheck = 0;
if( number == (unsigned long) expect )
return TRUE;
else
{
//throw ERROR_DAQ_CHECK;
return FALSE;
}
}
4. DAQmx conversion:
//I will comment out Check_Daq() in ThreadDisplay function. Then this whole single function will be called.
unsigned int CollectingSamples(LPVOID pParams)
{
CNatAcqView* ptr = (CNatAcqView*) pParams;
int32 error=0;
char errBuff[2048]={'\0'};
double gainValue = 0.5f;
uInt32 numChannels;
uInt32 reading=0;
static bool32 isDone;
ptr->totalRead = 0;
unsigned long HalfSize = (unsigned long)ptr->iTotalSize/2;
double DataBuffer[1000];
int32 read;
//TaskHandle taskHandle = ptr->taskHandle;
TaskHandle taskHandle=0;
ptr->dataA =0;
DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0:5","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));
DAQmxErrChk (DAQmxSetAIGain(taskHandle, "Dev1/ai0:5", gainValue));
// buffer(14400) setting with internal clock("") and continuous sampling(DAQmx_Val_ContSamps), DAQmx does double buffering basically in case of continuous sampling.
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",40000,DAQmx_Val_Rising,DAQmx_Val_ContSamps,14400)); //14400 = iTotalSize x 2; double buffer.
//DAQmxErrChk (DAQmxSetAIConvTimebaseDiv(taskHandle, (int)iSampInt*10));//sampleTicks*10 was 500 //iSampInt*10
//DAQmxErrChk (DAQmxSetSampClkTimebaseDiv(taskHandle, (int)iScanInt*10));//GroupTicks*10 was 2000 //iScanInt*10
//double buffer acquisition; the board transfers data when half its internal buffer is full
DAQmxErrChk (DAQmxSetAIDataXferReqCond(taskHandle, "Dev1/ai0:5", DAQmx_Val_OnBrdMemMoreThanHalfFull));
//Overwriting samples in the buffer that you have not yet read.
DAQmxErrChk (DAQmxSetReadOverWrite(taskHandle, DAQmx_Val_DoNotOverwriteUnreadSamps));
//Collecting data from buffer
//DAQmxErrChk (DAQmxRegisterEveryNSamplesEvent(taskHandle,DAQmx_Val_Acquired_Into_Buffer,10,0,AcquireCallBack,NULL)); // call back result
DAQmxErrChk (DAQmxStartTask(taskHandle));
while (!isDone)
{
ptr->IsTaskDone_ContAcqIntClkDigStartRef(taskHandle, &isDone);
//DAQmxErrChk( DAQmxIsTaskDone(staskHandle, isDone));
DAQmxErrChk (DAQmxGetReadAvailSampPerChan(taskHandle,&reading));
if( reading>0 )
{
// Each reading
DAQmxErrChk (DAQmxGetReadTotalSampPerChanAcquired(taskHandle, &ptr->dataA)); //Accumulated reading
while(reading > HalfSize ){ //More than a half full
DAQmxErrChk (DAQmxReadAnalogF64(taskHandle,-1,10.0,DAQmx_Val_GroupByScanNumber,DataBuffer,1000,&read,NULL)); //Read the buffer
ptr->totalRead+=read;
if( ptr->totalRead == ptr->iTotalSize || ptr->totalRead > ptr->iTotalSize )
{
if(ptr->iAvailableSample == 2){
//ptr->EvenBank=DataBuffer; //<******************** Error occurs here
return ptr->iAvailableSample == 1;
}
else if(ptr->iAvailableSample == 1){
//ptr->OddBank=DataBuffer; //<******************** Error occurs here, too.
return ptr->iAvailableSample == 2;
}
isDone = 1; //Stop
}//End of if( ptr->totalRead == ptr->iTotalSize || ptr->totalRead > ptr->iTotalSize )
}//End of while(reading > HalfSize )
}//Enf of if(reading>0)
}// while (!isDone)
AfxEndThread( 0 );
DAQmxErrChk (DAQmxStopTask(taskHandle));
DAQmxErrChk (DAQmxClearTask(taskHandle));
Error:
if(error)
CleanUp (error, taskHandle);
}
I'm converting DAQ to DAQmx..from Parkoz.com
