Using TDMS to stream from continuous data acquisition

[StevieZ]

Taking that example and placing the TDMS_AppendDataValues inside the DAQmx read loop worked just fine for me. Are you able to get this example to function correctly?

int CVICALLBACK StartCallback(...)
{
...
TDMSFileHandle          file = 0;
TDMSChannelGroupHandle  group;
TDMSChannelHandle*      channels;
channels = malloc (sizeof(TDMSChannelHandle) * 1);
...
...
while( gRunning ) {
	DAQmxErrChk (DAQmxReadAnalogF64(taskHandle,sampsPerChan,10.0,DAQmx_Val_GroupByScanNumber,data,sampsPerChan*numChannels,&numRead,NULL));
	printf ("%f\n", *data);
	TDMS_AppendDataValues (channels[0], data, 20, 1);
	if( numRead>0 )
		PlotStripChart(panel,PANEL_STRIPCHART,data,numRead*numChannels,0,0,VAL_DOUBLE);
		ProcessSystemEvents();
	}
}
...
}

Regards,

Steven Zittrower

Applications Engineer

National Instruments

http://www.ni.com/support

[bluemoose]

I'm getting a message saying "Invalid channel handle"... I'm thinking I need a bit more in there in terms of configuring the TDMS stuff?

[bluemoose]

I think I've found the solution to my problem, sort of.  I have separate functions for reading data from the DAQ and actually recording it, because I was interested in displaying the data on screen but not always recording it.  If I combine both functions I don't have the problem with repetition that I was having.  I think I can tweak things around a bit to fix it and still separate the two activities.