RN,
Because you're using NI-Scope, I'm assuming that you'll be sampling at a fairly fast rate. Thus, you will be saving fairly large chunks of data to file. Fortunately, there is a LabVIEW shipping example that is designed to stream data to file. In LabVIEW, go to HELP >> Find Examples to launch the LabVIEW example finder. Then browse to: Hardware Input and Output >> Modular Instruments >> NI-SCOPE >> Continuous Aquisition. Within that folder you will find an example called: "niScope EX Save to File - HWS Low Level - Single Channel Stream.vi." This VI is designed to stream large amounts of data into a HWS (Hierachical Waveform Storage) file. If you look at the code, a produce/consumer loop architecture is used to make sure that data is not lost but preserved in PC memory in a queue.
I would try running this example to start with. When I ran the example on my computer, I changed the MAX Queue size in the block diagram to be 1000. Because your digitizer can sample data faster than your PC can write it to file, it is important to use a large queue size to store data in memory. That way, the produce loop (which acquires from the scope), can continuously acquire data. The consumer loop (file writing loop), will run continuously until all samples have been written to file, even if this takes longer than your aquisition time. Hope this helps!
Regards,
David Hall | Applications Engineering | National Instruments