I run a NI-5133 USB oscilloscope and I'm trying to record data at a given interval (such as every 10 seconds). I continuously acquire waveforms and manipulate them arithmetically. The horizontal settings for waveform acquisition seem to work as expected, when I display them. However, when I try to write the waveform into an ASCII file, it is usually shorter. The record length is consistent from one record to the next (often it is an even number, such as 1000, 1500, or 2000 traces). But it is not consistent between starting and stopping the program repeatedly. That is, I can start the program and files with 1000 samples get written every 10 seconds. I then stop and restart they same program and now get different record lengths. Displaying the records on a waveform graph looks the same in both cases. Any ideas??
