I mean the number of samples wired into the DAQmx Read function. Right now you have nothing wired in which means it default to -1, which is whatever data is available. Since you just started your task, there is probably very little data in there to analyze.
Your VI doesn't contain any data we can look at. For some reason you turned your waveform graph into a typedef control. And it does not have any data saved in it as default before you saved your VI.
What is the frequency you are expecting to read with your task?
