What is it doing that seems to be incorrect?
From what I can see, you have the loop iteration value wired to the count input of the TDMS read. That means on the first iteration i=0, you will read zero items. Next i=1, you'll read one. next i=2 you'll read two. i=3, you'll read three. So every loop iteration, you'll be reading progressively larger chunks of the file.
You should just have a 1 wired to the count terminal.
