I am trying to hook up a pulse counter to measure RPM. I have one channel of a quadrature encoder hooked up to a USB cDAQ-9172. Everything seems to work OK except once every second or so (I'm reading the encoder at 4 hz) read vi returns zero counts. This is also the case when I use the example counter input VIs from NI.
I seem to be having the same problem as described in this thread, but I didn't see any solutions. Unfortunately, I don't have access to a scope.
I solved my own problem. After I posted this to the forum, I discovered that the CPU usage on the computer that is running this program was at 85% - 100% CPU usage. I went through and wiped out all the unneeded (several anti-virus, windows messenger, real player(!), ect) software with great prejudice, and now the CPU usage is ~30%. I haven't had any problems since.