CI Cnt Edges not counting a certain input signal

[InfinityDE]

Dear NI community,

today I ran into some trouble concerning a measurement program (see attached image). This program used to work fine for all measurement tasks up until today.

I am using this to count pulses from a counting tube for radiation measurements. Today I tried to use it with a slightly modified setup and suddenly there were no more counts. Yes, the setup does generate an output signal, which can be observed on an oscilloscope, as well as on a different timer/counter-setup.

This counter also works, when using a signal generated by a pulse generator.

I am using a NI cDAQ 9174 with an NI 9361 for data acquisition. The signal has an amplitude of around 5V with negative polarity.

I would be really thankful for any kind of advice!

[Kevin_Price · Accepted solution]

Things to check / try:

1. Try explicitly configuring the input terminal(s) for edge counting.  Maybe you're physically wired to the defaults for the counter(s) in the task, but I can't verify that from here.

2. I'd change the = comparison used for terminating the loop into a <= to make sure you don't miss the intended end point.

-Kevin P

[InfinityDE]

Hey, thank you for your advice.

I guess I have figured out my mistake by now. My input signal was wired to the DI+ and the ground to GND. By wiring the input signal to DI- and the ground to DI+ I am now able to detect negative input signals by just doing a differential measurement.