Negative Edge Detection DI

[Kevin Duerloo]

Hello,

I want to read in several counter inputs in my USB-6008 but this has only one counter input.

The frequency of the pulses (to read) isnt high so i thought maybe i could use a digital input. When the input is high, a certain value has to be incremented. The only problem is that the high-level of the pulse takes to long and the value is incremented more than once. To solve this problem I think I need an edge detection that generates a pulse when a negative edge has occured. Can somebody help me to solve this problem?

Greetings,

Kevin Duerloo

KaHo Sint-Lieven, Belgium

[JorisV]

Hi, There is no change detection available on the digital lines of these USB devices. So you will not be able to trigger on a Rising edge or Falling edge by using the Digital lines. The only thing you could do is to use the digital trigger line. So, create a program that starts an acquisition on a digital trigger (PFI0) and set it to Rising or Falling. Put this task inside a loop. Everytime a Rising edge occurs, the acquisition will start and each time the dataflow arrives at the DaqmxBaseRead.vi/DaqmxRead.vi you can add some code that increases a value. Put a sequence around the Read.vi and add the code. This is just a workaround. You can test if this good enough for you. Regards. JV