fpga edge detection for triggering

[rschmeling]

Hey Everyone

I am stumped and I was looking for some ideas on how to fix my problem.  I am using a NI 5761 to collect signals from a couple photodiodes and a PMT, I am also using the PFI line to send a digital signal to trigger a nitrogen pumped dye laser. 

The trouble that I am having is using one of my signals from my photodiode to trigger this PFI line.  Below I have attached my VI that I am working on and an example of the raw data that I am trying to trigger with.  I have been able to trigger the PFI line with a true constant and then collect the data from the two photodiodes in parallel.  Now I am trying to trigger the PFI line off the very first peak so the timing can be set for the measurements that I am making. 

The reason I have them in separate loops is because now I am looking to achieve parallel data collection between them.  Once I am able to trigger the PFI line off the signal, I will that have to put in an algorithm to calculate a desired time delay from when that first edge is detected to when I need the PFI signal and my laser to fire. 

Thanks,

Ryan

[rschmeling]

Long weekend to mull it over and still stuck...

[Zachmx]

Hi Ryan,

The NI 5761 examples installed with FlexRIO support for NI-RIO have an example of setting a Data Edge trigger based on an Analog Input value rising above a trigger level. This example can be found in <LabVIEW>\examples\FlexRIO\IO Modules\NI 5761\NI 5761 Getting Started. From here, open the NI 5761 - Getting Started.lvproj and look for the Getting Started VI under the RIO target you are using. The trigger loop looks like this:

The NI 5671 manual also has a good walkthrough of setting this up. You can find a PDF of the manual here.