Real-Time Measurement and Control

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can LabVIEW FPGA use global variables?

This soudns a little silly to ask becuase I know FPGA is all about transistor logic...but I would like to create have an event in software triggered by an external Digital trigger. Im my host I have an event loop running and I don't really want to use the "timeout" feature to "poll" for the digital line. I wanted to know if I use the FPGA to look for the digital and when it changes ont he rising edge maybe set a variable high that trigers a user event??


Any ideas or suggestions?



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Check out the example finder for a great example of what you are trying to do, this is written for a cRio, but you should be able to port the code over if you are using an R-series board:


Help->Find Examples-> Hardware Input and Output-> Compact Rio -> FPGA Fundamentals -> Triggers and Watchdog -> 'Trigger Detection - Software - cRio.lvproj'


Also attached a screenshot in case you can't find that example Smiley Surprised


Be careful firing events programatically, they are really designed to be triggered by front panel actions.  You should be able to just poll the variables until a change is detected, and then execute whatever code you are waiting on.

Message Edited by Rob_K on 09-30-2008 02:28 PM
Rob K
Measurements Mechanical Engineer (C-Series, USB X-Series)
National Instruments
CompactRIO Developers Guide
CompactRIO Out of the Box Video
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