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viSci

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Posts posted by viSci

  1. Amazing NI is still trying so hard to sell the DSC.  From what I can tell NSV events are possible in CVI without the DSC.  Here is an old thread that ends in some CVI code that show how to register NSV change callbacks.  Now all you have to figure out it how to trigger LV user events from CVI, which I believe is possible.

    http://forums.ni.com/t5/LabWindows-CVI/NSV-Async-Read-Callbacks/td-p/1329994

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  2. Nice, thanks!  I think this would be a good starting point.  Perhaps add auto ref level based on the measured amplitude and offset.  Also could add interpolated indexes since there is a small error between the thresholded index and the actual fractional index that would correspond to the precise point where the signal crossings occur.

  3. Does anyone remember if there was an older version of this vi written in pure G?  I would like to have a version that I can modify to return all pulse measurements in a waveform instead of just the one specified.  It seems like much of the work in finding one pulse could be applied for finding all pulses.  My interest comes from a requirement for real-time processing of a 32 channel AI at 100kHz with each ch containing ~ 500 pulses/s.  The current Pulse Measurement vi is about 10x too slow to keep up.  I am on my way to creating my own from scratch but still would be useful to have on hand for comparison.

  4. Greetings all - I have a LabVIEW 2014 executable that I am trying to put into a form that can be run as or from a Windows Service.  Of course I removed all possible dialog windows and any need for UI interaction.  I did my testing using a program called FireDaemon which can wrap any window exe as a Windows Service.  I found that I could not get it working until I included the NI Authentication Service (NIAuth) as a dependency within FireDaemon.  If I do not do this my application (which does not use any web services as far as I know) just hangs when the Windows Service activates.  Does anyone have a clue about this?  I would like to create a version of my app that does not require this dependency.

  5. Thanks folks, it does look like Gige is workable.  The next issue is streaming to disk.  I have tested out the IMAQ AVI vi's and they work nicely but performance is highly dependent on the codec selected.  So far it looks like the FF Video Codec 1, a mpeg derivative, is working well.  It allows me to achieve a 30 fps rate with 640x480 B&W frames and has impressive compression.  I will have to do more testing at my target resolution of 1024 x 768 and may need to further optimize my codec or try out a straight binary file instead of avi.  

  6. Curious to know if anyone has created a way for LabVIEW or TestStand to interact with a Instrumented Android APK file or 'App'.  The Standard Android Development environment includes tools like Robotium or Monkeyrunner which are great if you are using Java or Python.  In my case we already have LabVIEW in place for testing the embedded HW and subsystems but would like automated Android UI interaction as well.

  7. One thing that I found to be very helpful is a little utility call Process Tamer.  It does just what it says and immediately slowed down annoying windows background tasks.  I was going to revert back to Windows 7 but now everything is just groovy! 

  8. I took the plunge myself and was wondering how others are fairing on Windows10.  Most of the issues I encountered have to do with default settings in W10 that allow background processes (like anti-malware) to just pop into memory at any time and suck the cpu dry.  I spent a whole day disabling and tweaking things to prevent thoughtless cpu hogging.  

    • Like 1
  9. Yes that is the way it works in DAQmx.  It makes sense that the task would start directly and then the acquiring of data into the buffer is inhibited until the trigger occurs.  I believe you can check the state of a task to determine if it is still waiting for a trigger or not.

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