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Neil Pate

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Posts posted by Neil Pate

  1. I think there may be an error in the library. The "main" VI is not actually part of the library and the library references a file that does not exist, so I presume some form of renaming (outside the IDE) has gone on?

     

    After fixing this I tried this on the one TIFF file I have but it is compressed and looking at the code it appears there is not yet support for compressed TIFFs.

  2. Yamaeda,

     

    I do not know what is wrong with your code, but can offer you this advice. To the best of my knowledge .NET calls are actually very expensive in LabVIEW, a single call can be something like a few milliseconds! Now, it was a few versions of LabVIEW ago that I had this problem, but my understanding is that it is just the "managed" way of how .NET and LabVIEW operates that this is likely to always be the case.

     

    If you are trying to render lots of stuff I expect you will have lots of .NET calls so just be careful with performance.

     

    For reference, I was using SFML, it seemed like quite a nice library but performance was terrible from within LabVIEW.

  3. Food for thought:

    If huge amounts of analysis and tribal knowledge is required to not write bloated, unscalable and buggy code with a certain tool. Is it not a better strategy to just not use that tool?

     

    Those outcomes are possibilities, not guarantees. Not every application has 8000 VIs, and in a lot of situations the careful use of libraries can be really beneficial.

     

    I am not ready to give up on them yet.

  4. Massive no from me on LLBs. I do not need to distribute my code like that, so really have no purpose for them. As others have pointed out, no namespacing, no access scope makes these a stale technology (for my situation at least) in LabVIEW.

     

     

    I still do use libraries though (and classes of course, which are also libraries), even with all the pain associated with the loading the entire contents etc. It troubles me too much me to have to manually namespace every VI, so I am not sure I will move away from libraries or some form of them any time soon.

  5. OK, so the Slylandro now has some food :-)

     

    This is just a silly video of me controlling both the ship and the asteroid (now with animation) with an xbox controller.

     

    http://screencast.com/t/Z2s6ZDvFae

     

    The jing video messes up the frame-rate, it is buttery smooth without the video being recorded.

     

    Next step: battle music!

    • Like 1
  6. I didn't realize until a few years ago that pressing the thrust key on Slylandro made him immediately switch directions 180 degrees. Turns out to be a great tactical move for attacks with quick escapes.

     

    Pesky indeed!

     

    My favourite was the Utwig, although the Vux could be deadly (and terribly annoying) in the right hands.

  7. I know very little about the Simulation toolkit, or what you are trying to model, but looking at your diagram have you not perhaps put the feedback node in the wrong place? Do you really want the output from Summation 3 to be delayed before passing it into your Transfer Function?

     

    Try putting the feedback node only in the path back to Transfer Function 8.

     

     

    post-7375-0-54635000-1416927188_thumb.pn

  8. Thanks,

     

    No, I also just saw the youtube video last week, complete coincidence.

     

    My (probably very unrealistic) initial goal is actually to recreate SC2 melee in LabVIEW. A secondary goal for later is to get OpenGL working nicely with LabVIEW and SDL. I have started this bit several times and never really got enough momentum to keep development up.

    • Like 1
  9. I would also be careful with you local variable of "triggered" that is set to FALSE. There is no way, right now, that this is guaranteed to execute before or after the FOR loop, possibly causing unintended behavior. I would move it somewhere where you can guarantee the correct order of operation.

     

    You are right, but this is probably less true on FPGA. As there is no data-flow dependency on this I would be very surprised if it did not reliably get cleared at the start of each iteration of the acquisition loop.

     

    Defensive programming techniques are my preference so I would probably introduce some fake data-flow dependency to clear it at the start of each iteration.

  10. The rules of data-flow are still valid, the value of the Triggered indicator is taken from the tunnel going into your for loop, so will have the same value for every iteration of the loop as it is really only "sampled" once on the very first iteration of the loop.

     

    One thing to add, perhaps put in a control in the path of the Timed Out? feedback node to allow you to reset the timed-out latch, this can be useful during development.

    • Like 1
  11. Well, as acceleration is just the second derivative of position surely you just double integrate the acceleration.

     

    (I jest...)

     

    I think it will be very difficult to infer any kind of accurate absolute position and velocity in 3D space with the measurements you have available, especially on a rocket! As some of the other links show, a Kalman filter type approach may be a good starting point, but I still think this is a very tricky proposition given the speeds your rocket is likely to be travelling at.

     

    Can you not add a simple GPS device to your rocket?

    • Like 1
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