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Michael Aivaliotis

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Posts posted by Michael Aivaliotis

  4. Share your favorite tips and shortcuts

    in Development Environment (IDE)

    Posted

    Here's a helpful nugget for those of you who run multiple versions of LabVIEW at the same time. In LabVIEW 8.0 and later, you can place the following line in your LabVIEW INI file: showExePathInWindowTitle=True With this line in your INI file, the window title of every VI you have open will indicate the path on disk to the LabVIEW EXE file that is running. It only indicates the owning folder and the EXE name (without the .exe extension)...so for example, if you are running LabVIEW 8.0 from the default installed location, then your VIs will have "LabVIEW 8.0/LabVIEW" in their title bar. If you have LabVIEW installed in a custom location like c:\lv80\lv80.exe (that's where mine is installed), then your VI title bar will have "lv80/lv80". Note that this information is appended to the existing title bar contents, i.e. you'll still see your VI name (or customized Window Title) in the title bar, you'll just see this new information after it.
    Taken from Darren's weekly Nugget.

  5. Invalid Control Ref w/ FP Closed

    in LabVIEW General

    Posted

    Why did you run the sub? Typically VI's that are labeled MAIN are the ones taht you're supposed to run.
    Ya, I ran the sub because I was trying to figure out the issue.
    The issue is that in LV 7.1 I have observed that running the main will throw an error down in the sub because the child fp (which gives the sub the reference to the graph) was not open.
    I down-converted your code to 7.1.1 and could not observ what you describe. This makes sense really. I don't recall ever getting an error because a front panel is not open (but in memory). Are you sure about this error in 7.1? Perhaps you got the error in an executable that had its' panel removed?

    Download File:post-2-1157553136.llb (LV7.1.1)

  7. Read from Text File function looses refnum when ERROR = TRUE

    in LabVIEW Bugs

    Posted

    Original Posting:

    http://forums.ni.com/ni/board/message?boar...ssage.id=204042

    i'm using LV 8.0 PDS. When calling the "Read from Text File" of "Write to Text File" functions with an error and a refnum <> NULL the functions set the refnum to NULL. see attachment. The Binary File IO functions seem to work properly. could someone please confirm this? Best regards

    chris

    Download File:post-2-1157506227.vi

  11. Bug with "Show Constant Folding"

    in LabVIEW Bugs

    Posted

    In LabVIEW 8.20 Help:

    Performance Optimized with ConstantsLabVIEW uses constant folding to optimize the performance of VIs. With constant folding, LabVIEW stores constant values when it compiles VIs instead of calculating them at run time. For constants wired to structures, LabVIEW calculates the output values of the structures when it compiles VIs and stores the values so they are available at run time.

    You can display constant folding hash marks on the block diagram by selecting Tools

  13. Bug with "Show Constant Folding"

    in LabVIEW Bugs

    Posted

    Original Post:

    http://forums.ni.com/ni/board/message?boar...2&jump=true

    The attached picture shows where the problem is : LV thinks that the inside nested loop generates a constant. The vi must be run twice to generate a proper result. The first run always generates an array with a column number corresponding to the previous value of Numeric Workaround : carefull with the new show option (16x16_smiley-sad.gif) and wait for the next version... 16x16_smiley-wink.gif

    Bug%20Show%20Constant%20Folding.png

  15. While loop oddity

    in LabVIEW Bugs

    Posted

    Original Post:

    http://forums.ni.com/ni/board/message?boar...ssage.id=200378

    I was trying to make a bit of code in 7.1, win2k do the following:

    If an index is contained in a row of a 2D array of integers, output all of the integers for that row, otherwise, just output that index.

    My somewhat convoluted VI to do so is attached.

    Now, am I overthinking this (which I've been known to do 16x16_smiley-tongue.gif), or is it actually taking a modification of the row downstream and modifying the input array?

    I checked this on an 8.20 eval, win xp machine with the same results.

    Thanks,

    Joe Z.

    Reported: # 40DAF67U

    Download File:post-2-1156914149.vi

  16. Weird behaviour of Replace Array Subset

    in LabVIEW Bugs

    Posted

    Original Post:

    http://forums.ni.com/ni/board/message?boar...ssage.id=201906

    Today, I encountered (am still encountering actually) a weird behaviour with the Replace Array Subset icon.

    In my program, I use a Insert Into Array icon at one place.

    I replaced it (using Rt Click Replace) with the Replace Array Subset icon, it showed broken wires.

    So, I replaced it (using Rt Click Replace) with the Insert Into Array icon, it showed NO broken wires.

    Now, I did Undo (Ctrl+Z), it got replaced with the Replace Array Subset icon, but with NO broken wires.

    I'm stunned to see this weird behaviour... !

    But the program behaviour remains the same respectively for these respective icons.

    Even the other way around also results in the same behaviour of the Replace Array Subset icon.

    Normally, a Replace Array Subset icon cannot have two arrays of the same dimension connected to it, it'll show broken wires.

    Now, I replaced the Replace Array Subset icon with the Insert Into Array icon, it shows NO broken wires.

    Then, I did Undo (Ctrl+Z), and to my disbelief, it showed NO broken wires.

    Can experts explain me about this, if it is my fault of LV programming, I mean Undoing, or LV's odd behaviour ?

    I'm using LV7.1

    Regards & Thanks,

    Partha.

    Bug report: ID #40LD2E1W was filed.

  17. Custom Probe mystery behavior

    in LabVIEW Bugs

    Posted

    Original Bug Post:

    http://forums.ni.com/ni/board/message?boar...ssage.id=202978

    I recently updated code built in v7.1 to v8.2. In one section, I have a simple wire that contains I16 data array. When I put a probe on the wire, the probe shows the data as it should. When I select a custom probe via 'custom probe,' 'controls,' 'waveform graph.', the waveform graph probe remains grayed and does not show the data. Had no problem with this in v7.1.

    Download File:post-2-1156913422.vi

  18. VI Window titlebar loses focus

    in LabVIEW Bugs

    Posted

    This is not a show stopper but I noticed it.

    1. Go to the diagram.
    2. Click the coloring tool and select the system custom color picker.
    3. pick a color.
    4. go back to the diagram and color it.
    5. Notice that the VI titlebar does NOT have the focus.
    6. Switch to the select tool with the spacebar.
    7. Select some code and drag it around.
    8. Notice that the VI titlebar STILL does NOT have the focus.
    9. Grab the titlebar and move the window around.
    10. Eventually the focus will come back.

    <OBJECT CLASSID="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" WIDTH="881" HEIGHT="555" CODEBASE="http://active.macromedia.com/flash5/cabs/swflash.cab#version=5,0,0,0">

    <PARAM NAME=movie VALUE="temp.swf"><PARAM NAME=play VALUE=true><PARAM NAME=loop VALUE=false><PARAM NAME=quality VALUE=low>

    <EMBED SRC="http://forums.lavag.org/index.php?act=Attach&type=post&id=3408" WIDTH=881 HEIGHT=555 quality=low loop=false TYPE="application/x-shockwave-flash" PLUGINSPAGE="http://www.macromedia.com/shockwave/download/index.cgi?P1_Prod_Version=ShockwaveFlash">

    </EMBED></OBJECT>

    Download File:post-2-1156911542.swf

  19. File Dialog Express VI

    in Database and File IO

    Posted

    4) I use the daq assistant express VIs before generating the LV code form it (actually this is a pretty handy one)

    PJM

    I agree with this one use case. The DAQ assistant express VI's are usefull because they allow code auto-generation of standard VI's. Very usefull for creating real applications.

  20. File Dialog Express VI

    in Database and File IO

    Posted

    I don't use express VI's and I admit I was very dissapointed to see the file dialog function dissapear only to be replaced by an express VI. Perhaps more annoying than this is the fact that they added a new feature that is only available via a configuration page. I'm talking about the multi-select.

    post-2-1156833806.png?width=400

    So you think that if you break the express vi you will get the primitive with the multi-select as a wired input? Nope. You STILL have a property page. What's the solution? You end up creating your own wrapper that allows the wiring of the selection mode.

    post-2-1156834219.png?width=400

  21. Need way for user input without duplication

    in Application Design & Architecture

    Posted

    YES, that is what I was trying to say... Still learning to communicate...

    Currently I have a "maintenance" section of the front panel with this in it.

    It will only get changed when a box or chassis changes...

    I am guessing I won't have any trouble getting this into my .exe, but have not tried yet.

    I have yet to seriously tackle the process of generating an .exe, with all its' details.

    My few trials, while successful, made it seem pretty non intuitive to me.

    Been focused on getting the program functional first.

    It is essentially a data logging application, catering to a special scenario.

    tnx,

    Fred

    There's a lot going on here that perhaps you haven't considered. When your app is an exe, how will you store the settings so that they can be recalled later? You probably need to save them to a config file and then read them upon startup. Also, you need to decide on a storage mechanism of your variables that is internal to your program. You can use a local variable as stated to read the array but then how do you pass it throughout your app? Wires and shift registers come to mind but you might want to consider functional globals. Here is a link to a post I made way back that has a working example code of what you might want to do:

    http://forums.lavag.org/index.php?s=&s...post&p=8956

    Notice that, once the configuration panel is closed, the configuration is available from anywhere in the program via the functional global. If you look inside the functional global you will see a state that handles saving of the configuration. Here is where you would implement your preffered method of configuration saving so oan executable can read it. This design pattern may seem trivial but it works.

  22. Six LabVIEW 8.0 features no one talks about

    in Development Environment (IDE)

    Posted

    I think the scroll bar was a sleeper becuase it was already possible to do that in prior versions.

    See this thread (on the NI Deve-Exchange)

    http://forums.ni.com/ni/board/message?boar...ssage.id=127096

    starting at post # 17 we start talking about how to customize an array container to use a slider.

    Not as easy as LV 8 but still possible.

    And here is an even earlier posting by Jean-Pierre Drolet talking about the same trick.

    http://forums.ni.com/ni/board/message?boar...uireLogin=False

    Ben

    Also here:

    Replacing the Array Index with a slider, Tutorial

  25. Hate those "PC vs Mac" Ads? Check these out!

    in LAVA Lounge

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