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Tim_S

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Everything posted by Tim_S

  1. Sorta. DAQmx is the software interface the same way a print driver (software) is the interface to a printer (hardware).
  2. To add to what smithd said... The biggest difference with LabVIEW versus other languages is that it is a data-driven language, meaning if something has new data at all of the inputs then it executes. LabVIEW is inherently multi-threaded because of this (there is some exceptions to that when dealing with DLLs and the like). So, looking at your code... The while loop has no inputs, so it will start immediately. The "input path" control has no data coming in, so it outputs a value that goes to the 'output path' which will display the value as that's the only input. The event structure will start and wait as it's input is some event to occur. The event structure and input/output path will occur 'simultaneously' as there is no data dependency (output of one to input of another) between the two. Similarly, other VIs you have can continue to run the same way if there is no data dependency.
  3. Well, you don't do what you're describing in the way you're looking to. You could do what you're describing using invoke nodes to get/set control values and run the VI. What problem are you trying to solve?
  4. Not clear on what you're trying to do, but... Open VI reference does not need a type specifier to open a reference. When the type specifier is passed in, then the VI at the VI path must conform to the front panel layout and data types. When the type specifier is not passed in, the To More Specific Class primitive can be used to change.
  5. A while loop iterates once everything in the loop has completed. The event structure has a timeout (little blue box in the upper left corner of the structure) that defaults to -1 which is no timeout. So what is going on is the while loop is entered, the input path control is written to the output path indicator, and the event structure waits for something to happen. And waits. And waits. And waits. The while loop never iterates as the first iteration hasn't completed yet. With the probe, unless you have "Retain Wire Values" selected (icon up in the button bar of the block diagram) then the probe can be misleading. If you don't have it selected, the "not executed" really means not-executed-since-you-created-the-probe. Turning on "Retain Wire Values" before you run a VI changes that to a literal meaning.
  6. rscott9399... You may want to look through an Introduction to LabVIEW on NI's website and LabVIEW Basics at LabVIEW MakerHUB website.
  7. To provide the obligatory quote... " It just so happens that your friend here is only MOSTLY dead. There's a big difference between mostly dead and all dead. Mostly dead is slightly alive. With all dead, well, with all dead there's usually only one thing you can do. Go through his clothes and look for loose change. "
  8. Yes, I am assuming there is one pixel. Never found a way to create an actual borderless cluster with LabVIEW.
  9. I've gotten around this by selecting a region containing the control and then right-clicking on that.
  10. Total Harmonic Distortion (appears to have been renamed Harmonic Distortion Analyzer from when last used it) can be used to find the fundamental frequency.
  11. You could sample at the same sampling rate, or re-sample to the slower rate.
  12. Think I've narrowed down the cause... the uninstaller for VIPM 2017 is not on my hard drive anymore. The error message is misleading as the 'older version of VI Package Manager 2018' is actually version 2017.
  13. Posted this on the JKI VIPM forum a week back but haven't gotten a response yet. I've installed LabVIEW 2018 which also attempted to update VIPM. LabVIEW installed OK, but VIPM failed to install. Been getting the message "The older version of VI Package Manager 2018 f1 cannot be removed. Contact your technical support group." Anyone seen this before? Tried uninstalling VIPM then reinstalling through LabVIEW installer with no luck.
  14. Whenever I have something that an average human is going to edit I use INI files. It's a lot harder to completely mess up and easier to understand for non-software types. Otherwise, I've shifted to JSON.
  15. The only other company I know of that does XCP is Vector. Vector does have a .NET interface for their CANoe/CANAlyzer software, and there is a way to broadcast/receive UDP from their VN boxes. The price tag on Vector hardware and software is pretty hefty (I expect 14k to 25k USD every time I get a quote for a single station). Dearborn Group with their Gryphon boxes may be able to do XCP/CCP. Haven't done anything with them in a decade, so can't relate much more. Once again not cheap. Kvaser is an outfit I've heard about and briefly looked into a couple years back, but not used any of their products.
  16. Google produces: Queued State Machine with User Input Basic LabVIEW Design Patterns - National Instruments Queued State Machine QSM - LabVIEW Design Patterns
  17. Property and invoke nodes can also uncheck 'Remove front panel' when 'Use default save settings' is checked. Ones that reference the front panel certainly do (e.g., front panel->open), but I'm not sure about ones that reference controls.
  18. Tim_S

    NI DAQ alternatives

    What it sounds like you're asking for is where NI has gotten out of (<100 Hz) because there are tons of remote I/O options Rockwell, Siemens, GE, etc., already on the market. All of these use some form of bus (RS232, RS485, PROFIBUS/NET, Ethernet/IP, CAN...). Depending on what you pick you can spend just as much as a cDAQ in time and materials. NI acquired Measurement Computing some years ago. I've never used the hardware, but they do list having LabVIEW drivers. Some devices look to be able to handle industrial logic levels (24V).
  19. I'm not terribly proficient in Python, but wondering if Python is reacting to a termination character.
  20. Which is a big point to why we didn't use TestStand in that there is a cost in learning the system which has to be able to fit in budget and schedule of a project.
  21. I've run in to TestStand twice... The first was a project I got pulled in to at the 11th-and-then-some hour to make some changes. I got a quick intro to implementing LabVIEW code in TestStand and made the changes. I didn't get to do much with it, however the impression I got from people who had been with the project was very negative in how difficult the system was to use to do what was wanted and they intended not to use it again. This was with TestStand version 1 (and I believe LabVIEW 5) from people who (today) would be certified LabVIEW CLD, so take that for what you will. The second time I ran into it was as part of a major revision and re-write of an existing system including sequencer written in LabVIEW. We (two from my company and a local alliance partner) seriously considered using TestStand, but concluded that the amount of work learning TestStand, porting existing code to work with TestStand, build a system around this that did all the other things that were needed, and make it look like a homogeneous system would be more costly that just writing it in LabVIEW (version 8.6 at the time).
  22. Tim_S

    help please!

    You can easily check the work by calculating what the value by hand and then comparing the output of the VIs. If you had done this then you would have answered your question. You do have errors in your code. Things you need to watch for is the data types matter and how the logical shift primitive works. As for style, making code neat and organized is important with any language. LabVIEW is a 'visual' language rather than a text language so what constitutes neat and organized means something a little different; there is a code cleanup feature up in the button bar area that can help with this.
  23. Tim_S

    help please!

    It appears you need help with the math expression. The LabVIEW help topics of "Formula Node" and "Precedence of Operators in Formula Nodes and Expression Nodes" should help. Have you read these?
  24. Tim_S

    help please!

    If you are using a formula node then it's just a matter of setting up the inputs and outputs of the node and typing in the formula. LabVIEW has very good help that installs with it, but there is a little tutorial here. The first formula has one gotcha but the error message tells you what the issue is. The second formula is a little wonky in that it looks like x-squared is being squared. Make sure you read the help on the formula node.
  25. Had some good luck with Acromag modules the couple of times used them. Curious how these particular units work out (or don't) for you.
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