Jump to content

smithd

Members
  • Content Count

    763
  • Joined

  • Last visited

  • Days Won

    42

Everything posted by smithd

  1. https://www.ni.com/pdf/manuals/371780r.pdf yay! 🎉 too bad nxg breaks the code
  2. The term you are looking for is a cluster, equivalent to a C struct more or less. You create a type definition like this: https://zone.ni.com/reference/en-XX/help/371361R-01/lvhowto/creating_type_defs/ once you are in the control editor for the type definition, what you want to do is drop down a cluster control. ctrl+f for "clusters" on this document for a video: https://www.ni.com/getting-started/labview-basics/data-structures or in tutorial form: https://www.ni.com/tutorial/7571/en/ Depending on where you're at, you may have access to NI online training, or ot
  3. To go further, the timed loop is the not the right choice, and the RT FIFO has a negative performance impact on this application. The data source (daqmx) is nondeterministic, the data client (tdms) is nondeterministic, so using an RT FIFO as I understand it will result in performing a memory copy on every iteration to copy from the (newly allocated and thus non-deterministic) daqmx buffer to the preallocated RT FIFO buffer. In contrast a normal queue (again as I understand) will simply shuffle around a pointer to the buffer provided by daqmx*. No allocation past the one performed by daqmx
  4. What are you trying to output to? A graph? A daq card? If its in one of the pictures, only 2 came through on my end, the rest show up as blank squares.
  5. Generally RT code doesn't have a UI, and as mentioned you have to use a special add-on to use events with shared variables. The usual equivalent is to use a messaging tool to handle communication and generate events in your RT code. I personally use HTTP and/or websockets since its free and there are many clients out there. I believe there is a tcp handler for drjdp's messenger lib (https://sine.ni.com/nips/cds/view/p/lang/en/nid/213091), actor framework has a networking addon, and for quick and dirty, AMC (https://www.ni.com/example/31091/en/) works. To put it another way, where y
  6. there is hardly support in labview itself In reality this is a pretty easy fix to do on your own branch of the code. Inside here: https://bitbucket.org/drjdpowell/jsontext/src/default/Variant to JSON Text.vi and here: https://bitbucket.org/drjdpowell/jsontext/src/default/JSON text to Variant.vi If you look for every case structure using the type enum, find the case for "extended precision" and then add "Fixed Point" to the same case. Numeric variants automatically coerce so it should work as simple as that. (I suggest extended because of the different variations of fixed p
  7. I re-read your (rscott) post and it occurred to me you might be missing something more fundamental wrt labview applications. I don't claim that this code is good or bad, but it can serve as a reasonable example for this conversation: https://forums.ni.com/t5/Example-Program-Drafts/LabVIEW-Real-Time-Sample-Template-Embedded-UI/ta-p/3511679?profile.language=en Note that there is some UI code, but theres also a deterministic control loop and various monitoring loops.This is typical and in fact kind of on the low side. This is why message oriented frameworks like actor framework or drj
  8. to convert this into c-style: while(1) { pathwire=pathin waitforinput(timeout=forever) pathout=pathwire } you didnt 'hose the rest of the system' but your loop will stop because you told it to wait for input. You generally have many many many loops in a labview program. You can change this loop to a polling style by setting timeout to something besides forever. also note that the order of operations in the loop is not specified. I wrote one possibility.
  9. daqmx is a driver that supports all of NI's standalone daq cards as well as cdaq devices and now the newest generation of crio
  10. This is a good guide to look through: https://www.ni.com/en-us/shop/compactrio/compactrio-developers-guide.html Mark mostly covered it, the way I'd think about it: Default -> run on host Does my code protect human beings -> generally don't use NI products* and don't even touch the application unless you know what you're doing (*exception is maybe the SIL module but even then I'd want an experienced safety person consulting) To move to the compactRIO you want one or both of these to be true: Does my code need to run 24/7 headlessly Does my code need to op
  11. I dont know what an ENI is, but you can add third party slaves with the standard xml files: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P9CqSAK&l=en-US
  12. thats quite the hidden gem🎅 🦄
  13. I'm not bothered by the size of that guy, I'm bothered that everything is serially executing
  14. i think those variant functions should be a tiny meaningless fraction of the overall execution time. Have you profiled it?
  15. In the compiler doc here (https://www.ni.com/tutorial/11472/en/) theres mention of a yieldIfNeeded block which is inserted into loops which allows for coordination with the rest of the runtime. If you just have the one while loop, you are still having to check against the runtime engine if you should keep running or if you need to pause and let other code run. Its not just a simple jump. tl;dr I dont think there is any way to do this with a regular loop. A timed loop may work. The overhead should be minimal compared to any actual code you wish to run in the loop, and if that isn't true la
  16. You're also what?! Make sure your lavag email is not @ni.com and then pm Michael. He can fixit.
  17. Before or after you tell those darn kids to get off your lawn?
  18. 2019 is almost certainly done already. Since its integrating an addon, it could come in SP1, but I'd bet 2020 if it happens.
  19. isn't that...an xcontrol? anywho, voted up
  20. My vague understanding is that labview exes are basically special zip files with an executable header tacked on with the instruction to load the labview runtime. The runtime then takes over and loads the code. This obviously changes with the fast file format, but the general concept is probably about the same. Point being, the exe is still a separate OS process, it just happens to immediately load up a copy of the lvruntime dll which can be shared.
  21. I don't know the exact details, but it looks like you could use a system-wide mutex: https://docs.microsoft.com/en-us/windows/desktop/api/synchapi/nf-synchapi-createmutexa I'm assuming linux has something similar. Or since its long-running, another option would be to do whole thing where you make a "blah.lock" file somewhere, like what git does. But thats clearly iffy.
  22. That much is definite -- processes can't share anything
  23. I don't know for sure (maybe @Rolf Kalbermatter does) but looking at this KB (https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019L5JSAU&l=en-US) indicates that its basically calling win32 LoadLibrary, and the help for that (https://docs.microsoft.com/en-us/windows/desktop/api/libloaderapi/nf-libloaderapi-loadlibrarya) seems to indicate there can only be one (per process):
  24. Coincidentally I just wrote a couple as well. I agree they seem OK for simple things, but the whole question of when and how they wake up makes them less usable. The main reason I want an Xcontrol is that a lot of things are combined controls+indicators. For example I have an indicator with the current value and the setpoint and some other stuff, and a control for the setpoint -- but you can't bind to user events, so you have to pick a proper 'direction' for the control and use a property for the other way and you end up having to marshal data around anyway. I don't hate them as much as I once
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.