I am reading big TDMS files (~1GB) and I try to minimize memory usage.
I read a signal once and I want to keep it for later usage, so I tried to write it to a DVR in the hope that I have only one instance of the data in memory.
However the task manager tells me that uses 2 times more memory than it should.
I think the problem is that the array is not deallocated although I don't need it after writing it to the DVR.
Is there a solution to make sure I don't have copies of data?
By Ram Prakash
Can anyone please tell what a DVR [ Data value reference ] is ? I want to know at what situation it will be used and what are the advantages we get by using DVR. I am really confused in this topic . If someone has any code in which they have worked with DVRs. kindly share it to me.
By Ryan Vallieu
I have seemingly found an issue with the shipping example code for Nested Malleable VIs. Another user has verified that he saw the same behavior in 2019.
I am working through the examples and the presentation from NIWeek 2019. In running the Lesson 2b code (C:\Program Files (x86)\National Instruments\LabVIEW 2019\examples\Malleable VIs\Nested Malleable VIs) I found the Equals.vi in the class was not being leveraged and the search failed. When I went to my LabVIEW 2018 machine and ran the Lesson 2b.vi the code worked to find the element by correctly leveraging the in-class Equals.vi.
One difference I see is that in the 2018 example the Equal.vi is in the example folder with the code, and in 2019 the Equal.vi has been moved to VI.lib - otherwise the code looks to be the same. The Equals.vi code looks identical, and the calling VIM look identical. I posted on the LabVIEW NI.com forum here:
I am trying to determine what may have broken or changed between the implementation in 2018 and 2019, visually the code looks the same.
I'm running into something I don't really understand. Maybe you can help me here !
I've got a LVLIB that is used as an 'Interface': it exposes public VIs which wrap around public functions of a private class (see code attached) . The class is private because I want to force the users to use the 'interface' functions.
In one of my interface VI, I create a DVR on the private class (Interface_init). The DVR is stored into a typedef (FClass_DVR.ctl) and this typedef is the 'reference' that link all the interface public functions.
In TestCode.vi (which is not part of the lvlib and illustrates the standard code that a user can create to use my driver), I can call my public interface functions and link them without any problem.
But as soon as I create an indicator on that reference (to create a state-machine-context-cluster for example), my TestCode VI breaks !
The error returned is : This VI cannot use the LabVIEW class control because of library access scope. The LabVIEW class is a private library item and can only be accessed from inside the same library or libraries contained in that library.
I understand that the class is private. But the DVR is contained into a public control. Using an In Place structure on that DVR into TestCode would not work, since the class is private. So why is the DVR control problematic at that point ? Creating it do not breaks any access protection...
Am I missing something ?
DVR Private POC.zip
I am programming with LabVIEW for around 2 years and was recently stumbled upon LVOOP.
I am required to write a communication protocol to work with a micro-controller, which later will be also used for ATP and debug purposes.
I want to build the program "correctly" from the beginning so it will be maintainable and flexible to additions and changes.
My natural way of building a program would have been a queued state machine, with several loops, each loop is in charge of a different module (one for GUI obviously), but as I stated in the beginning, I want to use LVOOP.
Does anyone have a LVOOP project I can use as reference? I've searched online and found some nice examples, but they are small and teach you the basic stuff.
For me it's important to see the how to use the project tree wisely, where to place the classes, see the managing loop and to learn as much as possible before I create one of my own.
Thanks in advance,