LogMAN

In my opinion NI should finally make up their mind to whether objects are inherently serializable or not. The current situation is dissatisfying. There are native functions that clearly break encapsulation: Flatten To XML Variant To Flattened String Flatten To String Then there is one function that doesn't, although many users expect it to (not to mention all the other types it doesn't support): Flatten To JSON Of course users will eventually utilize one to "fix" the other. Whether or not it is a good design choice is a different question.

If you are leaning towards Mercurial you should visit the Mercurial User Group: https://forums.ni.com/t5/Mercurial-User-Group/gh-p/5107

Git I don't hate it - the centralized nature of SVN simply didn't cut it for us. No. It was my decision. Pro - everything is available at all times, even without access to a central server. Con - It has too many features, which makes it hard to learn for novice users. Only when I merge the unmergeable, so anything related to LabVIEW 😞

Please keep in mind that it is only my mental image and not based on any facts from NI. Perhaps both. If we can understand the current behavior it is easier to explain to NI how to change it in a way that works better for us. Here is an example that illustrates the different behavior when using indicators vs. property nodes. The lower breakpoint gets triggered as soon as the loop exits, as one would expect. I have tried synchronous display for the indicator and it doesn't affect the outcome. Not sure what to make of it, other than what I have explained above 🤷‍♂️ I agree, this is what most users expect from it anyway. It would be interesting to hear the reasoning from NI, maybe there is a technical reason it was done this way.

Disclaimer: The following is based on my own observations and experience, so take it with a grain of salt! The user interface does not follow the dataflow model. It runs in its own thread and grabs new data as it becomes available. In fact, the UI update rate is much slower than the actual execution speed of the VI -->VI Execution Speed - LabVIEW 2018 Help - National Instruments (ni.com). The location of the indicator on the block diagram simply defines which data is used, not necessarily when the data is being displayed. In your example, the numeric indicator uses the data from the output terminal of the upper while loop, but it does not have to wait for the wire to pass the data. Instead it grabs the data when it is available. Because of that you can't rely on the front panel to tell dataflow. Execution Highlighting is also misleading because it isn't based on VI execution, but rather on a simulation of the VI executing (it's a approximation at best). LabVIEW simply displays the dot and postpones UI updates until the dot reaches the next node. Not to forget that it also forces sequential execution. It probably isn't even aware of the execution system, which is why it will display the dot on wires that (during normal execution) wouldn't have passed any data yet. Breakpoints, however, are connected to the execution system, which is why they behave "strangely". In dataflow, data only gets passed to the next node when the current node has finished. The same is true for diagrams! The other thing about breakpoints to keep in mind is that "execution pauses after data passes through the wire" --> Managing Breakpoints - LabVIEW 2018 Help - National Instruments (ni.com) In your example, data passes on the wire after the block diagram is finished. Here is another example that illustrates the behavior (breakpoint is hit when the block diagram and all its subdiagrams are finished): Now think about indicators and controls as terminals from one block diagram (node) to another. According to the dataflow model, the left diagram (Block Diagram A) only passes data to the right diagram (Block Diagram B) after it is complete. And since the breakpoint only triggers after data has passed, it needs to wait for the entire block diagram to finish. Whether or not the indicator is connected to any terminal makes no difference. This is also not limited to indicators, but any data that is passed from one diagram to another: Hope that makes sense 😅

A Static VI Reference is simply a constant Generic VI Reference. There is no way to distinguish one from another. It's like asking for the difference between a string constant and a string returned by a function. The Strictly Typed VI Reference @Darren mentioned is easily distinguishable from a Generic VI Reference (notice the orange ⭐ on the Static VI Reference). However, if you wire the type specifier to the Open VI Refnum function, the types are - again - indistinguishable. Perhaps you can use VI Scripting to locate Static VI References on the block diagram?

Sure thing, it's also good to know there is a thread like that - first time I've head of it 😮

The number to string functions all have a width parameter: Number To Decimal String Function - LabVIEW 2018 Help - National Instruments (ni.com) As long as you can guarantee that the number of digits does not exceed the specified width, it will always produce a string with fixed length (padded with spaces).

Thanks, I'll report this to NI

I discovered a potential memory corruption when using Variant To Flattened String and Flattened String To Variant functions on Sets. Here is the test code: In this example, the set is serialized and de-serialized without changing any data. The code runs in a loop to increase the chance of crashing LabVIEW. Here is the type descriptor. If you are familiar with type descriptors, you'll notice that something is off: Here is the translation: 0x0008 - Length of the type descriptor in bytes, including the length word (8 bytes) => OK 0x0073 - Data type (Set) => OK 0x0001 - Number of dimensions (a set is essentially an array with dimension size 1) => OK 0x0004 - Length of the type descriptor for the internal type in bytes, including the length word (4 bytes) => OK ???? - Type descriptor for the internal data type (should be 0x0008 for U64) => What is going on? It turns out that the last two bytes are truncated. The Flatten String To Variant function actually reports error 116, which makes sense because the type descriptor is incomplete, BUT it does not always return an error! In fact, half of the time, no error is reported and LabVIEW eventually crashes (most often after adding a label to the numeric type in the set constant). I believe that this corrupts memory, which eventually crashes LabVIEW. Here is a video that illustrates the behavior: 2021-02-06_13-43-58.mp4 Can somebody please confirm this issue? LV2019SP1f3 (32-bit) Potential Memory Corruption when (de-)serializing Sets.vi

There is a VI in OpenG LabVIEW Data Library that does this for you. I took this as a challenge and added two VIs to my library on GitHub - https://github.com/LogMANOriginal/LabVIEW-Composition Decompose Map extracts variant keys and values of variant maps Decompose Set extracts variant elements of variant sets I have successfully tested these VIs with various different types, but there could still be bugs. Let me know if you find anything. I strongly discourage using these in production!

The library is now available on GitHub (including test cases) https://github.com/LogMANOriginal/LabVIEW-Composition I also discovered this project, which provides some useful methods to work with variant data.

It's a separate library. Object composition was actually much more difficult to figure out than the other way around. I have attached the library for LV2017 (without test suites and package configuration). I'll also put this on GitHub in the near future. Here is an example that overwrites elements in the private data cluster (the outer IPE addresses the class hierarchy). Here is an example that uses JSONtext to extract data from a private data cluster. I was looking into this particular case as a way to transition from clusters to/from objects Both examples are included in the package. Object Decomposition LV2017.zip

This was meant as a proof of concept to see if it can be done and if it's something worth investigating. I should probably mention that this branch has a few bugs that I haven't fixed yet. Certainly not something I would use in production right now but still, I believe there is some value in this - especially for general-purpose libraries like JSONtext. Anyway, I'll back save and upload when I have access to LV. By the way, the details are explained on the Wiki: LabVIEW Object - LabVIEW Wiki I haven't found a better way to do this without adding (or scripting) methods to every class. The only function that currently breaks encapsulation natively is Flatten To XML, which has its own limitations.

If you are interested in object (de-)composition, I have a library that does most of the heavy-lifting (extracting private data and putting it back together), including functions to work with clusters of any size and shape. I can save it back to LV2017 and post here.

Only the name is deleted, commits are left untouched. It is actually possible to restore the branch name if you know the commit hash - https://stackoverflow.com/a/2816728 This can be useful if you deleted a branch before it was merged into master, or if you want to branch off a specific commit in the history that is currently unlabeled. Here is some documentation from Atlassian, generally applicable to GitHub as well: Git Branch | Atlassian Git Tutorial Pull Requests | Atlassian Git Tutorial

The Network Graph mentioned by @JKSH does give you some visualization on GitHub. I personally prefer the visualization in Sourcetree and bash. Here is an example for GitHub - microsoft/vscode: Visual Studio Code The command I use is git log --oneline --graph You can see that branches still exist even after merging. Only the name of the branch, which is just a fast way to address a specific commit hash, is lost (although it is typically mentioned in the commit message). That said, some branches can be merged without an explicit merge commit. This is called "fast-forward" - https://stackoverflow.com/a/29673993. Maintainers on GitHub can decide if they always want a merge commit, or not.

Here is some information about this error: VISA Error -1073807339 (0xbfff0015) Timeout Expired Before Operation Completed - National Instruments (ni.com) There could be many reasons for a timeout error. The error message only indicates that a timeout occurred before a reply was received, which is not very useful. NI IO Trace might give you some additional clues. Maybe put the master in a shift-register on your while loop. Not sure if that makes a difference. This is specified in the Modbus Application Protocol, although implementations vary between 1-based and 0-based. The mapping of addresses is typically resolved internally.

You got it right. "Delete branch" will delete the branch on your fork. It does not affect the clone on your computer. The idea is that every pull request has its own branch, which, once merged into master, can safely be deleted. This can indeed be confusing if you are used to centralized VCSs. In Git, any repository can be remote. When you clone a Git repository, the source becomes remote to the clone. It doesn't matter if the remote is on your computer or on another server. You can even have multiple remote repositories if you wanted to. You'll notice that the clone - by default - only includes the master branch. Git allows you to pull other branches if you want, but that is not mandatory. Likewise, you can have as many branches of your own without having to push them to the remote (sometimes you can't because they are read-only). On GitHub, when you fork a project, the original project becomes remote to your fork (you could even fork a fork if you wanted to...). When you clone the fork, the fork becomes remote to your clone. When you add a branch, you can push it to your fork (because you have write-access). Then you can go to GitHub and open a pull request to ask the maintainer(s) of the original project to merge your changes (because you don't have write-access). Once merged, you can delete the branch from your fork, because the changes are now part of master in the original project (there is no reason to keep it). Notice that the master branch on your fork is now behind master of the original project (because your branch got merged). Notice also that this doesn't affect your local clone (you have to delete the branch manually). You can now update your fork on GitHub, pull from your fork, and finally delete the local branch (Git will warn you about deleting branches that have not been merged into master). There is a page which describes the general GitHub workflow: Understanding the GitHub flow · GitHub Guides Hope that helps.

You could run a VI via CLI to turn it on.

For starters, there are a few DWarns: c:\nimble\penguin\labview\components\mgcore\trunk\18.0\source\ThEvent.cpp(216) : DWarn 0xECE53844: DestroyPlatformEvent failed with MgErr 42. e:\builds\penguin\labview\branches\2018\dev\source\typedesc\TDTableCompatibilityHack.cpp(829) : DWarn 0xA0314B81: Accessing invalid index: 700 e:\builds\penguin\labview\branches\2018\dev\source\objmgr\OMLVClasses.cpp(2254) : DWarn 0x7E77990E: OMLVParam::OMLVParam: invalid datatype for "Build IGL" e:\builds\penguin\labview\branches\2018\dev\source\typedesc\TypeManagerObjects.cpp(818) : DWarn 0x43305D39: chgtosrc on null! VI = [VI "LSD_Example VI.vi" (0x396f46b8)] e:\builds\penguin\labview\branches\2018\dev\source\UDClass\OMUDClassMutation.cpp(1837) : DWarn 0xEFBFD9AB: Disposing OMUDClass definition [LinkIdentity "StatusHistory.lvclass" [ Poste de travail] even though 5 inflated data instances still reference it. e:\builds\penguin\labview\branches\2018\dev\source\UDClass\OMUDClassMutation.cpp(1837) : DWarn 0xEFBFD9AB: Disposing OMUDClass definition [LinkIdentity "Delacor_lib_QMH_Message Queue V2.lvclass" [ Poste de travail] even though 1 inflated data instances still reference it. This will almost certainly cause a crash next time we operate on one o Here is some information regarding the differences between DWarns and DAborts: I'd assume that one of the plugin VIs or classes is broken. You can try and clear the compiled object cache to see if that fixes it. Alternatively uninstall each plugin until the issue disappears. (start with LVOOP Assistant, I remember having issues with it in LV2015).

It could be open source and still be maintained by NI, as long as they have a way to generate revenue. There is also great potential in the NXG platform, which - as far as I know - is written in C#. Even if LabVIEW is not of interest to millions of people, keep in mind that most open source projects only receive contributions from a small portion of their users. The Linux kernel is probably not a good comparison, because it is orders of magnitudes more complex than LabVIEW. Nevertheless, Linux "only" received contributions from approx. 16k developers between 2005 and 2017 - 2017 Linux Kernel Report Highlights Developers’ Roles and Accelerating Pace of Change - Linux Foundation. Compare that to relatively young projects as Visual Studio Code (~1400 contributors), or the .NET Platform (~650 contributors). These are projects with millions of users, but (relatively speaking) few contributors. It depends. Companies might be willing to pay developers to fix issues. Enthusiasts might just dive into the code and open a pull-request with their solution. Some items might not be of particular importance to anyone, so they are just forgotten.

Good selection by @Mefistotelis Try to figure out what motivates them (games, machines, information, ...) and help them find the right resources. Try different things, perhaps something sticks. If not, move on to the next. Here are two links that can get you started with python in a few minutes. Take your first steps with Python - Learn | Microsoft Docs Python Getting Started (w3schools.com)

Not sure where you got that. It's a valid approach: Command pattern - LabVIEW Wiki The Actor Framework, for example, takes this idea to the extreme. I'm not a fan of the 0ms timeout case because it adds unnecessary polling. The rest sounds good to me. It is probably best if you build a prototype to see what works best for you.

You use some patterns in the wrong context. The Factory pattern is only a means to create new objects without explicitly referencing them. Here is a very simple example using a Boolean to select from two classes. In this example, Class 1 and Class 2 both are children of Superclass. Depending on the input value, one of them will be returned. The caller doesn't need to know how to create those objects and only sets the input value to True or False. A typical implementation uses a String instead of a Boolean, which allows for many more options and adding more classes later. In any case, the output of a Factory is the most common ancestor of all possible children (Superclass in this example). Dynamic dispatching is not something that magically merges different functions into one. It is only a way to change the behavior of a function at runtime. Perhaps you are familiar with Polymorphic VIs. Dynamic dispatching is actually very similar to polymorphism. The difference is how they are resolved. Polymorphic VIs are resolved at edit time. Dynamic dispatch VIs on the other hand are resolved at runtime. This is why dynamic dispatch VIs must always have the same terminal pattern. This is of course a very simplified explanation. For your particular question, there are two parts to it: Create specific subclasses for each type of power supply - For example, XNET and DAQmx are entirely different technologies, so it makes sense to have separate classes for each. Use the Strategy Pattern to change the behavior of a particular method - For example, your XNET class could use different strategies to do the actual read operation (XY, double, etc.). The Strategy Pattern encapsulates an operation in an object. You need to write one object for every possible strategy and then provide the desired strategy at runtime (i.e. using a Factory). Here is a basic example. In this example, XNET is a subclass of Power Supply, which has a Read Data method that returns an array of double. When XNET is created, the desired read strategy is passed as an argument. The strategy has another dynamic dispatch method to do the actual read operation. The Read Data method then uses the strategy to read the data. DAQmx would work similarly, perhaps with its own set of strategies. I believe that this comes very close to what you have in mind. Don't put events and queues inside the reader class. Instead, have a separate class that uses the reader class to produce events or populate queues (these should be separate classes altogether, one for queues and one for events). I suggest you play around with the different patterns to get used to them before you use them in production. OOP can get confusing very quickly if you are only used to functional programming.