Labview diagram creation API - labview

I need to drive a testbench with labview.
The test scenarios are written in a languages that can be automaticaly translated into labview diagrams.
Is this an API that allow to create "labview diagrams" from another software ? or with labview itself ?

I agree that LabVIEW scripting is one approach, but let me throw out another option.
If you are planning to do a one time migration from your test code to LabVIEW than scripting is great, but if you plan to regularly update your test code (because it's easier to use the "test" language than LabVIEW) than it could become quite painful to constantly perform the migration every time your test code has changed.
I've had great success with simply putting my state machine inside of a for loop and then reading in "commands" from a text file that was generated using my "test" language (see pic).
For example, to do an IV sweep my text file might say something like:
SourceV, 5
ReadI
Wait, 1
SourceV, 6
ReadI
This image is greatly simplified - I'm not using a state machine and I don't show how to use "parameters," but I can provide a more comprehensive example if needed. Again, I've had great success doing this with around 30 "commands" controlling multiple instruments and then I generated the text input using VBA or Python.

It's called LabVIEW scripting. You will need to enable an option in the VI Server page in the options dialog to see the relevant features.
A few things to note:
Scripting isn't complicated, but you do need to be aware of how LV code is built.
While scripting is public, it was initially created as an internal tool. There are still corners of it which are incomplete.
Scripting code can be tedious. If you can get away with it, try creating templates of code.
NI has something called CodeGen, which I believe are a series of functions which make some scripting easier, although I never really looked into it.

Related

Show me your ID(E)!

I often work on very small pieces of code, on the order of max 100 lines, especially in scenarios when I learn something new and just play with the code, or when I debug.
Because I frequently change code and want to see how that changes the contents of my variables and output, it is tedious to either
1) hit the debug button, wait for the debugger to start (in my case I use PyCharm as an IDE) and then inspect the output
or
2) insert some prints for the variables that I want to observe and compile the code (slightly faster than starting the debugger).
To eliminate this time consuming workflow, where I constantly hit the compile or debug button every few seconds, is there an IDE where I can set a watch to a few variables and then each time I change in my source code a single character (or, alternatively, every half a second) the IDE automatically compiles everything and I will see then new values of my variables?
(Of course while I intermediatelychange the code the compilation will give errors, but that is ok. This feature would be a big time saver. Maybe PyCharm has it already implemented? If not, ideally I would hope for a language agnostic IDE, similar to PyCharm, where variants for Java etc. also exist. If not, since I code in Python, a Python IDE would also be great.)
This might not be exactly what you are looking for but PyCharm (and IntelliJ and probably others) can run tests automatically when code changes.
In the PyCharm Run toolbar look for "Toggle auto-test" button.
For example in PyCharm you can create test cases that just runs the code you're interested in and prints the variables you need.
Then create a run configuration that runs only those tests and set it to run automatically.
For more details see PyCharm documentation on rerunning tests.
The Scala plugin for IntelliJ has exactly what you need in the form of "worksheets," where every expression is automatically recompiled when its value or the value of anything it references is changed.
Since (based on your usage of PyCharm), I assume you're using Python primarily, I think Jupyter notebook is your best bet. Jupyter is language agnostic but began as specific to python (it was called IPython notebook for this reason).
I have not tried it, but this guide purports to show to get Jupyter to work with PyCharm
EDIT: Here is another possibility called vim worksheet; I haven't tried it, but it purports to do the same thing as Scala worksheets, but in vim, and for a number of languages, including Python.
The python Spyder IDE (comes with Anaconda) has this feature. When you hit run, you can see all of the variables at the top right of the screen and you can click on them to see their values (this is very helpful with Numpy Arrays too!).
If your interest is in the actual workflow improvement:
I used to program like you, looking at what my variables changed to, and design or debug my code based on such modifications, however is way to inefficient and costly to set what variables to watch over and over again and besides when if it bugs, you have to go all over again for the debugging process.
I changed my design process to better my workflow and adopted Test Driven Development (TDD), with it you can look at tools for you specific implementations or IDEs but the principles and workflow stay with you, with it you stop looking on how the variables changed and instead focus on what the functions should do, meaning faster iteration (with real time tools for testing), easier debugging and far more better, safe refactoring.
My favorite tool for it is Cucumber, and agnostic tool (for IDE or programming language) which help you test your code scenarios and at the same time documenting your features.
Hope it helps, i know its a very opinionated answer but it's an honest advices for improvement in ones workflow.
You should try Thonny. It is developed by Institute of Computer Science of University of Tartu.
The 4 features which might be of help to you are below (verbatim from the website):
No-hassle variables.
Once you're done with hello-worlds, select View → Variables and see how your programs and shell commands affect Python variables.
Simple debugger.
Just press Ctrl+F5 instead of F5 and you can run your programs step-by-step, no breakpoints needed. Press F6 for a big step and F7 for a small step. Steps follow program structure, not just code lines.
Stepping through statements
Step through expression evaluation. If you use small steps, then you can even see how Python evaluates your expressions. You can think of this light-blue box as a piece of paper where Python replaces subexpressions with their values, piece-by-piece.
Visualization of expression evaluation
Faithful representation of function calls.
Stepping into a function call opens a new window with separate local variables table and code pointer. Good understanding of how function calls work is especially important for understanding recursion.

Can FsXaml be used in an F# interpreted script?

I just converted one of the FsXaml demo programs to an interpreted F# script so I could experiment with it and learn. It wouldn't run, and the interpreter gave me the following error message:
System.NotSupportedException: The invoked member is not supported in a
dynamic assembly.
at System.Reflection.Emit.InternalAssemblyBuilder.GetManifestResourceStream(String
name)
at FsXaml.InjectXaml.from(String file, Object root)
at
FsXaml.App.InitializeComponent() at FsXaml.App..ctor()
at
FSI_0002.main[a](a argv)
in C:\Users\bobmc\OneDrive\FSharp\Learning\WPFExamples\FsXaml\demos\WpfSimpleMvvmApplication\WPFApp.fsx:line 104
at .$FSI_0002.main#() in
C:\Users\bobmc\OneDrive\FSharp\Learning\WPFExamples\FsXaml\demos\WpfSimpleMvvmApplication\WPFApp.fsx:line
109
Can I use the F# interpreter with FsXaml? Thanks to all for your help.
Unfortunately, WPF and scripts don't play well together.
The exception occurs within the WPF runtime itself - FsXaml.InjectXaml is using a XamlObjectWriter to populate the type with the contents from the XAML file. This type doesn't work if you're using a dynamic assembly (like FSI), which unfortunately means that FsXaml will likely never be able to work from FSI.
That being said, even if there was a way around this, it'd be of very limited use. WPF also has restrictions that make it not play well with a scripting scenario, such as the "only one application can ever be created within a given AppDomain" restriction. That one makes it so closing the "main" (first) window makes it so you can never open another one. As such, I haven't prioritized trying to make this work in FSI.
I'd be happy to accept contributions if somebody has an idea of how to make FsXaml play more nicely within the context of FSI, but at this point, I don't see a good solution for that usage scenario.
Edit: FsXaml 3.1.6 now includes functionality to make this a lot easier. It works well, provided you don't close the main window, or you use dialogs. There is a demo application/script illustrating this.

How to find the size of a reg in verilog?

I was wondering if there were a way to compute the size of a reg in Verilog. I researched it quite a bit, and found $size(a), but it's only in SystemVerilog, and it won't work in my verilog program.
Does anyone know an alternative for this??
I also wanted to ask as a side note; I'm having some trouble with my test bench in the sense that when I update a value in the file, that change is not taken in consideration when I simulate. I've been told I might have been using an old test bench but the one I am continuously simulating is the only one available in this project.
EDIT:
To give you an idea of what's the problem: in my code there is a "start" signal and when it is set to 1, the operation starts. Otherwise, it stays idle. I began writing the test bench with start=0, tested it and simulated it, then edited the test bench by setting start to 1. But when I simulate it, the start signal remains 0 in the waveform. I tried to check whether I was using another test bench, but it is the only test bench I am using in this project.
Given that I was on a deadline, I worked on the code so that it would adapt to the "frozen" test bench. I am getting now all the results I want, but I wanted to test some other features of my code, so I created a new project and copy pasted the code in new files (including the same test bench). But when I ran a simulation, the waveform displayed wrong results (even though I was using the exact same code in all modules and test bench). Any idea why?
Any help would be appreciated :)
There is a standardised way to do this, but it requires you to use the VPI, which I don't think you get on Modelsim's student edition. In short, you have to write C code, and dynamically link it to the simulator. In the C code, you can get object properties using routines such as vpi_get. Useful properites might be vpiSize, which is what you want, vpiLeftRange, vpiRightRange, and so on.
Having said all that, Verilog is essentially a static language, and objects have to be declared with a static width using constant expressions. Having a run-time method to determine an object's size is therefore of pretty limited value (since you should already know it), and may not solve whatever problem you actually have. Your question would make more sense for VHDL (and SystemVerilog?), which are much more dynamic.
Note on Icarus: the developers have pushed lots of SystemVerilog stuff back into the main language. If you take advantge of this you may find that your code is not portable.
Second part of your question: you need to be specific on what your problem actually is.

A GUI frontend for a confusing command-line interface?

Windows XP
The small company I work for just started using this command-line software and it's rather confusing and tedious. I was wondering if it would be feasible to make a GUI frontend and how I would start going about it.
If possible, I would like to have it get data to fill in dropdown boxes and such, but at the very least I'd like to be able to hit a button and perform whatever task. I have never done anything like this before so any help at all would be appreciated.
Thanks
There are two options here:
If the command line exe calls a dll or assemlbly to do the work, then you can work on a front end for the DLL based on the methods that it exposes (ie you can cut out the command line front end completely.
Alternatively you need to wrap the process that the command line runs in and catch its output, and pass it input as appropriate. There's a guide on how to write such a wrapper here: http://support.microsoft.com/kb/305994 (This one is based on writing the wrapper in c#).
One comment though - while it would be possible to do this in VB.Net using the illustrated techniques, doing it in VB6 would be much harder, or even impossible.

How to encourage positive developer behavior with an IDE?

The goal of IDEs is increase productivity. They do a great job at that. Refactoring, navigation, inline documentation, auto completion help increase productivity immensely.
But: Every tool is a weapon. The very same IDE helps to produce chunk code. Some IDE features are an invitation to produce bad code: code generation, code formatting tools, refactoring tools.
IDE overuse tends to isolate developers from the necessary details. It is a good thing that you can start working but at some point in your career you have to be able to figure out how to start a process. You can ignore this detail for some time, in the end they are important to write a working product (vs. bolted together stuff that works 90% of the time).
How do you encourage positive behavior of other developers working with an IDE? This is a question as old as copy and paste.
To get the right impression: developers have to have the maximum freedom to mobilize their maximum creativity and motivation. They may use IDEs and all the related tools as they see fit. Nobody should impose draconian measures on them. I don't want to demotivate and force someone to do something. Good behavior has to be encouraged. It has to itch little a bit if you do the wrong thing. In the same line as the SO "accept rate" metric (and reputation). You can ignore it but life is better if you follow the rules.
(The solution should work in a given setting. You can ignore reviews, changing the staffing or more education as potential solutions.)
Train your IDE, instead of being trained by it.
Set up code formatting the way you (or your team) wants it. Heck, even disable it in cases where it makes sense. I've never seen an IDE align something like this with a sensible combination of tabs and spaces (where \t is obviously the tab character):
{
\tcout << "Hello "
\t << (some + long + expression +
\t to_produce_the_word(world))
\t << endl;
}
In languages like Java, you cannot avoid boilerplate. The best option you have is to check generated code, ensuring that it is the same as what you'd have written by hand. Modify it as necessary. Configure your IDE to generate the exact code that you need, if possible. Eclipse is pretty good at this.
Know what's going on under the hood.
Know that your IDE is actually invoking the compiler. Have some insight into the flags that it passes. Be able to invoke the compiler from the command line.
Know about the runtime system. Be aware of the flags that are used or needed to launch your program. Be able to launch the program from a command line.
I think before anyone uses a RAD tool of any type they should be able to write the application from scratch (scratch being wiring together the framework components) in notepad potentially on a computer that is 10 years older than current technology :P. Not knowing the ins and outs of a paradigm/framework leads to bad code from novice developers who only learn things at a mile high view of the platforms they develop for. Perhaps they should do this in a few technologies -- i.e., GTK programming is completely different to MVC which is then also different to SWING and .NET.
I think the end result should be a developer that thinks of the finer details of a problem before they jump to thinking of how they will write an interface to it in a specific RAD environment.
its an open ended question, but...
We have a Eclipse format file that everyone shares, so that we all format the code in the same manor. (Except the one lone InteliJ guy we have).
Everyone shares a dictionary file. It helps to remove all the red lines from the code. Making it look cleaner and more readable.
I run EMMA over the code to find out who isn't testing their code, and then moan at them.
The main problems we face is that most of the team don't know all the features/power of the IDE (eclipse). The didn't know about CTRL + O (twice), or auto code gen. All I can do as a 'hot key wizard' is keep sharing my knowledge with them to help them become more productive.
I look forward to the day when my problem is that they auto gen as much as possible.
Rather than me finding bugs where the wrong value is returned from a getter method due to a typo.
Attempt development (at least occasionally) using only a text editor and launching the compilation, testing, etc. from the command line.
Typing the commands will get tedious very quickly so create scripts or (even better) learn rake, ant, msbuild.
If the IDE does code generation for you and that code generation is really important (such as generating classes from xsd or proxy classes from wsdl), try to find out how to run the code generation from the command line - then hook the code generation into a build (so you'll never be tempted to edit the generated code).
The idea of autoformatting code is great but it usually just turns your code into a mess. If you have less code, minor formatting inconsistencies are just not a big deal.
Adding code quality tools into your build - style checks, class and method sizes, complexity, code duplication, test coverage, etc (complexian, simian, flog, flay, ndepend, ncover, etc.) will discourage IDE generated code.