LabVIEW
Im in trouble and I have a problem and error. Please HELP ME!!
Add "cmd /c " before your command. Go read the help for the System Exec VI for slightly more details.
Dear AnnihilationSpectrummm,
There was a famous TV/Radio Correspondent, Daniel Schorr, whom we always called "Cousin Daniel", even though he spelled his last name with an "extra r" (as you have done) ...
The "secret" to writing good LabVIEW (C, C++, Python, Matlab, Java, etc.) code has been known for a long time -- Write the Documentation First. This doesn't necessarily mean "write 5 pages that describe every step", but think about what data you have, what you want to do with it, what parameters you need to use, what intermediate steps you need to see, and what output you expect.
I have a colleague whose code resembles yours (and he's been doing LabVIEW probably longer than I), and the first thing I say when he asks for help is "What are you trying to do?". He then proceeds to tell me how he is manipulating the data, but I interrupt and say "Not How, but What?". Notice the paragraph above says "What", not "How".
I don't know (and can't be confident I'll be able to figure out from your code, it is so terse) what you are trying to do. I know you start with a 1D array of Dbls ("What" do they represent? I'm assuming data taken at equally-spaced time or space intervals). You have 4 parameters -- "what" do they represent?
From the answers to the above two "What" questions, the obvious next question is "Now what?", or "What" transformation do you want to do with the Data and the Parameters? Again, not "how" (i.e. don't say "Use a For Loop to compare ...", but "Use Parameter 1 to split the Array into ..." or "Use Parameters 1 and 2 to ...". As you identify intermediate quantities, name them ("Use Parameter 1 to ... and call this "X").
Identify where you need to create Outputs (for example, you may want to display "X" in a Chart/Graph, or as a parameter). Try to keep (in the initial Documentation) things at a fairly high level, concentrating on What.
When you are done (this might take no more than 2-3 paragraphs, and will certainly lack detail), you are (almost) ready to start coding, or at least thinking about coding. I sat down and in about 5-10 minutes knocked out the following Code:
The Top Level VI shows the Data (Array) and the 4 parameters, grouped in a Cluster (to expedite passing one or more of them to sub-VIs). I showed only the sub-VI for the First Step -- you seem to have 2 or 3 steps in your data processing, each with several sub-Steps. I also show Step 1, where you use Parameter 1 and the Data to get Data Out 1 (which might be all or some of the Input Data), use Parameters 1 and 2 to get Data Out 2, then combine them to get Data Out.
Some things to note.
- Using sub-VIs allows you to abstract the data processing and concentrate on the inputs, outputs, and parameters, "hiding the details" for now.
- As you go into the sub-VIs, more details are revealed, but you might still want some further abstraction.
- Clusters are extremely useful for passing "clusters" of Controls and Indicators around -- keeps things together, and 1 "cable" is much neater than 4 "wires" coming and going everywhere.
- Making Icons for sub-VIs (and TypeDefs) is easy, and allows you "self-document" your LabVIEW Code.
Once you've written your Paper Documentation, see if you can recreate some of these sub-VIs yourself and start populating them with code from your Documentation. Note that at the level I've shown here, the code is still concerned with "What" and is putting off to later the "How", i.e. the LabVIEW Loops, Functions, etc. Remember, at the lowest level of sub-VI where these LabVIEW "details" appear, you want to be doing "one thing" that you can express in 2-3 words on your VI's Icon.
Bob Schor
