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Input in Sub VI

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Hello people,

I am triyng to create a sub VI to get as an input 2 signals, take the maximum value of then an dive one from each other. 

That's easy following tutorials on youtube but when i soon create the VI and use in another VI, it understand that what suppouse to be an input data (left side of my sub VI) is an output data. 

Here is attached the sub VI and a picture about the erro i get when i try to use in another vi.


Thanks since now,


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Message 1 of 11
Accepted by topic author Arthuruuuuuu
02-09-2019 08:06 AM

Input connectors must be linked to controls and output connectors to indicators. You don't have any controls and the only defined connector is for the output.


(It would probably be simpler to get away from dynamic data here.)

LabVIEW Champion Do more with less code and in less time
Message 2 of 11

Dear mate,

now i am trying to create another sub VI to calculate output power and efficiency from a piezoelectric signal.

I can easily build on but once i try to put a waveform chart to monitore the calculed signal, the data does not goes. 

Here one can see attached the sub vi i am talking about and the new erro i got.

Can you just help me ? Thanks

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Message 3 of 11

Attach the main VI that calls this subVI.


The subVI looks okay.  Well, it needs a block diagram cleanup.  But beyond that, I can't see anything obviously wrong.


So if you aren't getting data on that graph, I guess the problem is in the main VI.

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Message 4 of 11

This is the main VI.

I didnt get yet because numerical indicators about output power inputpower and efficicnecy run all right but the graph indicators dosent.

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Message 5 of 11

You are using a graph instead of a chart. Big difference.

LabVIEW Champion Do more with less code and in less time
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Message 6 of 11

Great !!!! Its working now !

But my initial intention was to use graph to monitore the wave form signal and buffer size. As you can see in firts post of this topic, for each signal i use chart to see signal in time domain and graph to analyse the wave form. 

How can I build my subVI to have an output waveform graph as a result ?


Thanks since now,


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Message 7 of 11

Your subVI operates only on a single scalar. Graphs only display arrays, so operate on that.


(No advanced user here uses dynamic data much. I would highly recommend to use plain data structures.)

LabVIEW Champion Do more with less code and in less time
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Message 8 of 11


But what you mean with plain data structure ? can you help me please ?


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Message 9 of 11

You said i can only use controls for input my subVIs. So how can i build a subVI with a dynamic data coming and a dynamic data output also ?


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Message 10 of 11