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Analyzing a waveform for a complete newbie

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BobEdge

Electrical
May 15, 2012
2
Hi,

I am very new to labview, and for some reason I canot use the NI forums, it just goes to a blank page.

I have set up daq assistant to measure n samples when I give my daq a trigger signal. I am measuring voltage, & current of a short duration weld, very much like a spot weld. I have fed the data into a waveform graph, and can see my two traces.

The trouble I have is how do I now use that data to do some calculations & try to spot a bad weld. I know what I need to look for, current out of range, short circuits in the arc voltage, but how do I get at the data. It looks great on the waveform graph, but I cant figure out how to get to the data, and do anything with it.

Any advice greatly appreciated.
Bob.
 
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DAQ Assistants, yuck, akin to Express vi's.
This is the first time I have ever used a DAQ Assistant.

Anyways, they create Dynamic Data types, represented by the blue wire bundle.

You have already graphed them, so, right click on the blue bundle going to your graph. On the popup menu select String Manipulation Palette followed by From DDT. This will convert your 2 channels of data into a 2D array if you choose 2D are of Scalar- Columns are channels.

Once you have your data in the array you can then manipulate them the way you like.

-AK2DM

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"It's the questions that drive us"
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Thank you for that info.
Still struggling to get my head around how to do things that would be simple with a traditional programming language, but at least I have a starting point now.

Regards
Bob.
 
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