Plot multiple test runs data points on the same chart

[marlin12]

Hello, 

I am very new to Labview. 

I would like to know how if I can plot continue test data (AI voltage and time) into a chart on a multiple test runs.  For example the program would run for 300 seconds represent 300 plotting points on the chart each time test run.

I would like to be able to plot the second test run data points on the same chart (the chart would show two sets of data or 3 or 4 and etc…)?

Please help.

Thank you very much.

[altenbach]

A waveform graph would be much easier. Accumulate the various runs in a 2d array in a shift register.

[altenbach]

A waveform graph would be much easier. Accumulate the various runs in a 2d array in a shift register.

[marlin12]

Thank you very much for the quick respond.

I'll try your idea and let you know.

[thentangler]

But if you use a waveform graph, your X-Axis will be only time. you wont be able to change it. If you want to plot it wrt to another scale, say voltage, you have to use the XY graph.

Am I correct?

[altenbach]

The x-axis of a waveform graph is linked to the array index of the elements you are graphing. You can call it anything you want (e.g. "not time").

The array index it is always linear, starting with zero and there cannot be any gaps.: 0, 1, 2, 3, 4, ....)

You only need an xy graph is if the points are not spaced equally in x.

You can change the linear mapping between array index and actual x value by specifying the x0 and dx of the axis.

[thentangler]

How do I do that?

Suppose I want to specify Voltage from -1 to 1V in steps of 0.1V. And plot it with respect to current values that I am obtaining?

[altenbach]

You appended to a 2 year old thread with a new question and your questions are very vague. You probably should have started a new thread instead.

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thentangler wrote:

Suppose I want to specify Voltage from -1 to 1V in steps of 0.1V.

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Then set x0 to -1 and dx to 0.1 and name the axis "voltage".

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@thentangler wrote:

And plot it with respect to current values that I am obtaining?

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How are you "obtaining" the current value? There are million ways to do that. Please show us some code!

[thentangler]

Im Sorry, Im new to labview, and I was used to Matlab where you always specify the X and Y arrays in the plot function.

Im getting my current values from a Kiethley sourcemeter.

But I guess what im asking is that if I have a 2D array (i.e  n x 2 matrix)

How can I specify the first column of the array to be the X axis and the 2nd column to be the y axis using waveform graph?

[altenbach]

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thentangler wrote:

But I guess what im asking is that if I have a 2D array (i.e  n x 2 matrix)

How can I specify the first column of the array to be the X axis and the 2nd column to be the y axis using waveform graph?

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If the first column is equally spaced, you can extract x0 and dx from the first two elements. Use index array to get the second colimn as a 1D array and wire it to the graph. You can also bundle it into a waveform cluster (x0, dx, [Y]).

If the first column is NOT spaced regularly, get the first and second column uisng index array, bult them into a complex 1D array, and wire to an xy graph.

What is your LabVIEW version? Can you attach some data?