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Daq Assist and Graphing

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A very simple problem...

 

Very new to LabView, and I am struggling with wiring up my Daq Assistant in order to graph data from a load cell. I've connected my load cell to the Daq and want to measure force readings over a span of time/when I press stop. When I run my program it only graphs a finite number of readings and then erases the graph to copy new readings on top. I put my graph outside of the while loop so that it would graph one reading at a time as they were read but it's not working. If my wiring isn't what's wrong, I have a feeling that my time settings for the Daq Assist are not right (and I don't know how to set those either.) I don't understand the description/effects of Rate and Samples to Read.

 

Thanks for your help.

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Looked at my code some more. A more concise question would be: How do I get the Daq to continuously record the load cell measurements? Right now it's only measuring over the span of ~.07 seconds and then erases the graph for the next .07 seconds. I have my Daq set to continuous readings but the graph doesn't represent that.

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That is exactly what is supposed to happen. A graph has no buffer so each time you write to it, old data is deleted. You probably want to use a chart. A chart has a buffer that is set with a right click. You will need to set it to a length equal to a time you want to keep at once. There are obviously limits with memory size.
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Solution
Accepted by topic author AFLR

@AFLR wrote:

A very simple problem...

 

Very new to LabView, and I am struggling with wiring up my Daq Assistant in order to graph data from a load cell. I've connected my load cell to the Daq and want to measure force readings over a span of time/when I press stop. When I run my program it only graphs a finite number of readings and then erases the graph to copy new readings on top. I put my graph outside of the while loop so that it would graph one reading at a time as they were read but it's not working. If my wiring isn't what's wrong, I have a feeling that my time settings for the Daq Assist are not right (and I don't know how to set those either.) I don't understand the description/effects of Rate and Samples to Read.

 

Thanks for your help.


Hi AFLR,

 

I think settings are fine, you have set DAQ to read 100 samples at the rate of 100samples/second, so you'll get 100 samples every second.

Now in order to retain the previous data in the Graph (which is not the nature of Graph), you may need to preserve it by writing extra code.

If you already know about:

1. Shift registers and

2. Components of Waveform

You can easily implement this requirement, find the attached VI for your reference.

 

Learning Load Test_Modified.PNG


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Thank you very much for your help.

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