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Non-linear scaling


odinhg

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Hi!

I have a cDAQ which is reading a voltage value from a massflow sensor. The output voltage is not linear with the massflow, which makes things a little bit more difficult. Here is the voltage/massflow table from the sensors datasheet.

post-16558-125573405296_thumb.png

And by using the "Scaling and mapping" express VI I get the results I want.

post-16558-125573426608_thumb.png

But I've heard that using DDT isn't a good practice, and the express VI contains a lot of things I don't need for this.

So the question is, is there any way to do this without using express VIs? Is the DAQmx custom scales useable for this purpose?

All input is appreciated! Thanks in advance :)

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And by using the "Scaling and mapping" express VI I get the results I want. But I've heard that using DDT isn't a good practice, and the express VI contains a lot of things I don't need for this.

I only use the scaling functions in LabVIEW if I absolutely can't get real world signals in. You can (and should) define DAQ channels/tasks/scales/etc in the LabVIEW project - click on your target in the project window and select "New..." - then all of your DAQ settings can stay with your project (btw: I think this is an excellent feature - thanks NI thumbup1.gif ).

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I only use the scaling functions in LabVIEW if I absolutely can't get real world signals in.  You can (and should) define DAQ channels/tasks/scales/etc in the LabVIEW project - click on your target in the project window and select "New..." - then all of your DAQ settings can stay with your project (btw: I think this is an excellent feature - thanks NI thumbup1.gif  ).

Thanks asbo and crelf!

I think I'll rewrite the DAQ part of my program and use tasks, channels and scales defined in the project. Didn't know about that nice feature :)

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