Live plot of ratio of two measured quantites

PhysLogger
1

Hello,

How to live plot the ratio of two measured quantities. For example ratio of Voltage input A and Voltage input B, on live plot.

Thanks

2

It is very simple.

  1. At any stage in your session, bring up the workspace extension menu.
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  2. Choose to extend from scratch
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  3. From the menu, Choose Arithmetic > Binary Divider (the icon is missing in my build)

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This will create a new divider quantity and bring up the editor. where you can set a symbol and the quantities that it uses for the binary operation. (If you accidentally close this menu, do NOT create another divider quantity. Just go to the quantities menu and click on the relevant quantity icon.

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  1. Select the numerator and the denominator just like you’d choose any other quantity source in PhysLogger. For your case, for example. if you want to divide channel A on B, Choose the sources like this.

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There are a couple of things you need to keep in mind while using the binary divider.

a. A division of any number, including Zero, by absolute Zero results in, you guessed it wrong, Zero! instead of “Infinity” or “Undefined”. So you should select only those quantities as numerators the values of which cannot be zero or your results aren’t affected by this unorthodox approach. A range quantity can be used to stop a quantity from going outside a specific range.

b. The divider will take SI units of the selected quantites. So, no matter what unit you choose for the voltages, the divider, just like any other standard quantity in PhysLogger, will choose the SI unit i.e. Volt (V).

c. You can obviously use another divider (or other operators in that case) to evaluate in a nested formation to evaluate complex functions.

2 Likes
3

Thank you, nice community