Comparison Palatte Equal? Not working

[N8D11]

I have an Equal Comparison as a condition for a while loop. I probed the leads and they are equal however the output is false and the while loop continues to execute. I tried to typecast one wire to the other incase that was a problem(one being a numeric and the other a signed numeric) still not working. Please help?

[Dennis_Knutson · Accepted solution]

The equal function will work as long as you don't do some silly thing like comparing floating point numbers. If you are, you should do a search for this extremely well discussed subject.

[Jshu23]

Do you have any screenshots or the VI that you can attach?

I have found the equal function to be very specific and even something like an extra space would cause it to not be equal (at least for strings).  Make sure you are sure of what you are comparing.  Is there a different way you could check for comparison?

[smercurio_fc]

Is there another nickel in my retirement fund?

[MadhuriWare]

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@N8D11 wrote:

I have an Equal Comparison as a condition for a while loop. I probed the leads and they are equal however the output is false and the while loop continues to execute. I tried to typecast one wire to the other incase that was a problem(one being a numeric and the other a signed numeric) still not working. Please help?

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I m facing a similar problem using comparison palette Greater than equal to and Equal to. Two same values when compared, the output is false. Please find the example vi attached and help!

[jcarmody]

Precision...

[crossrulz]

There is no such thing as "Equals" when dealing with floating point numbers.  The best you can do is an "approximately equal" by subtracting the two values and making sure the difference is less than whatever precision you want.

[QFang]

'subtracting the two values' --> don't forget to get the absolute of the difference before you compare to your tolerance limit... 😉

[MadhuriWare]

Thank You for your help. The precision and taking its absolute value solved my problem. 🙂 🙂

[Hooovahh]

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@QFang wrote:

'subtracting the two values' --> don't forget to get the absolute of the difference before you compare to your tolerance limit... 😉

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Yup here is a made VI that is pretty much this.

https://lavag.org/files/file/259-floating-point-almost-equal/