Formula Express VI

[KeithAHurley]

I entered a formula with several variables with no problems (all green) but how do I define the variables outside of the Formula Express VI, since it has no inputs to wire up, other than the error in node. I tried using indicators and naming them same as my labels but that doesn't work and I can't find any examples. Thanks for any help someone may provide.

[crossrulz]

You would need to attach your VI for us to debug.  But it is sounding like you didn't name things correctly.

[Frozen · Accepted solution]

I have never use the "express" version before, but looks like you can have only have a single line of computation.

[KeithAHurley]

Thank you. I was able to fix the issue. The problem was that in the Express VI formula box I had: "Kxx= f(x1,x2,x3,...)" just like I have done with a formula node (which I am not using since my data is dynamic data). Anyway, when I replaced that with either "= f(x1,x2,x3,...)" or simply        

"f(x1,x2,x3,...)" then it worked fine and the Express VI icon was then populated with the inputs which were not there before removing the "Kxx" or "Kxx=". However, in all three cases the formula showed up as a valid formula, indicated buy the green box. Kxx was defined as a variable in all cases.

Thanks for you help and prompt response,

Keith

[alexderjuengere]

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@Frozen

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the formula express is a classic use-case of vi scripting!

https://forums.ni.com/t5/LabVIEW/I-can-change-the-formula-in-a-formula-node-programmatically/td-p/24...

https://lavag.org/topic/2327-updating-formula-node-dynamically/