How to use the calculated attributes tab?

Hy!

I have a doubt. How to use the calculated attributes tab?
In my aplication, my suntech send the signal in third input pin. This input pin have of the ADC function. So, how do I insert the equation in calculated attributes tab and where I see the result of the equation?

Thank you very much in advance.

Have you read the documentation? What is not clear specifically?

https://www.traccar.org/computed-attributes/

Yes, I read. I followed the step by step and it doesn't work.

When I select which attribute tath I need, the type of this attribute, is automactically selected to boolean type. But I don't need this type, I need to number type. Another problem I came across is that when I go to designate this calculated attribute to my device, I can't save this function because there is no save option in the tab.

My equation is this:

(io7 != null && !io7.isEmpty()) ? java.lang.Math.round(0.1856 * (
        java.lang.Math.pow(Double.parseDouble(io7), 6)
        - 4.8729 * java.lang.Math.pow(Double.parseDouble(io7), 5)
        + 51.867 * java.lang.Math.pow(Double.parseDouble(io7), 4)
        - 285.27 * java.lang.Math.pow(Double.parseDouble(io7), 3)
        + 853.52 * java.lang.Math.pow(Double.parseDouble(io7), 2)
        - 1305 * Double.parseDouble(io7)
        + 793.79
    ) / 100.0) : null;

I left an image attached so you can see what I'm doing.

Tank you so much.

You cannot change types for our standard attributes. Also your expression is almost definitely invalid.

So, what I need to do?

Not sure because I don't know what you're trying to achieve.

I need to calculate the coolant temperature. In ADC input, I get a voltage value in this input. This input variable is an "io7" from the suntech protocol. So, I need to get this variable ("io7") and calculate the coolant temperature. The function that calculates the temperature is this:

y = 0,1856*pow(x; 6) - 4,8729*pow(x; 5) + 51,867*pow(x; 4) - 285,27*pow(x; 3) + 853,52*pow(x; 2) - 1305*pow(x) + 793,79.

How I inseart this function in calculated attribute tab?

It seems like you're confused about what the attribute value is for. It's the resulting attribute, as outlined in our documentation.