Creating a heating curve

[Lemmuh]

Hello everybody, 

I am totally new to this business and hope someone can help me.

I want to regulate a heat pump depending on the outside temperature. 
Therefore I want to create a heating curve in the Block editor. 

My Input is the outside temperature. If the outside temperature (X) is for example 5 degrees I want the particular Y-value for this as an output (Deputy signal). 

In the FB editor I can find straight curve functions with 2 points at advanced math functions. Is there also a way to create a bent curve? 

Hope somebody can help me 

[admin]

It will be easier to write a short script for this. What kind of curve do you want? Do you have a math formula for that?