How to define variable resistance as a function of heat input?

Hi

I am trying to develop a transient thermal model that considers both convective heat transfer and evaporative heat transfer using a variable convective heat transfer block. If the input to the variable heat transfer block is selected based on the temperature of the system (i.e. if T<T_sat - convective heat transfer cofficient is used, else evaporative heat transfer coefficient is used). Here T, is taken from a temperature sensor monitoring the wall temperature of the heat source, whilst T_sat is the saturation temperature of the liquid.

I also need the convective heat transfer coefficient to be a function of the heat input, hence the PS from heat flow rate sensor to the function block.

When this model is simulated, I get an discontinutity error. Is there a better way to do this. Any thoughts would be much appreciated?

Many thanks

[Delika Weragoda]

Managed to solve this issue. Thanks