How to train and find suitable weights for this neural network system ?

I am trying to do a 4 zones temperature control using neural network , the idea is to take two inputs for each zone (Set temperature or desired temperature 120° and ActTemp which is the temperature displayed by the sensor) As I followed basic steps for Neural Network Design , I came up with the Model shown in the pictures attached , but Weights are all Ones " (1) " , don't know exaclty which will be the way to find the suitable weights for this system. PS : ANNPID is the basic idea for controlling this system , other suggestions or ideas might be also accepted if results have more accuracy.