Hello,
I want to make a temperature controller that has the following logic:
There are several stages set at 40, 50, 60, 70, 80, degrees centigrade. Will regulate the temperature by fueling chamber.
I want to set as 40 degrees be maintained by modifying raged fuel supply when they reach 40 to increase the time during which a fuel.
When the temperature drops below 40 to reduce the time between two passes also true for other values ​​The temperature which is selected individual buttons.
How to do this?

Sorry for my bed english