PID based temperature controller

hello,i am new to making controllers using matlab. iam trying to make a controller with inputs given by a temperature sensor and the setpoint value (which changes in intervals of time as specified by the user). The controller should match the input from sensor with the setpoint value. My idea is - sensor i/p- a/d-microcontroller- setpoint comparision-d/a-output to heater and display the temperaure value.

the feedback is taken through temperature sensor. Please guide.

Thank you.

Regards, Soumya.