-------------------------
 CLOSED LOOP CONTROLLER
-------------------------
This model simulates a closed loop air conditioner.
It is implemented by three threads:
- The "regulator" control software reads the set point (desiredTemp) 
and the feedback (measuredTemp) and computes the command for the 
heater/cooler actuator.
- The "heatercooler" emulates by software the effect of the actual 
device by increasing or decreasing the value of the temperature 
according to the received command.
- The "sensor" introduces a measurement error by adding a random 
to the measured temperature before sending it back to the regulator.

A simulation scenario initializes the desired temperature to 20°C 
and opens a probe on the measured temperature.