Control Loops
A home thermostat is an example of a closed control loop: It constantly assesses the current room temperature and controls a heater and/or air conditioner to increase or decrease the temperature according to user-defined setting(s). A simple (low-cost, cheap) thermostat merely switches the heater or air conditioner either on or off, and temporary overshoot and undershoot of the desired average temperature must be expected. A more expensive thermostat varies the amount of heat or cooling provided by the heater or cooler, depending on the difference between the required temperature (the "setpoint") and the actual temperature. This minimizes over/undershoot. The process is called PID and is implemented using a PID Controller.
Read more about this topic: Temperature Control
Famous quotes containing the words control and/or loops:
“The inability to control our children’s behavior feels the same as not being able to control it in ourselves. And the fact is that primitive behavior in children does unleash primitive behavior in mothers. That’s what frightens mothers most. For young children, even when out of control, do not have the power to destroy their mothers, but mothers who are out of control feel that they may destroy their children.”
—Elaine Heffner (20th century)
“An accurate charting of the American woman’s progress through history might look more like a corkscrew tilted slightly to one side, its loops inching closer to the line of freedom with the passage of time—but like a mathematical curve approaching infinity, never touching its goal. . . . Each time, the spiral turns her back just short of the finish line.”
—Susan Faludi (20th century)