ABSTRACT
A control loop is a complete control system where the transducer, controller, and control valve are connected. In such a loop, the transducer sends a signal to the controller, which then determines the appropriate output signal for manipulating a stream responsible for change in the process variable (the variable to be controlled) by actuating a ›nal control element, usually a control valve. An example of a control loop is shown in Figure 5.1.
