9.2 Functional Principle

9.2 Functional Principle

Fig. 3: Energy supply of control equipment

The performance of work requires energy. This physical law also applies when a control element is to be positioned against externally acting forces. Self-operated regulators withdraw this energy from the medium to be controlled.

Using the medium pressure or the thermal properties of the medium (see Fig. 3), the sensor unit of the self-operated regulator builds up a pressure which creates the required positioning forces on an actuator diaphragm or a so-called operating element.