Actuators Actuators may sometimes be called effectors. They are the components. That effect the desired change on the environment in which the system has been placed. The output from the sensor in a process becomes the input for a machine called an actuator. These carry out the activity that the conditions require according to the rules under which the controller is operating.
Some examples are solenoids, relays, VDUs, safety buzzers, or motors.
Actuators will be used to convert energy from one form to another. The general design for some actuators is similar e.g. piston, when a linear action is required, and some form of turbine-like device, when a rotary action is required. Control can be maintained by the addition of a servo valve on the input line. If the power transmission is hydraulic, the advantages are that the hoses providing the linkages can be located some distance from the power source, and that the linkages are extremely flexible. Hydraulic or pneumatic systems are efficient when compared with the conversion of power in electrical to mechanical systems, and also have an advantage of the relationship between low amount of pressure in the compressor becomes high pressure in the actuator.