Introduction and motivation
Regulation control

Higher level for regulation is control (automatic control). This means that the system is controlled so that one or more physical variables are maintained at the prescribed parameters. An example of such a system may be gas furnace (controlled system), which performs preheating of material for reasons of a surface treatment (e.g., tempering). Material supplied inside the oven must be heated to a specified temperature and the temperature of the furnace, the regulatory circuits (control and regulation) to maintain a certain period of time (set point). This means that the temperature must be measured (measuring member) and its size is controlled by control valve (actuator) supply of fuel gas. Schematic representation of the process is shown in Figure 1.3.

The system is controlled by one or more of the parameters measured. These may be any physical quantity: temperature, pressure, speed, power, voltage, etc. Measuring unit processes the measured value to the appropriate signal and passes it to the controller. Since this is a transfer of information from the system, this branch is called feedback. Also entering into the controller set point (value). It is the size of the regulated parameter. The difference between value and reference signals feedback control deviation occurs. Control deviation signal enters the control block, the size of which creates the appropriate control input to the actuator. Their activities affect the actuator system and its parameters.

Fig. 1.3: Control regulation scheme

The above example can be applied to the schema. The technological process is needed certain temperature - Set point value. In the area of gas furnaces is measured temperature, which is lower than the set point. The controller evaluates the difference between the desired and the measured temperature and creates the appropriate error value. The control enters a block, it is interpreted so that it is necessary to increase the gas supply to the furnace. Size control deviation corresponds to the position of the actuator - the gas control valve. The valve release more gas into the furnace and burning to be released greater amounts of energy and thus a rise in temperature. The entire control process is repeated until the endpoint reaches the preset value.