Photocoupler

The simplest control law in the control system currently used is the position control. It can be said that the position control can be used by almost all people, such as the switch light in the home, the switch faucet (especially the quick opening, quick closing faucet is more image) It is a process of positional control. The basic idea is the same as the positional control used in the production process. That is, the positional control is to determine the given value of a controlled variable, and then according to the deviation between the actual value and the given value. To determine the working process of the two state selections of the manipulated variable. Simply speaking, the control action of the position control is the alternating of the "open" and "off" states. So it is also called switch control.
Position control is a special case of proportional control. When the proportional control is set to 0 and the proportional gain approaches infinity, it becomes a position controller. The application of the position control system is very wide, such as: pressure control of the air storage tank, temperature control of the incubator and electric heating furnace. It is relatively simple to realize the position control in the production process. Any instrument with upper and lower contact points, such as electric contact pressure gauge, bimetal thermometer with relay contact output, display, recorder, etc., can be used for The position control, combined with some intermediate relays, solenoid valves, electric control valves, etc., can easily form a position control system.
The position control system has a simple structure and low investment, and can be used not only for small and medium-sized enterprises, but also for large enterprises. It is particularly suitable for heating objects with small time delay and large time constant.