Electromagnetic valve is an industrial equipment controlled by electromagnetic force. It is an automatic basic component to control fluid. It belongs to actuator and is not limited to hydraulic and pneumatic. It is used in industrial control system to adjust the direction, flow rate, speed and other parameters of medium. Solenoid valves can cooperate with different circuits to achieve the desired control, and the control accuracy and flexibility can be guaranteed. There are many kinds of solenoid valves. Different solenoid valves play different roles in different positions of the control system. The most commonly used are unidirectional valves, safety valves, directional control valves, speed control valves, etc.