Solenoid valves are electromagnetically controlled industrial equipment. They are the basic automation components used to control fluids. They are actuators and are not limited to hydraulic and pneumatic. It is used to adjust the direction, flow rate, speed and other parameters of the media in the industrial control system. Solenoid valves can be combined 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 a role in different positions of the control system. The most commonly used ones are check valves, safety valves, directional control valves, and speed control valves.