Pneumatic solenoid valve, also known as directional control valve, is a necessary configuration for a two-position valve that only needs to open and close. The solenoid valve controls the opening /closing of the pneumatic valve through excitation / demagnetization. Solenoid valves are often used to open and close valves, and control the opening and closing of the gas source and gas circuit through voltage signals to control the opening and closing of the valves. Definition: The valve that moves the spool with an electromagnet is generally controlled by a pneumatic acuator. The movement process realizes the opening and closing of the valve.