What are the two solenoid valves on the throttle?

Solenoid valve is a kind of control element, which is mainly used to control the cylinder. There are also analytical instruments or other spray guns for direct gas control. Solenoid valves are divided into pneumatic valves and hydraulic valves, and their working principles are the same, but the media are different. The working principle is to open several holes in a valve body, and then use electromagnetic induction to control the movement of the valve rod to control which hole is blocked or which hole is emptied. In order to achieve the purpose of control. You may not understand. To put it bluntly, just like two people blowing a ball, you can direct one or the other to blow. Forget it, there is no score. I don't know what state you are now and what degree of questions you want to ask. The basic principle is this.