1. Use the box to indicate the working position of the valve, each box represents a working position of the solenoid valve, that is, "position", there are several boxes to indicate how many "positions", such as two-position three-way solenoid valve There are two working positions.
2, the arrow in the box indicates that the oil circuit is on, but the direction of the arrow does not necessarily indicate the actual direction of the liquid flow;
3, the symbol "┻" or "┳" in the box indicates that the path is not accessible;
4. There are several interfaces connected to the outside of the box, which means that they are “passive”;
5. Generally, the oil inlet / air inlet of the valve connected to the system's oil supply or gas circuit is represented by the letter p; the oil return / air outlet of the valve that is in communication with the system oil / air circuit is t (sometimes o) Indicates; and the port / air port where the valve is connected to the actuator is indicated by a, b, etc. Sometimes l is used on the graphic symbol to indicate the leaking oil port;
4. Reversing valves have two or more working positions, one of which is the normal position, that is, the position where the valve core is not subjected to the operating force. The neutral position in the graphic symbol is the normal position of the three-position valve. The two-position valve using spring return is the normal position of the channel in the box close to the spring. When drawing the system diagram, the oil / gas path should generally be connected to the normal position of the directional valve.