How does a pneumatic valve work? What is a two-position three-way connection?

What is the working principle of pneumatic valve? What is a two-position three-way connection?

Working principle of two-position three-way solenoid valve: One in, two out: (ZC2/31) When the solenoid valve coil is energized, the first way of the outlet medium end (2) is opened, and the second way (3) is closed;when the solenoid When the valve coil is powered off, the first channel (2) at the media outlet is closed, and the second channel (3) is opened;Two in and one out: (ZC2/32) When the solenoid valve coil is powered on, the first channel (2) at the media outlet is opened ) is opened, and the second circuit (3) is closed;when the solenoid valve coil is powered off, the first circuit (2) at the medium inlet end is closed, and the second circuit (3) is opened;(there must be a one-way valve in front of the two inlet ends of the inner valve. Valve) One in and one out: Normally closed (ZC2/3) --- When the solenoid valve coil is powered on, interface 2 leads to interface 1, and interface 3 is closed;when the solenoid valve coil is powered off, interface 2 is closed, and interface 1 Leads to port 3;Normally open type (ZC2/3K) When the solenoid valve coil is powered off, port 3 leads to port 1, and port 2 is closed;when the solenoid valve coil is powered on, port 3 is closed, and port 1 leads to port 2;