# Pneumatic Valve
The pneumatic valve is a bidirectional valve controlled via a pressure input.
The pneumatic valve has 3 connections: input, output, and control.
The "input" side will be the input/output connection with the highest pressure, and can switch sides, making the valve bidirectional.
The valve will [color=green]open[/color] when the pressure on the output side is lower than the pressure on the control side by [color=orange][protodata="PressureControlledValve" comp="PressureControlledValve" member="Threshold"/] kPa[/color].
The valve will [color=red]close[/color] when the pressure of the output side reaches the pressure of the control side within [color=orange][protodata="PressureControlledValve" comp="PressureControlledValve" member="Threshold"/] kPa[/color].
For example, a pneumatic valve with a control pressure of 500 kPa will open when the output pressure is 500 kPa - [color=orange][protodata="PressureControlledValve" comp="PressureControlledValve" member="Threshold"/] kPa[/color] or lower, and it will close when the output pressure is 500 kPa - [color=orange][protodata="PressureControlledValve" comp="PressureControlledValve" member="Threshold"/] kPa[/color] or higher.
The valve's control pressure is determined by a pipenet connection, and as such can be adjusted on the fly by a [textlink="pump" link="Pumps"] or another source of pressure control.
## Differences to Pumps
The pneumatic valve is different from a [textlink="pump" link="Pumps"] which moves gas via work.
The pneumatic valve is a passive device that moves gas based on the higher pressure of the input gas, and as such it can sometimes fill volumes faster than a [textlink="pump" link="Pumps"] can.
For example, a pneumatic valve with a control pressure of 500 kPa will fill a volume faster than a pressure [textlink="pump" link="Pumps"] set to 500 kPa.
However, the [textlink="pump" link="Pumps"] will be able to maintain the pressure in the volume more accurately.
The pneumatic valve can be used in a variety of applications, for example:
- To automatically vent gasses in a burn chamber based on control input
- The filling of a volume quickly, based on a customizable control pressure