Pneumatic Pressure ControllersA pneumatic controller is a mechanical device designed to measure temperature or pressure and transmit a corrective air signal to the final control element. Pneumatic controllers are used in automatic control systems for flow rate, pressure, temperature, level, and other parameters of industrial processes. Bourdon tubes, bellows, temperature elements, or displacers are used as the sensing elements. The power supply and output of a pneumatic controller is compressed air or natural gas. The input signal to the controller is mechanical movement provided by the sensing element that is being used to sense the process. Sensing elements are sized to provide the optimum control for the application.