The paddle flow switch tells you that the pressure sensor measures the controlled pressure and converts it into a convenient signal form, such as voltage, current, displacement, rotation angle, etc. The comparison device compares the signal reflecting the magnitude of the pressure with the given pressure value to generate a deviation signal.

The deviation signal acts on the pressure regulating mechanism through the paddle flow switch, and changes the pressure of the measured point according to the direction of eliminating the deviation, and adjusts it to the given desired value. More complex systems often adjust the pressure by changing the speed of the pump or reducing the efficiency of the pump. In a simple paddle flow switch system, a throttle valve is often used to regulate the pressure.
Like other feedback control systems, the paddle flow switch system also has the possibility of self-excited oscillation. If the valve opens or closes too fast corresponding to a certain pressure deviation, self-oscillation may occur.
This oscillation can be eliminated by limiting feedback. The basic theory describing the performance and design of a paddle flow switch system is the same as the basic theory for any other feedback control system (see Classical Control Theory, Modern Control Theory).