What is a valve positioner?

The valve positioner (also known as the pneumatic valve positioner) is the main accessory of the regulating valve. It is usually used with the pneumatic regulating valve. It accepts the output signal of the regulator and then controls the pneumatic regulating valve with its output signal. After the action, the displacement of the valve stem is fed back to the valve positioner through the mechanical device, and the valve position condition is transmitted to the upper system through the electrical signal.