Accept control system or the controller command signal (usually 4 ~ 20 ma), through internal electrical switching device, the input source signal into the valve actuator for air pressure, so that the valve open to the corresponding position. In the process of the output pressure of valve, as a result of the existence of the locator feedback pole, detect whether locator action in place, after putting in place the locator will be according to the feedback stable output pressure, which have the effect of positioning.
