METHOD AND APPARATUS FOR CONTROLLING A FLUID OPERATED ACTUATOR

摘要

A positioner (102) for controlling a fluid operated actuator (101) including a first fluid chamber (109) and a second fluid chamber (110) is provided. The positioner (102) comprises a first fluid conduit (105) coupled to the first fluid chamber (109). The positioner (102) also comprises a second fluid conduit (106) coupled to the second fluid chamber (110). A differential pressure controller (240) provided in the positioner (102) is adapted to control a fluid supply to the first and second fluid conduits (105, 106) based on a differential pressure between the first and second fluid chamber (109, 110).