Abstract: A field device that includes a primary valve, a main actuator, a bypass line, a secondary valve, and a position controller. The primary valve can be configured to adjust a process fluid flow. The main actuator can be configured to control the primary valve. The main actuator includes a working chamber to be subjected with a process fluid and a return device configured to bias the valve member. The bypass line can be configured to fluidly connect an inlet and an outlet of the primary valve to feed the process fluid to the working chamber. The position controller configured to control a pneumatic actuator to control the secondary valve to change a process fluid pressure in the working chamber. The controlling of the pneumatic actuator can include generating a pneumatic control signal based on a position of the primary valve and supplying the pneumatic control signal to the pneumatic actuator.