A process valve positioner comprising an electronic unit having an electrical control output, and a pneumatic or hydraulic unit having a prestage (93, PR) and an output stage, the prestage being arranged to convert the electrical control output into a pilot fluid pressure which is sufficient to control the output stage, the output stage comprising a fluid valve assembly (20, 60) for connection to a supply of fluid under pressure for providing a hydraulic or pneumatic actuator with the actuator fluid pressure, the fluid valve assembly comprising: a valve body having a central bore with at least one supply port for receiving the supply of fluid under pressure, at least one actuator port (C1, C2) for providing the actuator fluid pressure to the hydraulic or pneumatic actuator, and at least one exhaust port (EX1, EX2); a stem movable within said central bore in an axial direction by an axial pilot force; a pilot diaphragm and a piston arranged at one end of the stem to provide the axial pilot force according the pilot fluid pressure affecting on the pilot diaphragm in a pilot pressure chamber, a counter diaphragm and a counter piston arranged at an opposite end of the stem to provide an axial counter force according to a counter pressure affecting on the counter diaphragm in a counter pressure chamber, at least one pair of counter-acting metering edges (PR1/PS1, PR2/PS2, PR3/PS3, PR4/PS4) operationally tied together by the stem, each metering edge of each counter-acting pair comprising a mating seat surface (PS1, PS2, PS3, PS4) on the valve body or the stem and a poppet ring (PR1, PSR2, PR3, PR4) supported by a flexible element (SD1, SD2, SD3, SD4) to the valve body or the stem in a manner allowing a relative axial movement of the poppet ring (PR1, PSR2, PR3, PR4) and the supporting valve body or stem also in a closed state of the respective metering edge, wherein each poppet ring (PR1, PSR2, PR3, PR4) is pressure-balanced to compensate fluid pressure forces exerted on the respective poppet ring so as to achieve a very small or zero resultant fluid pressure force affecting on the respective metering edge, a restricted flow path from the supply pressure inlet of the valve assembly to the prestage which controls the pilot pressure in the pilot pressure chamber and thereby the axial pilot force, and a further restricted flow path) from the supply pressure inlet of the valve assembly to the counter pressure chamber. a valve body having a central bore with at least one supply port for receiving the supply of fluid under pressure, at least one actuator port (C1, C2) for providing the actuator fluid pressure to the hydraulic or pneumatic actuator, and at least one exhaust port (EX1, EX2); a stem movable within said central bore in an axial direction by an axial pilot force; a pilot diaphragm and a piston arranged at one end of the stem to provide the axial pilot force according the pilot fluid pressure affecting on the pilot diaphragm in a pilot pressure chamber, a counter diaphragm and a counter piston arranged at an opposite end of the stem to provide an axial counter force according to a counter pressure affecting on the counter diaphragm in a counter pressure chamber, at least one pair of counter-acting metering edges (PR1/PS1, PR2/PS2, PR3/PS3, PR4/PS4) operationally tied together by the stem, each metering edge of each counter-acting pair comprising a mating seat surface (PS1, PS2, PS3, PS4) on the valve body or the stem and a poppet ring (PR1, PSR2, PR3, PR4) supported by a flexible element (SD1, SD2, SD3, SD4) to the valve body or the stem in a manner allowing a relative axial movement of the poppet ring (PR1, PSR2, PR3, PR4) and the supporting valve body or stem also in a closed state of the respective metering edge, wherein each poppet ring (PR1, PSR2, PR3, PR4) is pressure-balanced to compensate fluid pressure forces exerted on the respective poppet ring so as to achieve a very small or zero resultant fluid pressure force affecting on the respective metering edge, a restricted flow path from the supply pressure inlet of the valve assembly to the prestage which controls the pilot pressure in the pilot pressure chamber and thereby the axial pilot force, and a further restricted flow path) from the supply pressure inlet of the valve assembly to the counter pressure chamber.