The ZPD-2000 electric pneumatic valve positioner is the main supporting instrument for pneumatic actuators in industrial automation. It can be used to improve the linearity of valve position, overcome the friction force of valve stem, and eliminate the influence of unbalanced force of regulating valve, so as to ensure that the valve position is proportional to the current signal of 0-10mA, DC or 4-20mA transmitted by the regulating instrument, and achieve correct positioning. Electric pneumatic valve positioner can be equipped with pneumatic diaphragm actuator or pneumatic piston actuator; And the electric pneumatic valve positioner of Shanghai First Ring Road has dual functions of electric pneumatic converter and pneumatic valve positioner. Therefore, the actuator and accessories are widely used in industrial automation such as petroleum, chemical, metallurgical, power station, textile, papermaking, etc., and are an indispensable product in industrial automation instruments