Research On Low Power Design And Performance Optimization Of Intelligent Valve Positioner

Intelligent valve positioner was widely used in industrial control field as the valve's central control unit. Intelligent valve positioner has great development prospects for that it is of high sensitivity, high reliability, and offers optional tuning parameters and other characteristics as a digital system; that it is of low-power consumption, simple wiring, and high security performance as a kind of two-wire instrument; that it integrated digital communications function and can applied for distributed control as a bus device.This paper is on the research of the intelligent electric valve positioner of pneumatic actuator, nozzle baffle-style I/P conversion unit, and especially on low-power design as well as orientation performance optimization design. Pneumatic Intelligent valve positioner consists of control module, current sampling module, valve feedback module, Hart modem unit and so on, and the whole system is supplied by the two-wire industrial 4-20mA current bus. Control module compares the current position and aim position, and gives out PWM square wave according to Space-based PID algorithm. On the other hand, valve feedback module, made up by variable reluctance sensor, converts valve position into electrical signal. This paper proposed a tuning method of PID control parameters to meet the control of valves with different stroke, locator or Friction coefficient. Locator system enables rapid, accurate and stable positioning control system to meet the static and dynamic characteristics, and can be superimposed on the locator signal hart protocol configuration, parameter settings.