Intelligent Valve Positioner Based On HART Protocol

Intelligent valve positioner with high sensitivity,high reliability,and equipped with optional tuning parameters,so that dead zone of the valve dynamic response have been greatly improved,and make the valve stroke accurate and stable operation.The improvement of the valve positioned is digital,integrated an bus-oriented direction.HART protocol compatible with analog signals and digital signals,so valve positioner based on HART protocol the intelligent has large prospects of development.This paper is on the research of the intelligent electric valve positioner of pneumatic actuator,nozzle baffle-style I/P conversion unit.Pneumatic Intelligent valve positioner is consist of control module,sampling module, convert output circuit,I/P converting module,valve feedback module and so on.Control module compares the current position and aim position,and gives the PWM square wave according to the localization algorithm.This square wave through integral feedback circuits goes to the coils.At last,the electromagnetic field made by the coils,drives the valve actuator moving.Valve feedback module is made up of variable reluctance sensor,converting the angle signal to electrical signal.Using the muti-interal PID control algorithm,we are able to make the valve achieve the aim pos fast,accurate and stable.Through self-tuning algorithm to solve a wide variety of valves,stroke varies in different friction parameters of adaptive regulation problem.4-20mA current signal generator provides the power of total system,and can be superimposed hart protocol signal for configuration,parameter setting.