How Are Valve Positioners Classified?

Valve positioners are classified into pneumatic valve positioners, electro-pneumatic valve positioners, and intelligent valve positioners according to input signals. The input signal of pneumatic valve positioners is a standard pneumatic signal, for example, 20~100kPa pneumatic signal, and its output signal is also a standard pneumatic signal. The input signal of electric valve positioners is a standard current or voltage signal, for example, 4~20mA current signal or 1~5V voltage signal, etc. Inside the electric valve positioner, the electrical signal is converted into electromagnetic force, and then outputs a pneumatic signal to actuate the control valve. The intelligent electric valve positioner converts the current signal output from the control room into a pneumatic signal that drives the control valve. Based on the valve stem friction force when the control valve is working, it offsets the unbalanced force generated by medium pressure fluctuations, making the valve opening correspond to the current signal output from the control room, and can intelligently configure corresponding parameters to achieve the purpose of improving control valve performance.