Smart valve positioner with pneumatic control valve

Such structure and control valve control valve is the same, the main difference with a smart valve positioner of the control valve with intelligent features smart valve positioner with positioner
A different way to achieve control valve flow characteristics. The smart positioner's part linear feedback control valve flow characteristics required in setting circuit. The ordinary feedback part of the locator is a different shape of the cam to achieve the desired control valve flow characteristics, by changing the shape of the cam. Details, see section 5.3.angle seat valve
Input and output in different ways. Typically, smart valve positioner is intelligent electric valve positioner. Compared with the general electric valve positioner, intelligent electric valve positioner input signal is a standard 4 ~ 20mA or 1 ~ 5V electrical signal after analog-to-digital conversion, it takes as input signal of the microprocessor. General electric valve positioner input signal is 4-20mA or 1 ~~ 5V electrical signal, but it does not need by the analog-to-digital conversion, can be sent directly to the electromagnetic coil of the electromagnetic force, the force balance. Smart valve positioner output signal is a digital signal, it is usually sent the piezoelectric valve block, through the piezoelectric valve block switch to adjust the send control the pressure of the diaphragm head, general electric valve positioner output signal by pneumatic amplifier the gas signal.pneumatic accessory
3 different control mode. The intelligent positioner similar to the general computer control means, discrete control mode, therefore, in the sampling interval, the control valve opening degree does not change. During operation, the control valve opening degree of rendering a stepped change. Usually positioner continuous control mode, therefore, the entire control process, the control valve opening degree change is continuous (except for the hop caused due to the dead zone becomes outside).
The type of feedback signal detection process. Smart valve positioner control valve feedback signal required by the analog to digital conversion evacuation microprocessor processing, and general positioner feedback signal as a feedback force (torque), do not need the analog to digital conversion to electrical signals. Smart valve positioner input signal to a standard analog signal is transmitted in the same wire HART digital signal, composed of mixed-signal smart valve positioner, it does not belong to the field bus intelligent valve positioner, but still a smart valve positioner.electric solenoid valve