Valve positioner

Valve Positioner Models: ZPQ / ZPD-2000/1000 / DVC6200 / DVC2000 / 3800SA / EL100 / EL200 / SIPART PS2 / SITRANS VP300 / SIPART SP2 / AVP100 / AVP102 / AVP300 / AVP301 A valve positioner is a key accessory for pneumatic control valves. Its core function is to improve the control accuracy and response speed of the valve. It operates on a closed-loop control principle, comparing the actual position of the valve stem with the control signal, and accordingly adjusts the air pressure supplied to the actuator.The valve positioner receives a standard electrical signal (such as 4-20mA) or pneumatic signal (such as 0.02-0.1 MPa) from the control system, while simultaneously monitoring the valve opening in real time through a feedback lever. When a deviation exists between the two, the nozzle-flapper mechanism or electro-pneumatic converter inside the positioner regulates the output air pressure, driving the actuator until the valve reaches the commanded position.The main functions of a valve positioner are:Overcoming stem friction and medium unbalanced forces, eliminating valve dead bandAchieving split-range control and flow characteristic correctionAdapting to air-to-open or air-to-close actuators by switching between direct and reverse actionBased on explosion-proof requirements, positioners can be classified as intrinsically safe (Ex ia) or flameproof (Ex d) types.In installation and application, the positioner significantly improves both the dynamic and static accuracy of the control valve, making it suitable for applications with high control quality requirements. When selecting a positioner, it is necessary to confirm the input signal, air supply pressure, action mode, and whether communication protocols such as HART are supported.