شیر پروپرشنال NORGREN مدل VP23

All-digital control electronics
Variable pressure control, external pressure control upon request
Optional: serial interfacing with VP-Tool program
Optional actuation via fieldbus
Valve conforms to CE
Free of lacquer affecting substances

The fundamental function of a positioner is to deliver pressurized air to the valve actuator, such that the position of the valve stem or shaft corresponds to the set point from the control system. Positioners are typically used when a valve requires throttling action. A positioner requires position feedback from the valve stem or shaft and delivers pneumatic pressure to the actuator to open and close the valve. The positioner must be mounted on or near the control valve assembly. There are three main categories of positioners, depending on the type of control signal, the diagnostic capability, and the communication protocol: pneumatic, analog, and digital