Valve positioner with dynamic correction

摘要

In this invention, a valve positioner (50) receives a setpoint from a master (62) and provides a control pressure to a valve actuator (70) for controlling a valve (72). A sensing circuit (102) in the positioner (50) senses the position of the valve (72) and the control pressure, and a control circuit (94) in the positioner (50) uses both the sensed pressure and position to provide a command output to a pneumatic section (100) which produces the control pressure.