초록 ▼

A valve position controller tuning method avoids impact of friction in valve positioner tuning by building a dynamic model of a valve positioner from a monotonic open-loop response of a valve stem position to a change in valve position controller output. To this end, a model form is selected based o

A valve position controller tuning method avoids impact of friction in valve positioner tuning by building a dynamic model of a valve positioner from a monotonic open-loop response of a valve stem position to a change in valve position controller output. To this end, a model form is selected based on the type of pneumatic actuator and relay that controls valve flow modulating of member motion, and the valve position controller is operated in an open-loop mode. The method includes changing a valve position controller output signal to cause the valve positioner to move a valve flow modulating member, connected to valve positioner, monotonically from one stuck position to another stuck position immediately after a motion in that same direction. When a valve stem position reaches a position threshold, a first valve stem position change and a corresponding time change are measured. The method includes measuring valve stem position changes at times that depend on the first measured time change. Using the measured results, valve positioner response parameters are calculated for the selected model form from which valve position controller tuning constants are calculated.

대표청구항 ▼

[ What is claimed is:] [1.] A valve position controller tuning method that accounts for friction in valve motion by building a dynamic model of position response of a valve stem attached to a valve flow modulating member and controlled by a valve positioner, the method comprising:selecting a model f

[ What is claimed is:] [1.] A valve position controller tuning method that accounts for friction in valve motion by building a dynamic model of position response of a valve stem attached to a valve flow modulating member and controlled by a valve positioner, the method comprising:selecting a model form;operating the valve position controller in an open-loop mode;activating a valve position controller output signal that causes the valve stem to move monotonically from one stuck position to another stuck position immediately after a motion in that same direction;measuring a first valve stem position change and a corresponding valve stem position change time when a valve stem position exceeds a position threshold;measuring valve stem position changes at times that depend on the first measured valve stem position change time; andusing the measured results, calculating valve position response parameters for the selected model form.