Patent ID: 7769493

Claim:
A method for controlling fluid flow characteristics, comprising the steps of: providing a programmable flow controller; positioning the programmable flow controller between a flow process controller and a control valve positioner; programming desired user-selectable flow characteristics into the programmable flow controller, the programming of the desired user-selectable flow characteristics including a selected flow curve ƒ(u), wherein ƒ(u) represents a percentage flow rate and u represents a percentage of valve stem position controlled by said control valve positioner; storing the user-selectable flow characteristics in computer memory; inputting a set of inherent valve parameters into the programmable flow controller; calculating a set of desired valve parameters from the user-selectable flow characteristics; comparing the set of inherent valve parameters to the set of desired valve parameters to determine a difference; calculating a correction factor according to the difference between the set of inherent valve parameters and the set of desired valve parameters; correcting a control signal from the flow process controller according to the correction factor to form a modified control signal; and transmitting the modified control signal to the control valve positioner.