Feature set and methods for a digital positioner
AssigneeFisher Controls International LLC
InventorGeorge W. Gassman
Life of this patent
Estimating the term…
Abstract
A digital positioner for a valve includes a valve controller configured to obtain a set point value for a valve travel of a valve, and generate a pulse-width modulated current signal based on the set point value. The digital positioner also includes a current-to-pressure converter configured to receive the pulse-width modulated current signal from the valve controller, convert the pulse-width modulated current signal to a pulse-width modulated pressure signal, and provide the pulse-width modulated pressure signal to a pneumatic actuator in the valve to adjust a position of the valve.
Claims18
A digital positioner for a valve comprising:
- a valve controller including:
- one or more processors;
- and
- a non-transitory computer-readable memory coupled to the one or more processors and storing instructions thereon that, when executed by the one or more processors, cause the valve controller to:
- obtain a set point value for a valve travel of a valve or an amount of pressure at the valve;
- generate a drive signal as a function of the set point value, wherein the drive signal is adjusted in accordance with a rate of change of the valve travel or the valve pressure over a time period;
- and
- generate a pulse-width modulated current signal in accordance with the drive signal, wherein the time period for the rate of change of the valve travel or the valve pressure corresponds to a time period for the pulse-width modulated current signal;
- and
- a current-to-pressure converter configured to receive the pulse-width modulated current signal from the valve controller, convert the pulse-width modulated current signal to a pulse-width modulated pressure signal, and provide the pulse-width modulated pressure signal to a pneumatic actuator in the valve to adjust a position of the valve.
A digital positioner for a valve comprising:
- a valve controller including:
- one or more processors;
- and
- a non-transitory computer-readable memory coupled to the one or more processors, and storing thereon instructions that, when executed by the one or more processors, cause the valve controller to:
- obtain a set point value for a valve travel of a valve or an amount of pressure at the valve;
- generate a drive signal by calibrating the digital positioner using a plurality of predetermined set points to generate a model for determining the drive signal as a function of the set point value by modulating set point values for each of the predetermined set points and determining a change in drive signals across the modulated set point values, and applying the set point value to the model to determine a value for the drive signal;
- and
- generate a pulse-width modulated current signal in accordance with the drive signal;
- and
- a current-to-pressure converter configured to receive the pulse-width modulated current signal from the valve controller, convert the pulse-width modulated current signal to a pulse-width modulated pressure signal, and provide the pulse-width modulated pressure signal to a pneumatic actuator in the valve to adjust a position of the valve.
Dependencies are inferred from the claim text.