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US 9,063,540 B2Granted
Methods and apparatus to limit a change of a drive value in an electro-pneumatic controller
AssigneeFisher Controls International LLC
InventorStephen George Seberger
Life of this patent
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Abstract
Example methods and apparatus to limit a change of a drive value in an electro-pneumatic controller are disclosed. A disclosed example method includes determining a slew limit of a controller based on noise in at least one of a control signal or a feedback signal, calculating a drive value based on the control signal and the feedback signal, and changing the calculated drive value if a difference between the drive value and a previous drive value is greater than the slew limit of the controller.
Claims22
A method, comprising:
- determining a slew limit of a controller based on a characteristic of noise in at least one of a control signal or a feedback signal;
- calculating a drive value based on the control signal and the feedback signal;
- calculating a difference between the calculated drive value and a previous drive value;
- comparing the difference to the slew limit;
- and
- changing the calculated drive value if the difference is greater than the slew limit of the controller.
3 more elements
An apparatus, comprising:
- a noise detector to identify noise in at least one of a control signal or a feedback signal;
- and
- a drive current slew limiter to:
- determine a slew limit based on a characteristic of the noise;
- receive a drive value and a previous drive value;
- calculate the difference between the drive value and the previous drive value;
- compare the difference to the slew limit;
- and
- change the drive value if the difference is greater than the slew limit.
6 more elements
An apparatus, comprising:
- means for determining a slew limit of a controller based on a characteristic of noise in at least one of a control signal or a feedback signal;
- means for calculating a drive value based on the control signal and the feedback signal;
- means for calculating the difference between the calculated drive value and a previous drive value;
- means for comparing the difference to the slew limit;
- and
- means for changing the calculated drive value if the difference is greater than the slew limit of the controller.
3 more elements
Dependencies are inferred from the claim text.