Pressure transducer auto reference
AssigneeNational Semiconductor Corporation
InventorsArthur R. Zias, Duane R. Tandeske
Life of this patent
Estimating the term…
Abstract
A pressure transducer is automatically calibrated electronically by periodically subjecting the transducer to a reference pressure for a brief period of time. During this period of time the transducer electrical output is automatically adjusted to a level that represents the desired value for the reference pressure. The calibration can be accomplished just prior to taking a measurement or it can be accomplished at regular intervals spaced to ensure the accuracy of readings taken between calibrations.
Claims10
In an absolute pressure transducer capable of producing an analog potential representative of the absolute value of an applied pressure, means for calibrating said transducer to a standard reference pressure, said calibrating means comprising:
- means for producing upon command a reference pressure for a controlled period of time at said transducer input,
- means for generating a variable calibrating potential during said period of time,
- means responsive to said analog poential and to said calibrating potential to produce an output indication,
- means for producing a reference potential representative of the desired transducer output for said reference pressure, and
- means for stopping the variation in said calibrating potential and holding the calibrating potential fixed when said output indication is equal to said reference potential.
In the process for calibrating a pessure transducer, said transducer comprising means for converting the pressure input into a proportional output potential, the steps comprising:
- adding to said output potential a variable calibrating potential to produce a calibrated output potential,
- upon command temporarily establishing a reference pressure condition at said input,
- upon said command varying said variable calibrating potential,
- stopping said varying of said variable calibrating potential when said calibrated output potential reaches a desired potential,
- holding said variable calibrating potential constant at the level at which it was stopped until a subsequent command orders recalibration, and
- restoring said input to its measurement state.
Dependencies are inferred from the claim text.