Automatic calibration of sensor circuits in gear shapers
First Claim
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1. An apparatus for calibrating a sensor output by producing a corrected sensor output, said sensor for producing an analog electrical output signal representative of a predetermined sensed parameter, comprising:
- a signal conditioning circuit operatively connected to condition said output signal;
a reference signal means for producing first and second reference signals;
multiplexer means connected to said reference signal means and interposed betwen said sensor and said signal conditioning circuit for selectively passing said output signal or either of said first and second reference signals to said signal conditioning circuit;
an analog to digital converter operatively connected to the output of said sensor and said signal conditioning circuit; and
digital control means operatively connected to said converter output, said multiplexer and said reference signal means for periodically determining predetermined characteristics of said sensor and said signal conditioning circuit and for utilizing said predetermined sensor output signal, wherein said predetermined characteristics comprise the actual gain and output offset of said signal conditioning circuit utilizing said first and second reference signals as inputs thereto, and the output offset of said sensors.
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Abstract
A computer controlled apparatus for periodically calibrating the electrical outputs of pressure transducers to compensate for circuit-induced errors and produce accurate outputs in real time. Reference signals are periodically input into various circuit elements to determine resultant outputs. The relationship thus determined between these known inputs and corresponding outputs is used to correct the output of the circuit elements during operation.
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Citations
9 Claims
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1. An apparatus for calibrating a sensor output by producing a corrected sensor output, said sensor for producing an analog electrical output signal representative of a predetermined sensed parameter, comprising:
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a signal conditioning circuit operatively connected to condition said output signal; a reference signal means for producing first and second reference signals; multiplexer means connected to said reference signal means and interposed betwen said sensor and said signal conditioning circuit for selectively passing said output signal or either of said first and second reference signals to said signal conditioning circuit; an analog to digital converter operatively connected to the output of said sensor and said signal conditioning circuit; and digital control means operatively connected to said converter output, said multiplexer and said reference signal means for periodically determining predetermined characteristics of said sensor and said signal conditioning circuit and for utilizing said predetermined sensor output signal, wherein said predetermined characteristics comprise the actual gain and output offset of said signal conditioning circuit utilizing said first and second reference signals as inputs thereto, and the output offset of said sensors. - View Dependent Claims (4, 5, 6)
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2. An apparatus for calibrating a sensor output by producing a corrected sensor output, said sensor for producing an analog electrical output signal representative of a predetermined sensed parameter, comprising:
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a signal conditioning circuit operatively connected to condition said output signal; means for producing a reference signal; multiplexer means connected to said reference signal means and interposed betwen said sensor and said signal conditioning circuit for selectively passing said output signal or said reference signal to said signal conditioning circuit; an analog to digital converter operatively connected to the output of said sensor and said signal conditioning circuit; and digital control means operatively connected to said converter output, said multiplexer and said reference signal means for periodically determining predetermined characteristics of said sensor and said signal conditioning circuit and for utilizing said predetermined sensor output signal, wherein said predetermined characteristics comprise the actual gain and output offset of said signal conditioning circuit utilizing said reference signal as input thereto, and the output offset of said sensors. - View Dependent Claims (3)
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7. An apparatus for calibrating a sensor output by producing a corrected sensor output, said sensor for producing an analog electrical output signal representative of a predetermined sensed parameter, comprising:
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a signal conditioning circuit operatively connected to condition said output signal; a reference signal means for producing first and second reference signals; multiplexer means connected to said reference signal means and interposed betwen said sensor and said signal conditioning circuit for selectively passing said output signal or either of said first and second reference signals to said signal conditioning circuit; an analog to digital converter operatively connected to the output of said sensor and said signal conditioning circuit; digital control means operatively connected to said converter output, said multiplexer and said reference signal means for periodically determining predetermined electrical characteristics of said sensor and said signal conditioning circuit and for utilizing said predetermined electrical characteristics to produce corrected sensor output signal, wherein said predetermined characteristics comprise the actual gain and output offset of said signal conditioning circuit utilizing said first and second reference signals as inputs thereto, and the output offset of said sensors, and wherein said corrected signal is determined by the formula Sc =[So ±
(Sf ·
G)±
Of ](T.G./G) whereSc =corrected sensor output So =actual sensor output with zero input Sf =sensor offset determined with zero input G=actual gain of the signal conditioning circuit Of =output offset of the signal conditioning circuit T.G.=theoretical gain of the signal conditioning circuit. - View Dependent Claims (8, 9)
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Specification