Liquid gaging system sensor calibration
First Claim
1. In a liquid gaging system, an apparatus for measuring and storing a value related to an unwetted capacitance of a capacitive sensor, the stored value being available for use in liquid measurements, comprising:
- a capacitive sensor for mounting in a tank, the sensor having an unwetted capacitance variable in dependence on manufacturing tolerances, the sensor capacitance also being related to a stray capacitance in the system;
processor means having digital-to-analog converter means for automatically determining the sensor unwetted capacitance including the sensor capacitance contributed by the stray capacitance in the system, the processor means being connected to the sensor; and
means for storing a value related to the sensor unwetted capacitance determined by the processor means, the means for storing being connected to the processor means.
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Abstract
The present invention is part of a liquid gaging system and comprises an apparatus for measuring and storing a value related to an unwetted capacitance of a capacitive sensor, the stored value being available for use in liquid measurements. Included is a capacitive sensor for mounting in a tank, the sensor having an unwetted capacitance variable in dependence on manufacturing tolerances. The sensor capacitance is also related to stray capacitance in the system. The invention further includes apparatus for measuring the sensor unwetted capacitance including the sensor capacitance contributed by the stray capacitance in the system. The apparatus for measuring is connected to the sensor. The invention also comprises apparatus for storing a value related to the sensor unwetted capacitance measured by the apparatus for measuring, the apparatus for storing being connected to the apparatus for measuring.
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Citations
22 Claims
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1. In a liquid gaging system, an apparatus for measuring and storing a value related to an unwetted capacitance of a capacitive sensor, the stored value being available for use in liquid measurements, comprising:
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a capacitive sensor for mounting in a tank, the sensor having an unwetted capacitance variable in dependence on manufacturing tolerances, the sensor capacitance also being related to a stray capacitance in the system; processor means having digital-to-analog converter means for automatically determining the sensor unwetted capacitance including the sensor capacitance contributed by the stray capacitance in the system, the processor means being connected to the sensor; and means for storing a value related to the sensor unwetted capacitance determined by the processor means, the means for storing being connected to the processor means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In a liquid gaging system, an apparatus for measuring and storing a value related to an unwetted capacitance of a capacitive sensor, the stored value being available for use in liquid measurements, comprising:
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a plurality of capacitive sensors for mounting in a tank, each sensor having a capacitance variable in dependence on manufacturing tolerances, the capacitance of each sensor also being related to a stray capacitance in the system; means for selectively measuring the unwetted capacitance of an individual sensor including the capacitance of the individual sensor contributed by the stray capacitance in the system, the means for selectively measuring being connected to the sensors; and means for storing a value related to the sensor unwetted capacitance measured by the means for selectively measuring, the means for storing being connected to the means for selectively measuring. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification