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A liquid level height within a tank is measured by means of an elongated multi-segment capacitance probe that includes a column of capacitors extending through a liquid level interface. Each capacitor of the probe is sequentially measured in response to microprocessor controlled instructions as part

A liquid level height within a tank is measured by means of an elongated multi-segment capacitance probe that includes a column of capacitors extending through a liquid level interface. Each capacitor of the probe is sequentially measured in response to microprocessor controlled instructions as part of a measuring unit located at the tank. Up to sixteen measuring units may be interconnected in a field and individually connected to a microcomputer system at a central station. The microcomputer system addresses each of the measuring units and sends a select signal to the microprocessor controller of the measuring unit to sequentially measure each capacitor of the probe. By identifying the capacitor at the liquid level interface, the height of liquid within a tank is computed by the microcomputer system. From this height measurement and stored tank data, the volume of liquid within a tank is calculated. Associated with each of the capacitors of the probe is a temperature sensor for generating a temperature correction factor for the volume calculation.

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A method of measuring the volume of fuel within a tank by means of a micro-processor based measuring system sequentially connected by means of oscillator controlled gating logic to an elongated multi-segment capacitance probe that includes a column of capacitors extending through a liquid level of t

A method of measuring the volume of fuel within a tank by means of a micro-processor based measuring system sequentially connected by means of oscillator controlled gating logic to an elongated multi-segment capacitance probe that includes a column of capacitors extending through a liquid level of the fuel, comprising the steps of: generating and storing data corresponding to the capacitance value for each of the capacitors in the column, sequentially generating a signal representing the capacitance value of each of the capacitors in the column starting at one end thereof, comparing by means of a comparator in the measuring system the generated capacitance value signal for a given capacitor in the column with the generated data capacitance value thereof, interrupting the sequential generating of the capacitance value signal in the column when the comparison produces a result indicating a liquid level interface, generating a signal representing the capacitance value of a capacitor in the column below the capacitor at which the comparison indicates a liquid level interface, computing the height of the liquid level interface within the tank by means of the micro-processor from the generated capacitance value signal of the capacitor below the interface and the generated capacitance value signal of the capacitor at the interface, and calculating the volume of the fuel within the tank by means of the micro-processor from the computed height and from predetermined volume calibrations. Apparatus for measuring the location of the liquid level in a tank by means of an elongated multiple segment capacitive probe extending in the direction through the liquid level, comprising: a micro-processor for controlling the connection of a current source by means of oscillator controlled gating logic to the multiple segment capacitance probe, means for charging an identified capacitor in the column by connection to the current source in response to the oscillator controlled gating logic, means for comparing the charge on the identified capacitor with a stored reference level value, a counter for accumulating a count in response to the oscillator control gating logic until the charge on the identified capacitor equals the stored reference level value, wherein the accumulated count is a measure of the capacitance value of the capacitor, and means for computing the height of the liquid level in the tank by means of the micro-processor from the measured capacitance value of the capacitor in the column at the liquid level.