Multiplexed junction probe for fuel gaging system and system containing same
First Claim
1. A multiplexed junction probe fuel gaging system for aircraft having at least one fuel tank with multiple fuel sensing units comprising:
- a plurality of elements mounted within a tank for sensing fuel and providing signals corresponding to fuel measurement;
signal processing apparatus on board the aircraft for converting analog data signals to digital values corresponding to measured fuel quantity;
a junction probe installed in a tank and including circuitry separately coupled to the individual tank mounted elements, the junction probe also being coupled to the signal processing apparatus by a common signal path;
first circuit means included in the junction probe for electrically driving said elements; and
second circuit means in the junction probe for measuring each element in a predetermined sequence and forming a data stream of analog signals corresponding to the signals from said elements for transmission to the signal processing apparatus over said common signal path.
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Accused Products
Abstract
A true mass fuel gaging system for aircraft utilizing multiplexing of tank unit measurements in or adjacent a fuel tank for improved accuracy and fault isolation. The system provides dual equipment channels for redundancy throughout all data processing portions of the system and also uses extensive built-in testing (BIT) routines so that upon detection of a fault an alternative channel can be switched into use. Detected fault locations are displayed in the cockpit with the fuel quantity displays. The system also provides displays of center of gravity measurements derived from fuel mass and location.
53 Citations
29 Claims
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1. A multiplexed junction probe fuel gaging system for aircraft having at least one fuel tank with multiple fuel sensing units comprising:
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a plurality of elements mounted within a tank for sensing fuel and providing signals corresponding to fuel measurement; signal processing apparatus on board the aircraft for converting analog data signals to digital values corresponding to measured fuel quantity; a junction probe installed in a tank and including circuitry separately coupled to the individual tank mounted elements, the junction probe also being coupled to the signal processing apparatus by a common signal path; first circuit means included in the junction probe for electrically driving said elements; and second circuit means in the junction probe for measuring each element in a predetermined sequence and forming a data stream of analog signals corresponding to the signals from said elements for transmission to the signal processing apparatus over said common signal path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 20, 21, 22, 23)
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- 17. The system of claim a further including a load select display unit for receiving signals from the standard electronic module and providing a display of fuel quantity at a refueling panel.
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24. A junction probe for installation in the fuel tank of an aircraft to develop signals for measurement of fuel quantity in the tank comprising:
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means for individually coupling the junction probe to a plurality of fuel sensing elements mounted within the tank; means for electrically driving the tank mounted elements over a common connection to one side of each of said elements; and a multiplexer coupled to individual leads from the other side of each of said elements, said multiplexer being adapted to measure the signal level on each of said individual leads in a predetermined sequence and to develop a corresponding data stream of analog signals in said sequence on an output thereof. - View Dependent Claims (25, 26, 27, 28)
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29. A multiplexed fuel gaging system for aircraft having at least one fuel tank with multiple fuel sensing units comprising:
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a plurality of elements mounted within a tank for sensing fuel and providing signals corresponding to fuel measurement; signal processing apparatus on board the aircraft for converting analog data signals to digital values corresponding to measured fuel quantity; a multiplexer associated with a tank and including circuitry separately coupled to the individual tank mounted elements, the multiplexer also being coupled to the signal processing apparatus by a common signal path; first circuit means included in the multiplexer for electrically driving said elements; and second circuit means in the multiplexer for measuring each element in a predetermined sequence and forming a data stream of analog signals corresponding to the signals from said elements for transmission to the signal processing apparatus over said common signal path.
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Specification