Switch status monitoring system, single wire bus, smart sensor arrangement therefor
First Claim
1. A smart sensor multiplex system for monitoring the status of a plurality of individual switches disposed throughout a motor vehicle, each of said switches having one end of a series-resistor sensing element connected to a moving switch element of said switches, said system comprising:
- (a) a power and signal, bi-directional single-wire bus, said bus being routed throughout the vehicle near each of said plurality of switches;
(b) a plurality of smart switch sensors disposed throughout the vehicle, each of said sensors having means for forming a first connection across the series-resistor sensing element for each of said plurality of switches, and another means for forming a second connection across said bus and a chassis ground of said vehicle, each of said switch sensors having circuits for providing current signals which are placed on said bus, each of said sensor circuits placing a current signal on said bus during a predetermined time slot of a given polling cycle of said sensors, said current signals being indicative of a status of said switch contact of said switch and of said sensor associated with the predetermined time slot;
(c) a driver and receiver circuit connected single-ended across a chassis ground of the vehicle and a terminating end of said single-wire bus for generating power and voltage signals in the form of an offset square-wave pulse train, said pulse train being driven onto said bus from said driver and receiver circuit, said sensors being connected to said bus so as to receive said pulse train and to use a plurality of "states" of said pulse train to derive power for operation of circuits within said switch sensor so as to receive a voltage signal indicative of a polling of each sensor so that each of said plurality of sensors are addressed in sequence and then allotted individual predetermined time on said bus, the addressing of each sensor and the allotment of time on said bus being performed in a chosen sequential manner, the sequential manner forming the polling cycle of the sensors, the polling of each of said sensors being at a chosen polling cycle rate, said driver and receiver circuit also having means for receiving, interpreting and then converting said current signals sent over said bus by an addressed sensor into voltage signal indicative of the status of said addressed sensor and its associated switch;
(d) display means for displaying the status of each of said plurality of sensors and said associated switches;
(e) microcomputer means interconnecting said driver and receiver circuit and said display means for writing voltage and clock signals to said driver and receiver circuit that controls the generation of the offset square wave pulse train including the plurality of "states", for reading voltage signals from said driver and receiver circuit indicative of the status of each of said addressed sensor and its associated switch, for establishing a history of performance of each of said addressed sensor and of said bus during each polling cycle of said sensors and for transferring updated independent sensor and switch data indicative of the status of said sensors and said switches to said display means during each polling cycle.
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Accused Products
Abstract
Continuous status monitoring of a plurality of switches and smart sensors associated with the switches, wherein each sensor is connected to a separate single point on a single-wire bus is affected by a smart sensor multiplex arrangement. The multiplex arrangement employs a microcomputer and a driver and receiver circuit for developing a particular pulse train waveform, which is placed on the bus to provide power and control voltage signals to the plurality of smart sensors. The smart sensors contain circuits that respond to the waveform in a manner that causes each smart sensor to send current signals back over the single wire bus to the driver and receiver circuit and the microcomputer during designated repetitive and sequential time slots. The driver and receiver circuit receives, interprets and converts the current signals into voltage signals used by the microcomputer for establishing a history of the status of the bus, the sensors and the switches. The microcomputer supplies continuous and updated information to a display system indicative of the status of each sensor and its associated switch.
54 Citations
10 Claims
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1. A smart sensor multiplex system for monitoring the status of a plurality of individual switches disposed throughout a motor vehicle, each of said switches having one end of a series-resistor sensing element connected to a moving switch element of said switches, said system comprising:
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(a) a power and signal, bi-directional single-wire bus, said bus being routed throughout the vehicle near each of said plurality of switches; (b) a plurality of smart switch sensors disposed throughout the vehicle, each of said sensors having means for forming a first connection across the series-resistor sensing element for each of said plurality of switches, and another means for forming a second connection across said bus and a chassis ground of said vehicle, each of said switch sensors having circuits for providing current signals which are placed on said bus, each of said sensor circuits placing a current signal on said bus during a predetermined time slot of a given polling cycle of said sensors, said current signals being indicative of a status of said switch contact of said switch and of said sensor associated with the predetermined time slot; (c) a driver and receiver circuit connected single-ended across a chassis ground of the vehicle and a terminating end of said single-wire bus for generating power and voltage signals in the form of an offset square-wave pulse train, said pulse train being driven onto said bus from said driver and receiver circuit, said sensors being connected to said bus so as to receive said pulse train and to use a plurality of "states" of said pulse train to derive power for operation of circuits within said switch sensor so as to receive a voltage signal indicative of a polling of each sensor so that each of said plurality of sensors are addressed in sequence and then allotted individual predetermined time on said bus, the addressing of each sensor and the allotment of time on said bus being performed in a chosen sequential manner, the sequential manner forming the polling cycle of the sensors, the polling of each of said sensors being at a chosen polling cycle rate, said driver and receiver circuit also having means for receiving, interpreting and then converting said current signals sent over said bus by an addressed sensor into voltage signal indicative of the status of said addressed sensor and its associated switch; (d) display means for displaying the status of each of said plurality of sensors and said associated switches; (e) microcomputer means interconnecting said driver and receiver circuit and said display means for writing voltage and clock signals to said driver and receiver circuit that controls the generation of the offset square wave pulse train including the plurality of "states", for reading voltage signals from said driver and receiver circuit indicative of the status of each of said addressed sensor and its associated switch, for establishing a history of performance of each of said addressed sensor and of said bus during each polling cycle of said sensors and for transferring updated independent sensor and switch data indicative of the status of said sensors and said switches to said display means during each polling cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification