Single line multiplexing system for sensors and actuators
First Claim
1. A system for transmitting signals between a processor and at least one remotely located device, wherein the processor generates a plurality of command signals uniquely identifying each of the remotely located device, comprising:
- a bi-directional data transmission line;
interrogation signal generating means interconnecting the processor with said data transmission line for generating on said data transmission line interrogation signals having pulse widths ti, the pulse width of each of said interrogation signal is uniquely associated with a corresponding command signal;
interface means interconnecting each remotely located device with the data transmission line for selectively enabling communication between the processor and said device in response to said interrogation signals, each interface means responsive to an interrogation signal including one of said predetermined pulse widths which is different from the predetermined pulse width to which other interface means respond;
wherein each of said interface means includes;
a pulse width discriminator for generating a trigger signal in response to an interrogation signal having a predetermined pulse width;
means responsive to said trigger signal for establishing direct communication between the device and said transmission line, andwherein the predetermined pulse width of said interrogation signal has a time duration t1, said pulse width discriminator comprises;
first means responsive to the beginning of each interrogation signal appearing on said transmission line, for generating a first test pulse of duration (ti -Δ
);
second means, responsive to the termination of said first test pulse for generating a second test pulse having a duration 2Δ
where 2Δ
corresponds to a time increment smaller than t1 ; and
third means, responsive to said interrogation signals and said second test pulse, for generating a trigger signal indicative of the condition that said interrogation signal of duration ti has terminated during the time of said second test pulse.
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Accused Products
Abstract
A single line refigurable power transmission and signal multiplexing system having a central processor and a plurality of remotely located devices such as sensors, actuators and associated interfaces. Communications between the central processor and the remote devices is accomplished via a single bi-directional transmission line. A negative logic pulse width encoding technique is utilized to facilitate power and signal transmission. Selective activation is accomplished by a pulse width discriminator associated with each interface which employs a two-part recognition test to identify specific pulse width signals.
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Citations
33 Claims
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1. A system for transmitting signals between a processor and at least one remotely located device, wherein the processor generates a plurality of command signals uniquely identifying each of the remotely located device, comprising:
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a bi-directional data transmission line; interrogation signal generating means interconnecting the processor with said data transmission line for generating on said data transmission line interrogation signals having pulse widths ti, the pulse width of each of said interrogation signal is uniquely associated with a corresponding command signal; interface means interconnecting each remotely located device with the data transmission line for selectively enabling communication between the processor and said device in response to said interrogation signals, each interface means responsive to an interrogation signal including one of said predetermined pulse widths which is different from the predetermined pulse width to which other interface means respond; wherein each of said interface means includes; a pulse width discriminator for generating a trigger signal in response to an interrogation signal having a predetermined pulse width;
means responsive to said trigger signal for establishing direct communication between the device and said transmission line, andwherein the predetermined pulse width of said interrogation signal has a time duration t1, said pulse width discriminator comprises; first means responsive to the beginning of each interrogation signal appearing on said transmission line, for generating a first test pulse of duration (ti -Δ
);second means, responsive to the termination of said first test pulse for generating a second test pulse having a duration 2Δ
where 2Δ
corresponds to a time increment smaller than t1 ; andthird means, responsive to said interrogation signals and said second test pulse, for generating a trigger signal indicative of the condition that said interrogation signal of duration ti has terminated during the time of said second test pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for transmitting signals between a processor and at least one remotely located device, wherein the processor generates a plurality of command signals uniquely identifying each of the remotely located devices, comprising:
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a bi-directional data transmission line; interrogation signal generating means interconnecting the processor with said data transmission line for generating on said transmission line pulse width modulated interrogation signals of predetermined pulse width ti, the pulse width of each of said interrogation signals is uniquely associated with a corresponding command signal; interface means interconnecting each remotely located device with the data transmission line for selectively enabling communication between the processor and said device in response to said interrogation signals, each interface means responsive to an interrogation signal including one of said predetermined pulse widths and the pulse width to which each interface means responds is different from the predetermine pulse widths to which other interface means respond; wherein each of said interface means includes; a pulse width discriminator for generating a trigger signal in response to an interrogation signal having a predetermined pulse width;
means responsive to said trigger signal for establishing direct communication between the device and said transmission line, andwhere said pulse width discriminator comprises; fourth means connected to said transmission line, including a first monostable multivibrator (266), generating an output signal and a complementary output signal responsive to the negative going edge of a pulse width signal on said transmission for generating a first test pulse of predetermined duration (ti -Δ
); andfifth means including a second monostable multivibrator (268) generating an output signal and a complementary output signal connected to the output of said fourth means, responsive to the negative going edge of the signal appearing at the output of said fourth means for generating a second test pulse signal of predetermined duration 2Δ
;a logic signal inverter including a first NAND gate (258) connected to said transmission line; D-latch flipflop (257) receiving a data input signal from the output of said logic signal inverter and receiving a clock signal from the complementary output of said fourth means; a second NAND gate (260) receiving inputs from said transmission line and the output of said D-latch flip-flop (257) and generating an output; a second logic signal inverter, including a third NAND gate (262) receiving the output of said second NAND gate (260); second D-latch flip-flop (256) responsive to the output of said second logic signal inverter and further receiving a clocking signal from the complementary output of said fifth means; fourth NAND gate means (264) responsive to the output of said second D-latch flip-flop (256) and the output of said first D-latch flip-flop (257) for generating said trigger signal indicative of the condition that said interrogation signal of duration ti has terminated during the time of said second test pulse. - View Dependent Claims (11, 12, 13, 14)
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15. A system for transmitting signals between a processor and at least one remotely located device, wherein at least one of said devices is an actuator and wherein the processor generates a plurality of command signals uniquely identifying each of the remotely located device, including:
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a bi-directional data transmission line; interrogation signal generating means interconnecting the processor with said data transmission line for generating on said data transmission line pulse width modulated interrogation signals of predetermined pulse widths ti the pulse width of each of said interrogation signals is uniquely associated with a corresponding command signal and wherein said interrogation signals further comprises a predetermined pulse width ta, indicative of an actuator turn-on command corresponding to one of the command signals and switching between a first value to a second value wherein the time that said interrogation signal is at said second value identifies a specific actuator corresponding to the command signal and where said interrogation signal is returned to said first level for a determinable time td, indicative of the data command signal to be transmitted to said actuator, and where said interrogation signal is returned to said second level for a second predetermined period tb, indicative of a turn-off command signal; interface means interconnecting each remotely located device with the data transmission line for selectively enabling communication between the processor and said device in response to said interrogation signals, each interface means responsive to an interrogation signal including one of said predetermined pulse widths and the pulse width to which each interface means responds is different from the predetermined pulse widths to which other interface means respond, said interface means further comprising; actuator turn-on means disposed between said transmission line and said actuator responsive to said turn on command signal, for generating a signal to turn on said actuator when said interrogation signal contains a predetermined pulse width such as ta ; and a pulse width discriminator for generating a trigger signal in response to an interrogation signal having a predetermined pulse width;
means responsive to said trigger signal for establishing direct communication between the device and said transmission line. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A system for transmitting signals between a processor and at last one remotely located device, wherein the processor generates a plurality of command signals uniquely identifying each of the remotely located device, comprising:
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a bi-directional data transmission line; interrogation signal generating means interconnecting the processor with said data transmission line for generating on said data transmission line pulse width modulated interrogation signals of predetermined pulse width ti, the pulse width of each of said interrogation signals is uniquely associated with a corresponding command signal and wherein said interrogation signal generating means further includes; pulse width generator means responsive to said command signals for generating signals having determinable pulse widths; level shifting means, receiving said pulse width signals from said pulse width generator means, for translating the magnitude of said pulse width signals into amplified bilevel pulse width signals, each having a magnitude of a first level of voltage potential, and where said level shifting means is disposed between said pulse width generator means and a driver means; driver means for impressing said translated pulse width generator means signals onto said transmission line; composite circuitry means comprising a current limiter means interconnecting said driver means and said transmission line for limiting the output current flowing into said transmission line, and where said level shifting means said driver means and said current limiter means cooperate to establish said interrogation signals having a magnitude defined by said first level of voltage potential and a second voltage potential, such that said first level of voltage potential is impressed upon said transmission line; interface means interconnecting each remotely located device with the data transmission line for selectively enabling communication between the processor and said device in response to said interrogation signals, each interface means responsive to an interrogation signal including one of said predetermined pulse widths and the pulse width to which each interface means responds is different from the predetermined pulse widths to which other interface means respond. - View Dependent Claims (27, 28, 29, 30)
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31. A ground reset system interposing signal generating stations A and B comprising:
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a bi-directional transmission line for carrying signals between stations A and B; and means connected to said bi-directional transmission line for generating a ground reset signal in response to a ground potential signal which originates at station B while ignoring ground potential signals originating at station A. - View Dependent Claims (32)
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33. A method of transmitting power from one location to at least one of a plurality of device means and of selectively communicating with said device means, the steps of which comprise:
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energizing a transmission line at a first voltage potential; communicating said first voltage to a storage and discharge means therein generating a stored voltage; communicating said stored voltage to said device means; generating processor commands identifying the specific device means; generating a coded bi-level pulse width signal, in response to said processor commands, wherein a unique code is associated with each of said device means; combining said coded bi-level pulse width signal with said first voltage potential to generate a negative logic coded signal in such a manner as to reduce the voltage on said transmission line to a second voltage potential for a determinable time corresponding to the pulse width ti, assigned to a specific device means; generating a first test pulse signal having a duration of ti -Δ
seconds in response to the leading edge of said combined signal, wherein a different ti is associated with each device means;generating a second test pulse signal, in response to said first test pulse, having a duration 2Δ
seconds, where 2Δ
is a time period substantially smaller than any of said combined signals;generating an activation signal indicative of the fact that said combined signal returned to said first voltage potential during the existence of said second test signal indicating that said combined signal was of duration ti which is uniquely assigned to a specific device.
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Specification