System and method for distinguishing a device failure from an inter-device communication failure
First Claim
1. For use in a control system containing first and second devices coupled together for inter-device communication, a circuit for distinguishing a failure of said first device from a failure of said inter-device communication, comprising:
- a device failure signal generator, associated with and separately powered from said first device, that communicates a device failure signal to said second device upon occurrence of a predetermined condition; and
a device failure signal detector, associated with said second device, that detects said device failure signal, detection of said device failure signal contraindicating a failure of said inter-device communication.
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Accused Products
Abstract
For use in a control system containing first and second devices coupled together for inter-device communication, a circuit for and method of distinguishing a failure of the first device from a failure of the inter-device communication and a real-time process control system employing the circuit or the method. In one embodiment, the circuit includes: (1) a device failure signal generator, associated with and separately powered from the first device, that communicates a device failure signal to the second device upon occurrence of a predetermined condition and (2) a device failure signal detector, associated with the second device, that detects the device failure signal. Detection of the device failure signal contraindicates a failure of the inter-device communication.
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Citations
20 Claims
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1. For use in a control system containing first and second devices coupled together for inter-device communication, a circuit for distinguishing a failure of said first device from a failure of said inter-device communication, comprising:
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a device failure signal generator, associated with and separately powered from said first device, that communicates a device failure signal to said second device upon occurrence of a predetermined condition; and
a device failure signal detector, associated with said second device, that detects said device failure signal, detection of said device failure signal contraindicating a failure of said inter-device communication. - View Dependent Claims (2, 3, 4, 5, 6, 7)
a hardware command, a software command, and a signal generated by hardware external to a processor that monitors system integrity.
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5. The circuit as recited in claim 1 wherein said device failure signal contains a predetermined data pattern.
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6. The circuit as recited in claim 1 wherein said device failure signal generator is powered by a power supply that derives power from a power supply of said first device.
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7. The circuit as recited in claim 1 wherein said inter-device communication occurs over a selected one of:
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an electrical conductor, and an optical fiber.
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8. For use in a control system containing first and second devices coupled together for inter-device communication, a method of distinguishing a failure of said first device from a failure of said inter-device communication, comprising the steps of:
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communicating, with a device failure signal generator associated with and separately powered from said first device, a device failure signal to said second device upon occurrence of a predetermined condition; and
detecting said device failure signal at said second device, detection of said device failure signal contraindicating a failure of said inter-device communication. - View Dependent Claims (9, 10, 11, 12, 13, 14)
a hardware command, a software command, and a signal generated by hardware external to a processor that monitors system integrity.
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12. The method as recited in claim 8 wherein said device failure signal contains a predetermined data pattern.
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13. The method as recited in claim 8 wherein said device failure signal generator is powered by a power supply that derives power from a power supply of said first device.
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14. The method as recited in claim 8 wherein said step of communicating comprises the step of transmitting said device failure signal over a selected one of:
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an electrical conductor, and an optical fiber.
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15. A real-time process control system, comprising:
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a primary controller that controls said system;
a secondary controller that assumes control of said system upon failure of said primary controller;
a communication channel coupling said primary and secondary controllers that allows said primary and secondary controllers to communicate; and
a circuit for distinguishing a failure of said primary controller from a failure of said communication channel, including;
a device failure signal generator, associated with and separately powered from said primary controller, that communicates a device failure signal to said secondary controller upon occurrence of a predetermined condition, and a device failure signal detector, associated with said secondary controller, that detects said device failure signal, detection of said device failure signal contraindicating a failure of said communication channel and prompting said secondary controller to assume said control of said system. - View Dependent Claims (16, 17, 18, 19, 20)
a hardware command, a software command, and a signal generated by hardware external to a processor that monitors system integrity.
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18. The system as recited in claim 15 wherein said device failure signal contains a predetermined data pattern.
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19. The system as recited in claim 15 wherein said device failure signal generator is powered by a power supply that derives power from a power supply of said primary controller.
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20. The system as recited in claim 15 wherein said communication channel is over a selected one of:
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an electrical conductor, and an optical fiber.
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Specification