Field transmitter with diagnostic self-test mode
First Claim
1. A field transmitter for transmitting signals representative of process variables, the field transmitter comprising:
- a physical sensor for sensing a process variable and generating a physical sensor signal which is representative of the process variable;
a surrogate sensor for producing a surrogate sensor signal which is independent of the process variable;
a signal processing circuit which converts an input signal to a measurement;
means for supplying the physical parameter sensor as the input signal to the signal processing circuit during a normal mode and supplying the surrogate sensor as the input signal to the signal processing circuit during a diagnostic mode;
means for transmitting an output signal over a communication link as a function of the measurement produced during the normal mode; and
means for performing a diagnostic evaluation based upon the measurement produced during the diagnostic mode.
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Accused Products
Abstract
A field transmitter for transmitting signals representative of process variables has both a normal operating mode and a diagnostic self-test mode. The field transmitter has a physical sensor for sensing a process variable and generating a physical sensor signal which is representative of the process variable. A signal processing circuit converts the sensor signal to a measurement which is transmitted to a control room. The field transmitter also has a surrogate sensor for producing a surrogate sensor signal which is independent of the process variable. During the diagnostic self-test mode, the surrogate sensor is connected to the signal processing circuit in place of the physical sensor. If the output of the signal processing circuit does not correspond to an expected value, a diagnostic code is produced.
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Citations
35 Claims
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1. A field transmitter for transmitting signals representative of process variables, the field transmitter comprising:
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a physical sensor for sensing a process variable and generating a physical sensor signal which is representative of the process variable;
a surrogate sensor for producing a surrogate sensor signal which is independent of the process variable;
a signal processing circuit which converts an input signal to a measurement;
means for supplying the physical parameter sensor as the input signal to the signal processing circuit during a normal mode and supplying the surrogate sensor as the input signal to the signal processing circuit during a diagnostic mode;
means for transmitting an output signal over a communication link as a function of the measurement produced during the normal mode; and
means for performing a diagnostic evaluation based upon the measurement produced during the diagnostic mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A field transmitter comprising:
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a sensor;
a signal processor for producing a measurement output as a function of an input from the sensor;
a communication interface for providing a transmitter output as a function of the measurement output; and
a diagnostic self-test circuit for providing, during a diagnostic mode, a diagnostic input to the signal processor in place of the input from the sensor; and
means for providing a diagnostic output based upon the measurement output of the signal processor in response to the diagnostic input. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A field transmitter having a normal operating mode in which a sensor produces a sensor signal which is a function of a sensed parameter, a signal processor converts the sensor signal to a measurement value, and a communication interface transmits a transmitter output as a function of the measurement value, characterized by:
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a diagnostic self-test circuit which substitutes a surrogate signal for the sensor signal during a diagnostic mode; and
means for producing a diagnostic output based upon the measurement value produced by the signal processor during the diagnostic mode. - View Dependent Claims (29, 30)
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31. A field transmitter having a normal mode and a diagnostic self-test mode, the field transmitter comprising:
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a sensor for sensing a parameter and producing a sensor signal;
a sigma delta modulator for producing a data signal as a function of the sensor signal during the normal mode and as a function of a surrogate signal during the diagnostic self-test mode;
a data processor for selecting the normal and diagnostic self-test modes, controlling transmission of a transmitter output as a function of the data signal produced during the normal mode, and causing transmission of a diagnostic code if the data signal produced during the diagnostic self-test mode indicates a malfunction.
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32. A method of operating a field transmitter to provide a diagnostic self-test, the method comprising:
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initiating a diagnostic self-test mode in which a surrogate input replaces a sensor input to signal processing circuitry of the field transmitters; and
comparing an output of the signal processing circuitry with an expected output based upon the surrogate input. - View Dependent Claims (33)
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34. An integrated circuit for use in a field transmitter which produces an output as a function of a parameter sensed by a sensor, the integrated circuit comprising:
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a signal processor for producing a measurement output as a function of an input from the sensor; and
a diagnostic self-test circuit for providing, during a diagnostic mode, a diagnostic input to the signal processor in place of the input from the sensor, so that the measurement output of the signal processor during the diagnostic mode is a function of the diagnostic input. - View Dependent Claims (35)
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Specification