Thermal-based diagnostic system for process transmitter
First Claim
1. A process transmitter for measuring a process variable, the process transmitter comprising:
- a sensor module comprising;
a sensor for measuring a process variable of an industrial process and generating a sensor signal;
a housing containing the sensor;
a flexible sensor element disposed within the sensor, a position of which corresponds to a magnitude of the sensor signal;
an isolation diaphragm positioned on an exterior of the housing;
an isolation tube connecting the flexible sensor element with the isolation diaphragm; and
a fill fluid positioned within the isolation tube to influence a position of the flexible sensor element based on a magnitude of the process variable;
a heating device connected to the sensor module for generating a heat pulse to influence generation of the sensor signal; and
transmitter circuitry connected to the sensor and the heating device;
wherein the transmitter circuitry verifies operation of the sensor by measuring a change in the sensor signal due to the heat pulse.
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Accused Products
Abstract
A process transmitter for measuring a process variable in an industrial process comprises a sensor module, a heating device and transmitter circuitry. The sensor module has a sensor for sensing a process variable of an industrial process and generating a sensor signal. The heating device is connected to the sensor module for generating a heat pulse to influence generation of the sensor signal. The transmitter circuitry is connected to the sensor and the heating device. The transmitter circuitry verifies operation of the sensor by measuring a change in the sensor signal due to the heat pulse. In one embodiment of the invention, the heat pulse thermally expands a volume of a fill fluid within the process transmitter. In another embodiment, the heat pulse changes a physical property, such as dielectric, of a fill fluid within the process transmitter.
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Citations
63 Claims
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1. A process transmitter for measuring a process variable, the process transmitter comprising:
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a sensor module comprising; a sensor for measuring a process variable of an industrial process and generating a sensor signal; a housing containing the sensor; a flexible sensor element disposed within the sensor, a position of which corresponds to a magnitude of the sensor signal; an isolation diaphragm positioned on an exterior of the housing; an isolation tube connecting the flexible sensor element with the isolation diaphragm; and a fill fluid positioned within the isolation tube to influence a position of the flexible sensor element based on a magnitude of the process variable; a heating device connected to the sensor module for generating a heat pulse to influence generation of the sensor signal; and transmitter circuitry connected to the sensor and the heating device; wherein the transmitter circuitry verifies operation of the sensor by measuring a change in the sensor signal due to the heat pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A method for diagnosing performance of a pressure sensor in an industrial process transmitter, the method comprising:
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applying fluid pressure to a pressure sensor to produce a pressure signal representative of sensed pressure; applying a heat pulse capable of causing a change in the sensed pressure; and producing a diagnostic test result based upon how the heat pulse affects the pressure signal. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. An industrial process transmitter for sensing a pressure of a process fluid, the transmitter comprising:
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a transmitter housing; a pressure sensor disposed within the housing for sensing the process fluid pressure, the pressure sensor having a sensing diaphragm for generating a capacitive pressure signal; an isolation diaphragm positioned on the transmitter housing to interact with the process fluid; an isolation tube connecting the isolation diaphragm with the pressure diaphragm; a fill fluid disposed within the isolation tube to transmit pressure from the isolation diaphragm to the sensing diaphragm to change the pressure signal as the process fluid pressure changes; a heating device positioned to heat the fill fluid in the isolation tube to affect the capacitive pressure signal; a temperature sensor disposed adjacent the heating device to monitor heat output of the heating device; and transmitter electronics disposed within the housing and connected with the pressure sensor, the heating device and the temperature sensor, wherein the transmitter electronics perform diagnostics of the pressure sensor including verification of operation of the sensing diaphragm and calibration of the pressure sensor based on the capacitive pressure signal from the pressure sensor and heat output from the heating device.
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Specification