PROCESS FLUID TEMPERATURE MEASUREMENT
First Claim
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1. An apparatus for measuring a temperature of a process fluid comprising:
- a resistance based temperature sensor (RTD) sensor configuration to thermally couple to the process fluid;
first and second electrical connections configured to apply a current through an RTD;
third and fourth electrical connections configured to measure a voltage across the RTD; and
measurement circuitry configured to identify a degraded connection to the RTD and responsively measure a temperature of the process fluid using less than all of the first, second, third and fourth electrical connections, wherein the measurement circuitry is configured to measure the temperature of the process fluid during an occurrence of a degraded connection to the RTD.
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Abstract
An apparatus for measuring a temperature of a process fluid includes a resistance based temperature sensor (RTD) sensor configured to thermally couple to the process fluid. First and second electrical connections are configured to apply a current through the RTD. Measurement circuitry is configured to measure a voltage across the RTD and identify a degraded connection to the RTD and responsively measure a temperature of the process fluid using the electrical connections.
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Citations
21 Claims
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1. An apparatus for measuring a temperature of a process fluid comprising:
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a resistance based temperature sensor (RTD) sensor configuration to thermally couple to the process fluid; first and second electrical connections configured to apply a current through an RTD; third and fourth electrical connections configured to measure a voltage across the RTD; and measurement circuitry configured to identify a degraded connection to the RTD and responsively measure a temperature of the process fluid using less than all of the first, second, third and fourth electrical connections, wherein the measurement circuitry is configured to measure the temperature of the process fluid during an occurrence of a degraded connection to the RTD. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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- 10. The apparatus of claim I including an I/O circuitry configured to provide an output indicating a degraded connection to the RTD has been detected.
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12. A method of sensing temperature of a process fluid, comprising:
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thermally coupling a resistance based temperature sensor (RTD) to the process fluid; causing a current to flow through the RTD using a first and second connection to the RTD; measuring a voltage across the RTD using a third and a fourth connection to the RTD; identifying a degraded connection to the RTD based upon a change in EMF or line resistance; and responsively measuring a temperature of the process fluid using less than all of the first, second, third and fourth connections to the RTD wherein the measuring of the temperature occurs during an occurrence of a degraded connection to the RTD. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification