US5703575A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Open sensor diagnostic system for temperature transmitter in a process control system
Assignee: Rosemount Inc
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Filing: 1996-09-26
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Granted: 1997-12-30
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Expires: 2016-09-26
Abstract
Abstract A temperature transmitter in a process control system includes a temperature sensor which senses temperature and provides a sensor output related to sensed temperature. An analog-to-digital converter coupled to the sensor output provides a digitized output related to the sensor output. A microprocessor receives the digitized output, compensates the digitized output and provides a temperature output. Comparison circuitry compares the sensor output to a first threshold and provides an inhibit signal to the microprocessor if the sensor is outside of the first threshold.
Inventors
- 👤 William R. Kirkpatrick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:34
CPC Classifications
G; G01; G01K; G01K7/00; G01K7/16; G01K7/18; G01K7/20; G01K15/00; G01K7/02; G01K7/026
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
91 words
A temperature transmitter in a process control system, comprising: a temperature sensor sensing a temperature and providing a sensor output related to a sensed temperature; an A/D converter coupled to the sensor output providing a digitized output related to the sensor output; a microprocessor coupled to the digitized output which compensates and processes the digitized output and provides a temperature output; and comparison circuitry which compares the sensor output to a first threshold and provides an inhibit signal to the microprocessor if the sensor output is outside of the first threshold.
Claim 2
Dependent Claim
91 words
A temperature transmitter in a process control system, comprising: a temperature sensor sensing a temperature and providing a sensor output related to a sensed temperature; an A/D converter coupled to the sensor output providing a digitized output related to the sensor output; a microprocessor coupled to the digitized output which compensates and processes the digitized output and provides a temperature output; and comparison circuitry which compares the sensor output to a first threshold and provides an inhibit signal to the microprocessor if the sensor output is outside of the first threshold.
Claim 3
Dependent Claim
27 words
The temperature transmitter of claim 1 wherein the sensor output includes a plurality of sensor leads which are individually coupled to the comparison circuitry through a multiplexer.
Claim 4
Dependent Claim
34 words
The temperature transmitter of claim 1 wherein the comparison circuitry compares the sensor output to a second threshold and provides the inhibit signal if the sensor output is outside the first and second thresholds.
Claim 5
Dependent Claim
43 words
The temperature transmitter of claim 2 including a switch connected to the first and second thresholds and an input to the comparison circuitry connecting the first or second thresholds to the comparison circuitry input in response to a control signal from the microprocessor.
Claim 6
Dependent Claim
23 words
The temperature transmitter of claim 1 wherein the microprocessor is coupled to the inhibit signal and the inhibit signal inhibits the temperature output.
Claim 7
Dependent Claim
23 words
The temperature transmitter of claim 1 wherein the comparison circuitry has a faster response time than a response time of the A/D converter.
Claim 8
Dependent Claim
21 words
The temperature transmitter of claim 1 wherein the comparison circuitry includes a polarity control input for selectively inverting the inhibit output.
Claim 9
Dependent Claim
16 words
The temperature transmitter of claim 7 wherein the polarity control input is coupled to the microprocessor.
Claim 10
Dependent Claim
26 words
The temperature transmitter of claim 1 including output circuitry coupled to a two-wire process control loop which transmits the temperature output on the process control loop.
Claim 11
Dependent Claim
12 words
The temperature transmitter of claim 1 wherein the sensor is an RTD.
Claim 12
Dependent Claim
12 words
The temperature transmitter of claim 1 wherein the sensor is a thermocouple.
Claim 13
Dependent Claim
21 words
The temperature transmitter of claim 1 wherein the microprocessor is coupled to the inhibit signal and responsively provides a diagnostic output.
Claim 14
Independent Claim
68 words
A method of measuring temperature of a process in a process control system, comprising the steps of: obtaining a sensor input related to temperature of the process; providing a digitized output related to the sensor output; compensating the digitized output and providing a compensated output indicative of temperature of the process; comparing the first sensor input with a threshold; and providing an error signal based upon the comparison.
Claim 15
Independent Claim
68 words
A method of measuring temperature of a process in a process control system, comprising the steps of: obtaining a sensor input related to temperature of the process; providing a digitized output related to the sensor output; compensating the digitized output and providing a compensated output indicative of temperature of the process; comparing the first sensor input with a threshold; and providing an error signal based upon the comparison.
Claim 16
Dependent Claim
16 words
The method of claim 13 including inhibiting the compensated output in response to the error signal.
Claim 17
Dependent Claim
27 words
The method of claim 13 including: comparing the sensor input with a second threshold; and providing the error signal based upon the comparison with the second threshold.
Claim 18
Dependent Claim
21 words
The method of claim 13 including adjusting the first threshold based upon a type of sensor which provides the sensor input.
Claim 19
Dependent Claim
20 words
The method of claim 13 wherein the step of comparing is faster than the step of providing the digitized output.
Claim 20
Dependent Claim
16 words
The method of claim 13 including transmitting the compensated output over a two-wire process control loop.
Claim 21
Dependent Claim
14 words
The method of claim 13 including selectively inverting the polarity of the error signal.
Claim 22
Dependent Claim
30 words
The method of claim 13 wherein the sensor input includes a plurality of sensor leads, the method including individually comparing a sensor input from each sensor lead with a threshold.
Claim 23
Dependent Claim
16 words
The method of claim 13 including providing a diagnostic output in response to the error signal.
References Cited (Backward Citations)
US3872389A
Cited
US4279151A
Cited
US4475823A
Cited
US4727359A
Cited
US4783659A
Cited
US5319576A
Cited
US4841286A
Cited
US4882564A
Cited
US5051743A
Cited
US5235527A
Cited
US5350237A
Cited
US5294890A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-12-29 | 2001-06-30 | 2001-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-29 | 2005-06-30 | 2005-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-29 | 2009-06-30 | 2009-12-30 | $7700.00 | Window Closed / Lapsed |