US3750155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Temperature monitoring circuit
Assignee: Johnson Service Co
•
Filing: 1971-08-03
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Granted: 1973-07-31
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Expires: 1991-08-03
Abstract
Abstract A data acquisition system including a plurality of temperature monitoring circuits, each including an operational amplifier having a resistance-type temperature sensing element connected in a feedback loop of the amplifier and operable to provide an output voltage that is a function of the temperature measured by the circuit, a reference source which supplies a reference voltage to the amplifiers, enabling each amplifier to provide a constant current to the sensing element, a reference source monitoring circuit operable to provide an output voltage proportional to the reference voltage, and a multiplexing circuit for selectively extending the output voltages provided by the temperature monitoring circuits and the reference source monitoring circuit to a central processor. The output voltage provided by the reference source monitoring circuit is processed at the central processor to permit adjustment of the output voltages extended to the central processor from the temperature monitoring circuits to compensate for changes in the amplitude of the reference voltage.
Inventors
- 👤 G Oman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:41
CPC Classifications
G; G01; G01K; G01K1/00; G01K1/02; G01K1/026
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
371 words
In a data acquisition system, central processing means, a plurality of temperature transmitter circuits at locations of said system remote from said central processing means, each of said temperature transmitter circuits including operational amplifier means having an inverting input, an output, and a noninverting input, feedback means including temperature sensing means connected between the amplifier inverting input and the amplifier output, said temperature sensing means having a resistance that varies as a function of the temperature at the location of the corresponding temperature transmitter circuit, reference voltage means connected between the amplifier inverting input of at least one of said temperature transmitter circuits and the amplifier non-inverting input of said one temperature transmitter circuit, said reference voltage means supplying a constant reference voltage to the amplifier inputs for providing a constant current through the temperature sensing means of at least said one temperature transmitter circuit whereby the votlage developed across the temperature sensing means of said one temperature transmitter circuit establishes a potential at the amplifier output of said one temperature transmitter circuit relative to the amplifier non-inverting input which varies as a function of the temperature at the location of said one temperature transmitter circuit, reference voltage monitoring means including reference amplifier means having an inverting input, an output, and a noninverting input and fixed resistance means connected between the reference amplifier inverting input and the reference amplifier output, said reference voltage means being connected across the reference amplifier inputs for supplying a constant current to said fixed resistance means whereby said reference amplifier means provides a potential at the reference amplifier output relative to the reference amplifier non-inverting input that is proportional to the voltage provided by said reference voltage means, and multiplexing means including individual switching means for each of said temperature transmitter circuits each operable when enabled to extend the potential provided at the amplifier output of an associated one of said temperature transmitting circuits to said central processing means and further switching meaNs operable when enabled to extend the output potential of said reference amplifier means to said central processing means, said central processing means including select means for selectively enabling the switching means associated with said temperature transmitter circuits and said reference voltage monitoring means.
Claim 2
Dependent Claim
371 words
In a data acquisition system, central processing means, a plurality of temperature transmitter circuits at locations of said system remote from said central processing means, each of said temperature transmitter circuits including operational amplifier means having an inverting input, an output, and a noninverting input, feedback means including temperature sensing means connected between the amplifier inverting input and the amplifier output, said temperature sensing means having a resistance that varies as a function of the temperature at the location of the corresponding temperature transmitter circuit, reference voltage means connected between the amplifier inverting input of at least one of said temperature transmitter circuits and the amplifier non-inverting input of said one temperature transmitter circuit, said reference voltage means supplying a constant reference voltage to the amplifier inputs for providing a constant current through the temperature sensing means of at least said one temperature transmitter circuit whereby the votlage developed across the temperature sensing means of said one temperature transmitter circuit establishes a potential at the amplifier output of said one temperature transmitter circuit relative to the amplifier non-inverting input which varies as a function of the temperature at the location of said one temperature transmitter circuit, reference voltage monitoring means including reference amplifier means having an inverting input, an output, and a noninverting input and fixed resistance means connected between the reference amplifier inverting input and the reference amplifier output, said reference voltage means being connected across the reference amplifier inputs for supplying a constant current to said fixed resistance means whereby said reference amplifier means provides a potential at the reference amplifier output relative to the reference amplifier non-inverting input that is proportional to the voltage provided by said reference voltage means, and multiplexing means including individual switching means for each of said temperature transmitter circuits each operable when enabled to extend the potential provided at the amplifier output of an associated one of said temperature transmitting circuits to said central processing means and further switching meaNs operable when enabled to extend the output potential of said reference amplifier means to said central processing means, said central processing means including select means for selectively enabling the switching means associated with said temperature transmitter circuits and said reference voltage monitoring means.
Claim 3
Dependent Claim
56 words
A data acquision circuit as set forth in claim 1 wherein said central processing means includes means for adjusting the value of the potentials extended to said central processing means from said temperature transmitter circuits to compensate for changes in the reference voltage as indicated by the output potential provided by said reference voltage monitoring means.
Claim 4
Dependent Claim
272 words
In a data acquisition system, central processing means, at least one temperature monitoring means at a location of said system that is remote from said central processing means, said temperature monitoring means including temperature sensing means having a resistance that varies as a function of the temperature at the location of said temperature monitoring circuit, reference voltage means for supplying a reference voltage of a predetermined amplitude to inputs of said temperature monitoring means whereby said temperature monitoring means provides an output voltage that is proportional to the product of the amplitude of said reference votlage and the resistance of said temperature sensing means, reference source monitoring means, said reference source further supplying said reference voltage to inputs of said reference source monitoring means whereby said reference source monitoring means provides an output voltage that is proportional to the amplitude of said reference voltage, and multiplexing means including first switching means associated with said temperature monitoring means and operable when enabled to extend the output voltage provided by said temperature monitoring means to said central processing means and second switching means associated with said reference voltage monitoring means and operable when enabled to extend the output voltage provided by said reference source monitoring means to said central processing means, said central processing means including select means for selectively enabling said first and second switch means, and means for adjusting the value of the output voltage extended to said central processing means from said temperature monitoring means to compensate for changes in the reference voltage as indicated by the output voltage extended to said central processing means by said reference source monitoring means.
Claim 5
Dependent Claim
272 words
In a data acquisition system, central processing means, at least one temperature monitoring means at a location of said system that is remote from said central processing means, said temperature monitoring means including temperature sensing means having a resistance that varies as a function of the temperature at the location of said temperature monitoring circuit, reference voltage means for supplying a reference voltage of a predetermined amplitude to inputs of said temperature monitoring means whereby said temperature monitoring means provides an output voltage that is proportional to the product of the amplitude of said reference votlage and the resistance of said temperature sensing means, reference source monitoring means, said reference source further supplying said reference voltage to inputs of said reference source monitoring means whereby said reference source monitoring means provides an output voltage that is proportional to the amplitude of said reference voltage, and multiplexing means including first switching means associated with said temperature monitoring means and operable when enabled to extend the output voltage provided by said temperature monitoring means to said central processing means and second switching means associated with said reference voltage monitoring means and operable when enabled to extend the output voltage provided by said reference source monitoring means to said central processing means, said central processing means including select means for selectively enabling said first and second switch means, and means for adjusting the value of the output voltage extended to said central processing means from said temperature monitoring means to compensate for changes in the reference voltage as indicated by the output voltage extended to said central processing means by said reference source monitoring means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |