US3628129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process controller including a rate circuit responsive solely to process variable signal changes
Assignee: General Electric Co
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Filing: 1970-10-01
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Granted: 1971-12-14
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Expires: 1990-10-01
Abstract
Abstract An improved process controller wherein rate action occurs only during changes in the process variable signal. The process variable signal is applied to one input terminal of a first differential amplifier having a rate circuit connected in a feedback loop between the output terminal and the second input terminal of the amplifier. The first differential amplifier provides one input to a second differential amplifier, a second input to which is provided by a setpoint signal source. Proportional and reset action may be applied to the output signal of the second differential amplifier.
Inventors
- 👤 John E Riley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:07
CPC Classifications
G; G05; G05B; G05B5/00; G05B5/01
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
For use in a process control system having process variable and setpoint signal sources, a process controller comprising: a. a first differential amplifier having a first input terminal adapted to be connected to the process variable signal source, a second input terminal, and an output terminal; b. a rate circuit in a feedback loop connecting the output terminal and the second input terminal of said first differential amplifier; and c. a second differential amplifier having a first input terminal connected to the output terminal of said first differential amplifier, a second input terminal adapted to be connected to the setpoint signal source, and an output terminal, the signal on said last-mentioned output terminal being characterized by the application of rate action to changes in only the process variable signal.
Claim 2
Dependent Claim
129 words
For use in a process control system having process variable and setpoint signal sources, a process controller comprising: a. a first differential amplifier having a first input terminal adapted to be connected to the process variable signal source, a second input terminal, and an output terminal; b. a rate circuit in a feedback loop connecting the output terminal and the second input terminal of said first differential amplifier; and c. a second differential amplifier having a first input terminal connected to the output terminal of said first differential amplifier, a second input terminal adapted to be connected to the setpoint signal source, and an output terminal, the signal on said last-mentioned output terminal being characterized by the application of rate action to changes in only the process variable signal.
Claim 3
Dependent Claim
43 words
A process controller as recited in claim 1 wherein said rate circuit includes: a. a first resistor and a first capacitor connected in parallel in the feedback loop; and b. a second capacitor connected between a ground terminal and the second input terminal.
Claim 4
Dependent Claim
112 words
For use in a process control system having process variable and setpoint signal sources, a process controller comprising: a. a first amplifier having an input terminal adapted to be connected to the process variable signal source, and an output terminal; b. a rate circuit in a negative feedback loop for said first amplifier; and c. signal-combining means having a first input terminal connected to the output terminal of said first differential amplifier, a second input terminal adapted to be connected to the setpoint signal source, and an output terminal, the signal on said last-mentioned output terminal being characterized by the application of rate action to changes in only the process variable signal.
Claim 5
Dependent Claim
112 words
For use in a process control system having process variable and setpoint signal sources, a process controller comprising: a. a first amplifier having an input terminal adapted to be connected to the process variable signal source, and an output terminal; b. a rate circuit in a negative feedback loop for said first amplifier; and c. signal-combining means having a first input terminal connected to the output terminal of said first differential amplifier, a second input terminal adapted to be connected to the setpoint signal source, and an output terminal, the signal on said last-mentioned output terminal being characterized by the application of rate action to changes in only the process variable signal.
Claim 6
Dependent Claim
16 words
A process controller as recited in claim 3 wherein said signal-combining means comprises a differential amplifier.
Claim 7
Dependent Claim
43 words
A process controller as recited in claim 3 wherein said rate circuit includes a first resistor and first capacitor connected in parallel in the negative feedback loop and a second capacitor connected between one end of the parallel connection and an electrical ground.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |