US3552428A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatically tuned process controller
Assignee: Applied Automation Inc
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Filing: 1968-06-20
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Granted: 1971-01-05
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Expires: 1988-06-20
Abstract
Abstract A process control system is compensated for nonlinearities in the control loop by means of a variable gain feedback element in the controller. The gain of the feedback element is adjusted by the output signal from a function generator, the input of which is the measured variable. The function generator is calibrated to compensate for the nonlinearity of the control loop.
Inventors
- 👤 Troy J Pemberton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:39
CPC Classifications
G; G05; G05D; G05D7/00; G05D7/06; G05D7/0617; G05D7/0629; G05D7/0688; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7758; Y10T137/7759; Y10T137/7761
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
166 words
In a process control system which includes means to sense a process variable and establish a first signal representative thereof, means to compare said first signal with a set point signal and establish a second signal representative of the difference therebetween, and means responsive to said second signal to establish an output control signal; the improvement comprising: feedback means connected between the output and the input of said means to establish an output signal, said feedback means having a variable gain means included therein; a function generator having an input and an output, to establish an output signal which varies in a predetermined nonlinear manner with respect to changes in amplitude of an input signal applied thereto; means independent of said set point signal to apply said first signal to the input of said function generator as the sole input signal thereto; and means to apply the output signal from said function generator to said variable gain means to regulate the gain of said feedback means.
Claim 2
Dependent Claim
166 words
In a process control system which includes means to sense a process variable and establish a first signal representative thereof, means to compare said first signal with a set point signal and establish a second signal representative of the difference therebetween, and means responsive to said second signal to establish an output control signal; the improvement comprising: feedback means connected between the output and the input of said means to establish an output signal, said feedback means having a variable gain means included therein; a function generator having an input and an output, to establish an output signal which varies in a predetermined nonlinear manner with respect to changes in amplitude of an input signal applied thereto; means independent of said set point signal to apply said first signal to the input of said function generator as the sole input signal thereto; and means to apply the output signal from said function generator to said variable gain means to regulate the gain of said feedback means.
Claim 3
Dependent Claim
37 words
The system of claim 1 wherein said process variable is the rate of fluid flow through a conduit; and further comprising a valve in said conduit, and means responsive to said output signal to regulate said valve.
Claim 4
Dependent Claim
36 words
The system of claim 2 wherein said means to sense said process variable is an orifice in said conduit and means to establish a first signal which is representative of the pressure differential across said orifice.
Claim 5
Dependent Claim
78 words
The system of Claim 1 wherein said first signal is an electrical signal, said means to establish an output signal comprises a first amplifier having an input and an output, and said feedback means comprises a variable gain amplifier having an input and an output, the input of said variable gain amplifier being connected to the output of said first amplifier and the output of said variable gain amplifier being connected to the input of said first amplifier.
Claim 6
Dependent Claim
208 words
In a process control system which includes means to sense a process variable and establish a first electrical signal representative thereof, means to compare said first signal with a set point signal and establish a second signal representative of the difference therebetween, and a first amplifier responsive to said second signal to establish an output control signal, said first amplifier having an inpUt and an output; the improvement comprising: a variable gain feedback amplifier having an input and an output, the input of said variable gain amplifier being connected to the output of said first amplifier and the output of said variable gain amplifier being connected to the input of said first amplifier; a function generator to establish an output signal which varies in a predetermined manner with respect to changes in an input signal applied thereto, said function generator comprising circuit means having a plurality of diodes connected in parallel between the input and output thereof, and means biasing each of said diodes so that conduction takes place therethrough at a predetermined voltage; means to apply said first signal to the input of said function generator; and means to apply the output signal from said function generator to said variable gain amplifier to regulate the gain thereof.
Claim 7
Dependent Claim
208 words
In a process control system which includes means to sense a process variable and establish a first electrical signal representative thereof, means to compare said first signal with a set point signal and establish a second signal representative of the difference therebetween, and a first amplifier responsive to said second signal to establish an output control signal, said first amplifier having an inpUt and an output; the improvement comprising: a variable gain feedback amplifier having an input and an output, the input of said variable gain amplifier being connected to the output of said first amplifier and the output of said variable gain amplifier being connected to the input of said first amplifier; a function generator to establish an output signal which varies in a predetermined manner with respect to changes in an input signal applied thereto, said function generator comprising circuit means having a plurality of diodes connected in parallel between the input and output thereof, and means biasing each of said diodes so that conduction takes place therethrough at a predetermined voltage; means to apply said first signal to the input of said function generator; and means to apply the output signal from said function generator to said variable gain amplifier to regulate the gain thereof.
Claim 8
Dependent Claim
37 words
The system of claim 5 wherein said process variable is the rate of fluid flow through a conduit; and further comprising a valve in said conduit, and means responsive to said output signal to regulate said valve.
Claim 9
Dependent Claim
36 words
The system of claim 6 wherein said means to sense said process variable is an orifice in said conduit and means to establish a first signal which is representative of the pressure differential across said orifice.
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) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |