US4069413A
Expired / Lapsed
US
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Process measurement and control
Assignee: Applied Automation Inc
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Filing: 1976-10-29
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Granted: 1978-01-17
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Expires: 1996-10-29
Abstract
Abstract In the measurement of a variable process parameter and control of the process in response thereto, the time derivative of a second order or higher lagged process measurement signal is utilized to provide predictive capability in generating a process variable signal, in generating a process control signal, and in controlling the process in response to the measured parameter. The system is particularly well adapted to control of a non-self-regulating process.
Inventors
- 👤 Robert W. Rutledge
- 👤 Franklin D. Ganaway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:04
CPC Classifications
G; G05; G05B; G05B11/00; G05B11/01; G05B11/36; G05B11/42
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
89 words
Apparatus comprising: second or higher order lag means for accepting a process measurement signal and delivering in response thereto a lagged process measurement signal; differentiator means for accepting said lagged process measurement signal and delivering in response thereto a derivative signal representative of the time derivative of said lagged process measurement signal; and signal combining means for accepting said process measurement signal and said derivative signal and delivering in response thereto a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal.
Claim 2
Dependent Claim
89 words
Apparatus comprising: second or higher order lag means for accepting a process measurement signal and delivering in response thereto a lagged process measurement signal; differentiator means for accepting said lagged process measurement signal and delivering in response thereto a derivative signal representative of the time derivative of said lagged process measurement signal; and signal combining means for accepting said process measurement signal and said derivative signal and delivering in response thereto a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal.
Claim 3
Dependent Claim
74 words
Apparatus in accordance with claim 1 wherein said signal combining means comprises: first scaling means for applying a first scaling factor to said process measurement signal to produce a scaled process measurement signal; second scaling means for applying a second scaling factor to said derivative signal to produce a scaled lagged derivative signal; and adding means for adding said scaled process measurement signal and said scaled derivative signal to produce said process variable signal.
Claim 4
Dependent Claim
78 words
Apparatus in accordance with claim 1 wherein said signal combining means comprises: scaling means for accepting said derivative signal and delivering in response thereto a scaled derivative signal representative of the product of said derivative signal and a preselected scaling factor; and adding means for accepting said process measurement signal and said scaled derivative signal and delivering in response thereto a process variable signal representative of the sum of said process measurement signal and said scaled derivative signal.
Claim 5
Dependent Claim
53 words
Apparatus in accordance with claim 1 wherein said process variable signal satisfies the condition ##EQU6## where V p is said process variable signal, M p is said process measurement signal, M p1 is said lagged process measurement signal, t is time, and K 1 and K 2 are constants not equal to zero.
Claim 6
Dependent Claim
44 words
Apparatus in accordance with claim 1 additionally comprising controller means for accepting said process variable signal and a process variable set point signal representative of a desired value of said process variable signal as inputs and delivering in response thereto a process control signal.
Claim 7
Dependent Claim
14 words
Apparatus in accordance with claim 5 wherein said controller means comprises a proportional-integral controller.
Claim 8
Dependent Claim
74 words
Apparatus in accordance with claim 6 wherein said signal combining means comprises: first scaling means for applying a first scaling factor to said process measurement signal to produce a scaled process measurement signal; second scaling means for applying a second scaling factor to said derivative signal to produce a scaled lagged derivative signal; and adding means for adding said scaled process measurement signal and said scaled derivative signal to produce said process variable signal.
Claim 9
Dependent Claim
78 words
Apparatus in accordance with claim 6 wherein said signal combining means comprises: scaling means for accepting said derivative signal and delivering in response thereto a scaled derivative signal representative of the product of said derivative signal and a preselected scaling factor; and adding means for accepting said process measurement signal and said scaled derivative signal and delivering in response thereto a process variable signal representative of the sum of said process measurement signal and said scaled derivative signal.
Claim 10
Dependent Claim
63 words
Apparatus in accordance with claim 6 wherein said process control signal satisfies the condition C.sub.p = K.sub.3 (V.sub.p - SP) + K.sub.4 ∫ (V.sub.P - SP) dt where C p is said process control signal, V p is said process variable signal, SP is said set point signal, t is time, and K 3 and K 4 are constants not equal to zero.
Claim 11
Dependent Claim
53 words
Apparatus in accordance with claim 9 wherein said process variable signal satisfies the condition ##EQU7## where V p is said process variable signal, M p is said process measurement signal, M p1 is said lagged process measurement signal, t is time, and K 1 and K 2 are constants not equal to zero.
Claim 12
Dependent Claim
75 words
Apparatus in accordance with claim 6 additionally comprising: ammonia synthesis reactor means for converting hydrogen and nitrogen to ammonia; feed gas conduit means for supplying a flow of hydrogen-containing material to said synthesis reactor means; air conduit means for supplying a flow of nitrogen-containing material to said synthesis reactor means; and means for controlling the flow of air through said air conduit means to said ammonia synthesis reactor in response to said process control signal.
Claim 13
Dependent Claim
65 words
Apparatus in accordance with claim 11 wherein said means for controlling the flow of air comprises: second controller means for comparing said process control signal with a second process measurement signal and generating an air flow control signal in response to said comparison; and means for altering the flow rate of air to said ammonia synthesis reaction in response to said air flow control signal.
Claim 14
Independent Claim
99 words
A method for generating a process variable signal, said method comprising: generating a process measurement signal representative of the value of a preselected process parameter; applying a second or higher order lag factor to said process measurement signal to produce a lagged process measurement signal; generating, in response to said lagged process measurement signal, a derivative signal representative of the time derivative of said lagged process measurement signal; and generating, in response to said process measurement signal and said derivative signal, a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal.
Claim 15
Independent Claim
99 words
A method for generating a process variable signal, said method comprising: generating a process measurement signal representative of the value of a preselected process parameter; applying a second or higher order lag factor to said process measurement signal to produce a lagged process measurement signal; generating, in response to said lagged process measurement signal, a derivative signal representative of the time derivative of said lagged process measurement signal; and generating, in response to said process measurement signal and said derivative signal, a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal.
Claim 16
Dependent Claim
54 words
A method in accordance with claim 13 wherein said process variable signal satisfies the condition ##EQU8## where V p is said process variable signal, M p is said process measurement signal, M p1 is said lagged process measurement signal, t is time, and K 1 and K 2 are constants not equal to zero.
Claim 17
Dependent Claim
78 words
A method in accordance with claim 13 wherein the response of said lagged process measurement signal to a unit step change in said process measurement signal satisfies the general condition ##EQU9## where M p1 is said lagged process measurement signal, M p is said process measurement signal, C 1 , C 2 . . . C n and K 1 , K 2 . . . K n are constants, and n is an integer greater than 1.
Claim 18
Independent Claim
131 words
A method for generating a process control signal, said method comprising: generating a process measurement signal representative of the value of a preselected process parameter; applying a second or higher order lag factor to said process measurement signal to produce a lagged process measurement signal; generating, in response to said lagged process measurement signal, a derivative signal representative of the time derivative of said lagged process measurement signal; generating, in response to said process measurement signal and said derivative signal, a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal; comparing said process variable signal with a set point signal to produce a process variable error signal; and generating a process control signal bearing a predetermined relationship to said process variable error signal.
Claim 19
Independent Claim
131 words
A method for generating a process control signal, said method comprising: generating a process measurement signal representative of the value of a preselected process parameter; applying a second or higher order lag factor to said process measurement signal to produce a lagged process measurement signal; generating, in response to said lagged process measurement signal, a derivative signal representative of the time derivative of said lagged process measurement signal; generating, in response to said process measurement signal and said derivative signal, a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal; comparing said process variable signal with a set point signal to produce a process variable error signal; and generating a process control signal bearing a predetermined relationship to said process variable error signal.
Claim 20
Dependent Claim
54 words
A method in accordance with claim 16 wherein said process control signal satisfies the condition C.sub.p = K.sub.3 E + K.sub.4 ∫ E dt where C p is said process control signal, E is said process variable error signal, t is time, and K 3 and K 4 are constants not equal to zero.
Claim 21
Dependent Claim
78 words
A method in accordance with claim 17 wherein the response of said lagged process measurement signal to a unit step change in said process measurement signal satisfies the general condition ##EQU10## where M p1 is said lagged process measurement signal, M p is said process measurement signal, C 1 , C 2 . . . C n and K 1 , K 2 . . . K n are constants, and n is an integer greater than 1.
Claim 22
Dependent Claim
54 words
A method in accordance with claim 18 wherein said process variable signal satisfies the condition ##EQU11## where V p is said process variable signal, M p is said process measurement signal, M p1 is said lagged process measurement signal, t is time, and K 1 and K 2 are constants not equal to zero.
Claim 23
Independent Claim
160 words
A method of controlling the air flow to an ammonia synthesis reaction, said method comprising: generating a first process measurement signal representative of the ratio of hydrogen to nitrogen entering the synthesis reaction zone; applying a second or higher order lag factor to said process measurement signal to produce a lagged process measurement signal; generating, in response to said lagged process measurement signal, a derivative signal representative of the time derivative of said lagged process measurement signal; generating, in response to said process measurement signal and said derivative signal, a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal; employing said process variable signal as the variable input to a first controller producing a first process control signal in response to a comparison of said process variable signal and a preselected set point signal; and controlling the flow of air to said reaction zone in response to said first process control signal.
Claim 24
Independent Claim
160 words
A method of controlling the air flow to an ammonia synthesis reaction, said method comprising: generating a first process measurement signal representative of the ratio of hydrogen to nitrogen entering the synthesis reaction zone; applying a second or higher order lag factor to said process measurement signal to produce a lagged process measurement signal; generating, in response to said lagged process measurement signal, a derivative signal representative of the time derivative of said lagged process measurement signal; generating, in response to said process measurement signal and said derivative signal, a process variable signal representative of the weighted sum of said process measurement signal and said derivative signal; employing said process variable signal as the variable input to a first controller producing a first process control signal in response to a comparison of said process variable signal and a preselected set point signal; and controlling the flow of air to said reaction zone in response to said first process control signal.
Claim 25
Dependent Claim
78 words
A method in accordance with claim 20 wherein the response of said lagged process measurement signal to a unit step change in said process measurement signal satisfies the general condition ##EQU12## where M p1 is said lagged process measurement signal, M p is said process measurement signal, C 1 , C 2 . . . C n and K 1 , K 2 . . . K n are constants, and n is an integer greater than 1.
Claim 26
Dependent Claim
54 words
A method in accordance with claim 21 wherein said process variable signal satisfies the condition ##EQU13## where V p is said process variable signal, M p is said process measurement signal, M p1 is said lagged process measurement signal, t is time, and K 1 and K 2 are constants not equal to zero.
Claim 27
Dependent Claim
53 words
A method in accordance with claim 22 wherein said process control signal satisfies the condition C.sub.p = K.sub.3 E + K.sub.4 E dt where C p is said process control signal, E is said process variable error signal, t is time, and K 3 and K 4 are constants not equal to zero.
Claim 28
Dependent Claim
113 words
A method in accordance with claim 23 wherein controlling the flow of air to said reaction zone comprises: generating a second process measurement signal representative of the hydrogen to nitrogen ratio upstream from the introduction of any recycle stream from the synthesis reaction zone into the stream leading to said synthesis reaction zone; employing said second process measurement signal and said first process control signal as inputs to a second process controller producing a second process control signal in response to a comparison of said second process measurement signal and said first process control signal; and controlling the flow of air to said reaction zone in response to said second process control signal.
Claim 29
Dependent Claim
17 words
A method in accordance with claim 15 wherein said lag factor is a second order lag factor.
Claim 30
Dependent Claim
17 words
A method in accordance with claim 18 wherein said lag factor is a second order lag factor.
Claim 31
Dependent Claim
17 words
A method in accordance with claim 21 wherein said lag factor is a second order lag factor.
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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) | 1981-01-16 | 1981-07-18 | 1982-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-16 | 1985-07-18 | 1986-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-16 | 1989-07-18 | 1990-01-17 | $7700.00 | Window Closed / Lapsed |