Patent US5642301A successfully refreshed from Google Patents.
US5642301A
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Transmitter with improved compensation
Assignee: Rosemount Inc
•
Filing: 1994-01-25
•
Granted: 1997-06-24
•
Expires: 2014-01-25
Abstract
Abstract A circuit for compensating variables in a measurement transmitter. Within the transmitter, a sensor senses a primary process variable such as differential pressure and a converter digitizes the sensed process variable. The sensor senses pressures within a span of pressures values. A memory inside the transmitter stores at least two membership functions, each membership function having a non-zero value over a predetermined region of the process variable span and a substantially zero value over the remainder of the span. The memory also stores a set of compensation formulas, each formula corresponding to a membership function. A selection circuit in the transmitter selects those membership functions which have a non-zero value at the digitized process variable and a correction circuit provides at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function. A weighting circuit multiplies each correction value by its corresponding selected membership function, and combines the multiplicands to provide a compensated process variable. The compensated process variable is coupled to a control circuit connecting the transmitter to a control system.
Inventors
- 👤 Jogesh Warrior
- 👤 Scott E. Brigham
- 👤 Gary A. Lenz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:48
CPC Classifications
G; G01; G01D; G01D3/00; G01D3/028; G01D3/036; G01D3/0365; G01D18/00; G01D3/02; G01D3/022; Y; Y10; Y10S; Y10S706/00; Y10S706/90; Y10S706/902; Y10S706/903; Y10S706/906
Claims Analysis
Total Claims: 101
Claim 1
Independent Claim
209 words
A measurement transmitter, comprising: conversion means for sensing a process variable related to pressure within a span of process variable values and for providing a digitized output representative of the sensed pressure process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are at least three membership functions for the pressure process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 2
Dependent Claim
209 words
A measurement transmitter, comprising: conversion means for sensing a process variable related to pressure within a span of process variable values and for providing a digitized output representative of the sensed pressure process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are at least three membership functions for the pressure process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 3
Dependent Claim
17 words
The transmitter of claim 1 where non-zero regions of two of the membership functions overlap each other.
Claim 4
Dependent Claim
15 words
The transmitter of claim 2 where the control circuit is a two wire current loop.
Claim 5
Dependent Claim
19 words
The transmitter of claim 3 where current in the loop has a magnitude representative of the compensated process variable.
Claim 6
Dependent Claim
14 words
The transmitter of claim 1 where the control circuit is a three wire circuit.
Claim 7
Dependent Claim
14 words
The transmitter of claim 1 where at least one membership function is triangularly shaped.
Claim 8
Dependent Claim
15 words
The transmitter of claim 1 where at least one membership function is a gaussian function.
Claim 9
Dependent Claim
18 words
The transmitter of claim 1 where the weighting means combine the correction values according to a weighted average.
Claim 10
Dependent Claim
17 words
The transmitter of claim 1 where at least one of the compensation formulas is a polynomial function.
Claim 11
Dependent Claim
22 words
The transmitter of claim 1 where the at least three membership functions each overlap at least one other membership function by 50%.
Claim 12
Dependent Claim
32 words
The transmitter of claim 1 where the conversion means include a differential pressure sensor and the conversion means provide a digitized representation of a variable related in time to the differential pressure.
Claim 13
Dependent Claim
15 words
The transmitter of claim 1 where the pressure process variable is a time dependent variable.
Claim 14
Dependent Claim
14 words
The transmitter of claim 12 where the time dependent variable is a first derivative.
Claim 15
Dependent Claim
14 words
The transmitter of claim 12 where the time dependent variable is a second derivative.
Claim 16
Dependent Claim
13 words
The transmitter of claim 12 where the time dependent variable is an integral.
Claim 17
Dependent Claim
15 words
The transmitter of claim 1 where the pressure process variable is a history dependent variable.
Claim 18
Dependent Claim
15 words
The transmitter of claim 1 where the pressure process variable is a position dependent variable.
Claim 19
Dependent Claim
15 words
The transmitter of claim 1 where the pressure process variable is a device dependent variable.
Claim 20
Dependent Claim
169 words
A transmitter in a process control system comprising: a sensor for sensing a physical variable in the system, the physical variable taking on values within a span of values, the sensor having an output representative of the physical variable within the span; digitizing means for digitizing the sensor output; selection and storing means for selecting a region from a set of regions in a different portion of the span, a region becoming selected when the sensor output is included within the region, each region having a compensation formula and a membership function corresponding thereto; computation means for retrieving the membership functions and the compensation formulas corresponding to the selected regions, and for providing the ordinates of the membership functions at the value of the sensor output and for providing the value of the compensation formulas at the value of the sensor output; and compensation means for weighting the value of the compensation formulas by the ordinate of the corresponding membership functions so as to provide a compensated transmitter output.
Claim 21
Dependent Claim
169 words
A transmitter in a process control system comprising: a sensor for sensing a physical variable in the system, the physical variable taking on values within a span of values, the sensor having an output representative of the physical variable within the span; digitizing means for digitizing the sensor output; selection and storing means for selecting a region from a set of regions in a different portion of the span, a region becoming selected when the sensor output is included within the region, each region having a compensation formula and a membership function corresponding thereto; computation means for retrieving the membership functions and the compensation formulas corresponding to the selected regions, and for providing the ordinates of the membership functions at the value of the sensor output and for providing the value of the compensation formulas at the value of the sensor output; and compensation means for weighting the value of the compensation formulas by the ordinate of the corresponding membership functions so as to provide a compensated transmitter output.
Claim 22
Dependent Claim
82 words
The transmitter of claim 19 where each variable is assigned at least one membership function and the weighting means further comprise: forming means for forming a combination of the ordinates of each of the selected membership functions, each combination comprising one ordinate related to each variable; a fuzzy AND circuit for selecting the minimum value in each of the combinations; where the weighting means weight each correction value by the ordinate of the corresponding membership functions to provide a compensated transmitter output.
Claim 23
Dependent Claim
18 words
The transmitter of claim 19 where an output circuit couples the compensated physical variable to a control circuit.
Claim 24
Dependent Claim
15 words
The transmitter of claim 21 wherein the transmitter couples to a two wire current loop.
Claim 25
Dependent Claim
19 words
The transmitter of claim 23 where current in the loop has a magnitude representative of the compensated physical variable.
Claim 26
Dependent Claim
17 words
The transmitter of claim 19 where non-zero regions of two of the membership functions overlap each other.
Claim 27
Dependent Claim
14 words
The transmitter of claim 19 where at least one membership function is triangularly shaped.
Claim 28
Dependent Claim
15 words
The transmitter of claim 19 where at least one membership function is a gaussian function.
Claim 29
Dependent Claim
17 words
The transmitter of claim 19 where at least one of the compensation formulas is a polynomial function.
Claim 30
Dependent Claim
37 words
The transmitter of claim 19 where the physical variable is selected from the group of physical variables consisting of differential pressure, position, volumetric flow, mass flow, temperature, level, density, displacement, pH, turbidity, dissolved oxygen and ion concentration.
Claim 31
Dependent Claim
12 words
The transmitter of claim 19 wherein the physical variable comprises differential pressure.
Claim 32
Dependent Claim
46 words
The transmitter of claim 29 where there are three membership functions for the differential pressure, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of physical variables values.
Claim 33
Dependent Claim
11 words
The transmitter of claim 19 wherein the physical variable comprises level.
Claim 34
Dependent Claim
11 words
The transmitter of claim 19 wherein the physical variable comprises temperature.
Claim 35
Dependent Claim
11 words
The transmitter of claim 19 wherein the physical variable comprises flow.
Claim 36
Dependent Claim
11 words
The transmitter of claim 19 wherein the physical variable comprises position.
Claim 37
Dependent Claim
21 words
The transmitter of claim 19 where there are three membership functions each overlapping at least one other membership function by 50%.
Claim 38
Dependent Claim
14 words
The transmitter of claim 19 where the physical variable is a time dependent variable.
Claim 39
Dependent Claim
14 words
The transmitter of claim 36 where the time dependent variable is a first derivative.
Claim 40
Dependent Claim
14 words
The transmitter of claim 36 where the time dependent variable is a second derivative.
Claim 41
Dependent Claim
13 words
The transmitter of claim 36 where the time dependent variable is an integral.
Claim 42
Dependent Claim
14 words
The transmitter of claim 19 where the physical variable is a history dependent variable.
Claim 43
Dependent Claim
14 words
The transmitter of claim 19 where the physical variable is a position dependent variable.
Claim 44
Dependent Claim
14 words
The transmitter of claim 19 where the physical variable is a device dependent variable.
Claim 45
Dependent Claim
206 words
A measurement transmitter, comprising: conversion means for sensing a process variable related to temperature within a span of process variable values and for providing a digitized output representative of the sensed process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are three membership functions for the temperature process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 46
Dependent Claim
206 words
A measurement transmitter, comprising: conversion means for sensing a process variable related to temperature within a span of process variable values and for providing a digitized output representative of the sensed process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are three membership functions for the temperature process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 47
Dependent Claim
17 words
The transmitter of claim 43 where non-zero regions of two of the membership functions overlap each other.
Claim 48
Dependent Claim
15 words
The transmitter of claim 43 where the control circuit is a two wire current loop.
Claim 49
Dependent Claim
19 words
The transmitter of claim 45 where current in the loop has a magnitude representative of the compensated process variable.
Claim 50
Dependent Claim
14 words
The transmitter of claim 43 where the control circuit is a three wire circuit.
Claim 51
Dependent Claim
14 words
The transmitter of claim 43 where at least one membership function is triangularly shaped.
Claim 52
Dependent Claim
15 words
The transmitter of claim 43 where at least one membership function is a gaussian function.
Claim 53
Dependent Claim
18 words
The transmitter of claim 43 where the weighting means combine the correction values according to a weighted average.
Claim 54
Dependent Claim
17 words
The transmitter of claim 43 where at least one of the compensation formulas is a polynomial function.
Claim 55
Dependent Claim
20 words
The transmitter of claim 43 where the three membership functions each overlapping at least one other membership function by 50%.
Claim 56
Dependent Claim
32 words
The transmitter of claim 43 where the conversion means include a differential pressure sensor and the conversion means provide a digitized representation of a variable related in time to the differential pressure.
Claim 57
Dependent Claim
15 words
The transmitter of claim 43 where the temperature process variable is a time dependent variable.
Claim 58
Dependent Claim
14 words
The transmitter of claim 54 where the time dependent variable is a first derivative.
Claim 59
Dependent Claim
14 words
The transmitter of claim 54 where the time dependent variable is a second derivative.
Claim 60
Dependent Claim
13 words
The transmitter of claim 54 where the time dependent variable is an integral.
Claim 61
Dependent Claim
15 words
The transmitter of claim 43 where the temperature process variable is a history dependent variable.
Claim 62
Dependent Claim
15 words
The transmitter of claim 43 where the temperature process variable is a position dependent variable.
Claim 63
Dependent Claim
15 words
The transmitter of claim 43 where the temperature process variable is a device dependent variable.
Claim 64
Dependent Claim
205 words
A measurement transmitter, comprising: conversion meads for sensing a flow process variable within a span of process variable values and for providing a digitized output representative of the sensed process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the flow process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are three membership functions for the flow process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 65
Dependent Claim
205 words
A measurement transmitter, comprising: conversion meads for sensing a flow process variable within a span of process variable values and for providing a digitized output representative of the sensed process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the flow process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are three membership functions for the flow process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 66
Dependent Claim
17 words
The transmitter of claim 61 where non-zero regions of two of the membership functions overlap each other.
Claim 67
Dependent Claim
14 words
The transmitter of claim 61 where the control circuit is two wire current loop.
Claim 68
Dependent Claim
18 words
The transmitter of claim 63 where current in the loop has magnitude representative of the compensated process variable.
Claim 69
Dependent Claim
14 words
The transmitter of claim 61 where the control circuit is a three wire circuit.
Claim 70
Dependent Claim
14 words
The transmitter of claim 61 where at least one membership function is triangularly shaped.
Claim 71
Dependent Claim
15 words
The transmitter of claim 61 where at least one membership function is a gaussian function.
Claim 72
Dependent Claim
18 words
The transmitter of claim 61 where the weighting means combine the correction values according to a weighted average.
Claim 73
Dependent Claim
17 words
The transmitter of claim 61 where at least one of the compensation formulas is a polynomial function.
Claim 74
Dependent Claim
20 words
The transmitter of claim 61 where the three membership functions each overlap at least one other membership function by 50%.
Claim 75
Dependent Claim
32 words
The transmitter of claim 61 where the conversion means include a differential pressure sensor and the conversion means provide a digitized representation of a variable related in time to the differential pressure.
Claim 76
Dependent Claim
15 words
The transmitter of claim 61 where the flow process variable is a time dependent variable.
Claim 77
Dependent Claim
14 words
The transmitter of claim 72 where the time dependent variable is a first derivative.
Claim 78
Dependent Claim
14 words
The transmitter of claim 72 where the time dependent variable is a second derivative.
Claim 79
Dependent Claim
13 words
The transmitter of claim 72 where the time dependent variable is an integral.
Claim 80
Dependent Claim
15 words
The transmitter of claim 61 where the flow process variable is a history dependent variable.
Claim 81
Dependent Claim
15 words
The transmitter of claim 61 where the flow process variable is a position dependent variable.
Claim 82
Dependent Claim
15 words
The transmitter of claim 61 where the flow process variable is a device dependent variable.
Claim 83
Dependent Claim
205 words
A measurement transmitter, comprising: conversion means for sensing a level process variable within a span of process variable values and for providing a digitized output representative of the sensed process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the level process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are three membership functions for the level process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 84
Dependent Claim
205 words
A measurement transmitter, comprising: conversion means for sensing a level process variable within a span of process variable values and for providing a digitized output representative of the sensed process variable; a memory for storing at least two membership functions, each membership function having a non-zero value over a predetermined region of the level process variable span and a substantially zero value over the remainder of the span, and for storing a set of compensation formulas, each formula corresponding to a membership function; selection means for selecting those membership functions which have a non-zero value at the digitized process variable; correction means for providing at least one correction value, each correction value calculated from a compensation formula corresponding to a selected membership function; weighting means for weighting each correction value by its corresponding selected membership function, and for combining the weighted correction values to provide a compensated process variable; an output circuit for coupling the compensated process variable to a control circuit; and wherein there are three membership functions for the level process variable, the membership functions each having a center point corresponding to a maximum value of the membership function, where the center points are evenly spaced along the span of process variable values.
Claim 85
Dependent Claim
17 words
The transmitter of claim 79 where non-zero regions of two of the membership functions overlap each other.
Claim 86
Dependent Claim
15 words
The transmitter of claim 79 where the control circuit is a two wire current loop.
Claim 87
Dependent Claim
19 words
The transmitter of claim 81 where current in the loop has a magnitude representative of the compensated process variable.
Claim 88
Dependent Claim
14 words
The transmitter of claim 79 where the control circuit is a three wire circuit.
Claim 89
Dependent Claim
14 words
The transmitter of claim 79 where at least one membership function is triangularly shaped.
Claim 90
Dependent Claim
15 words
The transmitter of claim 79 where at least one membership function is a gaussian function.
Claim 91
Dependent Claim
18 words
The transmitter of claim 79 where the weighting means combine the correction values according to a weighted average.
Claim 92
Dependent Claim
17 words
The transmitter of claim 79 where at least one of the compensation formulas is a polynomial function.
Claim 93
Dependent Claim
20 words
The transmitter of claim 79 where the three membership functions each overlap at least one other membership function by 50%.
Claim 94
Dependent Claim
32 words
The transmitter of claim 79 where the conversion means include a differential pressure sensor and the conversion means provide a digitized representation of a variable related in time to the differential pressure.
Claim 95
Dependent Claim
15 words
The transmitter of claim 79 where the level process variable is a time dependent variable.
Claim 96
Dependent Claim
14 words
The transmitter of claim 90 where the time dependent variable is a first derivative.
Claim 97
Dependent Claim
14 words
The transmitter of claim 90 where the time dependent variable is a second derivative.
Claim 98
Dependent Claim
13 words
The transmitter of claim 90 where the time dependent variable is an integral.
Claim 99
Dependent Claim
15 words
The transmitter of claim 79 where the level process variable is a history dependent variable.
Claim 100
Dependent Claim
15 words
The transmitter of claim 79 where the level process variable is a position dependent variable.
Claim 101
Dependent Claim
15 words
The transmitter of claim 79 where the level process variable is a device dependent variable.
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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) | 2000-06-23 | 2000-12-23 | 2001-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-06-23 | 2004-12-23 | 2005-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-06-23 | 2008-12-23 | 2009-06-24 | $7700.00 | Window Closed / Lapsed |