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Publication numberUS3748446 A
Publication typeGrant
Publication dateJul 24, 1973
Filing dateApr 1, 1971
Priority dateApr 1, 1971
Publication numberUS 3748446 A, US 3748446A, US-A-3748446, US3748446 A, US3748446A
InventorsGass E, Hammond J, Lorenzino P, Thomas J
Original AssigneeHalliburton Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Digital pulse count correction circuit
US 3748446 A
Abstract
Method and apparatus for linearizing an electrical signal comprising a series of electrical pulses non-linearly related in number to a sensed condition. The series of electrical pulses are counted in groups and a predetermined number of pulses are generated independently for each group of pulses counted. The method and apparatus has particular utility with a net oil analyzer where the condition is the oil/water ratio and where an initial offset is required at an oil/water ratio of one.
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I Umted States Patent 1 [111 3,748,446

Gass et al. July 24, 1973 I54] DIGITAL PULSE COUNT CORRECTION 2,92l,740 1/1960 Dobbins ct a]. 235/92 CC CIRCUIT 2,886,243 5 1959 Sprague at al. 235/197 3,445,840 5/1969 Carlstead 235/92 PL [75] Inventors: Edward W. Gass; Jack a 3,566,685 3/1971 Zimmerman etal. 235 151.34 x Paul Lorenzino, all of Duncan; 2,913,179 11/1959 Gordon 235/l50.3 Joseph E. Thomas, Tulsa, all of Okla. [73] Assignee: Halliburton Company, Duncan, Primary Emmiflerchal'les Atkinson ()k1 Assistant Examiner-Edward J. Wise Filed p 1 1971 Attorney-Burns, Doane, Swecker & Mathis [21] Appl. No.: 130,375 ABSTRACT [52] US. Cl t 235/15L35 73/194 235,92 Method and apparatus for linearizing an electrical sig- 2355/1503: nal comprising a series of electrical pulses non-linearly [51] Cl u u n Go" 1/00 GO 7/38 related in number to a sensed condition. The series of 581 Field oi's'g'nh.............II.... 235/15135 92 PL elecm'cal Pulses are muted gmuPs and a predeter- 235/92 CC 92 DE 1503. 73/194 E R 1 mined number of pulses are generated independently 328/311 1 6 for each group of pulses counted. The method and apparatus has particular utility with a net oil analyzer [561 Retereuces Cited where the condition is the oil/water ratio and where an initial offset is required at an oil/water ratio of one.

23 Claims, 9'Drawing Figures FLUID C(XMT ER LIEARIZATION CIRCUIT COUNTER Pmmzumz 3.748.446

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NET OIL 22 ANALYZER LINEARIZATION CIRCUIT $28 COUNTER -30 FIGI g SIGNAL couomomue MW 25 25 NET OIL ANALYZER INVENTORS EDWARD W. GASS JACK HAMMOND PAUL LORENZINO,JR. JOSEPH E. THOMAS PAIENIEDJULZMQIS 3 148,446

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b--|Q-- COUNTER l GRWP PULSE COUNTER DIGITAL PULSE COUNT CORRECTION CIRCUIT BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for linearizing a condition responsive digital electrical signal and more particularly to a method and pulse count correction circuit for a digital net oil analy- ZBI'.

The linearizing method and apparatus of the present invention has particular utility and will hereinafter be disclosed in connection with a net oil analyzer. Net oil analyzers are well known in the art and generally utilize a radio frequency oscillator having a capacitance probe disposed in the fluid for measuring the constituency thereof, i.e., the net volume of oil and water in the well effluent. A signal from the net oil analyzer may be nonlinearly related to the net oil in the fluid by reason of a non-linearity in the digital output signal from the condition responsive transducer or in the digital output signal from the flow meter utilized to measure gross fluid flow.

The non-linearity of particular importance in net oil systems is related to the character of the well effluent. The well effluent is generally pumped to an oil/water separator or settling tank wherein the effluent quickly stratfies into three layers. The lowermost layer is substantially pure water and is separated by an emulsion of oil and water from the uppermost layer which is substantially pure oil. Periodically, the fluid from the oil/- water separator is dumped and passed through a single fluid pipeline having a capacitance probe and a flow meter disposed therein.

The capacitance probe generally utilized in such system is operative only when the fluid is more than 50 percent oil, i.e., the water droplets are surrounded by oil. In the event that the oil/water ratio is reversed and the droplets of oil are surrounded by water, the electrodes of the capacitance probe tend to short out and will thus provide an erroneous indication of the amount of oil within the fluid.

Since the percentage of oil and water may vary widely in a given separator dump, it is difficult to anticipate the volume of fluid in each of the three layers sequentially passed through the pipeline. The output signal from the capacitance probe during the passage of the substantially pure water must, however, be disregarded in order to provide an accurate indication of the net oil within the well effluent.

It is accordingly an object of the present invention to provide a novel method and apparatus for obviating the deficiencies of the prior art and for linearizing a condition responsive digital signal.

It is another object of the present invention to provide a novel method and apparatus for correcting the pulse count output of a net oil analyzer.

It is yet another object of the present invention to provide a novel method and apparatus for modifying the output signal of a net oil analyzer in accordance with the constituency of the fluid analyzed.

It is yet a further object of the present invention to provide a novel method and apparatus for increasing the accuracy of the output signal from a net oil analyzer.

It is still yet another object of the present invention to provide a novel method and apparatus for linearizing a digital output signal.

These and other objects and advantages will be apparent to one skilled in the art to which the invention pertains from the claims and from the following detailed description when read in conjunction with the appended drawings.

THE DRAWINGS FIG. 1 is a functional block diagram of the apparatus of the present invention;

FIG. 2 is a functional block diagram of the net oil analyzer of FIG. 1;

FIG. 3 is a functional block diagram of the linearzation circuit of FIG. 1;

FIG. 4 is a functional block diagram of the subtractor of the linearization circuit of FIG. 3;

FIG. 5 is a functional block diagram of the group pulse counter circuit of the linearziation circuit of FIG.

FIG. 6 is a functional block diagram of the segment selector shift register of the linearization circuit of FIG.

FIG. 7 is a functional block diagram of the gating circuit of the linearization circuit of FIG. 3;

FIG. 8 is a typical graph of capacitance transducer frequency response plotted against net oil; and,

FIG. 9 is a graph of the number of pulses applied to the group pulse counter when plotted against the number of pulses produced by the linearization circuit.

DETAILED DESCRIPTION The present invention may be more easily understood by reference to the following detailed description of a net oil analyzer lineariza-tion circuit as set in accordance with the following Table of Contents.

TABLE OF CONTENTS I. System (FIGS. 1-3) A. Circuit Description B. Circuit Operation II. Linearization Circuit (FIGS. 4-9) A. Circuit Description B. Circuit Operation C. Example III. Advantages and Scope of Invention I. SYSTEM A. Circuit Description With reference now to FIG. 1, the effluent from a conventional separator or settling tank (not shown) is conveyed by way of a pipeline 10 in which is disposed a capacitance probe 12 and a flow meter I4.

The capacitance probe 12 may be of the type claimed and described in U. S. Pat. No. 3,523,245 to R.G. Love et al. entitled Fluid Monitoring Capacitance Probe Having The Electric Circuitry Mounted Within The Probe" and assigned to the assignee of the present invention. The flowmeter 14 may be of any suitable type such as the turbine mass flowmeter disclosed and claimed in U. S. Pat. No. 3,164,020 to Edward Groner et al. entitled Flowmeter and assigned to the assignee of the present invention. alternatively, a suitable positive displacement meter may be employed.

The output signal from the transducer 12 is a series of electrical pulses having a frequency or pulse repetition rate related to the dielectric constant of the fluid flowing within the pipeline 10. This digital output signal f, is applied by way of an output terminal 16 to a net oil analyzer l8 and a linearization circuit 20. The output signal from the flowmeter M is likewise a series of pulses having a frequency or pulse repitition rate related to the volume of fluid flowing through the pipeline It). This output signalf is applied by way of an output terminal 22 to the net oil analyzer l8 and to a gross fluid counter 24. The counter 24 may be any conventional electrical or electro-mechanical counter and may, but need not, provide a visual indication of the number of pulses counted. A suitable counter, for example, is the I-Iecon serial FR967 counter commercially available from Hengstler Numerics, Inc., of Palisades Park, NJ.

The net oil analyzer 18 is desirably of the type disclosed and claimed in U. S. Application Ser. No. 750,675, filed July 5, 1968, entitled Fluid Flow Metering Method and System by Zimmerman et al., and assigned to the assignee of the present invention. The output signals from the net oil analyzer 18 are applied by way of terminals 25 and 26 to the linearization circuit 20, and the output signal from the linearization circuit 20 is applied by way of a terminal 28 to a conventional counter 30 similar both in circuitry and operation to the gross fluid counter 24 earlier described.

As illustrated in more detail in FIG. 2, the net oil analyzer 18 of FIG. 1 receives the input signal f, from the flowmeter 14 by way of the input terminal 22. The pulses applied to the input terminal 22 are applied by way of a signal conditioning circuit 32 to the trigger input terminal of a conventional monostable or oneshot multivibrator 34. The circuitry of the signal conditioning circuit 32 may be conventional and is designed to provide a steep wave front triggering pulse suitable for operating the multivibrator 34. The false output terminal 25 of the multivibrator 34 is connected to a like numbered terminal 25 of the net oil analyzer, and the true output terminal 38 of the multivibrator 34 is connected to an input terminal 40 of a conventional two-input terminal AND gate 42.

The pulses in the output signal f from the transducer 12 of FIG. 1 are applied by way of the input terminal 16 and a signal conditioning circuit 44 to the other input terminal 46 of the AND gate 42. The signal conditioning circuit 44 may be similar in all respects to the signal conditioning circuit 32 earlier described. The output terminal 88 of the AND gate 42 is connected to the second output terminal 26 of the net oil analyzer l8.

With reference now to FIG. .3, the output signal f from the transducer 12 of FIG. 1 is also applied by way of the terminal 16 to a frequency detector 50 of the linearization circuit 20. The output signal from the frequency detector 50 is applied by way of a terminal 52 to a subtractor 54 which also receives the output signals from the terminals 25 and 26 of the net oil analyzer 18 of FIG. 2.

The output signal taken from the terminal 25 of the multivibrator 34 of the net oil analyzer of FIG. 2 is also way of a terminal 64 to the segment selector shift register 58 and a second output signal is applied by way of a terminal 65 to the gating circuit 60 which also receives, by way of a terminal 66, the output signal from the segment selector shift register 58. The output signal of the gating circuit 60 is the output signal from the linearization circuit and is applied by way of the terminal 28 to the counter 30 of FIG. 1.

B. Circuit Operation The system of the present invention, as heretofore described in connection with FIGS. 1-3, is operative to generate packets of pulses in which the number of packets is related to the fluid flow and in which the number of pulses in each packet is related to the constituency of the well effluent. The flow related pulses in the signal f are utilized to trigger the monostable multivibrator 34 for a predetermined period of time during which period the output signal from the true" output terminal 38 thereof enables the AND gate 42 to pass the condition responsive pulses from the transducer 12 through the AND gate 42 to the output terminal 26. These net oil related output pulses are applied to the subtractor circuit 54 of the linearization circuit of FIG. 3.

However, the condition related pulses f are continuously being applied to the frequency detector of FIG. 3. The frequency detector 50 is conventional in circuitry and operation and is operative to enable the subtracotr 54 only when the frequency or pulse repetition rate of the condition response signals exceeds a predetermined value.

The subtractor 54 is operative to subtract a predetermined number of pulses from the packet of pulses from the net oil analyzer and to thereafter pass a predetermined number of pulses next occurring in the packet to the counter 30 of FIG. 1 by way of the terminal 62 and the gating circuit 60.

The subtractor 54 thereafter passes the remaining pulses in the packet from the net oil analyzer 18 to the group pulse counter where the pulses are counted in groups. The segment selector shift register counts the number group and provides a signal to the gating circuit indicating the number of the group in which the condition-responsive pulses are being counted.

The pulses from the group pulse counter 56 are applied to the gating circuit 60 and a number thereof, as determined by the number of the particular group then being counted, are passed through the gating circuit 60 to the counter 30 of FIG. 1.

In summary then, no pulses are passed through the subtractor 54 unless the frequency detector indicates that the oil/water ratio is greater than 1. An initial offset of a predetermined number of pulses is applied directly through the gating circuit 60 to the counter 30 and the remaining pulses thereafter occurring in the pulse packet from the net oil analyzer 118 are selectively scaled to correct for any non-linearity.

II. LINEARIZATION CIRCUIT A. Description The linearization circuit 20 of FIG. 1 is hereinafter described in more detail in connection with FIGS. 4-7. With reference now to FIG. 4, the subtractor 54 of FIG. 3 receives the packets of pulses from the net oil analyzer 18 by way of the input terminal 26. This signal is directly applied to a like numbered terminal of a threeinput terminal AND gate 68 whose output terminal 62 is connected to the gating circuit 60 of FIG. 7.

The subtractor 54 also receives the false" output signal from terminal 25 of the multivibrator 34 of FIG. 2. This signal is applied to the reset input terminal of a counter 72 and to the reset input terminal R of a bistable multivibrator or flip-flop 73. The packets of pulses from the output terminal 26 of the AND gate 42 of FIG. 2 are also applied to the subtractor 54. These packets of pulses are applied to the counter 72 and to one-input terminal of a two-input terminal AND gate 74. The output terminal 70 of the AND gate 74 is connected to the group pulse counter 56 of FIG. 5.

The counter 72 is conventional both in circuitry and operations and may comprise a number of serially connected bistable elements. The true and false output signals of each of these binary elements are taken therefrom in a manner well known in the art as representative of their state of conduction at a particular count. These output signals are available, as illustrated, as input signals to two input terminal AND gates 78 and 80. In the interest of clarity, the connections between the output terminals of the counter 72 and the input terminals of the AND gates 78 and 80 have not been illustrated. The nomenclature adopted for the various signals is conventional, i.e., the binary numbers 2, 4, 8, 16, etc., indicating that a particular flip-flop has a binary logic 1 at the true output terminal thereof. The presence of a binary 1 output signal at the false output terminal is indicated by the binary number with a line thereover (1, 2, 4, etc.).

The output signal from the AND gate 78 is applied to the set input terminal of a bistable multivibrator or flip-flop 82 and the true output terminal thereof is directly connected to an input terminal 84 of the AND gate 68. The output terminal of the AND gate 80 is directly connected to the set input terminal of the flipflop 73 and to the reset input terminal of the flip-flop 82. The true output terminal of the flip-flop 73 is directly connected to the other input terminal 85 of the AND gate 74.

The output signal from the output terminal 52 of the frequency detector 50 of FIG. 3 is applied to a like numbered input terminal of the AND gate 68.

With reference now to FIG. 5, the pulse group counter 56 of FIG. 3 receives the packets of pulses from the subtractor 54 by way of the input terminal 70. These pulses are applied to a conventional counter 86 which may be similar in circuitry and operation to the counter 72 earlier described in connection with FIG. 4 and may be internally wired to reset upon generation of the 16 signal. The counter 86 provides a plurality of binary output signals, each taken from the true or false output terminal of one of the serially connected binary elements within the counter 86, and each applied across a capacitor 88 and a resistor 90 for shaping purposes. The false 16" or 16 signal is taken from the junction of the capacitor 88 and the resistor 90 and is directly applied by way of the termianl 64 to the segment selector shift register 58 of FIG. 6.

As illustrated in FIG. 5, the binary 1 signal from the counter 86 is directly applied to an output terminal 94 and the binary 8 output signal is directly applied to three output terminals 96, 98 and 100. The binary 8 output signal is applied together with the binary 16 output signal to the two input terminals of a OR gate 102 which provides an output signal on the three output terminals 104, 106, and 108. The binary 4 and binary 8 signals are applied by way of the two input terminals of an OR gate to an output terminal 112. The binary 4 output signal is also directly applied to an output terminal 114. The binary 16 output signal is applied together with the binary 2 signal to the two input tenninals of a OR gate 116 and the output signal therefrom is applied to an output terminal 1 18. The output terminals 96, 98, 104, 106, 108, 114, 112, 118, 94 and 100 are connected to the gating circuit 60 of FIG. 7 by way of the collective terminal 65.

With reference now to FIG. 6, the segment selector shift register 58 of FIG. 3 receives the 16 signal from the terminal 64 of the counter 86 of FIG. 5. This 16 signal is applied through a conventional inventer 120 to the toggle input terminal T of the last one 122 of a series of JK flip-flops -122 serially connected to form a conventional shift register. The remaining flip-flops in the series are successively toggled by the 16 signal. Two aditional inverters 142 and 144 are inserted between adjacent flip-flops to introduce a short delay and to prevent the toggling of one flip-flop from effecting those subsequent thereto. The first flip-flop 140 in the series is toggled through an OR gate 146.

The segment selector shift register also receives the false output signal from the multivibrator 34 of FIG. 2 by way of the terminal 25. This signal is applied to the pre-clear (PC) input terminals of each of the flip-flops 140-122, to the set steering input terminal S of the first flip-flop 140, and through an inverter 148 to the reset steering terminal R of the first flip-flop 140 and the other input terminal of the OR gate 146.

The false output terminal of each of the flip-flops 140-124 are directly connected to the reset steering input terminal of the immediately adjacent flip-flop. The true output terminals 150-166 of the flip-flops 140-124 are directly connected to the set steering input terminal of the immediately adjacent flip-flop and also by way of a collective output terminal 66 to like numbered terminals of the gating circuit 60 of FIG. 7.

Referring now to FIG. 7, the input terminals 150-168 are directly connected respectively to one input terminal of OR gates -188. The other input terminal of the OR gates 170-188 are connected respectively to the output terminals 100, 94, 118, 114, 108-104, 98 and 96 of the counter 86 of FIG. 5.

The output terminals of the OR 'gates 170-188 are connected through a ten input terminal OR gate to the counter 30 of FIG. 1 by way of the terminal 28. Also connected to the output terminal 28 through the OR gate 190 is the output termianl 62 of the AND gate 68 of FIG. 4.

B. Circuit Operation As earlier explained in connection with FIG. 3, a frequency detector 50, e.g., a conventional rate meter, receives the condition responsive pulses in the output signal f, from the transducer 12 FIG. 1 and is operative to provide an enabling signal on the input terminal 52 of the AND gate 68 of the substractor illustrated in FIG. 4. The AND gate 68 thus receives one of the two necessary enabling signals whenever the frequency or pulse repetition rate of the output signal f, of the condition responsive transducer is above a predetermined minimum.

The subtractor of FIG. 4 also receives the false" output signal from the multivibrator 34 of the net oil analyzer of FIG. 2. This gating signal is utilized to reset the counter 72 of the subtractor 54 so that the packets of condition-responsive pulses from the AND gate 42 of the net oil analyzer of FIG. 2 may be counted.

The individual binary elements of the counter 72 are connected to the AND gate 78 in a manner so that the AND gate 78 produces an output signal when a predetermined count is attained by the counter 72. This signal is used to set the flip-flop 82 thereby providing the second enabling signal to the AND gate 68 and permitting the passage of the pulses in the packets from the net oil analyzer through the AND gate 68 of FIG. 4 and the OR gate 190 of FIG. 7 to the counter 30 of FIG. I.

The counter 72 will continue to count the pulses in the packets of pulses from the net oil analyzer and will provide, by way of the AND gate 80, a signal which resets the flip-flop 82 to inhibit the AND gate 68 and thereby limit the number of pulses passed through the AND gates 68 and 190 to the counter 30.

The AND gate 74 of FIG. 4 is, however, enabled simultaneously with the disabling of the AND gate 68 and the pulses in the packet of pulses from the net oil analyzer are thereafter passed through the enabled AND gate 74 to the group pulse counter of FIG. 5. The counter 86 of the group pulse counter 56 is also reset for the duration of a pulse packet by the output signal from the false output terminal 25 of the multivibraotr 34 of FIG. 2. The counter 86 accumulates a count of 16 and thereafter internally resets to begin counting a new group of pulses.

An inhibiting signal is taken from the 16 output terminal 92 of the counter 86 and is utilized to toggle the selector shift register 58 of FIG. 6 after each group of 16 pulses has been counted. The various true output terminals of the counter 86 of FIG. are selectively combined in the OR gates of FIG. 5 and utilized to enable the AND gates of the gating circuit 60 of FIG. 7. Also applied to the AND gates of the circuit 60 of FIG. 7 are the output signals from the various flip-flops of the segment selector shift register 58 of FIG. 6. The AND gates of the gating circuit of FIG. 7 are thus effective, when enabled by the segment selector shift register 58 of FIG. 6, to pass the signals taken from the counter 86 of FIG. 5 through the OR gate 190 to the counter 30 of FIG. 1.

C. Example By way of example, consider the graph of FIG. 8 wherein a typical frequency response curve of a capacitance probe is illustrated. As noted from the graph, the 50 percent net oil point of the curve is at a frequency of 880 kilohertz and the frequency of the transducer thereafter increases to a frequency of 1,026 hilohertz at 100 percent oil. Selecting the gating interval of the net oil analyzer, i.e., the duration of the output pulse from the multivibrator 34 of FIG. 2, to be lmillisecond, the number of pulses which can be applied from the transducer can vary from 880 to 1,026 as the net oil in the well effluent varies from 50 to 100 percent.

The pulses in a given packet of pulses are applied from the net oil analyzer of FIG. 2 to the subtractor 54 of FIG. 4 wherein the first 880 pulses are utilized to fill the counter 72. The 880 pulses are, of course, required for a 50 percent oil/water ratio. Since it is not desirable to count the number of pulses in a packet for an oil/water ratio less than 1, the frequency detector 50 generates an enabling signal only if the transducer 12 senses an oil/water ratio of 1 or more. Thus, the first 830 pulses are not passed through either of the AND gates 68 or 74 of the subtractor. However, and assuming an enabling signal from the frequency detector, when the counter 72 reaches a count of 830, an enabling signal is applied, by way of the AND gate 78 and flip-flop 82, to the AND gate 68 and the pulses in the packet from the net oil analyzer are passed therethrough and through the gating circuit 60 to the counter 30. When, however, the counter 72 reaches a count of 880, the AND gate resets the flip-flop 82 thereby inhibiting the AND gate 68 and limiting the number of pulses directly passed to the counter 30 to 50 in number. These 50 pulses are introduced into the counter 30 in the nature of an offset thereby placing 50 pulses in the counter for a condition of 50 percent oil in lieu of the first 880 pulses of the pulse packet.

The AND gate 80 of the subtractor 54 of FIG. 4 also sets the flip-flop 74 thereby enabling the AND gate 74 thereby permitting the passage of those pulses in the packet from the net oil analyzer in excess of the number 880 through the AND gate 74 to the group pulse counter 56 of FIG. 5.

As indicated in the graph of FIG. 9, it is desirable to convert the number of pulses in the packet in excess of 880 into a linear curve for application to the counter 30. This is accomplished in the illustrated embodiment by dividing the curve into segments of 16 pulses. The logic circuit of the group pulse counter of FIG. 5, in conjunction with the particular segment of the curve as indicated by the segment selector register 58 of FIG. 6, is operative through the logic circuitry of the gating circuit 60 of FIG. 7 to provide the additional pulses to the counter.

Reference may be had to the following Table wherein the pulses over 880 have a number applied to the group pulse counter of FIG. 5 are tabulated against the number of pulses generated by the gating circuit 60 of FIG. 7 for the graph of FIG. 9.

TABLE POINT Pulses Pulses Counted A A 0 50 B 16 S2 2 C 32 54 2 D 48 S7 3 E 64 60 3 F 80 63 3 G 96 67 4 H 1 I2 73 6 J 128 82 9 1K 144 98 16 L I46 I00 2 Total 50 It may be seen from the above thatthe number of pulses counted for each of the segments of the curve of FIG. 9 may vary from a minimum of 2 to a maximum of 16 to effect linearization of the curve and thus improve accuracy when the number in the counter 30 is translated by a suitable scaling factor into the desired units of net oil.

ADVANTAGES AND SCOPE OF THE INVENTION From the foregoing detailed description to a preferred embodiment, it is apparant that a nonlinearity in a digital signal may be corrected by dividing the frequency response curve into a plurality of segments and utilizing logic circuitry to provide a specific number of pulses for each of the identifiable segments. Not only may continually increasing or decreasing nonlinearity be corrected, but a combination of increasing and decreasing nonlinearities may be accommodated through the logic circuitry. The size of these segments may be seleted and may be made to vary within the curve as is done, for example, in the illustrated example wherein 50 pulses are introduced into the counter for the 880 pulses in the signal to be linearized.

The linearization circuit heretofore described has particular utility when utilized in combination with a net oil analyzer due to the characteristics of the capacitive transducer with respect to the fluid from a producing oil well. In such an adaptation, the utility of the transducer over less than the entire oil/water ratio variation must be considered, as must the offset required to place the transducer output signal on the desired curve at the time that the accuracy of the transducer is sufficient for its utilization.

These and other advantages will be apparent to one skilled in the art from a perusal of the froegoing as will many modifications within the spirit of the present invention. The present invention is, therefore, to be limited solely by the language of the appended claims when accorded in full range of equivalents.

What is claimed is:

l. A method of linearizing a digital electrical signal comprising the steps of:

a. generating a series of electrical pulses non-linearly related in number to a condition sensed;

b. counting the pulses in said series of electrical pulses in groups, each of the groups including a predetermined number of pulses;

c. generating a predetermined number of electrical pulses for each of the groups of pulses counted; and,

d. totaling the number of electrical pulses generated responsively to the groups of pulses counted to provide a number of electrical pulses linearly related to the condition sensed.

2. The method of claim 1 including the step of providing an initial offset by:

counting a first predetermined number of pulses in the series of electrical pulses prior to counting the pulses thereof in groups; and,

generating a predetermined number of electrical pulses in response to the counting of the first predetermined number of pulses in said series of electrical pulses.

3. The method of claim 2 wherein the first predetermined number of electrical pulses in larger than the predetermined number of electrical pulses counted in groups, and,

a. wherein the predetermined number of pulses in each of the groups is equal to the predetermined number of pulses in each of the other groups.

4. The method of claim 1 wherein the predetermined number of pulses in each of the groups is equal to the predetermined number in each of the other groups.

5. A method of linearizing a digital signal nonlinearly related to a condition sensed comprising the steps of:

a. generating a first series of pulses non-linearly related in number to the condition sensed;

b. counting the pulses in the first series of pulses in groups, each of said groups having a predetermined number of pulses; and,

c. generating a second series of pulses related in number to the number of pulses in said first series of pulses by a factor independently related to the group in which the pulses in said first series of pulses are counted.

6. A method of compensating a manifestation of fluid flow for a variable physical condition of the fluid comprising the steps of:

a. generating a first series of electrical pulses related in number to fluid flow;

b. generating a second series of electrical pulses related in number to a condition of the fluid;

c. generating a third series of electrical pulses responsively to the first and the second series of electrical pulses, the number of pulses in the third series of electrical pulses being non-linearly related in number either to the volume of fluid flow or to the condition of the fluid;

d. counting the pulses in said third series of electrical pulses in groups;

e. generating a predetermined number of electrical pulses for each group of pulses counted; and,

f. manifesting the number of generated group related electrical pulses to manifest fluid flow compensated for a variable condition of the fluid.

7. The method of claim 6 including the steps of:

a. counting a first predetermined number of pulses in the series of electrical pulses prior to counting the pulses thereof in groups; and,

b. generating a predetermined number of electrical pulses in response to the counting of the first predetermined number of pulses in said series of electrical pulses.

8. The method of claim 7 wherein the first predetermined number of electrical pulses is larger than the predetermined number of electrical pulses counted in groups, and,

a. wherein the predetermined number of pulses in each of the groups is equal to the predetermined number of pulses in each of the other groups.

9. The method of claim 8 wherein the condition of the fluid is the constituency thereof.

10. The method of claim 6 wherein the predetermined number of pulses in each of the groups is equal to the predetermined number in each of the other groups.

11. Apparatus for compensating a manifestation of fluid flow for a variable condition of the fluid compris means for generating a first series of electrical pulses related in number to fluid flow;

means for generating a second series of electrical pulses related in number to a condition of the fluid;

means responsive to said first and second series of electrical pulses for generating a third series of electrical pulses non-linearly related in number to either fluid flow or to said condition of the fluid;

means for generating a fourth series of electrical pulses related in number to the number of pulses in said third series of electrical pulses by a factor related to the number of pulses in said third series of electrical pulses; and,

means for counting the pulses in said fourth series of electrical pulses.

12. The apparatus of claim 11 wherein said fourth series of electrical pulses generating means includes means for counting the number of pulses in said third series of electrical pulses; and,

wherein said factor is the identity of a group of pulses in which the pulse in said third series of electrical pulses is counted.

13. The apparatus of claim l2 wherein said fourth series of electrical pulses generating means further includes means for inhibiting the counting of pulses in said third series of electrical pulses in groups, said inhibiting means being responsive to the pulse repetition rate of said second series of electrical pulses.

14. The apparatus of claim 13 wherein said fourth series of electrical pulses generating means further includes means for applying a predetermined number of pulses to said counting means responsively to said inhibiting means.

15. The apparatus of claim l4 wherein said fourth series of electrical pulses generating means includes:

a frequency detector responsive to said second series of electrical pulses;

a group pulse counter;

a gating circuit;

a subtractor circuit responsive to said frequency detector and said third series of electrical pulses for applying a predetermined number of electrical pulses to said gating circuit and for applying a number of pulses to said group pulse counter, said number being less than the number of pulses in said third series of electrical pulses but related thereto; and,

a segment selector responsive to said group pulse counter for applying to said gating circuit a signal related to the number of groups counted,

said gating circuit being responsive to said segment selector and to said group pulse counter for generating said fourth series of electrical pulses.

16. The apparatus of claim 15 wherein said subtractor includes:

a counter;

first and second bistable elements;

first and second AND gates connected respectively to said first and second bistable elements;

a third AND gate responsive to said counter for setting said first bistable element; and,

a fourth AND gate responsive to said counter for set ting said second AND gate and for resetting said first AND gate.

17. The apparatus of claim 16 wherein said third series of electrical pulses is applied to said first and second AND gates; and,

wherein said first AND gate is also responsive to said frequency detector.

18. The apparatus of claim 17 wherein said group pulse includes:

a counter and logic circuit means;

wherein said segment selector includes a shift register; and,

wherein said gating circuit includes a plurality of AND gates and an OR gate.

19. A linearizing circuit for a digitalelectrical signal comprising:

a frequency detector;

a subtractor connected to said frequency detector and adopted to receive said digial signal;

a group pulse counter connected to said subtractor;

a segment selector connected to said group pulse counter; and,

a gating circuit connected to said subtractor, to said group pulse counter, and to said segment selector.

20. The apparatus of claim 19 wherein said subtractor includes:

minal of said first AND gate is connected to said frequency detector.

22. The apparatus of claim 21 including a third bistable element,

said subtractor, said group pulse counter, and said segment selector being enabled by said third bistable element.

23. A method of displaying a pulse count less than the number of pulses in a series of pulses comprising the steps of:

a. providing a series of pulses;

b. counting a predetermined number of the pulses in the series of pulses which occur within a predetermined period of time;

c. counting the pulses in the series of pulses which occur in the same period of time subsequent to the counting of the predetermined number of pulses; and,

d. displaying a count related to the pulses counted in the same period of time in excess of the predetermined number of pulses.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4012622 *Dec 20, 1974Mar 15, 1977Standard Pressed Steel Co.Method and apparatus for counting small parts
US4266277 *Apr 24, 1979May 5, 1981Compagnie GeofinanciereChromatographic analysis of gaseous matter
US5861755 *Nov 6, 1995Jan 19, 1999The United States Of America As Represented By The Adminstrator Of National Aeronautics And Space AdministrationTwo-phase quality/flow meter
Classifications
U.S. Classification702/86, 377/21, 377/50, 73/861.4, 702/46
International ClassificationG01F1/05, G01F1/115, G01F1/12
Cooperative ClassificationG01F1/125, G01F1/115
European ClassificationG01F1/115, G01F1/12A