CN102809698B - Measurement system adopting excitation signals with two waveforms for conductivity of solution - Google Patents
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- CN102809698B CN102809698B CN201210305789.2A CN201210305789A CN102809698B CN 102809698 B CN102809698 B CN 102809698B CN 201210305789 A CN201210305789 A CN 201210305789A CN 102809698 B CN102809698 B CN 102809698B
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- 238000004364 calculation method Methods 0.000 claims abstract description 8
- 238000005086 pumping Methods 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 18
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- 230000010287 polarization Effects 0.000 description 4
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- 238000000840 electrochemical analysis Methods 0.000 description 2
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Abstract
The invention discloses a measurement system adopting excitation signals with two waveforms for the conductivity of a solution, which comprises 6 modules which are a double-waveform generator, a conductance cell, a signal conditioning circuit, a parameter detection circuit, an operation and control device and a man-machine interface; and the double-waveform generator can be used for generating two excitation signals with different waveforms, a generated excitation signal with a first waveform is used for measuring and calculating the distributed capacitance of an electrode, and the distributed capacitance of the electrode, which is obtained by measurement and calculation, is combined with an excitation signal with a second waveform, which is generated by the double-waveform generator, so as to measure and calculate the resistance and the conductivity of the solution. The scheme can be used for carrying out dynamic measurement on the distributed capacitance of the electrode, is used for eliminating the influence of the distributed capacitance of the electrode and the electric double-layer capacitance of the electrode on measurement and is a reference scheme for the accurate measurement on the conductivity of the solution.
Description
Technical field
The present invention relates to the measuring system of electrical conductivity of solution or resistivity, relate in particular to the measuring system of the electrical conductivity of solution that adopts two kinds of waveform stimulus signals.
Background technology
The fundamental method of measurement of electrical conductivity of solution is the voltage U of measuring on the two ends that are applied to the electrode of inserting solution
dwith the electric current I that flows through electrode, calculate the resistance R=U between electrode
d/ I, by the conductivity of G=K/R calculating solution, wherein K is electrode constant.But the electrode of inserting in solution can produce polarization after energising, makes the voltage U recording
dnot in fact the voltage at the two ends of solution own, but be applied to solution resistance and relate to the voltage on the virtual electronic device of these two series connection of electric double layer capacitance (hereinafter to be referred as the electric double layer capacitance of electrode) of solution/metal electrode interface process, therefore formula R=U
dthere is theoretical error in/I; In order to reduce the impact of electrode polarization on accuracy of measurement, basic skills is the alternating current that applies positive-negative polarity symmetry on electrode, but under ac-excited signal function, the electric current I recording not is the electric current that flows through merely solution, but flow through the total current of solution resistance branch circuit parallel connection distribution of electrodes electric capacity (comprising electrode interelectrode capacity, contact conductor electric capacity) branch road, therefore use ac-excited method in reducing electrode polarization impact, but to introduce distribution of electrodes electric capacity to the impact of measuring.
The research that adopts electrochemical analysis method to measure electrical conductivity of solution at present all uses resistance-capacitance network as conductance cell equivalent physical model, and these resistance-capacitance networks as conductance cell equivalent physical model are mainly divided into two classes, the first kind is with detected solution resistance distribution of electrodes electric capacity in parallel, this is better simply model, also the research institute that is most electrical conductivity of solution tests aspect relates to, Equations of The Second Kind is with distribution of electrodes electric capacity in parallel again after the electric double layer capacitance of detected solution resistance series connection electrode, this is relative complex and more unmanageable model, referring to this Figure of description 1, it is the conductance cell equivalent physical model that is applicable to precision measurement.To eliminate the impact of distribution of electrodes electric capacity for the problem mainly solving as the research of conductance cell equivalent physical model taking first kind resistance-capacitance network, obtain in this respect a large amount of achievements in research, there is the phase sensitive detection of employing, there is the dynamic pulse method of adopting, there is the method for double pulse measurement, adopt in addition bifrequency square wave excitation etc. method, these achievements in research have obtained positive effect, but because conductance cell equivalent physical model used is not taken into account the electric double layer capacitance of electrode, naturally also just ignored the electric double layer capacitance of electrode to the impact of measuring, in precision measurement, the impact of the electric double layer capacitance of electrode can not be ignored, even the capacitive reactance of the electric double layer capacitance of electrode only has 1% size of detected solution resistance, just because of this, research for first kind resistance-capacitance network model is restricted to the development of more precision measurement.
Realize the precision measurement of electrical conductivity of solution, require links all accurate as far as possible, comprise: 1, the resistance-capacitance network model of simulation conductance cell principle of work must more approach truth, according to the achievement in research of electrochemical analysis aspect, above-mentioned Equations of The Second Kind model (with after the electric double layer capacitance of a detected solution resistance series connection electrode again distribution of electrodes electric capacity in parallel) approaches real conductance cell, more accurate more than first kind model (using detected solution resistance distribution of electrodes electric capacity in parallel); 2, be based upon the derivation that solves mathematic(al) representation on resistance-capacitance network basis accurate as far as possible, few approximate with preferably not existing; 3, mathematic(al) representation is that enclosed solves instead of iterative as far as possible, mathematic(al) representation do not occur as far as possible denominator close to zero situation to avoid the amplification of error in numerical calculation; 4, carry out numerical evaluation time error according to mathematic(al) representation as far as possible little; 5, the detection of electrode excitation signal and electrode response signal is as far as possible little in current value, magnitude of voltage, performance number equal error.The 4th link is numerical evaluation theoretical category problem, specially refers to the input storage of numerical value and effective word length problem of calculating; The 5th link is the problem of circuit design aspect; 1st ~ 3 environment are determined by overall plan, are the cores of electrical conductivity of solution measurement scheme.Research based on above-mentioned Equations of The Second Kind conductance cell equivalent physical model is also less at present, especially yet there are no the calculation expression without approximate derivation that solves electrical conductivity of solution based on Equations of The Second Kind conductance cell equivalent physical model, in the application for patent that inventor herein was once 200910113046.3 in Chinese Patent Application No. the measuring method of disclosed a kind of electrical conductivity of solution.Claims in this patented method do not relate to the method for solving of distribution of electrodes electric capacity, just using distribution of electrodes electric capacity as the input parameter solving in detected solution resistance expression formula, and there are some defects in the scaling method of the distribution of electrodes electric capacity of recommending in this patent specification, because in the time of the conductivity of test solution, between conductance cell electrode, be full of detected solution, and the solution being full of between conductance cell electrode is equivalent to a kind of medium between electrode pad, the specific inductive capacity of detected solution and the meeting of air as medium are variant, so described in this patented method electrode is placed in to the real distribution of electrodes electric capacity that distribution of electrodes electric capacity that air acceptance of the bid location survey goes out and electrode be placed in detected solution can be variant.One of object of patent of the present invention is that the one of aforementioned patent is supplemented, the measuring system of the electrical conductivity of solution that adopts two kinds of waveform stimulus signals is proposed, the pumping signal that this measuring system comprises two kinds of waveforms, the first waveform stimulus signal solves distribution of electrodes electric capacity for measuring, and the second waveform stimulus signal is for measuring the resistance and the conductivity that solve solution.
Summary of the invention
The object of this invention is to provide a kind of electric double layer capacitance and the electrical conductivity of solution with two kinds of waveform stimulus signal characteristics of the adverse effect of distribution of electrodes electric capacity (comprising electrode interelectrode capacity and contact conductor electric capacity) dual factors to measurement or the measuring system of resistivity that can eliminate electrode.
The technical scheme that realizes above-mentioned purpose is: adopt the measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals, be made up of two waveform generators, conductance cell, signal conditioning circuit, parameter detecting circuit, computing and controller and 6 modules of man-machine interface; The function of each module and mutual connected mode are as follows:
Two waveform generators can produce the pumping signal of two kinds of different wave, and being subject to the control of computing and controller to determine being to produce the first waveform stimulus signal or the moment of the second waveform stimulus signal and generation pumping signal, the pumping signal that two waveform generators produce exports the electrode of conductance cell to and this electrode is encouraged; The first waveform stimulus signal that two waveform generators produce is used for calculating distribution of electrodes electric capacity, and the second waveform stimulus signal that the distribution of electrodes electric capacity that measuring and calculating obtains produces in conjunction with double wave shape generator is for calculating resistance and the conductivity of solution;
Conductance cell includes electrode and detected solution, and the electrode including receives the pumping signal producing from two waveform generators and encouraged by it, produces electrode response signal and exports signal conditioning circuit to;
Signal conditioning circuit receives from the electrode response signal of conductance cell and to electrode response signal and carries out filtering and signal amplification, filtering mode (as logical in low pass, high pass or band) and signal amplification factor are subject to the control of computing and controller, and the output of signal conditioning circuit is connected to parameter detecting circuit;
Parameter detecting circuit is subject to the control of computing and controller carry out parameter detecting (as instantaneous value or the effective value etc. of voltage, electric current, power) and export the result of parameter detecting to computing and controller the signal from signal conditioning circuit;
The connection of computing and controller and function comprise 7 aspects: a, are to produce the first waveform stimulus signal or the moment of the second waveform stimulus signal and generation pumping signal to two waveform generator control with decision; B, to signal conditioning circuit control to determine filtering mode and the signal amplification factor of signal conditioning circuit; C, to the control of parameter detecting circuit to determine to detect the moment (as the detection moment of instantaneous value) of which kind of parameter and detected parameters; D, receive from the output signal of parameter detecting circuit; E, the signal from parameter detecting circuit is carried out to data operation processing; F, the result of data calculation process is exported to man-machine interface show; G, receive from the input of man-machine interface (carrying out the parameter setting example of measuring system as selected conductivity measurement scope etc.);
Man-machine interface is connected with computing and controller, the function that comprises two aspects: a, the result of the data operation processing from computing and controller is shown; B, in key-press input mode, the parameter of need setting is sent into computing and controller.
Principle of the present invention:
Core concept of the present invention is the pumping signal that adopts two kinds of waveforms, wherein uses the pumping signal of the first waveform to be convenient to calculate distribution of electrodes electric capacity, but is not easy to carry out the measuring and calculating of electrical conductivity of solution; The in the situation that of known electrodes distributed capacitance, use the pumping signal of the second waveform to be convenient to calculate the conductivity of solution, but use the pumping signal of the second waveform to be not easy to calculate distribution of electrodes electric capacity; Be independent of the principle (being that distribution of electrodes electric capacity and excitation signal waveforms are irrelevant) of excitation signal waveforms based on distribution of electrodes electric capacity, two kinds of waveform stimulus signal combination are got up, make two kinds of waveform stimulus signals be opposite to respectively identical electrodes in identical detected solution and carry out timesharing excitation detecting electrode response signal, calculate by suitable expression formula, the pumping signal of use the first waveform is calculated to the distribution of electrodes electric capacity that obtains for using the expression formula of measuring and calculating electrical conductivity of solution of pumping signal of the second waveform.
The measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals of employing of the present invention is compared existing measuring method and is had following beneficial effect: distribution of electrodes electric capacity can dynamic measurement, and its impact can be eliminated completely; Exciting signal frequency size is not had to special requirement, can in relative broad range, select arbitrarily; In electrode exists polarization and is embodied in conductance cell equivalent physical model with the electric double layer capacitance of electrode time, can quantitatively count its impact, be the reference technique scheme of accurately measuring electrical conductivity of solution.
Brief description of the drawings
Fig. 1 is the equivalent physical model figure of conductance cell.
Fig. 2 is conductivity measurement system figure;
Embodiment
Below in conjunction with accompanying drawing, technical scheme of the present invention is further described:
The measuring system that adopts the electrical conductivity of solution of two kinds of waveform stimulus signals, is made up of two waveform generators (10), conductance cell (20), signal conditioning circuit (30), parameter detecting circuit (40), computing and controller (50) and (60) 6 modules of man-machine interface; The function of each module and mutual connected mode are as follows:
Two waveform generators (10) can produce the pumping signal of two kinds of different wave, and being subject to the control of computing and controller (50) to determine being to produce the first waveform stimulus signal or the moment of the second waveform stimulus signal and generation pumping signal, the pumping signal that two waveform generators (10) produce exports the electrode of conductance cell (20) to and this electrode is encouraged; The first waveform stimulus signal that two waveform generators (10) produce is used for calculating distribution of electrodes electric capacity, and the second waveform stimulus signal that the distribution of electrodes electric capacity that measuring and calculating obtains produces in conjunction with double wave shape generator (10) is for calculating resistance and the conductivity of solution;
Conductance cell (20) includes electrode and detected solution, and the electrode including receives the pumping signal producing from two waveform generators (10) and encouraged by it, produces electrode response signal and exports signal conditioning circuit (30) to;
Signal conditioning circuit (30) receives from the electrode response signal of conductance cell (20) and to electrode response signal and carries out filtering and signal amplification, filtering mode and signal amplification factor are subject to the control of computing and controller (50), and the output of signal conditioning circuit (30) is connected to parameter detecting circuit (40);
Parameter detecting circuit (40) is subject to the control of computing and controller (50) to carrying out parameter detecting from the signal of signal conditioning circuit (30) and exporting the result of parameter detecting to computing and controller (50);
The connection of computing and controller (50) and function comprise 7 aspects: a, two waveform generators (10) are controlled to determine it is to produce the first waveform stimulus signal or the moment of the second waveform stimulus signal and generation pumping signal; B, to signal conditioning circuit (30) control with determine signal conditioning circuit (30) filtering mode and signal amplification factor; C, parameter detecting circuit (40) is controlled to the moment to determine to detect which kind of parameter and detected parameters; D, receive from the output signal of parameter detecting circuit (40); E, to carrying out data operation processing from the signal of parameter detecting circuit (40); F, the result of data calculation process is exported to man-machine interface (60) show; G, receive from the input of man-machine interface (60);
Man-machine interface (60) is connected with computing and controller (50), the function that comprises two aspects: a, the result of the data operation processing from computing and controller (50) is shown; B, in key-press input mode, the parameter of need setting is sent into computing and controller (50).
Embodiment mono-:
Functional module and connected mode be the description to technical scheme with above-mentioned embodiment, the first waveform stimulus signal adopts interchange symmetric triangular wave voltage signal, and (interchange symmetric triangular ripple refers to the finger crest of triangular wave and the polarity of trough is contrary, amplitude equates, upper wave band equates with the slope absolute value of lower wave band), the second waveform stimulus signal adopts sinusoidal voltage signal.The electrical conductivity of solution measurement procedure of the described measuring system of technical solution of the present invention is as follows:
Electrode is placed in to detected solution, electrode is encouraged as the first waveform stimulus signal with exchanging symmetric triangular wave voltage signal, detecting electrode response current, calculate distribution of electrodes electric capacity with suitable calculation expression, electrode is remained in detected solution, electrode is comprised to contact conductor do not do the movement of any physical location, as the second waveform stimulus signal, electrode is encouraged with sinusoidal voltage signal, the active power of detecting electrode response current and consumption of electrode, calculate resistance and the conductivity of solution in conjunction with the distribution of electrodes electric capacity having recorded with suitable calculation expression.
The term that above embodiment is used, symbol is not construed as limiting application of the present invention, just for convenience of explanation.Those skilled in the art can make some according to embodiments of the present invention and replace, but these are done according to embodiment of the present invention, all equivalences are replaced and amendment, belong to invention thought of the present invention and the scope of the claims of being defined by claim in.
Claims (7)
1. the measuring system that adopts the electrical conductivity of solution of two kinds of waveform stimulus signals, is made up of two waveform generators (10), conductance cell (20), signal conditioning circuit (30), parameter detecting circuit (40), computing and controller (50) and (60) 6 modules of man-machine interface; It is characterized in that comprising two waveform generators (10), two waveform generators (10) can produce the pumping signal of two kinds of different wave, the first waveform stimulus signal producing is used for calculating distribution of electrodes electric capacity, and the second waveform stimulus signal that the distribution of electrodes electric capacity that measuring and calculating obtains produces in conjunction with double wave shape generator (10) is for calculating resistance and the conductivity of solution.
2. the measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals of employing as claimed in claim 1, it is characterized in that: described two waveform generators (10) are subject to the control of computing and controller (50) to determine being to produce the first waveform stimulus signal or the moment of the second waveform stimulus signal and generation pumping signal, and the pumping signal that two waveform generators (10) produce exports the electrode of conductance cell (20) to and this electrode is encouraged.
3. the measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals of employing as claimed in claim 1, it is characterized in that: described conductance cell (20) includes electrode and detected solution, the electrode including receives the pumping signal producing from two waveform generators (10) and is encouraged by it, produces electrode response signal and exports signal conditioning circuit (30) to.
4. the measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals of employing as claimed in claim 1, it is characterized in that: described signal conditioning circuit (30) receives from the electrode response signal of conductance cell (20) and to electrode response signal and carries out filtering and signal amplification, filtering mode and signal amplification factor are subject to the control of computing and controller (50), and the output of signal conditioning circuit (30) is connected to parameter detecting circuit (40).
5. the measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals of employing as claimed in claim 1, is characterized in that: described parameter detecting circuit (40) is subject to the control of computing and controller (50) to carrying out parameter detecting from the signal of signal conditioning circuit (30) and exporting the result of parameter detecting to computing and controller (50).
6. the measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals of employing as claimed in claim 1, is characterized in that: the connection of described computing and controller (50) and function comprise 7 aspects: a, two waveform generators (10) are controlled to determine it is to produce the first waveform stimulus signal or the moment of the second waveform stimulus signal and generation pumping signal; B, to signal conditioning circuit (30) control with determine signal conditioning circuit (30) filtering mode and signal amplification factor; C, parameter detecting circuit (40) is controlled to the moment to determine to detect which kind of parameter and detected parameters; D, receive from the output signal of parameter detecting circuit (40); E, to carrying out data operation processing from the signal of parameter detecting circuit (40); F, the result of data calculation process is exported to man-machine interface (60) show; G, receive from the input of man-machine interface (60).
7. the measuring system of the electrical conductivity of solution of two kinds of waveform stimulus signals of employing as claimed in claim 1, it is characterized in that: described man-machine interface (60) is connected with computing and controller (50), the function that comprises two aspects: a, the result of the data operation processing from computing and controller (50) is shown; B, in key-press input mode, the parameter of need setting is sent into computing and controller (50).
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3919627A (en) * | 1970-08-06 | 1975-11-11 | Gerald F Allen | Conductivity measuring method and apparatus utilizing coaxial electrode cells |
| JPS61151474A (en) * | 1984-12-26 | 1986-07-10 | Nichimou Kk | Apparatus for measuring solution conductivity |
| US5025219A (en) * | 1988-09-20 | 1991-06-18 | Pechiney Recherche | Apparatus and method continuous measurement of the electrical conductivity of liquid media in a dynamic cell |
| CN201322773Y (en) * | 2008-12-16 | 2009-10-07 | 河南省日立信电子有限公司 | Electrical conductivity measuring instrument |
| CN101629925A (en) * | 2008-06-23 | 2010-01-20 | 米利波尔公司 | Method and device for measuring the conductivity of a pure or ultrarapture liquid |
| CN101650211A (en) * | 2009-09-15 | 2010-02-17 | 天津大学 | Method and device for measuring conductive liquid level and conductivity based on double coils |
| CN201673209U (en) * | 2010-05-28 | 2010-12-15 | 深圳市计量质量检测研究院 | Edible oil electric conductivity tester |
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2012
- 2012-08-24 CN CN201210305789.2A patent/CN102809698B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3919627A (en) * | 1970-08-06 | 1975-11-11 | Gerald F Allen | Conductivity measuring method and apparatus utilizing coaxial electrode cells |
| JPS61151474A (en) * | 1984-12-26 | 1986-07-10 | Nichimou Kk | Apparatus for measuring solution conductivity |
| US5025219A (en) * | 1988-09-20 | 1991-06-18 | Pechiney Recherche | Apparatus and method continuous measurement of the electrical conductivity of liquid media in a dynamic cell |
| CN101629925A (en) * | 2008-06-23 | 2010-01-20 | 米利波尔公司 | Method and device for measuring the conductivity of a pure or ultrarapture liquid |
| CN201322773Y (en) * | 2008-12-16 | 2009-10-07 | 河南省日立信电子有限公司 | Electrical conductivity measuring instrument |
| CN101650211A (en) * | 2009-09-15 | 2010-02-17 | 天津大学 | Method and device for measuring conductive liquid level and conductivity based on double coils |
| CN201673209U (en) * | 2010-05-28 | 2010-12-15 | 深圳市计量质量检测研究院 | Edible oil electric conductivity tester |
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