CN219475728U - Voltage acquisition device for conductivity measurement - Google Patents
Voltage acquisition device for conductivity measurement Download PDFInfo
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- CN219475728U CN219475728U CN202320648671.3U CN202320648671U CN219475728U CN 219475728 U CN219475728 U CN 219475728U CN 202320648671 U CN202320648671 U CN 202320648671U CN 219475728 U CN219475728 U CN 219475728U
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Abstract
The application relates to the technical field of industrial measurement, and provides a voltage acquisition device for conductivity measurement. The voltage acquisition device includes: the device comprises a conductivity cell, an excitation signal output circuit, a conductivity signal conditioning circuit and at least one voltage acquisition circuit; the input end of the excitation signal output circuit is used for being connected with a power supply, and the output end of the excitation signal output circuit is connected with the conductance cell; the electric conduction signal conditioning circuit comprises at least one precise rectification circuit for rectifying an alternating voltage signal input into the electric conduction signal conditioning circuit, wherein the input end of the electric conduction signal conditioning circuit is connected with the electric conduction pool, and the output end of the electric conduction signal conditioning circuit is connected with the input end of at least one voltage acquisition circuit. The embodiment of the application can improve the accuracy of the conductivity measurement of the solution.
Description
Technical Field
The application relates to the technical field of industrial measurement, in particular to a voltage acquisition device for conductivity measurement.
Background
Conductivity is the ability of a solution to conduct current when an electric field is applied to it, and is a parameter used to indicate how easily the solution conducts electricity. Conductivity is one of the characteristics of a solution and is important in providing information about the chemical structure of the solution. As it may provide information about the chemical structure of the solution based on the total concentration of ions in the solution and the transport characteristics, such as example mobility, diffusivity, and viscosity.
Currently, for the measurement of the conductivity of a solution, this is usually achieved by means of applying a direct current. Such as a measurement circuit applying a direct current to a conductivity cell immersed in the solution to measure the conductivity of the solution by collecting a direct current voltage. This method has been commonly applied to measure solutions with high conductivity. However, when the conductivity measurement of the solution is performed by applying a direct current, the ion concentration near the electrode surface may be different from that in the solution due to the slow diffusion of ions, or when the direct current is applied, the electrode charge degree may be different from that in the reversible case due to the slow progress of the electrochemical reaction, so that the electrode potential deviates from the reversible electrode potential, causing electrode polarization, thereby affecting the accuracy of voltage acquisition, and causing a conductivity measurement error.
Disclosure of Invention
The present application aims to solve at least one of the technical problems existing in the related art. Therefore, the application provides a voltage acquisition device for conductivity measurement, which can improve the accuracy of the conductivity measurement of a solution.
According to an embodiment of the first aspect of the present application, a voltage acquisition device for conductivity measurement includes:
the device comprises a conductivity cell, an excitation signal output circuit, a conductivity signal conditioning circuit and at least one voltage acquisition circuit;
the input end of the excitation signal output circuit is used for being connected with a power supply, and the output end of the excitation signal output circuit is connected with the conductance cell;
the electric conduction signal conditioning circuit comprises at least one precise rectification circuit for rectifying an alternating voltage signal input into the electric conduction signal conditioning circuit, wherein the input end of the electric conduction signal conditioning circuit is connected with the electric conduction pool, and the output end of the electric conduction signal conditioning circuit is connected with the input end of at least one voltage acquisition circuit.
The square wave excitation signal is provided for the conductivity cell through the excitation signal output circuit, meanwhile, the precise rectification circuit in the conductivity signal conditioning circuit is utilized to precisely rectify the alternating current voltage signal generated by the conductivity cell, the alternating current-direct current conversion precision is guaranteed, and the direct current voltage signal obtained after rectification is collected through the voltage collecting circuit, so that the conductivity of the solution immersed in the conductivity cell can be accurately measured by the direct current voltage signal obtained after precise rectification, a complicated root mean square detection circuit is not needed, and the accuracy of the conductivity measurement of the solution is improved while the circuit design is simplified.
According to one embodiment of the application, the conductance signal conditioning circuit further comprises an alternating voltage amplifying circuit and a first filtering amplifying circuit;
the input end of the alternating current voltage amplifying circuit is connected with the conductance cell, and the output end of the alternating current voltage amplifying circuit is connected with the input end of a first precise rectifying circuit in each precise rectifying circuit;
the output end of the first precise rectifying circuit is connected with the input end of the first filtering and amplifying circuit, and the output end of the first filtering and amplifying circuit is connected with the input end of a first voltage acquisition circuit in each voltage acquisition circuit.
According to one embodiment of the present application, the conductance signal conditioning circuit further comprises I ac Turn V ac A circuit and a second filter amplifier circuit;
the I is ac Turn V ac The input end of the circuit is connected with the conductance cell, the I ac Turn V ac The output end of the circuit is connected with the input end of a second precise rectifying circuit in each precise rectifying circuit;
the output end of the second precise rectifying circuit is connected with the input end of the second filtering and amplifying circuit, and the output end of the second filtering and amplifying circuit is connected with the input end of a second voltage acquisition circuit in each voltage acquisition circuit.
According to one embodiment of the present application, the precision rectification circuit includes an operational amplifier, a first diode, and a second diode;
the positive electrode of the first diode is connected with the negative electrode of the second diode, the negative electrode of the first diode is connected with the inverting input end of the operational amplifier, and the positive electrode of the second diode is connected with the inverting input end of the operational amplifier through a resistor;
the negative input end of the operational amplifier is used for receiving the alternating voltage signal, the positive input end of the operational amplifier is grounded, and the output end of the operational amplifier is connected with the positive electrode of the first diode and the negative electrode of the second diode.
According to one embodiment of the present application, the excitation signal output circuit includes a DC-DC module, a voltage regulator, and an electronic switch;
one end of the DC-DC module is used for being connected with a power supply, and the other end of the DC-DC module is connected with the first end of the voltage stabilizer;
the second end of the voltage stabilizer is connected with the first end of the electronic switch, and the second end of the electronic switch is connected with the conductance cell.
According to one embodiment of the application, the voltage acquisition device further comprises a processing circuit for outputting a control signal of a preset frequency;
and the output end of the processing circuit is connected with the third end of the electronic switch.
According to one embodiment of the present application, an output terminal of the processing circuit is connected to a third terminal of the voltage regulator.
According to one embodiment of the application, an input of the processing circuit is connected to an output of each of the voltage acquisition circuits.
According to one embodiment of the application, the voltage acquisition device further comprises a temperature measurement circuit for performing temperature measurements;
the output end of the temperature measuring circuit is connected with the input end of the processing circuit.
According to one embodiment of the application, the voltage acquisition device further comprises a communication circuit;
the input end of the communication circuit is connected with the output end of the processing circuit.
The above technical solutions in the embodiments of the present application have at least one of the following technical effects:
the square wave excitation signal is provided for the conductivity cell through the excitation signal output circuit, meanwhile, the precise rectification circuit in the conductivity signal conditioning circuit is utilized to precisely rectify the alternating current voltage signal generated by the conductivity cell, the alternating current-direct current conversion precision is guaranteed, and the direct current voltage signal obtained after rectification is collected through the voltage collecting circuit, so that the conductivity of the solution immersed in the conductivity cell can be accurately measured by the direct current voltage signal obtained after precise rectification, a complicated root mean square detection circuit is not needed, and the accuracy of the conductivity measurement of the solution is improved while the circuit design is simplified.
Drawings
For a clearer description of the present application or of the prior art, the drawings that are used in the description of the embodiments or of the prior art will be briefly described, it being apparent that the drawings in the description below are some embodiments of the present application, and that other drawings may be obtained from these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a first structure of a voltage acquisition device for conductivity measurement according to an embodiment of the present application;
fig. 2 is a second schematic structural diagram of a voltage acquisition device for conductivity measurement according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a filtering amplifying circuit according to an embodiment of the present application;
fig. 4 is a schematic diagram of a third structure of a voltage acquisition device for conductivity measurement according to an embodiment of the present application;
FIG. 5 is a diagram of I provided by an embodiment of the present application ac Turn V ac A schematic structural diagram of the circuit;
fig. 6 is a schematic structural diagram of a precision rectifying circuit according to an embodiment of the present disclosure;
fig. 7 is a fourth schematic structural diagram of a voltage acquisition device for conductivity measurement according to an embodiment of the present application;
fig. 8 is a schematic view of a fifth structure of a voltage acquisition device for conductivity measurement according to an embodiment of the present application;
fig. 9 is a sixth structural schematic diagram of a voltage acquisition device for conductivity measurement according to an embodiment of the present application.
Reference numerals in the specific embodiments are as follows:
100-conductivity cell; 200-power supply; 300-a temperature sensor; 400-upper computer; 1-an excitation signal output circuit; a 2-conductance signal conditioning circuit; 3-a voltage acquisition circuit; 4-a processing circuit; 5-a temperature measurement circuit; a 6-communication circuit; 11-a precision rectifying circuit; 12-an alternating voltage amplifying circuit; 13-a first filter amplification circuit; 14-I ac Turn V ac A circuit; 15-a second filter amplification circuit; a 21-DC-DC module; 22-voltage stabilizer; 23-electronic switch.
Detailed Description
Embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present application, and thus are only examples, and are not intended to limit the scope of protection of the present application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions.
In the description of the embodiments of the present application, the technical terms "first," "second," etc. are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, which means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), and similarly, "plural sets" refers to two or more (including two), and "plural sheets" refers to two or more (including two).
In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to the specific circumstances.
Conductivity is the ability of a material to conduct current when an electric field is applied to it, a parameter that is used to indicate how easily the material conducts electricity. Conductivity is one of the characteristics of a solution, which is important in providing useful information about the chemical structure of the solution based on the total concentration of ions in the solution and the transport characteristics (e.g., example mobility, diffusivity, viscosity, etc.).
Currently, for measurement of the conductivity of a solution, a direct current is typically applied to a conductivity cell immersed in the solution by a measurement circuit to measure the conductivity of the solution by collecting a direct current voltage. However, when the conductivity of a solution is measured by applying a direct current, the concentration of ions near the electrode surface is different from that in the solution due to the retardation of ion diffusion, or when the direct current is applied, the electrode potential is deviated from the reversible electrode potential due to the retardation of the electrochemical reaction, and the electrode polarization is caused, resulting in the occurrence of a conductivity measurement error.
In order to solve the above technical problems, the method of applying alternating current can be used to perform conductivity measurement instead of the method of applying direct current. That is, an ac voltage is applied to the conductivity cell immersed in the solution by a voltage collecting device for conductivity measurement, and ac voltage measurement of the conductivity cell and ac current measurement of the conductivity cell are performed to determine conductivity. The alternating voltage measurement of the conductivity cell and the alternating current measurement of the conductivity cell can be realized by constructing root mean square detection circuits such as a mean value detection circuit, a peak value detection circuit and the like through diodes in a voltage acquisition device for conductivity measurement. In order to improve the accuracy of conductivity measurement, a root mean square detection circuit can be used for measurement, but the root mean square detection circuit has high implementation complexity.
Therefore, the square wave excitation signal is provided for the conductivity cell through the excitation signal output circuit, at least one precise rectification circuit in the conductivity signal conditioning circuit is utilized for rectifying an alternating voltage signal input into the conductivity signal conditioning circuit to rectify the alternating voltage signal generated by the conductivity cell, alternating-current/direct-current conversion precision is guaranteed, the rectified alternating voltage signal is collected through the voltage collecting circuit, and therefore conductivity of a solution immersed in the conductivity cell can be accurately measured by the rectified alternating voltage signal.
A voltage acquisition device for conductivity measurement according to some embodiments of the present application, as shown in fig. 1, includes: a conductivity cell 100, an excitation signal output circuit 1, a conductivity signal conditioning circuit 2 and at least one voltage acquisition circuit 3; the input end of the excitation signal output circuit 1 is used for being connected with a power supply 200, and the output end of the excitation signal output circuit 1 is connected with the conductance cell 100; the conductance signal conditioning circuit 2 comprises at least one precise rectifying circuit 11 for rectifying an alternating voltage signal input into the conductance signal conditioning circuit 2, the input end of the conductance signal conditioning circuit 2 is connected with the conductance cell 100, and the output end of the conductance signal conditioning circuit 11 is connected with the input end of at least one voltage acquisition circuit 3.
Wherein the conductivity cell 100 is a conductivity sensor immersed in a solution for measuring the conductivity of the solution. The excitation signal output circuit 1 is a circuit for ensuring the normal operation of the conductivity cell 100, and is configured to supply a square wave voltage or a sine wave voltage as an excitation signal to the conductivity cell 100.
The conductance signal conditioning circuit 2 includes at least one precision rectifying circuit 11 for rectifying an ac voltage signal inputted to the conductance signal conditioning circuit 2. The precision rectifying circuit 11 may be any one of precision full-wave rectifying circuits, and the output of the full-wave rectifying circuit retains the shape of the input voltage, but changes only the phase of the input voltage. Specifically, the precision rectifying circuit 11 may be V ac Turn V dc The circuit is used for precisely rectifying the alternating current voltage signals acquired by the conductivity signal conditioning circuit 2 from the conductivity cell 100, outputting the direct current voltage signals obtained after rectification to the voltage acquisition circuit 3 through the conductivity signal conditioning circuit 2, and synchronously acquiring the direct current voltage signals output by the conductivity signal conditioning circuit 2 through the voltage acquisition circuit 3 so that the subsequent direct current voltage signals output by the voltage acquisition circuit 3 can determine the conductivity of the solution immersed in the conductivity cell 100.
The square wave excitation signal is provided for the conductivity cell through the excitation signal output circuit, meanwhile, the precise rectification circuit in the conductivity signal conditioning circuit is utilized to precisely rectify the alternating current voltage signal generated by the conductivity cell, the alternating current-direct current conversion precision is guaranteed, and the direct current voltage signal obtained after rectification is collected through the voltage collecting circuit, so that the conductivity of the solution immersed in the conductivity cell can be accurately measured by the direct current voltage signal obtained after precise rectification, a complicated root mean square detection circuit is not needed, and the accuracy of the conductivity measurement of the solution is improved while the circuit design is simplified.
To further improve the accuracy of the conductivity measurement, in some embodiments, as shown in fig. 2, the conductivity signal conditioning circuit 2 further includes an ac voltage amplifying circuit 12 and a first filtering amplifying circuit 13;
an input end of the alternating current voltage amplifying circuit 12 is connected with the conductance cell 100, and an output end of the alternating current voltage amplifying circuit 12 is connected with an input end of a first precise rectifying circuit in each precise rectifying circuit 11;
the output end of the first precise rectifying circuit is connected with the input end of the first filtering and amplifying circuit 13, and the output end of the first filtering and amplifying circuit is connected with the input end of a first voltage acquisition circuit in each voltage acquisition circuit 3.
The first precision rectifying circuit may be any precision rectifying circuit 11. The ac voltage amplifying circuit 12 is configured to collect an ac voltage signal output by the conductivity cell 100, and amplify the collected ac voltage signal to increase a signal-to-noise ratio, so as to facilitate the processing by the first precision rectifying circuit. The ac voltage amplifying circuit 12 may employ a conventional voltage amplifying circuit such as an instrumentation amplifying circuit or the like.
The first filtering and amplifying circuit 13 may be a butterworth low-pass filtering circuit and a negative feedback amplifying circuit, and is configured to filter high-frequency noise in the dc voltage signal output by the first precise rectifying circuit, and then perform amplification, so as to filter the high-frequency noise signal introduced by the first precise rectifying circuit in the rectifying process, thereby improving accuracy of the dc voltage signal acquired by the first voltage acquisition circuit, and further improving measurement accuracy of conductivity. The first filter amplifier circuit 13 may be exemplified as shown in fig. 3. The first voltage acquisition circuit is any voltage acquisition circuit 3.
In some embodiments, as shown in FIG. 4, the conductance signal conditioning circuit 2 further includes I ac Turn V ac A circuit 14 and a second filter amplification circuit 15;
the I is ac Turn V ac The input of the circuit 14 is connected with the conductance cell 100, the I ac Turn V ac The output end of the circuit 14 is connected with the input end of a second precision rectifying circuit in each precision rectifying circuit 11;
the output end of the second precise rectification circuit is connected with the input end of the second filter amplification circuit 15, and the output end of the second filter amplification circuit 15 is connected with the input end of a second voltage acquisition circuit in each voltage acquisition circuit 3.
The second precision rectifying circuit may be another precision rectifying circuit other than the first precision rectifying circuit in each precision rectifying circuit 11, and the circuit structure thereof may be the same as that of the first precision rectifying circuit.
I ac Turn V ac The circuit 14 is configured to collect an ac current signal output from the conductivity cell 100, and convert the collected ac current signal into an ac voltage signal, and amplify the ac voltage signal at the same time, so as to increase a signal-to-noise ratio, so that the second precision rectifying circuit is convenient to process. Exemplary, I ac Turn V ac The circuit 14 may effect current signal conversion and amplification by an ac op-amp, as shown in fig. 5. Wherein R1 and R2 are the resistivity of the current-to-voltage, and can be selected by the switch SW 1.
The second filtering and amplifying circuit 15 is the same as the first filtering and amplifying circuit 13, and may be a butterworth low-pass filtering circuit and a negative feedback amplifying circuit, and is configured to filter out high-frequency noise in the dc voltage signal output by the second precise rectifying circuit, and then perform amplification, so as to filter out the high-frequency noise signal introduced by the second precise rectifying circuit in the rectifying process, thereby improving the accuracy of the dc voltage signal acquired by the second voltage acquisition circuit, and further improving the measurement accuracy of the conductivity. Similarly, the second filter amplifier circuit 13 may be as shown in fig. 3. The second voltage acquisition circuit is any voltage acquisition circuit 3 except the first voltage acquisition circuit.
Through I ac Turn V ac The circuit converts an alternating current signal output by the conductivity cell into an alternating current signal, rectifies the alternating current signal through the second precise rectification circuit, carries out filtering treatment through the second filtering circuit and outputs the alternating current signal to the second voltage acquisition circuit, so that the influence of alternating current is considered when conductivity measurement is carried out, meanwhile, the accuracy of a direct current voltage signal acquired by the second voltage acquisition circuit is improved, and further the measurement accuracy of conductivity is improved.
To further improve the measurement accuracy of the conductivity, in some embodiments, as shown in fig. 6, the precision rectification circuit includes an operational amplifier U3, a first diode D1, and a second diode D2;
the positive electrode of the first diode D1 is connected with the negative electrode of the second diode D2, the negative electrode of the first diode D1 is connected with the inverting input end of the operational amplifier U3, and the positive electrode of the second diode D2 is connected with the inverting input end of the operational amplifier U3 through a resistor R6;
the reverse input end of the operational amplifier U3 is used for receiving the alternating voltage signal, the positive input end of the operational amplifier U3 is grounded, and the output end of the operational amplifier U3 is connected with the positive electrode of the first diode D1 and the negative electrode of the second diode D2.
The first diode D1 and the second diode D2 may be zener diodes. The diode is connected with the reverse input end of the operational amplifier U3, so that errors caused by forward voltage drop of the diode can be effectively eliminated, namely, the first diode D1, the second diode D2 and the operational amplifier U3 form a full-wave rectification super diode at the moment, precise rectification of alternating current input signals can be realized, and the accuracy of output direct current voltage signals and the measurement accuracy of conductivity are improved.
It is considered that the square wave signal output to the conductivity cell also has an effect on the voltage acquisition result, and thus on the conductivity measurement of the solution immersed in the conductivity cell. Thus, to improve the square wave accuracy of the excitation signal output circuit, including, in some embodiments, a DC-DC module 21, a voltage regulator 22, and an electronic switch 23, as shown in fig. 7, to improve the accuracy of the conductivity measurement;
one end of the DC-DC module 21 is used for accessing a power supply, and the other end of the DC-DC module 21 is connected with the first end of the voltage stabilizer 22;
the second end of the voltage stabilizer 22 is connected with the first end of the electronic switch 23, and the second end of the electronic switch 23 is connected with the conductance cell 100.
The DC-DC module 21 is used for isolating a power supply, so that after the external power supply is isolated by the DC-DC module 21, a stable voltage is provided by the voltage stabilizer 22. The voltage regulator 22 may be a linear voltage regulator, such as an LDO voltage regulator. Because the electronic switch 23 has a signal switching function, the electronic switch 23 is connected between the voltage stabilizer 22 and the conductivity cell 100, and two levels output by the voltage stabilizer 22 can be alternately output through the electronic switch 23, so that the output of high-precision square waves is realized, and the accuracy of conductivity measurement is further improved.
In order to improve the safety of square wave output, an interface protection can be performed between the electronic switch 23 and the conductivity cell 22, for example, a borrowing protection circuit is connected between the electronic switch 23 and the conductivity cell 22 to improve the safety of square wave output.
In order to further improve the output accuracy of the square wave, in an embodiment, as shown in fig. 8, the voltage acquisition device further includes a processing circuit 4 for outputting a control signal with a preset frequency;
an output terminal of the processing circuit 4 is connected to a third terminal of the electronic switch 23.
The processing circuit 4 may be configured to control on/off of the electronic switch 23 according to a PWM wave with a certain preset frequency, so that the excitation signal output circuit 1 may output a square wave voltage with the preset frequency by setting the PWM wave with the certain preset frequency in the processing circuit 4, thereby improving the output accuracy of the square wave.
In some embodiments, as shown in fig. 8, the output terminal of the processing circuit 4 may also be connected to the third terminal of the voltage regulator 22, so as to provide the possibility of adjusting the voltage regulator 22, so as to enable the excitation signal output circuit 1 to output a square-wave voltage with a specific magnitude.
In some embodiments, as shown in fig. 8, the input end of the processing circuit 4 may also be connected to the output end of each voltage acquisition circuit 3, so as to facilitate the subsequent conductivity calculation of the voltages acquired by each voltage acquisition circuit 3 by the processing circuit 4, to determine the conductivity of the solution immersed in the conductivity cell, and to control the voltage stabilizer 22 and/or the electronic switch 23 according to the voltages acquired by each voltage acquisition circuit 3.
Considering that the measurement of conductivity is greatly affected by temperature, in one embodiment, as shown in fig. 9, the voltage acquisition device further comprises a temperature measurement circuit 5 for taking temperature measurements;
the output of the temperature measuring circuit 5 is connected to the input of the processing circuit 4.
The temperature measurement circuit 5 is used for being connected to an external temperature sensor 300 for measuring the temperature of the environment where the conductivity cell is located, so that a temperature signal measured by the temperature sensor 300 is transmitted to the processing circuit 4, and the processing circuit can take the influence of the temperature into consideration to perform conductivity temperature compensation when performing conductivity calculation, so that the accuracy of the conductivity measured subsequently is improved.
In one embodiment, as shown in fig. 9, the voltage acquisition device may further include a communication circuit 6;
the input end of the communication circuit 6 is connected to the output end of the processing circuit 4, and is used for outputting the conductance calculation result to the outside, for example, to the external host computer 400. The upper computer 400 may be any electronic device that needs to obtain a conductivity calculation result.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (10)
1. A voltage acquisition device for conductivity measurement, comprising:
the device comprises a conductivity cell, an excitation signal output circuit, a conductivity signal conditioning circuit and at least one voltage acquisition circuit;
the input end of the excitation signal output circuit is used for being connected with a power supply, and the output end of the excitation signal output circuit is connected with the conductance cell;
the electric conduction signal conditioning circuit comprises at least one precise rectification circuit for rectifying an alternating voltage signal input into the electric conduction signal conditioning circuit, wherein the input end of the electric conduction signal conditioning circuit is connected with the electric conduction pool, and the output end of the electric conduction signal conditioning circuit is connected with the input end of at least one voltage acquisition circuit.
2. The voltage acquisition device for conductivity measurement according to claim 1, wherein the conductivity signal conditioning circuit further comprises an ac voltage amplifying circuit and a first filter amplifying circuit;
the input end of the alternating current voltage amplifying circuit is connected with the conductance cell, and the output end of the alternating current voltage amplifying circuit is connected with the input end of a first precise rectifying circuit in each precise rectifying circuit;
the output end of the first precise rectifying circuit is connected with the input end of the first filtering and amplifying circuit, and the output end of the first filtering and amplifying circuit is connected with the input end of a first voltage acquisition circuit in each voltage acquisition circuit.
3. The voltage acquisition device for conductivity measurement according to claim 1 or 2, wherein the conductivity signal conditioning circuit further comprises I ac Turn V ac A circuit and a second filter amplifier circuit;
the I is ac Turn V ac The input end of the circuit is connected with the conductance cell, the I ac Turn V ac The output end of the circuit is connected with the input end of a second precise rectifying circuit in each precise rectifying circuit;
the output end of the second precise rectifying circuit is connected with the input end of the second filtering and amplifying circuit, and the output end of the second filtering and amplifying circuit is connected with the input end of a second voltage acquisition circuit in each voltage acquisition circuit.
4. The voltage acquisition device for conductivity measurement according to claim 1, wherein the precision rectifying circuit comprises an operational amplifier, a first diode, and a second diode;
the positive electrode of the first diode is connected with the negative electrode of the second diode, the negative electrode of the first diode is connected with the inverting input end of the operational amplifier, and the positive electrode of the second diode is connected with the inverting input end of the operational amplifier through a resistor;
the negative input end of the operational amplifier is used for receiving the alternating voltage signal, the positive input end of the operational amplifier is grounded, and the output end of the operational amplifier is connected with the positive electrode of the first diode and the negative electrode of the second diode.
5. The voltage acquisition device for conductivity measurement according to claim 1, wherein the excitation signal output circuit comprises a DC-DC module, a voltage regulator, and an electronic switch;
one end of the DC-DC module is used for being connected with a power supply, and the other end of the DC-DC module is connected with the first end of the voltage stabilizer;
the second end of the voltage stabilizer is connected with the first end of the electronic switch, and the second end of the electronic switch is connected with the conductance cell.
6. The voltage acquisition device for conductivity measurement according to claim 5, further comprising a processing circuit for outputting a control signal of a preset frequency;
and the output end of the processing circuit is connected with the third end of the electronic switch.
7. The voltage acquisition device for conductivity measurements according to claim 6, wherein the output of the processing circuit is connected to a third terminal of the voltage regulator.
8. The voltage acquisition device for conductivity measurement according to claim 6 or 7, wherein an input of the processing circuit is connected to an output of each of the voltage acquisition circuits.
9. The voltage acquisition device for conductivity measurement according to claim 6 or 7, further comprising a temperature measurement circuit for taking temperature measurements;
the output end of the temperature measuring circuit is connected with the input end of the processing circuit.
10. The voltage acquisition device for conductivity measurement according to claim 6 or 7, further comprising a communication circuit;
the input end of the communication circuit is connected with the output end of the processing circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202320648671.3U CN219475728U (en) | 2023-03-29 | 2023-03-29 | Voltage acquisition device for conductivity measurement |
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| CN202320648671.3U CN219475728U (en) | 2023-03-29 | 2023-03-29 | Voltage acquisition device for conductivity measurement |
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