CN113311030B - Moisture sensing module - Google Patents
Moisture sensing module Download PDFInfo
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- CN113311030B CN113311030B CN202010119639.7A CN202010119639A CN113311030B CN 113311030 B CN113311030 B CN 113311030B CN 202010119639 A CN202010119639 A CN 202010119639A CN 113311030 B CN113311030 B CN 113311030B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/223—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance for determining moisture content, e.g. humidity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/226—Construction of measuring vessels; Electrodes therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
- G01N27/228—Circuits therefor
Abstract
The invention discloses a moisture sensing module which is used for sensing a moisture value of a material and comprises a sensing module and a control module, wherein the sensing module comprises a first electrode module and a second electrode module. The first electrode module provides a first amplitude signal in response to the material and the second electrode module provides a second amplitude signal in response to the material; and the control module carries out moisture calculation on the first amplitude signal and the second amplitude signal to obtain a moisture value of the material.
Description
Technical Field
The present invention relates to a moisture sensing module, and more particularly, to a moisture sensing module for accurately sensing moisture of a material by canceling environmental influences.
Background
Moisture control is a very important part of the manufacturing process of articles, which involves poor feed quality, process control, and finished product manufacture. Such as the moisture control of tobacco industry, the granulation control of feed industry, the powder moisture control of food industry, the ripening control of food industry and cement industry, the plastic granulation finished product control of chemical fiber industry, the finished product control of paper industry, etc. In the manufacturing process of these articles, the requirement for moisture content is very high, and the moisture content of the material must be controlled very precisely, so that the sensing accuracy and the sensing range of the moisture content of the material require very high resolution.
Conventional moisture sensing devices are generally classified into optical moisture sensing devices, microwave moisture sensing devices and capacitive moisture sensing devices. The optical moisture sensor is commonly used in laboratory sampling tests, and the microwave moisture sensor and the capacitive moisture sensor are used in online process comparison. The microwave type moisture sensing device is suitable for being applied to high-temperature, non-contact and low-precision environments, and has the advantages of being non-contact and resistant to abrasion. The capacitance type moisture sensing device is in a contact type, detects the change of the flowing components in a volume range, and has higher sensing precision.
However, since the capacitive moisture sensing device senses the substance change in a stable range by using a low frequency, the capacitive moisture sensing device is easily affected by the process environment change, and particularly in a small-signal environment, sensitive noise caused by the environmental temperature and humidity is easily covered up a real signal.
Therefore, how to design a moisture sensing module to solve the above technical problems is an important subject of the present inventors.
Disclosure of Invention
In order to solve the above problems, the present invention provides a moisture sensing module to overcome the problems of the prior art. Therefore, the moisture sensing module of the present invention senses a moisture value of a material, the moisture sensing module comprising: a sensing module, comprising: the first electrode module generates a first electric field and provides a reference signal responding to the material through the first electric field, and the reference signal is a first amplitude signal. And the second electrode module generates a second electric field and provides a sensing signal responding to the material through the second electric field, wherein the sensing signal is a second amplitude signal. And a control module coupled to the sensing module and receiving the first amplitude signal and the second amplitude signal. And the control module calculates the moisture of the first amplitude signal and the second amplitude signal to obtain a moisture value of the material.
In one embodiment, the control module includes: the signal processing unit is coupled to the sensing module. And the control unit is coupled with the signal processing unit. The first amplitude signal and the second amplitude signal are converted into a first voltage signal and a second voltage signal through the signal processing unit, and the control unit performs moisture calculation on the first voltage signal and the second voltage signal to obtain a moisture value.
In one embodiment, the first electrode module includes: the first oscillation unit provides a first oscillation signal. The first electrode is coupled to the first oscillating unit and receives a first oscillating signal. And the first reference electrode is coupled with the signal processing unit, and the first oscillating signal generates a first electric field through a first stray capacitance between the first electrode and the first reference electrode. The second electrode module includes: and a second oscillation unit providing a second oscillation signal. The second electrode is coupled to the second oscillating unit and receives a second oscillating signal. And a second reference electrode coupled to the signal processing unit, wherein the second oscillating signal generates a second electric field through a second stray capacitance between the second electrode and the second reference electrode. The first reference electrode provides a first amplitude signal to the signal processing unit according to the first electric field, and the second reference electrode provides a second amplitude signal to the signal processing unit according to the second electric field.
In one embodiment, the first oscillating signal and the second oscillating signal are ac signals with a constant amplitude and a constant frequency.
In one embodiment, the first electrode module and the second electrode module are both coupled to the material; the reference signal represents the moisture value of the material under the first material parameter value, and the sensing signal represents the moisture value of the material under the second material parameter value; the control unit obtains a moisture value which is not influenced by the first material parameter value and the second material parameter value through the moisture calculation of the average value obtained by adding the first voltage signal corresponding to the reference signal and the second voltage signal corresponding to the sensing signal.
In one embodiment, the first material parameter value and the second material parameter value are at least one of a first material temperature value and a second material temperature value, a first material density value and a second material density value, a first material pressure value and a second material pressure value, and a first moisture value and a second moisture value, respectively.
In one embodiment, the first electrode module is not coupled to the material, and the second electrode module is coupled to the material; the reference signal represents a medium parameter value of an environment medium surrounding the first electrode module, and the sensing signal represents a moisture value of the material under the medium parameter value; the control unit obtains a moisture value which is not influenced by the medium parameter value through the moisture calculation of the difference between the first voltage signal corresponding to the reference signal and the second voltage signal corresponding to the sensing signal.
In one embodiment, the medium parameter value is at least one of a medium temperature value, a medium pressure value and a medium moisture value.
In one embodiment, the signal processing unit includes: a first signal processing unit comprising: the first voltage conversion unit is coupled to the first reference electrode. The first multiplying power adjusting unit is coupled with the first reference electrode and the first voltage converting unit. And the first conversion unit is coupled with the first multiplying power adjusting unit and the control unit. A second signal processing unit comprising: the second voltage conversion unit is coupled to the second reference electrode. The second magnification adjustment unit is coupled to the second reference electrode and the second voltage conversion unit. And a second conversion unit coupled to the second magnification adjustment unit and the control unit. The first amplitude signal is converted into a first analog signal through the first voltage conversion unit, and the second amplitude signal is converted into a second analog signal through the second voltage conversion unit; the first multiplying power adjusting unit adjusts multiplying power of the first analog signal, and the first converting unit carries out analog/digital conversion on the first analog signal after the rate adjustment to obtain a first voltage signal; the second multiplying power adjusting unit adjusts multiplying power of the second analog signal, and the second converting unit performs analog/digital conversion on the second analog signal after the rate adjustment to obtain a second voltage signal.
In one embodiment, the first voltage converting unit and the second voltage converting unit are resistors or capacitors; the first amplitude signal generates a first analog signal at a node between the first magnification adjustment unit and the first reference electrode through a resistor or a capacitor; the second amplitude signal generates a second analog signal at a node between the second magnification adjustment unit and the second reference electrode through a resistor or a capacitor.
In one embodiment, the sensing module further includes: and an oscillation unit providing an oscillation signal. And the switch unit is coupled with the oscillation unit and the control unit. The first electrode module comprises a first electrode and a reference electrode, the second electrode module comprises a second electrode and a reference electrode, the first electrode and the second electrode are coupled with the switch unit, and the reference electrode is coupled with the signal processing unit; the control unit drives the switch unit to repeatedly switch and conduct the first electrode to be coupled with the oscillation unit or the second electrode to be coupled with the oscillation unit through switching frequency, so that the oscillation signal generates a first electric field through a first stray capacitance between the first electrode and the reference electrode, or the oscillation signal generates a second electric field through a second stray capacitance between the second electrode and the reference electrode; the reference electrode provides a first amplitude signal to the signal processing unit according to the first electric field, and provides a second amplitude signal to the signal processing unit according to the second electric field.
In one embodiment, the oscillating signal is an ac signal with a fixed amplitude and a fixed frequency.
In one embodiment, the first electrode, the second electrode and the reference electrode are concentrically arranged.
In one embodiment, the area of the second electrode is larger than that of the reference electrode, and the area of the reference electrode is larger than that of the first electrode, wherein the area ratio of the first electrode to the second electrode is 10.
In one embodiment, the area of the second electrode is larger than that of the reference electrode, and the area of the reference electrode is larger than that of the first electrode, wherein the area ratio of the first electrode to the second electrode is 2.
In one embodiment, the first electrode module and the second electrode module are both coupled to the material; the reference signal represents a first moisture value of the material under an environmental change value of an environment surrounding the first electrode module, and the sensing signal represents a second moisture value of the material under the same environmental change value; the control module obtains a moisture value which is not influenced by the environmental change value through the moisture calculation of the differential difference between the first voltage signal corresponding to the reference signal and the second voltage signal corresponding to the sensing signal.
In one embodiment, the environmental change value is at least one of a material temperature change value, a material density change value, and a material pressure change value.
In one embodiment, the signal processing unit includes: and the voltage conversion unit is coupled with the reference electrode. And the multiplying power adjusting unit is coupled with the reference electrode and the voltage conversion unit. And the conversion unit is coupled with the multiplying power adjusting unit and the control unit. The first amplitude signal and the second amplitude signal are converted into a first analog signal and a second analog signal through a voltage conversion unit; the multiplying power adjusting unit adjusts multiplying power of the first analog signal and the second analog signal, and the conversion unit carries out analog/digital conversion on the first analog signal and the second analog signal after the rate adjustment to obtain a first voltage signal and a second voltage signal.
In one embodiment, the voltage conversion unit is a resistor or a capacitor; the first amplitude signal and the second amplitude signal generate a first analog signal and a second analog signal at a node between the magnification adjustment unit and the reference electrode through a resistor or a capacitor.
In summary, the main advantages and effects of the present invention are that the moisture sensing module constructed by the dual-electrode module input obtains two sets of sensing signals by using the capacitive moisture sensing principle, and then calculates the two sets of sensing signals by the moisture calculation method to offset the environmental impact, so as to achieve the effect of accurately sensing the moisture value of the material.
For a further understanding of the technology, means, and efficacy of the invention to be achieved, reference should be made to the following detailed description of the invention and accompanying drawings which are believed to be a further and specific understanding of the invention, and to the following drawings which are provided for purposes of illustration and description and are not intended to be limiting.
Drawings
FIG. 1 is a block diagram of a moisture sensing module according to the present invention;
FIG. 2 is a block diagram of a moisture sensing module according to a first embodiment of the present invention;
FIG. 3A is a diagram illustrating a moisture calculation method using average calculation according to the moisture sensing module of the first embodiment of the present invention;
FIG. 3B is a diagram illustrating a second embodiment of the average calculation method used by the moisture sensing module according to the first embodiment of the present invention;
FIG. 4 is a schematic diagram of a waveform illustrating a density difference calculated by the moisture sensing module according to the first embodiment of the present invention;
FIG. 5A is a diagram illustrating a moisture calculation method using differential calculation according to the moisture sensing module of the first embodiment of the present invention;
FIG. 5B is a diagram illustrating a moisture calculation method using differential calculation for the moisture sensing module according to the first embodiment of the present invention;
FIG. 6 is a schematic diagram of a moisture calculation method using a moisture sensing module according to a first embodiment of the present invention, wherein the calculated ambient medium value is a waveform of air;
FIG. 7 is a block diagram of a moisture sensing module according to a second embodiment of the present invention;
FIG. 8A is a diagram of a second embodiment of a moisture sensing module according to the present invention;
FIG. 8B is a diagram of a second embodiment of a moisture sensor module according to the present invention;
FIG. 9A is a diagram illustrating a moisture calculation method using differential calculation according to a moisture sensing module of the second embodiment of the present invention;
FIG. 9B is a diagram illustrating a moisture calculation method using differential calculation for the moisture sensing module according to the second embodiment of the present invention; and
fig. 10 is a waveform diagram illustrating a method of calculating an environmental change value as a material temperature change value according to a method of using a moisture calculation method of a moisture sensing module using a differential calculation according to a second embodiment of the present invention.
Wherein, the reference numbers:
100. 100' \ 8230and moisture sensing module
1. 1' \ 8230and sensing module
12. 12' \ 8230and first electrode module
122 \ 8230and a first oscillation unit
124. 124' \ 8230first electrode
126 \ 8230and the first reference electrode
14. 14' \ 8230and second electrode module
142 \ 8230and a second oscillating unit
144. 144' \ 8230and a second electrode
146' \ 8230and a second reference electrode
A1 \ 8230and oscillating circuit
A2 \ 8230and amplifying circuit
26 \ 8230and oscillation unit
27 \ 8230and switch unit
28 \ 8230and reference electrode
2. 2' \ 8230and control module
22. 22' \ 8230and signal processing unit
22-1 \8230anda first signal processing unit
222-1 (8230), a first voltage conversion unit
224-1 (8230), first magnification adjusting unit
226-1 (8230), a first conversion unit
22-2 (8230); second signal processing unit
222-2 (8230), and a second voltage conversion unit
224-2 (8230); second magnification adjusting unit
226-2 (8230), and a second conversion unit
222 \ 8230and voltage conversion unit
224 \ 8230and magnification adjusting unit
226 \ 8230and conversion unit
24. 24' \8230andcontrol unit
3 8230a shell
32 \ 8230and space for holding it
34 method 8230opening
4-8230and insulating board
200 of 8230and the material
X8230and storage tank
Y8230and pipeline
Vm value 8230and moisture value
Sa1, sa1' \ 8230first amplitude signal
Sa2, sa2' \ 8230and a second amplitude signal
Sv1, sv1' \ 8230first voltage signal
Sv2, sv2' \ 8230and the second voltage signal
So 8230and oscillation signal
So1 \8230firstoscillation signal
So2 \8230andthe second oscillating signal
Sn1, sn1' \ 8230and the first analog signal
Sn2, sn2' \ 8230and the second analog signal
Cm 8230and water content calculation
C1 \ 8230and first stray capacitance
C2 \ 8230and second stray capacitance
E1 \ 8230
E2 8230a second electric field
C1-C3 (8230); curve
T8230and temperature variation value
Detailed Description
The technical content and the detailed description of the present invention are described below with reference to the drawings:
fig. 1 is a block diagram of a moisture sensing module according to the present invention. The moisture sensing module 100 is coupled to the material 200 and is used for sensing a moisture value Vm of the material 200. The moisture sensing module 100 can be disposed on a surface of a storage tank or a pipeline containing the material 200, for example, but not limited thereto, and can sense the moisture value Vm of the material 200 by using a capacitive coupling method. The moisture sensing module 100 is constructed by using a capacitive moisture sensing principle, and includes a sensing module 1 and a control module 2, wherein the sensing module 1 is disposed on a surface of a storage tank or a pipeline containing the material 200, and the control module 2 is coupled to the sensing module 1. The sensing module 1 includes a first electrode module 12 and a second electrode module 14. The first electrode module 12 generates a first electric field, and when the first electrode module 12 is disposed on the surface of a storage tank or a pipeline containing the material 200, the value of the first electric field will change (for example, but not limited to, the moisture value Vm of the material 200, the moisture value Vm of the air inside the tank, etc.) due to the detected moisture change. Therefore, a reference signal corresponding to the material 200 can be provided by the variation of the value of the first electric field, and the reference signal is the first amplitude signal Sa1. The second electrode module 14 generates a second electric field, and when the second electrode module 14 is disposed on a surface of a storage tank or a pipeline containing the material 200, a value of the second electric field changes (for example, but not limited to, the moisture value Vm of the material 200) according to the detected change of the moisture. Therefore, the variation of the second electric field value can correspondingly provide the sensing signal responding to the material 200, and the sensing signal is the second amplitude signal Sa2.
The control module 2 is coupled to the first electrode module 12 and the second electrode module 14, and receives the first amplitude signal Sa1 and the second amplitude signal Sa2. The control module 2 calculates the moisture content Cm of the first amplitude signal Sa1 and the second amplitude signal Sa2 to obtain a moisture value Vm of the material 200. Specifically, when the first electric field or the second electric field changes, the value of the first amplitude signal Sa1 responds to the change of the first electric field, and the value of the second amplitude signal Sa2 responds to the change of the second electric field. The first amplitude signal Sa1 is a reference signal, and the reference signal can represent a moisture value Vm of an environmental parameter (e.g., a parameter such as an electrical limitation, an environmental temperature or an environmental medium value) of the environment surrounding the material 200. The second amplitude signal Sa2 is a sensing signal, which can represent the moisture value Vm of the material 200 under the environmental parameter corresponding to the first electrode module 12. The moisture calculation Cm of the control module 2 depends on the sensing manner of the moisture sensing module 100, which uses the moisture calculation Cm manner of the average calculation or the differential calculation according to the position where the electrode modules (12, 14) are disposed.
The main objective of the present invention is to provide a moisture sensing module 100 constructed by using the capacitive moisture sensing principle, which has dual-electrode module (12, 14) input, and accurately senses the moisture value Vm of the material 200 by offsetting the environmental impact in a differential or averaged moisture calculation Cm manner. Further, the control module 2 includes a signal processing unit 22 and a control unit 24, and the signal processing unit 22 is coupled to the first electrode module 12, the second electrode module 14 and the control unit 24. The first amplitude signal Sa1 and the second amplitude signal Sa2 are converted into a first voltage signal Sv1 and a second voltage signal Sv2 by the signal processing unit 22, and the control unit 24 obtains the moisture value Vm of the material 200 by performing the moisture calculation Cm obtained by averaging or differentiating the first voltage signal Sv1 and the second voltage signal Sv 2. It should be noted that in an embodiment of the present invention, the environmental parameters include material parameter values, quality parameter values and environmental variation values, and the operation and calculation methods related to the detailed circuit structure of the moisture sensing module 100 and the material parameter values, quality parameter values and environmental variation values corresponding to the circuit structure are further described below.
Fig. 2 is a circuit block diagram of a moisture sensing module according to a first embodiment of the invention, and fig. 1 is also included. The first electrode module 12 includes a first oscillation unit 122, a first electrode 124 and a first reference electrode 126, and the second electrode module 14 includes a second oscillation unit 142, a second electrode 144 and a second reference electrode 146. The first electrode 124 is coupled to the first oscillating unit 122, and the first oscillating unit 122 provides a first oscillating signal So1 to the first electrode 124. A first stray capacitance C1 (also called parasitic capacitance) is generated between the first electrode 124 and the first reference electrode 126 due to the close relationship of the two electrodes, and a voltage difference is generated between the first electrode 124 and the first reference electrode 126 due to the relationship of the first oscillating signal So1 provided to the first electrode 124, and the first stray capacitance C1 stores charges to generate a first electric field E1. The first reference electrode 126 is coupled to the signal processing unit 22, and provides the first amplitude signal Sa1 to the signal processing unit 22 according to the variation of the first electric field E1. It should be noted that the coupling manner of the components inside the second electrode module 14, the transmission manner of the second oscillation signal So2 and the second amplitude signal Sa2, and the generation manner of the second stray capacitor C2 and the second electric field E2 are the same as those of the first electrode module 12, and are not repeated herein.
The first oscillating unit 122 and the second oscillating unit 142 respectively include an oscillating circuit A1 therein, the oscillating circuit A1 of the first oscillating unit 122 is coupled to the first electrode 124, and the oscillating circuit A1 of the second oscillating unit 142 is coupled to the second electrode 144. The oscillating circuit A1 is used to generate an ac signal with a fixed frequency and a fixed amplitude, and the oscillating circuit A1 can use devices such as, but not limited to, an oscillating transistor, a colpitts oscillating circuit, or an ac signal generating controller. An amplifying circuit A2 as shown in fig. 2 may be included between the oscillating circuit A1 and the electrodes (124, 144) to amplify the oscillating signals (So 1, so 2). Specifically, the oscillation circuit A1 can be directly coupled to the electrodes (124, 144) when the driving capability of the oscillation signals (So 1, so 2) is sufficient for the electrode modules (12, 14) to operate normally. On the contrary, when the driving capability of the oscillation signals (So 1, so 2) is not enough to enable the electrode modules (12, 14) to operate normally, the oscillation circuit A1 needs to couple the electrodes (124, 144) through the amplifying circuit A2, so that the oscillation signals (So 1, so 2) are amplified and then provided to the electrodes (124, 144). It should be noted that, in an embodiment of the present invention, the amplifying circuit A2 is not limited to be configured by the circuit shown in fig. 2, and for example, the amplifying circuit A2 for signal amplification should be included in the scope of the present embodiment.
Referring back to fig. 2, the signal processing unit 22 includes a first signal processing unit 22-1 and a second signal processing unit 22-2. The first signal processing unit 22-1 includes a first voltage converting unit 222-1, a first magnification adjusting unit 224-1 and a first converting unit 226-1, and the second signal processing unit 22-2 includes a second voltage converting unit 222-2, a second magnification adjusting unit 224-2 and a second converting unit 226-2. The first voltage conversion unit 222-1 is coupled to the first reference electrode 126 and the first magnification adjustment unit 224-1, and the first conversion unit 226-1 is coupled to the first magnification adjustment unit 224-1 and the control unit 24. The first voltage converting unit 222-1 is a resistor or a capacitor. The first amplitude signal Sa1 provided by the first reference electrode 126 generates a first analog signal Sn1 at a node between the first magnification adjustment unit 224-1, the first reference electrode 126 and the first voltage conversion unit 222-1 through a resistor or a capacitor. The first magnification adjustment unit 224-1 adjusts the magnification of the first analog signal Sn1, and the first conversion unit 226-1 performs analog/digital conversion on the first analog signal Sn1 with the adjusted magnification to provide a first voltage signal Sv1 to the control unit 24.
Specifically, as shown in fig. 2, the first voltage conversion unit 222-1 and the first magnification adjustment unit 224-1 may constitute an amplification circuit (or an inverse amplification circuit). The amplifying circuit amplifies the first analog signal Sn1 to obtain a clear and obvious first analog signal Sn1, so as to avoid the situation that the control unit 24 is difficult to calculate Cm due to too small signal value. It should be noted that the coupling manner of the components inside the second signal processing unit 22-2 and the transmission and processing manner of the second analog signal Sn2 are the same as the first signal processing unit 22-1, and are not described herein again.
Please refer to fig. 3A for a usage diagram of a moisture calculation method using average calculation for the moisture sensing module according to the first embodiment of the present invention, and fig. 3B for a usage diagram of a moisture calculation method using average calculation for the moisture sensing module according to the first embodiment of the present invention, which are combined with fig. 1-2. In fig. 3A, the first electrode module 12 and the second electrode module 14 are disposed on the outer surface of the storage tank X containing the material 200, and both the first electrode module 12 and the second electrode module 14 are coupled to the material 200. In fig. 3B, the first electrode module 12 and the second electrode module 14 are disposed on the outer surface of the pipeline Y containing the material 200, and both the first electrode module 12 and the second electrode module 14 are coupled to the material 200. The first electrode module 12 provides a reference signal (i.e., a first amplitude signal Sa 1) to the control module 2 according to the coupled position. The reference signal represents the moisture value Vm sensed at the coupling location of the first electrode module 12. The material 200 at the coupling location of the first electrode module 12 has a first material parameter value that affects the moisture value Vm sensed by the first electrode module 12. The second electrode module 14 provides a sensing signal (i.e., the second amplitude signal Sa 2) to the control module 2 according to the coupled position. The sensing signal represents the moisture value Vm sensed by the second electrode module 14 at the coupling position. The material 200 at the coupling location of the second electrode module 14 has a second material parameter value that also affects the moisture value Vm sensed by the second electrode module 14. The control unit 24 obtains the moisture value Vm independent of the first material parameter value and the second material parameter value by summing the average moisture calculation Cm with the first voltage signal Sv1 corresponding to the reference signal and the second voltage signal Sv2 corresponding to the sensing signal.
Specifically, the material 200 may have different values of material parameters such as pressure, density, temperature and actual moisture due to different positions in the storage tank X (and the material 200 may also be in the pipeline Y). For example, in the storage tank X, the density, temperature and pressure of the material 200 generally at the upper part are generally lower, while the density, temperature and pressure of the material 200 at the lower part are generally higher. Therefore, although the first electrode module 12 and the second electrode module 14 sense the same material 200, the moisture value Vm sensed by the first electrode module 12 is different from the moisture value Vm sensed by the first electrode module 14 due to the influence of the material parameter values. Therefore, the control unit 24 obtains the average moisture value Vm by using the moisture calculation Cm method of adding the two different moisture values Vm to the average value. Through the calculation mode, the influence of material parameter values such as pressure, density, temperature and actual moisture on the moisture value Vm sensed by the moisture sensing module 100 can be eliminated, and the moisture value Vm with higher accuracy can be obtained.
Fig. 4 is a schematic diagram showing waveforms of calculating density differences of the moisture sensing module according to the first embodiment of the present invention, in which the moisture calculating method using average calculation is adopted, and refer to fig. 1 to 3B, and refer to fig. 3A and 4 repeatedly. In the illustrative example of calculating the density difference using the method of FIG. 3A, the first electrode module 12 and the second electrode module 14 perform the moisture value Vm sensing a plurality of times, respectively. Assume that the moisture value sensed by the first electrode module 12 is 11 (as shown by curve C1) and the moisture value sensed by the second electrode module 14 is 12 (as shown by curve C2). The difference between the two is the difference of the density effect, and the control unit 24 sums the moisture value 11 and the moisture value 12 to obtain the moisture value Vm of 11.5 (as shown by the curve C3 and indicated by the dashed line), thereby reducing the error of sensing the moisture value Vm caused by the density difference.
Please refer to fig. 5A for a diagram illustrating a usage of a moisture calculation method using a differential calculation in a moisture sensing module according to a first embodiment of the present invention, and fig. 5B for a diagram illustrating a usage of a moisture calculation method using a differential calculation in a moisture sensing module according to a second embodiment of the present invention. In fig. 5A, the first electrode module 12 and the second electrode module 14 are disposed on the outer surface of the storage tank X containing the material 200, and the first electrode module 12 is not coupled to the material 200, and the second electrode module 14 is coupled to the material 200. In fig. 5B, the first electrode module 12 and the second electrode module 14 are disposed on the outer surface of the pipeline Y containing the material 200, and the first electrode module 12 is not coupled to the material 200, and the second electrode module 14 is coupled to the material 200. The first electrode module 12 provides a reference signal (i.e., a first amplitude signal Sa 1) to the control module 2 according to the coupled position. The reference signal represents the moisture value Vm sensed by the first electrode module 12 at the coupling location. The coupling position of the first electrode module 12 is the ambient medium around the material 200, and the ambient medium has an ambient medium value, which affects the moisture value Vm sensed by the first electrode module 12. The second electrode module 14 provides a sensing signal (i.e., the second amplitude signal Sa 2) to the control module 2 according to the coupled position. The sensing signal represents the moisture value Vm sensed by the second electrode module 14 at the coupling position. Since the material 200 at the coupling position of the second electrode module 14 has the same environmental medium value as the first electrode module 12 in the same environmental medium (such as, but not limited to, air), the same environmental medium value will also affect the moisture value Vm sensed by the second electrode module 14. The control unit 24 obtains the moisture value Vm that is not affected by the environmental medium value by the moisture calculation Cm in which the difference between the first voltage signal Sv1 corresponding to the reference signal and the second voltage signal Sv2 corresponding to the sensing signal is taken.
Specifically, since the medium value (e.g., without limitation, air) in the storage tank X has a specific environmental medium value (e.g., without limitation, air temperature, air humidity, moisture, and air pressure), and since the material 200 is also in the storage tank X, the moisture value Vm of the material 200 is affected by the medium environmental medium value (and vice versa for the material 200 in the pipeline Y). Therefore, it is necessary to obtain an accurate moisture value Vm by excluding the influence of the environmental medium value. Therefore, the control unit 24 calculates Cm by using the water difference between two different water content values Vm, and can deduct the influence of the ambient medium value of the medium temperature, medium humidity (medium water content) and medium pressure, thereby obtaining the water content value Vm with higher accuracy.
Fig. 6 is a schematic diagram showing a method of calculating the ambient medium value as a waveform of air according to the moisture calculating method of the moisture sensing module using differential calculation according to the first embodiment of the present invention, and refer to fig. 1 to 5B, and refer to fig. 5A and 6 repeatedly. Taking the illustrative example of the usage of FIG. 5A to calculate the environmental medium as air, the first electrode module 12 and the second electrode module 14 perform a plurality of moisture value Vm senses respectively. Assume that the moisture value sensed by the first electrode module 12 is 2 (as shown by curve C1) and the moisture value sensed by the second electrode module 14 is 14 (as shown by curve C2). The difference between the two is the difference of the medium value influence, and the control unit 24 performs the difference calculation between the moisture value 14 and the moisture value 2 to obtain the moisture value 12 (as shown by the curve C3 and indicated by the dashed line), thereby reducing the error of sensing the moisture value Vm caused by the environmental medium value.
Fig. 7 is a circuit block diagram of a moisture sensing module according to a second embodiment of the present invention, which is combined with fig. 1 to 6. The difference between the moisture sensing module 100 'of fig. 7 and the moisture sensing module 100 of fig. 2 is that the sensing module 1' further includes an oscillating unit 26 and a switching unit 27, and the first electrode module 12 'includes a first electrode 124' and a reference electrode 28, and the second electrode module 14 'includes a second electrode 144' and a reference electrode 28. The reference electrodes 28 of the first electrode module 12 'and the second electrode module 14' are common electrodes (i.e., the same electrodes). The switch unit 27 is coupled to the oscillation unit 26, the first electrode 124', the second electrode 144' and the control unit 24', and the reference electrode 28 is coupled to the signal processing unit 22'. The control unit 24' drives the switch unit 27 to repeatedly switch on by switching the frequency, so that the first electrode 124' is coupled to the oscillation unit 26 through the switch unit 27 or the second electrode 144' is coupled to the oscillation unit 26 through the switch unit 27. The oscillating unit 26 provides an oscillating signal So to the switch unit 27, when the switch unit 27 turns on the first electrode 124 'to couple with the oscillating unit 26, the oscillating signal So is provided to the first electrode 124', and when the switch unit 27 turns on the second electrode 144 'to couple with the oscillating unit 26, the oscillating signal So is provided to the second electrode 144'.
A first stray capacitance C1 (also called a parasitic capacitance) is generated between the first electrode 124' and the reference electrode 28 due to the close relationship of the two electrodes, and a voltage difference is generated between the first electrode 124' and the reference electrode 28 due to the relationship of the oscillation signal So provided to the first electrode 124', and the first stray capacitance C1 stores charges to generate a first electric field E1. The reference electrode 28 is coupled to the signal processing unit 22' and provides a first amplitude signal Sa1' to the signal processing unit 22' according to the variation of the first electric field E1. A second stray capacitance C2 (also called parasitic capacitance) is generated between the second electrode 144' and the reference electrode 28 due to the close relationship of the two electrodes, and a voltage difference is generated between the second electrode 144' and the reference electrode 28 due to the relationship of the oscillation signal So provided to the second electrode 144', and the second stray capacitance C2 stores charges to generate a second electric field E2. The reference electrode 28 is coupled to the signal processing unit 22' and provides a second amplitude signal Sa2' to the signal processing unit 22' according to the variation of the second electric field E2. It should be noted that, in an embodiment of the present invention, the circuit structures and operation manners of the oscillating unit 26 and the first oscillating unit 122 and the second oscillating unit 142 of fig. 2 are the same, and are not repeated herein.
The signal processing unit 22 'includes a voltage converting unit 222, a magnification adjusting unit 224 and a converting unit 226, wherein the voltage converting unit 222 is coupled to the reference electrode 28 and the magnification adjusting unit 224, and the converting unit 226 is coupled to the magnification adjusting unit 224 and the control unit 24'. The voltage converting unit 222 is a resistor or a capacitor. The first amplitude signal Sa1 'and the second amplitude signal Sa2' provided by the reference electrode 28 generate the first analog signal Sn1 'and the second analog signal Sn2' at nodes among the magnification adjustment unit 224, the reference electrode 28, and the voltage conversion unit 222 through resistance or capacitance. The magnification adjustment unit 224 adjusts the magnifications of the first analog signal Sn1' and the second analog signal Sn2', and the conversion unit 226 performs analog/digital conversion on the first analog signal Sn1' and the second analog signal Sn2' after the magnification adjustment to provide a first voltage signal Sv1' and a second voltage signal Sv2' to the control unit 24'. Specifically, as shown in fig. 7, the voltage conversion unit 222 and the magnification adjustment unit 224 may constitute an amplification circuit (or an inverse amplification circuit). The amplifying circuit amplifies the first analog signal Sn1' and the second analog signal Sn2' to obtain the first analog signal Sn1' and the second analog signal Sn2' which are relatively clear and obvious, so as to avoid the situation that the moisture calculation Cm is difficult for the control unit 24' due to too small signal values.
Fig. 8A is a structural diagram of a moisture sensing module according to a second embodiment of the present invention, and fig. 8B is a structural diagram of a sensing module according to the second embodiment of the moisture sensing module according to the present invention, which are combined with fig. 1 to 7. As shown in fig. 8A, the moisture sensing module 100' includes a housing 3 and an insulating plate 4. The housing 3 has an accommodating space 32 and an opening 34 therein, and the insulating plate 4 covers the opening 34 of the housing 3. The sensing module 1' and the control module 2' of the moisture sensing module 100' are accommodated in the accommodating space 32, and the sensing module 1' is disposed at the opening 34, so that the sensing module 1' can sense the moisture value Vm of the material 200 by penetrating the insulating plate 4 through radiation in a capacitive coupling manner.
As shown in fig. 8B, the first electrode 124', the second electrode 144' and the reference electrode 28 of the sensing module 1' are concentrically arranged (fig. 8 illustrates concentric circles, but not limited thereto, such as but not limited to oval, square, etc.), and the area of the second electrode 144' is larger than that of the reference electrode 28, and the area of the reference electrode 28 is larger than that of the first electrode 124'. Specifically, the larger the difference in area between the first electrode 124 'and the second electrode 144', the better the dynamic response, but the first electrode 124 'needs to have a sufficient area to sense the moisture value Vm, and therefore the area of the first electrode 124' is not necessarily too small. When the area ratio of the first electrode 124 'to the second electrode 144' is 2, the moisture values Vm sensed by the two electrodes (124 ', 144') are relatively close, and the dynamic range of the moisture value Vm after moisture calculation Cm is relatively small. If the area ratio of the first electrode 124 'to the second electrode 144' is 10, the area of the first electrode 124 'is much smaller than that of the second electrode 144'. The difference between the sensed moisture values Vm of the two electrodes (124 ', 144') is large, and the dynamic range of the moisture value Vm after moisture calculation Cm is large. Therefore, the area ratio of the first electrode 124' to the second electrode 144' is 10, which has a better dynamic response, and the area of the first electrode 124' is not too small, which is a preferable area ratio.
Fig. 9A is a diagram illustrating a usage of a moisture calculation method of a moisture sensing module according to a second embodiment of the present invention using differential calculation, and fig. 9B is a diagram illustrating a usage of a moisture calculation method of a moisture sensing module according to a second embodiment of the present invention using differential calculation, which are combined with fig. 1 to 8. In fig. 9A, the sensing module 1' is disposed on the outer surface of the storage tank X containing the material 200, such that the first electrode module 12' and the second electrode module 14' are both coupled to the material 200. In fig. 9B, the sensing module 1' is disposed on the outer surface of the pipeline Y containing the material 200, such that the first electrode module 12' and the second electrode module 14' are both coupled to the material 200. The first electrode module 12' provides a reference signal (i.e., the first amplitude signal Sa1 ') to the control module 2' according to the coupled position. The reference signal represents the moisture value Vm sensed by the first electrode module 12' coupled position. The coupling position of the first electrode module 12 'is a first moisture value of the material 200, and the first moisture value is influenced by the environmental variation value of the surrounding environment, and the environmental parameter value influences the moisture value Vm sensed by the first electrode module 12'. The second electrode module 14' provides a sensing signal (i.e., the second amplitude signal Sa2 ') to the control module 2' according to the coupled position. The sensing signal represents a second moisture value sensed by the second electrode module 14' at the coupled position. Since the first electrode module 12 'and the second electrode module 14' are concentrically arranged, they have the same environmental variation value for the same coupling position. However, since the coupling areas are different, the moisture values sensed by the first electrode module 12 'and the second electrode module 14' are slightly different. The control unit 24' obtains the moisture value Vm that is not affected by the environmental change value by the moisture calculation Cm in which the difference between the first voltage signal Sv1' corresponding to the reference signal and the second voltage signal Sv2' corresponding to the sensing signal is taken. That is, the control unit 24' obtains the moisture value Vm that is not affected by the environmental change value by differentiating the sensed first moisture value and second moisture value.
Specifically, since the materials 200 are located at the same position in the storage tank X, when the temperature, density and pressure of the materials are changed, the sensed moisture value Vm is also shifted. Therefore, the influence of the material temperature variation value, the material density variation value and the material pressure variation value can be deducted through the calculation mode of taking the difference between the first moisture value and the second moisture value sensed by the first electrode module 12 'and the second electrode module 14', and the moisture value Vm with higher accuracy is obtained. For example, if the temperature in the storage tank X varies with the amount of solar radiation in a day, the first moisture value sensed by the first electrode module 12 'will shift with the temperature rising or falling, and the second moisture value sensed by the second electrode module 14' will also shift substantially the same because the second electrode module 14 'and the first electrode module 12' are concentrically arranged. Therefore, the control unit 24' obtains the moisture value Vm with high accuracy by using the moisture calculation Cm method in which the two different moisture values Vm are differentiated. Through the calculation mode, the influence of the moisture value Vm sensed by the moisture sensing module 100 on the material temperature change value, the material density change value and the material pressure change value can be eliminated.
Fig. 10 is a schematic diagram of a usage of a moisture calculating method in which a moisture sensing module according to a second embodiment of the present invention uses differential calculation, and a waveform of a calculated environmental change value as a material temperature change value is shown in fig. 1 to 9B, and fig. 9A and 10 are repeated. In the exemplary embodiment of fig. 9A, the environmental change value is calculated as the temperature change value, assuming that the temperature change value is T, and the switch unit 27 repeatedly switches on to enable the first electrode module 12 'and the second electrode module 14' to sense the moisture value for a plurality of times. Connecting the first moisture values sensed by the first electrode module 12 'results in curve C1, and connecting the second moisture values sensed by the second electrode module 14' results in curve C2. As can be seen from fig. 10, the first moisture value and the second moisture value are displaced upward when the temperature variation value T increases, and are displaced downward when the temperature variation value T increases. The control unit 24' obtains a moisture value Vm with high accuracy (shown as a curve C3 and indicated by a dotted line) by performing differential moisture calculation Cm, and subtracts the temperature variation value T from the moisture value Vm such that the curve of the moisture value Vm is substantially linear (i.e., is not affected by the temperature variation value T).
Referring again to fig. 2 and 7, the moisture sensing module (1, 1') of the above-described embodiments of the circuit is also suitable for sensing moisture values Vm of materials 200 having low dielectric constants or small volume, thin layers of material. In particular, low dielectric constant or small volume, thin layer material 200 such as, but not limited to, plastic, pulp, etc., material 200 that has a low conductivity or is difficult to sense. For the above reasons, the conventional capacitive moisture sensor cannot smoothly sense the moisture value Vm of the material 200 due to too small variation of the electric field during sensing. However, since the moisture sensing module (1, 1 ') of the present invention uses a sensing method with dual-electrode module (12, 14) input, which can calculate the moisture Cm by using the difference of the sensed signals between the first electrode module (12, 12 ') and the second electrode module (14, 14 '), it is still able to accurately measure the moisture value Vm of the material 200 with low dielectric constant or small volume and thin layer material. Therefore, the moisture sensing module (1, 1') of the present invention is particularly suitable for sensing moisture values Vm of materials 200 having low dielectric constants or small volumes of thin materials, as compared to existing moisture sensors.
It should be understood, however, that the detailed description and drawings are only illustrative of the preferred embodiments of the present invention, but are not intended to limit the present invention.
The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. A moisture sensing module for sensing a moisture value of a material, the moisture sensing module comprising:
a sensing module, comprising:
a first electrode module generating a first electric field and providing a reference signal responsive to the material via the first electric field, the reference signal being a first amplitude signal, the first electrode module comprising:
a first oscillating unit for providing a first oscillating signal;
a first electrode coupled to the first oscillating unit and receiving the first oscillating signal; and
a first reference electrode, the first oscillating signal generating the first electric field through a first stray capacitance between the first electrode and the first reference electrode; and
a second electrode module generating a second electric field and providing a sensing signal in response to the material through the second electric field, the sensing signal being a second amplitude signal, the second electrode module comprising:
a second oscillating unit for providing a second oscillating signal;
a second electrode coupled to the second oscillating unit and receiving the second oscillating signal; and
a second reference electrode, wherein the second oscillating signal generates the second electric field through a second stray capacitance between the second electrode and the second reference electrode; and
a control module, coupled to the sensing module, for receiving the first amplitude signal and the second amplitude signal, the control module comprising:
a signal processing unit coupled to the first reference electrode and the second reference electrode; and
a control unit coupled to the signal processing unit;
the control module carries out moisture calculation on the first amplitude signal and the second amplitude signal to obtain a moisture value of the material;
the first amplitude signal and the second amplitude signal are converted into a first voltage signal and a second voltage signal through the signal processing unit, and the control unit performs the moisture calculation on the first voltage signal and the second voltage signal to obtain the moisture value; and
the first reference electrode provides the first amplitude signal to the signal processing unit according to the first electric field, and the second reference electrode provides the second amplitude signal to the signal processing unit according to the second electric field.
2. The moisture sensing module of claim 1, wherein the first and second oscillating signals are ac signals having a fixed amplitude and a fixed frequency.
3. The moisture sensing module of claim 1, wherein the first electrode module and the second electrode module are both coupled to the material; the first amplitude signal represents the moisture value of the material at a first material parameter value and the second amplitude signal represents the moisture value of the material at a second material parameter value; the control unit obtains a moisture value which is not influenced by the first material parameter value and the second material parameter value through the moisture calculation of the average value obtained by adding the first voltage signal corresponding to the first amplitude signal and the second voltage signal corresponding to the second amplitude signal.
4. The moisture sensing module of claim 3, wherein the first material parameter value and the second material parameter value are at least one of a first material temperature value and a second material temperature value, a first material density value and a second material density value, a first material pressure value and a second material pressure value, and a first moisture value and a second moisture value, respectively.
5. The moisture sensing module of claim 1, wherein the first electrode module is not coupled to the material and the second electrode module is coupled to the material; the first amplitude signal represents a medium parameter value of an environmental medium surrounding the first electrode module, and the second amplitude signal represents a moisture value of the material at the medium parameter value; the control unit obtains a moisture value which is not influenced by the medium parameter value through the moisture calculation by taking the difference between a first voltage signal corresponding to the first amplitude signal and a second voltage signal corresponding to the second amplitude signal.
6. The moisture sensing module of claim 5, wherein the media parameter value is at least one of a media temperature value, a media pressure value, and a media moisture value.
7. The moisture sensing module of claim 1, wherein the signal processing unit comprises:
a first signal processing unit, comprising:
a first voltage conversion unit coupled to the first reference electrode;
a first multiplying power adjusting unit coupled to the first reference electrode and the first voltage converting unit; and
a first conversion unit coupled to the first magnification adjustment unit and the control unit;
a second signal processing unit, comprising:
a second voltage conversion unit coupled to the second reference electrode;
a second power adjusting unit coupled to the second reference electrode and the second voltage converting unit; and
a second conversion unit coupled to the second power adjustment unit and the control unit;
the first amplitude signal is converted into a first analog signal through the first voltage conversion unit, and the second amplitude signal is converted into a second analog signal through the second voltage conversion unit; the first multiplying power adjusting unit adjusts multiplying power of the first analog signal, and the first converting unit carries out analog/digital conversion on the first analog signal after rate adjustment to the first voltage signal; the second multiplying power adjusting unit adjusts multiplying power of the second analog signal, and the second converting unit performs analog/digital conversion on the second analog signal after the rate adjustment to the second voltage signal.
8. The moisture sensing module of claim 7, wherein the first voltage converting unit and the second voltage converting unit are a resistor or a capacitor; the first amplitude signal generates the first analog signal at a node between the first magnification adjustment unit and the first reference electrode through the resistor or the capacitor; the second amplitude signal generates the second analog signal at a node between the second magnification adjustment unit and the second reference electrode through the resistor or the capacitor.
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