CN112945346A - Liquid level height measuring device and method - Google Patents
Liquid level height measuring device and method Download PDFInfo
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- CN112945346A CN112945346A CN202110353023.0A CN202110353023A CN112945346A CN 112945346 A CN112945346 A CN 112945346A CN 202110353023 A CN202110353023 A CN 202110353023A CN 112945346 A CN112945346 A CN 112945346A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
- G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
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Abstract
The application discloses a liquid level height measuring device and a liquid level height measuring method, the liquid level height measuring device comprises a vertically arranged PCB, wherein two metal nails which are used for measuring the conductivity and are positioned at the same horizontal height are arranged at the bottom of the PCB; a pair of electrodes which are arranged in parallel are arranged above the metal nail; a temperature sensor is also arranged between the two metal nails; and a processor containing a measuring code is arranged at the top of the PCB and is electrically connected with the electrode and the metal nail respectively, and the measuring code is a method execution code for measuring the liquid level height. The application solves the problem that the existing water body liquid level sensor cannot be widely used under the digital farmland environment because of too high cost or too poor precision.
Description
Technical Field
The application relates to the technical field of agricultural irrigation, in particular to a liquid level height measuring device and method.
Background
At present, along with the increasing shortage of water resources, more and more occasions are paid attention to the monitoring of water consumption, wherein agricultural irrigation water is a very important water use scene, and irrigation in the past is mostly extensive, and the water utilization ratio is very low. However, with the further development of agriculture in China towards the direction of digital automation, effective utilization of water resources is required to be better, so that accurate monitoring of the water level of farmland irrigation becomes a very important link. However, most of the existing water level sensors on the market are not widely used in the digital farmland environment due to relatively high cost or poor precision.
Therefore, it is desirable to provide a liquid level height measuring device with low cost and high measuring accuracy.
Disclosure of Invention
The application mainly aims to provide liquid level height measuring equipment and method, and solves the problem that an existing water level sensor cannot be widely used in a digital farmland environment due to too high cost or too poor precision.
In order to achieve the above object, according to a first aspect of the present application, there is provided a liquid level measuring apparatus, comprising a vertically arranged PCB board, two metal pins at the same horizontal height for measuring electrical conductivity are provided at the bottom of the PCB board; a pair of electrodes which are arranged in parallel are arranged above the metal nail; a temperature sensor is also arranged between the two metal nails; and a processor containing a measuring code is arranged at the top of the PCB and is electrically connected with the electrode and the metal nail respectively, and the measuring code is a method execution code for measuring the liquid level height.
Further, the two metal nails for measuring the conductivity are made of stainless steel.
Further, the temperature sensor is: thermistor temperature sensor.
In order to achieve the above object, according to a second aspect of the present application, another liquid level height measuring method is provided.
The liquid level height measuring method comprises the following steps: detecting the conductivity between two metal nails on the PCB and the capacitance between two electrodes; if the conductivity is greater than or equal to a preset conductivity and the capacitance value is greater than or equal to a preset capacitance value, acquiring a temperature value of the temperature sensor; the preset capacitance value is the capacitance value when the liquid level height of the detected liquid reaches the bottommost part of the electrode, and the preset conductivity is smaller than the conductivity of the detected liquid; and calculating the liquid level height of the measured liquid according to the temperature value and the capacitance value.
Further, the calculating the liquid level height of the measured liquid according to the temperature value and the capacitance value comprises: calculating the height of the electrode immersed in the measured liquid according to the capacitance value between the two electrodes; and (4) compensating and calculating the capacitance value between the two electrodes according to the conductivity between the two metal nails and the temperature value of the temperature sensor to obtain the liquid level height of the detected liquid.
Further, the calculating the height of the electrode immersed in the measured liquid according to the capacitance value between the two electrodes comprises: and detecting the capacitance value between the two electrodes, and calculating the height of the electrodes immersed in the detected liquid according to the following formula:
where C is the capacitance between the two electrodes, d is the distance between the two electrodes, h is the height of the electrodes immersed in the liquid, ε is the dielectric constant of the dielectric between the two electrodes, and ω is a fixed value associated with the two electrodes.
Further, the calculating of the liquid level height of the measured liquid by compensating the capacitance value between the two electrodes according to the conductivity between the two metal pins and the temperature value of the temperature sensor comprises: detecting the conductivity between the two metal nails and the temperature value of the temperature sensor, and calculating the liquid level height of the detected liquid according to the following formula:
wherein H is the liquid level height of the liquid to be measured, H0The value of the height at which the lowermost part of the electrode is located, C the capacitance between the two electrodes, d the distance between the two electrodes, h the height of the electrodes immersed in the liquid, ε the dielectric constant of the dielectric between the two electrodes, ω a fixed value associated with the two electrodes, and EC twoThe electrical conductivity between the metal pins, T being the temperature value of the temperature sensor, f (EC, T) being a compensation function with respect to the electrical conductivity of the liquid and the temperature value.
Further, still include: and if the detected conductivity is smaller than the preset conductivity, determining that the liquid level height of the detected liquid is smaller than the height value of the metal nail.
Further, still include: further comprising: and if the detected conductivity is greater than or equal to the preset conductivity and the capacitance value between the two electrodes is smaller than the preset capacitance value, determining that the liquid level height of the detected liquid is greater than or equal to the height value of the metal nail and smaller than the height value of the bottommost part of the electrode.
In the embodiment of the application, in the liquid level height measuring equipment and the liquid level height measuring method, the conductivity between two metal nails on a PCB and the capacitance between two electrodes are detected; if the conductivity is greater than or equal to a preset conductivity and the capacitance value is greater than or equal to a preset capacitance value, acquiring a temperature value of the temperature sensor; and calculating the liquid level height of the measured liquid according to the temperature value and the capacitance value. This application just can measure the liquid level height of surveyed liquid through two metal pegs and two electrodes to and a temperature sensor, need not metal structure, adopts the mature PCB system board technique of technique, has effectively reduced equipment cost, can also adapt to various liquid measuring environment, the strong technological effect of stability. In addition, on the basis of reducing equipment cost, consider that the dielectric constant of the liquid of being surveyed can change along with the conductivity of the liquid of being surveyed and the temperature of liquid, influence the capacitance value between the electrode, then can cause the error for liquid level height measurement, this application obtains the temperature value through setting up temperature sensor, and compensate the capacitance value through the compensation function of liquid conductivity and temperature, thereby obtain the measuring error of millimeter level precision, the accurate measurement's of liquid level height purpose has been realized, then solved current water body level sensor because the cost is too high or the precision is too poor and can not be under the wide-spread technical problem of digital farmland environment.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, serve to provide a further understanding of the application and to enable other features, objects, and advantages of the application to be more apparent. The drawings and their description illustrate the embodiments of the invention and do not limit it. In the drawings:
FIG. 1 is a schematic structural diagram of a liquid level measuring device according to an embodiment of the present application;
FIG. 2 is a flow chart of a method for measuring a liquid level according to an embodiment of the present disclosure;
FIG. 3 is a flow chart of another method for measuring liquid level height according to an embodiment of the present application;
FIG. 4 is a flow chart of yet another method for measuring liquid level height provided in accordance with an embodiment of the present application;
FIG. 5 is a flow chart of an embodiment of the present application, illustrating a method of the present application.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
According to an embodiment of the present application, there is also provided a liquid level measuring apparatus, as shown in fig. 1, including:
the PCB is vertically arranged, and two metal nails TP1 and TP2 which are used for measuring the conductivity and are positioned at the same horizontal height are arranged at the bottom of the PCB; a pair of electrodes P1, P2 disposed in parallel are disposed above the metal pins; a temperature sensor RT is also arranged between the two metal nails; a processor U3 containing measuring codes is arranged on the top of the PCB, the processor U3 is respectively electrically connected with the electrodes and the metal nails, and the measuring codes are codes for executing a method for measuring the liquid level height.
Two metal pegs set up same level in PCB board bottom, consider that the measurement accuracy of this equipment is millimeter level, will avoid unnecessary error. Therefore, the vertical distance between the metal nail and the bottommost part of the PCB is not more than 1cm, and the specific distance can be set by itself, and is preferably 0.5 cm. The width between the metal nails is not more than the width of the PCB.
The metal nail can be made of alloy, copper, stainless steel and aluminum. The selection of the metal nail material should consider whether the material will react with the tested liquid, so as to improve the stability and the service life of the measuring equipment, and adapt to various liquid measuring environments. For example: the material which is easy to corrode and rust cannot be used in the environment of strong acid and strong alkali liquid. Preferably, in agricultural irrigation, the level height of the water is measured with stainless steel nails.
The temperature sensor for acquiring the temperature of the liquid to be measured may be a thermistor temperature sensor, and may be disposed at a position below the bottommost portion of the electrode, preferably at a position midway between the two metal pins.
A pair of electrodes placed in parallel are arranged above the two metal nails, the height value of the bottommost part of the electrode is larger than the height value of the metal nails, and the height value of the bottommost part of the electrode is set according to the measurement requirement. For example: when the measurement requirement is that the liquid level height reaches above 0.5cm, accurate millimeter-level measurement is carried out, and the accurate measurement is not carried out below 0.5cm, the bottommost part of the electrode needs to be arranged at a position 0.5cm away from the bottommost part of the PCB; the measurement requirement is that the accurate millimeter-level measurement is carried out when the liquid level height reaches more than 2cm, and the accurate measurement is not carried out below 2cm, so that the bottommost part of the electrode needs to be arranged at a position 2cm away from the bottommost part of the PCB. The distance between the two electrodes is not limited, and the electrodes can be placed on a PCB.
The processor is arranged at the topmost part of the PCB and is positioned above the electrodes, and the specific position is not limited.
The flow of liquid level detection based on the liquid level height measuring device in fig. 1 is described as follows:
after the liquid level height measuring device is vertically placed in the measured liquid, the device is started, and the processor is used for executing the execution code of the method for measuring the liquid level height, and the specific execution flow is as follows:
firstly, detecting the conductivity between two metal nails on a PCB (printed Circuit Board), and if the conductivity between the two metal nails is smaller than a preset conductivity, indicating that the liquid level height of the detected liquid does not reach the height value of the metal nails, wherein the preset conductivity is smaller than the conductivity of the detected liquid;
if the conductivity between the two metal nails is greater than or equal to the preset conductivity, but the capacitance between the two electrodes is smaller than the capacitance when the liquid level height of the detected liquid reaches the bottommost part of the electrodes, the liquid level height of the detected liquid is greater than the height value of the metal nails but less than the height value of the bottommost parts of the electrodes;
if the conductivity between the two metal pins is greater than or equal to the preset conductivity, and the capacitance between the two electrodes is greater than or equal to the capacitance when the liquid level height of the detected liquid reaches the bottommost part of the electrodes, it indicates that the liquid level height of the detected liquid reaches the bottommost part of the electrodes, and at this time, the liquid level height needs to be accurately calculated through the following process. The method specifically comprises the following steps: acquiring a temperature value of a temperature sensor; and calculating the height of the electrode immersed in the measured liquid according to the following formula according to the detected capacitance value:
wherein C is the capacitance between the two electrodes, d is the distance between the two electrodes, h is the height of the electrodes immersed in the liquid, ε is the dielectric constant of the dielectric between the two electrodes, ω is a fixed value associated with the two electrodes;
after the height immersed in the liquid to be measured is obtained, the capacitance value between the two electrodes is compensated and calculated according to the detected conductivity and temperature value, and the liquid level height of the liquid to be measured is calculated according to the following formula:
wherein H is the liquid level height of the liquid to be measured, H0C is the value of the height at which the bottommost electrode is located, d is the distance between the two electrodes, h is the height at which the electrodes are immersed in the liquid, e is the dielectric constant of the dielectric between the two electrodes, ω is a fixed value associated with the two electrodes, EC is the electrical conductivity between the two metal pins, and T is the temperature value f (EC, T) of the temperature sensor as a compensation function for the electrical conductivity of the liquid and the temperature value.
From the above description, it can be seen that, in the liquid level height measuring device according to the embodiment of the present application, the liquid level height is preliminarily determined by detecting the conductivity between two metal pins on the PCB and the capacitance between two electrodes, according to the comparison relationship between the detected conductivity and the measured liquid conductivity and the comparison relationship between the detected capacitance and the preset capacitance; the liquid level height of the measured liquid is calculated by compensating the capacitance value through the compensation function of the liquid conductivity and the temperature, so that the stability and the accuracy of liquid level height measurement are effectively improved, the technical effect of adapting to various liquid measurement environments is achieved, and the technical problem that the existing water body liquid level sensor cannot be widely used under the digital farmland environment due to too high cost or too poor precision is solved.
According to an embodiment of the present application, there is also provided a method implemented based on the above liquid level height measuring apparatus, as shown in fig. 2, the method including the following steps:
s101, detecting the conductivity between two metal nails on the PCB and the capacitance between two electrodes.
The processor U3 detects the conductivity of the dielectric between two metal pins TP1, TP2 on the PCB; when the liquid level height of the detected liquid does not reach the height value of the metal nails, the conductivity of the air between the two metal nails is detected; when the liquid level of the liquid to be detected reaches or exceeds the height value of the metal nail, the conductivity of the liquid to be detected is detected.
The processor U3 detects the capacitance value between the electrodes P1 and P2, and when the liquid level of the detected liquid does not reach the bottommost part of the electrodes, the capacitance value that the dielectric medium between the two electrodes is air is detected; when the liquid level of the liquid to be detected reaches or exceeds the bottommost part of the electrode, the dielectric medium between the two electrodes is detected as the capacitance value of the liquid to be detected.
The conductivity between two metal pins on the PCB and the capacitance between two electrodes are detected, so as to accurately measure the liquid level height of the detected liquid,
wherein, the material of metal nail is stainless steel, copper, alloy, aluminium etc. and preferred in the agricultural irrigation application, the metal nail is stainless steel nail when detecting the water level height.
S102, if the conductivity is larger than or equal to a preset conductivity and the capacitance value is larger than or equal to a preset capacitance value, acquiring a temperature value of a temperature sensor; the preset capacitance value is the capacitance value when the liquid level of the liquid to be detected is positioned at the bottommost part of the electrode, and the preset conductivity is smaller than the conductivity of the liquid to be detected.
And detecting the conductivity between the two metal nails and the capacitance between the two electrodes, and acquiring the temperature value of the temperature sensor if the detected conductivity is greater than or equal to the preset conductivity and the detected capacitance is greater than or equal to the capacitance when the liquid level height of the detected liquid reaches the bottommost part of the electrodes.
For example, the following steps are carried out: assuming EC as the conductivity between two metal pins, EC0Is the conductivity of the dielectric medium between two metal pins when water is used, C is the capacitance between two electrodes P1 and P2, C is the capacitance between two electrodes0The capacitance value between the two electrodes when the liquid level of the water reaches or exceeds the bottommost part of the electrodes,
the implementation of this step is then: when EC is more than or equal to EC0And C is not less than C0When the liquid level of the water enters a millimeter-level high-precision measurement interval, the temperature value of the liquid to be measured at the current moment is acquired by a temperature sensor RT arranged between two stainless steel nails. Wherein the temperature sensor may be a thermistor temperature sensor.
And S104, calculating the liquid level height of the liquid to be measured according to the temperature value and the capacitance value.
The specific steps for measuring the liquid level height of the measured liquid are as follows:
and step one, calculating the height of the electrode immersed in the measured liquid according to the capacitance value between the two electrodes.
Specifically, the height of the electrode immersed in the liquid to be measured is calculated by the following formula:
where C is the capacitance between the two electrodes; ε is the dielectric constant of the dielectric between the two electrodes; s is the area of the two electrodes; ω is a fixed value associated with electrodes P1, P2; h is the height of the electrodes P1, P2 immersed in the water body; d is the distance between the two electrodes;
And secondly, compensating and calculating the capacitance value between the two electrodes according to the conductivity between the two metal nails and the temperature value of the temperature sensor to obtain the liquid level height of the detected liquid.
The liquid level height of the measured liquid is calculated according to the following formula:
wherein H is the liquid level height of the liquid to be measured, H0Is the value of the height at which the bottommost electrode is located, C is the capacitance between the two electrodes, d is the distance between the two electrodes, h is the height at which the electrodes are immersed in the liquid, e is the dielectric constant of the dielectric between the two electrodes, EC is the electrical conductivity between the two metal pins, T is the temperature value of the temperature sensor, ω is a fixed value associated with the two electrodes, and f (EC, T) is a compensation function for the liquid conductivity and the temperature value.
From the above description, it can be seen that in the liquid level height measuring method of the embodiment of the present application, the conductivity between two metal pins on the PCB and the capacitance between two electrodes are detected; if the conductivity is greater than or equal to a preset conductivity and the capacitance value is greater than or equal to a preset capacitance value, acquiring a temperature value of the temperature sensor; and calculating the liquid level height of the measured liquid according to the temperature value and the capacitance value. Considering that the dielectric constant of the measured liquid can change along with the conductivity of the measured liquid and the temperature of the liquid, the capacitance value between the electrodes is influenced, and then errors can be caused to the measurement of the height of the liquid level, the temperature sensor is arranged to obtain the temperature value, the capacitance value is compensated through the compensation function of the conductivity and the temperature of the liquid, thereby obtaining the measurement error with millimeter-scale precision, realizing the purpose of accurately measuring the liquid level height only by two metal nails, two electrodes and one temperature sensor, and still have and need not metal structure spare, adopt the mature PCB system board technique of technology, effectively reduced equipment cost, can also adapt to various liquid measurement environment, the technological effect that stability is strong has solved current water body level sensor then and can not widely used technical problem under digital farmland environment because the cost is too high or the precision is too poor.
In addition to or as a refinement of the above embodiments, the present embodiment further provides a liquid level measuring method. As shown in fig. 3, the method includes steps S201 to S202 as follows:
s201, detecting the conductivity between two metal nails on the PCB and the capacitance between two electrodes;
the implementation of this step is the same as the implementation of step S101 in fig. 1, and is not described here again.
S202, if the detected conductivity is smaller than the preset conductivity, the liquid level height is confirmed to not reach the position of the metal nail.
Considering that the conductivity when the dielectric medium between the two metal pins is air is much smaller than that when the dielectric medium is water, when the detected conductivity is smaller than that of the detected liquid, it indicates that the current liquid level height does not reach the height value of the metal pin.
If EC<EC0And the water level does not reach the level height of the stainless steel nail by 0.5cm, and the processor gives the water level height measurement result as follows: h<0.5 cm; this is the case for rough liquid level height determination.
In addition to or as a refinement of the above embodiments, the present embodiment further provides a liquid level measuring method. As shown in fig. 4, the method includes steps S301 to S302 as follows:
s301, detecting the conductivity between two metal nails on the PCB and the capacitance between two electrodes;
the implementation of this step is the same as the implementation of step S101 in fig. 1, and is not described here again.
S302, if the detected conductivity is larger than or equal to the preset conductivity and the capacitance value between the two electrodes is smaller than the preset capacitance value, determining that the liquid level height of the detected liquid is larger than or equal to the height value of the metal nail and smaller than the height value of the bottommost part of the electrode.
And detecting the conductivity between the two metal pins and the capacitance value between the two electrodes, and if the detected conductivity is greater than or equal to the preset conductivity and the detected capacitance value is less than the capacitance value when the liquid level height of the detected liquid reaches the bottommost part of the electrodes, confirming that the liquid level height of the detected liquid is at the position between the metal pins and the bottommost part of the electrodes.
Considering that the conductivity when the dielectric medium between the two metal pins is air is far smaller than that when the dielectric medium is water, when the detected conductivity is larger than or the conductivity of the detected liquid, the current liquid level height reaches or exceeds the height value of the metal pins; considering that the preset capacitance value is a capacitance value between two electrodes when the liquid level of the detected liquid reaches the bottommost part of the electrodes, when the detected capacitance value is smaller than the preset capacitance value, it indicates that the liquid level of the detected liquid is lower than the height value of the bottommost part of the electrodes. Therefore, the liquid level height of the measured liquid is determined to be greater than or equal to the height value of the metal nail and smaller than the height value of the bottommost part of the electrode.
For example, the following steps are carried out: assuming EC as the conductivity between two metal pins, EC0To a predetermined conductivity, less than that of water, C is the capacitance between the two electrodes P1 and P2, C0The capacitance value between the two electrodes when the liquid level of the water reaches or exceeds the bottommost part of the electrodes,
the implementation of this step is then: if EC is more than or equal to EC0 and C is less than C0, the water level height H is more than 0.5cm of the height of the stainless steel nails TP1 and TP2 but not reaches 1cm of the lowest height of the electrodes P1 and P2, so that the processor gives the water level height measurement result that: h is more than or equal to 0.5cm and less than 1 cm;
finally, the method is implemented by the liquid level height measuring device, and the measuring environment using water as the measured liquid is specifically described, and the specific process is as shown in fig. 5:
(1) the processor first checks the conductivity EC between the two stainless steel spikes TP1 and TP2 and if EC < EC0, indicating that the water level has not reached 0.5cm from the level of the stainless steel spike, the processor gives a water level height measurement of: h <0.5 cm;
(2) if EC ≧ EC0, but the capacitance measurement C < C0 between electrodes P1 and P2 indicates that the water level height H exceeds the height (0.5cm) of stainless steel pins TP1, TP2, but has not yet reached the lowest height (1cm) of electrodes P1, P2, so the processor gives the water level height measurement as: h is more than or equal to 0.5cm and less than 1 cm;
(3) when EC is more than or equal to EC0, and the capacitance measurement value C between the electrodes P1 and P2 is more than or equal to C0, the water liquid level height enters a millimeter-level high-precision measurement interval, the temperature value of the temperature sensor is obtained, and the processor U3 calculates the precision height of the current water liquid level according to the following formula;
it should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer-executable instructions and that, although a logical order is illustrated in the flowcharts, in some cases, the steps illustrated or described may be performed in an order different than presented herein.
It will be apparent to those skilled in the art that the modules or steps of the present application described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and they may alternatively be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, or fabricated separately as individual integrated circuit modules, or fabricated as a single integrated circuit module from multiple modules or steps. Thus, the present application is not limited to any specific combination of hardware and software.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (9)
1. The liquid level height measuring equipment is characterized by comprising a vertically arranged PCB, wherein the bottom of the PCB is provided with two metal nails which are used for measuring the conductivity and are positioned at the same horizontal height; a pair of electrodes which are arranged in parallel are arranged above the metal nail; a temperature sensor is also arranged between the two metal nails; and a processor containing a measuring code is arranged at the top of the PCB and is electrically connected with the electrode and the metal nail respectively, and the measuring code is a method execution code for measuring the liquid level height.
2. The apparatus of claim 1, wherein the two metal pins for measuring conductivity are made of stainless steel.
3. The aqueous fluid level measurement device of claim 1, wherein the temperature sensor is: thermistor temperature sensor.
4. A level measurement method, implemented on the basis of a level measurement device according to any one of claims 1 to 3, the method being performed in a processor, comprising:
detecting the conductivity between two metal nails on the PCB and the capacitance between two electrodes;
if the conductivity is greater than or equal to a preset conductivity and the capacitance value is greater than or equal to a preset capacitance value, acquiring a temperature value of the temperature sensor, wherein the preset capacitance value is a capacitance value when the liquid level height of the detected liquid reaches the bottommost part of the electrode, and the preset conductivity is smaller than the conductivity of the detected liquid;
and calculating the liquid level height of the measured liquid according to the temperature value and the capacitance value.
5. The method of claim 4, wherein calculating the level height of the measured liquid from the temperature value and the capacitance value comprises:
calculating the height of the electrode immersed in the measured liquid according to the capacitance value between the two electrodes;
and (4) compensating and calculating the capacitance value between the two electrodes according to the conductivity between the two metal nails and the temperature value of the temperature sensor to obtain the liquid level height of the detected liquid.
6. The method of claim 5, wherein calculating the height of the electrode immersed in the liquid based on the capacitance between the two electrodes comprises:
and detecting the capacitance value between the two electrodes, and calculating the height of the electrodes immersed in the detected liquid according to the following formula:
where C is the capacitance between the two electrodes, d is the distance between the two electrodes, h is the height of the electrodes immersed in the liquid, ε is the dielectric constant of the dielectric between the two electrodes, and ω is a fixed value associated with the two electrodes.
7. The method as claimed in claim 6, wherein the calculating of the liquid level height of the measured liquid by compensating the capacitance value between the two electrodes according to the conductivity between the two metal pins and the temperature value of the temperature sensor comprises: detecting the conductivity between the two metal nails and the temperature value of the temperature sensor, and calculating the liquid level height of the detected liquid according to the following formula:
wherein H is the liquid level height of the liquid to be measured, H0The value of the height at which the bottommost electrode is located, C the capacitance between the two electrodes, d the distance between the two electrodes, h the height of the electrode immersed in the measured liquid, e the dielectric constant of the dielectric between the two electrodes, ω a fixed value associated with the two electrodes, EC the electrical conductivity between the two metal pins, T the temperature value of the temperature sensor, and f (EC, T) a compensation function for the electrical conductivity of the liquid and the temperature value.
8. The liquid level height measurement method of claim 4, further comprising: and if the detected conductivity is smaller than the preset conductivity, determining that the liquid level height of the detected liquid is smaller than the height value of the metal nail.
9. The liquid level height measurement method of claim 4, further comprising: and if the detected conductivity is greater than or equal to the preset conductivity and the capacitance value between the two electrodes is smaller than the preset capacitance value, determining that the liquid level height of the detected liquid is greater than or equal to the height value of the metal nail and smaller than the height value of the bottommost part of the electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202110353023.0A CN112945346A (en) | 2021-03-31 | 2021-03-31 | Liquid level height measuring device and method |
Applications Claiming Priority (1)
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| CN201225997Y (en) * | 2008-06-03 | 2009-04-22 | 华南农业大学 | Paddy field moisture sensor |
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