CN107389737A - A kind of soil parameters measurement apparatus - Google Patents
A kind of soil parameters measurement apparatus Download PDFInfo
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- CN107389737A CN107389737A CN201710538733.4A CN201710538733A CN107389737A CN 107389737 A CN107389737 A CN 107389737A CN 201710538733 A CN201710538733 A CN 201710538733A CN 107389737 A CN107389737 A CN 107389737A
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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
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/048—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance for determining moisture content of the material
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
- G01K7/20—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit
-
- 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
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body
-
- 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
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/045—Circuits
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
Abstract
The present invention provides a kind of soil parameters measurement apparatus, including：Soil moisture detection module, including double probes, double probes include the first probe and the second probe；Soil conductivity detection module, include four probes of Wenner configurations, wherein, a probe in four probes positioned at outside is second probe, positioned at the axially inside setting receiving space of another probe in outside；And soil moisture detection module, include the proof armored platinum resistor for the four-wire system being arranged in the receiving space, the proof armored platinum resistor of the four-wire system and described another probe positioned at outside insulate.Probe structure of the present invention is reasonable in design, avoid because caused by soil space abnormity multisensor measurement when existing for influence each other, precision is low and the big problem of error.
Description
Technical field
The present invention relates to Soil K+adsorption technical field, more particularly, to a kind of soil parameters measurement apparatus.
Background technology
Soil is the basis for carrying out agriculture and forestry production, quickly and efficiently gathers and describe to influence the field letter of plant growth
Breath, it is the important foundation for carrying out fine agriculture and forestry practice.Soil moisture, temperature and electrical conductivity are the important parameters of soil, are being made
Played an important role in the growth course of thing.
At present, there are a variety of soil moistures, temperature, the measuring method of electrical conductivity and device both at home and abroad：
The measuring method of soil moisture content is broadly divided into two classes, and one kind is traditional measurement method, such as oven drying method and calcium carbide
Method etc.；Another kind of is modern surveying method, as tensometer method, Near-Infrared Absorption Method, time domain reflectometry, frequency domain bounce technique, capacitance method, in
Sub- scattering method and heat flow method etc..
Thermometer can directly be inserted into soil and obtain temperature or using temperature-sensing element (device) by the measurement soil moisture
(such as RTD, thermistor, thermocouple, digital temperature sensor) measures.
The measuring method of soil conductivity is broadly divided into two classes, and one kind is chemical method, and Typical Representative is soil extraction side
Method；Another kind of is to measure electrical conductivity, including electromagnetic induction method, time domain reflectometry, electric-resistivity method etc. using the electrical characteristic of soil.
Larger coupled relation between soil moisture, temperature, electrical conductivity be present, in order to more comprehensively understand soil letter
Breath, while it is significant to obtain above-mentioned three parameter.At present sensor on the market be mostly gather one of three parameters or
Two, although can be measured using multiple different sensors to obtain three parameters, because soil Existential Space is heterogeneous, i.e.,
Same soil types, the soil property on different time, different spaces is different, first, difficult when being measured using multiple sensors
To be in the same space when ensureing that different sensors measure same soil, the difference of different spaces soil in itself will cause multiple biographies
The drawbacks of sensor measurement error is big, precision is low, secondly, the hole left after previous sensor measurement can be to next sensor
Measurement produce interference, finally, non-integral multiple sensors are all inconvenient in carrying and operation, and cost is also higher.
The content of the invention
The present invention provides a kind of a kind of soil parameters for overcoming above mentioned problem or solving the above problems at least in part and surveyed
Measure device.
According to an aspect of the present invention, there is provided a kind of soil parameters measurement apparatus, including：
Soil moisture detection module, including double probes, double probes include the first probe and the second probe；
Soil conductivity detection module, include four probes of Wenner configurations, wherein, four of the Wenner configurations
A probe in probe positioned at outside is second probe, and the axially inside setting positioned at another probe in outside is held
Receive space；And
Soil moisture detection module, includes the proof armored platinum resistor for the four-wire system being arranged in the receiving space, and described four
The proof armored platinum resistor of line insulate with described another probe positioned at outside.
Preferably, the soil parameters measurement apparatus also includes：
Energy supply control module, examined with the soil moisture detection module, soil conductivity detection module and the soil moisture
Module connection is surveyed, for the soil moisture detection module, soil conductivity detection module and soil moisture detection module
Time sharing power supply.
Preferably, the soil moisture detection module also includes：
Signal source, for producing 100MHz electromagnetic wave；
Coaxial transmission line, the signal source is connected with double probes, the coaxial transmission line is used for by described in
The electromagnetic wave that electromagnetic transmission is reflected back to double probes and transmission from double probes；
Rf power measurement circuit, the both ends of the coaxial transmission line are connected, to detect the coaxial transmission line both ends
Voltage；
First differential amplification unit, it is connected with the rf power measurement circuit, the differential amplification unit is used to obtain
The voltage difference at the coaxial transmission line both ends, it is poor as first voltage, and output is amplified to the first voltage difference.
Preferably, the soil conductivity detection module also includes：
Sine wave emission source, for producing -0.5V~+0.5V sine waves；
AC constant-current source：For using-the 0.5V~+0.5V sine waves as input, exporting stable 100uA constant-current sources；
Precision resistance, it is arranged on the AC constant-current source and two spies in four probes of Wenner configurations positioned at outside
Between any one probe in pin；
First voltage detection unit, positioned at two middle probes in four probes for detecting the Wenner configurations
Voltage difference, it is poor as second voltage；
Second differential amplification unit, it is connected with the first voltage detection unit, second differential amplification unit is used for
Amplify and to export the second voltage poor.
Preferably, the soil moisture detection module also includes：
Current source, exported for producing direct current constant current, and to the proof armored platinum resistor of the four-wire system；
Second voltage detection unit, the voltage difference at the proof armored platinum resistor both ends for detecting the four-wire system, as the 3rd
Voltage difference；
3rd differential amplification unit, it is connected with the second voltage detection unit, the 3rd differential amplification unit is used for
By tertiary voltage difference amplification output.
Preferably, the soil parameters measurement apparatus also includes：Processor, the processor include：
Soil moisture acquiring unit, obtain voltage difference-soil moisture content model, the soil moisture acquiring unit with it is described
First differential amplification unit connects, and poor according to the first voltage after amplification, from the voltage difference-soil moisture content model
Obtain the soil moisture content of matching；
Soil conductivity acquiring unit, obtain voltage difference-soil conductivity module, the soil conductivity acquiring unit with
The second differential amplification unit connection, and it is poor according to the second voltage after amplification, from the voltage difference-soil conductivity
Rate model obtains the acquisition soil conductivity of matching；
Soil moisture acquiring unit, obtains resistance v. temperature table, and the soil moisture acquiring unit is put with the 3rd difference
Big unit is connected, and poor according to the tertiary voltage after amplification, and the soil moisture of matching is obtained from the resistance v. temperature table
Value.
Preferably, the soil parameters measurement apparatus also includes：Memory module, with the soil moisture acquiring unit, soil
Earth electrical conductivity acquiring unit and the connection of soil moisture acquiring unit, the memory cell include flash storage sections and SD card
Store section；
Wherein, unique identification information, the electricity of the described soil parameters measurement apparatus of the flash storages section storage
The operation of pressure difference-soil moisture content model, the resistance v. temperature table, the voltage difference-soil conductivity model and processor
Frequency；
The SD card storage section stores soil moisture content, soil conductivity and the soil moisture value.
Preferably, the soil parameters measurement apparatus also includes：Clock module, it is connected with the processor, the clock
Module is used to provide time reference to the processor；
Wherein, the processor is also connected with the energy supply control module, and the processor was additionally operable to according to the time
Benchmark, the instruction of time sharing power supply is sent to the energy supply control module, so that the energy supply control module is to the soil moisture
Detection module, soil conductivity detection module and soil moisture detection module time sharing power supply.
Preferably, the soil parameters measurement apparatus also includes：
Display module, it is connected with the processor, the display module is used to show the soil moisture content, soil conductivity
Rate and soil moisture value.
Communication module, it is connected with the processor, the communication module is used for the soil water-containing for obtaining processor
Rate, soil conductivity and soil moisture value are converted into 485 signals by rs 232 serial interface signal, with realization and external communication.
Preferably, the soil parameters measurement apparatus also includes：Power transfer module, with the energy supply control module, place
Device, display module, communication module, memory module and clock module connection are managed, to be powered.
A kind of soil parameters measurement apparatus that the application proposes, by the way that the probe between different detection modules is multiplexed：Soil
Earth water content detection module and the probe of soil conductivity detection module multiplexing ground connection, soil conductivity detection module and the soil moisture
Detection module is multiplexed a probe, and five probes are independent of each other, and probe structure is reasonable in design, avoids because soil space abnormity is led
Cause multisensor measurement when it is existing influence each other, precision is low and the big problem of error, it is often more important that, soil conductivity inspection
Polarization phenomena can be effectively avoided when surveying module using the measurement electrical conductivity for exchanging " four-end method ", prevents probe from getting rusty rotten, enters one
Step extends the usage time of this soil parameter measuring apparatus.
Brief description of the drawings
Fig. 1 is the structural representation according to the soil parameters measurement apparatus of the embodiment of the present invention；
Fig. 2 is the schematic diagram that soil moisture content is measured according to the standing wave ratio method of the embodiment of the present invention；
Fig. 3 is the schematic diagram according to the measurement soil moisture of the embodiment of the present invention；
Fig. 4 is the schematic diagram according to the measurement soil conductivity of the embodiment of the present invention；
Fig. 5 is the schematic diagram according to the energy supply control module of the embodiment of the present invention；
Fig. 6 is the functional block diagram according to the soil parameters measurement apparatus of the embodiment of the present invention.
Embodiment
With reference to the accompanying drawings and examples, the embodiment of the present invention is described in further detail.Implement below
Example is used to illustrate the present invention, but is not limited to the scope of the present invention.
Sensor on the market is one or two of three parameters of collection mostly at present, although multiple not simultaneous interpretations can be used
Sensor is measured to obtain three parameters, but because soil Existential Space is heterogeneous, i.e., same soil types, different time, difference
Soil property spatially is different, first, is difficult to ensure that different sensors measure same soil when being measured using multiple sensors
The same space is in during earth, the difference of different spaces soil in itself will cause the disadvantage that multiple sensor measurement errors are big, precision is low
End, secondly, the measurement that the hole left after previous sensor measurement can be to next sensor produce interference, finally, non-collection
Multiple sensors of an accepted way of doing sth are all inconvenient in carrying and operation, and cost is also higher.
In order to overcome the above mentioned problem of prior art, the embodiment of the present invention provides a kind of soil parameters measurement apparatus, such as Fig. 1
It is shown, including：
Soil moisture detection module, including double probes, double probes include the first probe W and the second probe J.
Soil moisture detection module is based on standing wave ratio method measurement soil moisture in the embodiment of the present invention, and operation principle is：When
Electromagnetic wave signal is in the junction of transmission line and probe because the impedance mismatch between transmission line impedance and the probes of WJ two occurs
Signal reflex, reflected signal ripple meet to be superimposed to form standing wave on the transmission line with incoming signal ripple, the electricity at detection transmission line both ends
Pressure difference, volumetric soil water content can be obtained indirectly by the voltage difference.
Soil conductivity detection module, include four probes of Wenner configurations, including two current terminal J probes and K are visited
Pin, two voltage end M probes and N probes, wherein, J probes are used to be grounded, and are total to the second probe of soil moisture detection module
With, it is same probe, the axially inside setting receiving space of K probes.
Soil conductivity detection module is based on exchange " four-end method " and obtains sign soil conductivity in the embodiment of the present invention
Magnitude of voltage, in embodiments of the present invention, shared for the probe of ground connection and the second probe J of soil moisture detection module, work as survey
The constant current for measuring pumping signal flows into the earth by two current terminals, by the electrical potential difference for checking M probes and N probes, so that it may
It is converted into the electrical conductivity of dielectric material (soil).
Soil moisture detection module, include the proof armored platinum resistor for the four-wire system being arranged in receiving space, the armour of four-wire system
RTD is filled to insulate with another probe positioned at outside.
Soil moisture detection module is by obtaining the proof armored platinum resistor of four-wire system under current state in the embodiment of the present invention
Resistance, the temperature of the proof armored platinum resistor of four-wire system can be obtained by look-up table, this temperature is the soil moisture to be measured.Four-wire system platinum electricity
Resistance respectively has both threads at its both ends, and wherein both threads are used to measure proof armored platinum resistor voltage, and both threads are used to pass through armouring in addition
RTD electric current, this method can remove the measurement error caused by cable length.By being provided for placing armouring in K probes
The receiving space of RTD, on the one hand make the probe using the shell of K probes as soil conductivity detection module, realize electrical conductivity
Electric current injects, and on the other hand realizes temperature survey in the inside of K probes, both do not interfere with each other.
It should be noted that the embodiment of the present invention is by the way that the probe between different detection modules is multiplexed：Soil water go-on-go
Survey the probe of module and soil conductivity detection module multiplexing ground connection, soil conductivity detection module and soil moisture detection module
A probe is multiplexed, five probes are independent of each other, and probe structure is reasonable in design, avoids more biographies caused by soil space abnormity
Sensor measure when it is existing influence each other, precision is low and the big problem of error, prior theory, soil conductivity detection module are adopted
Polarization phenomena can be effectively avoided during with the measurement electrical conductivity of exchange " four-end method ", prevents probe from getting rusty rotten, further extends
The usage time of this soil parameter measuring apparatus.
On the basis of above-described embodiment, the length of five probes is 50mm, a diameter of 3mm of W, J, M, N probe, adjacent
The spacing of two probes is 25mm, and material is 316L stainless steels, a diameter of 4mm of K probes, a diameter of 3mm of receiving space, with
The diameter of proof armored platinum resistor is equal, and the length of proof armored platinum resistor is 40mm.
Fig. 2 shows the schematic diagram of standing wave ratio method measurement soil moisture content, OSC in figureRFSignal source is represented, a and b represent to pass
The both ends of defeated line, ZLThe impedance of probe is represented, research shows, when transmission line physical length is about electromagnetic wavelength 1/4,
The voltage difference expression formula at transmission line both ends is as follows：
In formula (1), Δ VabElectrical potential difference, A between transmission line a, b both ends are the width of the pumping signal of signal source output
Value, ZLFor the impedance of sensor probe, Z0For the characteristic impedance of transmission line.
Due to A and Z0It is known, Δ VabOnly and ZLCorrelation, and in the design of sensor, the geometry of probe is
It is changeless, sensor probe impedance ZLDepending on its insertion environment --- dielectric constant of soil, according to Topp equations：
In formula (2), volumetric soil water content θvWith soil dielectric constant εraIn the multiple non-linear relation of unitary.
In formula (3), a, b are the constants relevant with soil types.Soil is mainly made up of soil, water and air, wherein,
The dielectric constant of soil is about 4, and the dielectric constant of air is 1, and the dielectric constant of pure water is 80, is to influence soil volume of aqueous
The principal element of rate, therefore, only Δ V need to be measured according to formula (1)-(3)abCan to obtain soil moisture content indirectly,
Fig. 3 shows the schematic diagram of the measurement soil moisture, is the 1mA constant currents being barricaded as using amplifier in Fig. 3 dashed rectangle
Source, at the both ends of RTD, the voltage at RTD both ends can be amplified by connection difference amplifier, so that subsequent conditioning circuit is carried out
Collection.According to " empty short " principle of operational amplifier, 1mA constant-current source circuits can be represented with following formula：
Vout=AOPEN/DC(Vin-Vsample)=AOPEN/DC(Vin-Iout*Rsample) (4)
Therefore,
In formula (4) and (5), Vin--- reference voltage 2.5V, A of amplifier in-phase end inputOPEN/DC--- U1 amplifiers
Open loop gain cofficient, Iout--- flow through the electric current of RTD.Work as AOPEN/DCDuring=+ ∞, above formula can using abbreviation as：
AU2、Vin, it is known that it can be obtained according to formula (4)-(6)： Institute
With the magnitude of voltage V according to acquisitiontout, the resistance R of RTD can be obtainedload, temperature value is obtained by look-up table.
Fig. 4 shows the schematic diagram of measurement soil conductivity, in figure, dJM=dMN=dNKFour equal electrodes of=a spacing
Arrange successively and form Wenner configurations, the calculation formula of electrical conductivity is under the configuration：
In formula (7), a represents the distance between two neighboring electrode, and Δ U is precision resistance R both end voltages, and Δ V is M, N
Two inter-electrode voltages are poor, and R is the resistance of precision resistance.On the premise of known electrodes spacing a and resistance R, pass through measurement
M, the voltage difference delta U and voltage Δ V at precision resistance R both ends between N electrode, the electrical conductivity of soil can be measured.
On the basis of above-described embodiment, soil parameters measurement apparatus also includes：
Energy supply control module, mould is detected with soil moisture detection module, soil conductivity detection module and the soil moisture
Block connects, for soil moisture detection module, soil conductivity detection module and soil moisture detection module time sharing power supply.
It should be noted that energy supply control module can set different power-on times to different detection modules so that
Each detection module is disturbed in gathered data all without by other detection modules, is tested through anti-Interference Analysis (with for the moment
Between electricity only in a detection unit, the not upper electricity of other units so can be using the probe of other detection units as tested native
Foreign matter in earth is treated, and studies other probes one by one to being detected the influence of unit) show to visit corresponding to three detection modules
Pin is independent of each other, and probe structure is reasonable in design.
On the basis of the various embodiments described above, soil moisture detection module also includes：
Signal source, for producing 100MHz electromagnetic wave, for example, can be using 100MHz crystal oscillators as exciting signal source
The detection of soil moisture content to be measured provides energy；
Coaxial transmission line, signal source is connected with double probes, coaxial transmission line is used for electromagnetic transmission to double spies
Pin is popped one's head in, and sinusoidal signal caused by crystal oscillator is along transmission line to popping one's head in, if probe impedance is different from transmission line impedance,
A part of incoming signal is reflected back toward signal source.The signal being reflected back is superimposed with incoming signal, is formed on the transmission line
Standing wave and can produce voltage magnitude change；
Rf power measurement circuit, the both ends of coaxial transmission line are connected, to detect the voltage at coaxial transmission line both ends；
First differential amplification unit, it is connected with rf power measurement circuit, differential amplification unit is used for according to coaxial transmission
The voltage at line both ends, the voltage difference at coaxial transmission line both ends is obtained, it is poor as first voltage, and first voltage difference is amplified
Output.
On the basis of the various embodiments described above, soil conductivity detection module also includes：
Sine wave emission source, constant current is exchanged for producing, and exported to four probes, specifically, sine wave emission source
Including high frequency DDS chip AD9851, for producing amplitude 1V, frequency 1KHz sine waves, the sine wave is after passive filtering
Waveform is more smooth, then carry out bipolarity conversion, using high-pass filter realize 0~1V of amplitude sine waves to -0.5V~+
The conversion of 0.5V sine waves；
AC constant-current source：Using -0.5V~+0.5V sine waves as input, pass through three operating amplifier with current feedback
The effect of OPA4684 and its matching component produces stable 100uA constant-current sources；
Precision resistance, the sine wave emission source is arranged on being located at two of outside in four probes of Wenner configurations
Between any one probe (J probes or K probes) in probe；
First voltage detection unit, for being located at the voltage of two middle probes in four probes of Wenner configurations
Difference, it is poor as second voltage；
Second differential amplification unit, be connected with first voltage detection unit, the second differential amplification unit be used for amplify and it is defeated
It is poor to go out second voltage.
On the basis of the various embodiments described above, soil moisture detection module also includes：
Current source, exported for producing direct current constant current, and to the proof armored platinum resistor of four-wire system；
Second voltage detection unit, the voltage at the proof armored platinum resistor both ends for detecting four-wire system are poor as tertiary voltage；
3rd differential amplification unit, it is connected with second voltage detection unit, the 3rd differential amplification unit is used for the 3rd electricity
Pressure difference amplification output.
On the basis of the various embodiments described above, processor includes：
Soil moisture acquiring unit, obtain voltage difference-soil moisture content model, soil moisture acquiring unit and the first difference
Amplifying unit connects, and poor according to the first voltage after amplification, and the soil that matching is obtained from voltage difference-soil moisture content model contains
Water rate；
Soil conductivity acquiring unit, obtain voltage difference-soil conductivity module, the soil conductivity acquiring unit with
Second differential amplification unit connects, and poor according to the second voltage after amplification, is obtained from voltage difference-soil conductivity rate model
The acquisition soil conductivity matched somebody with somebody；
Soil moisture acquiring unit, obtains resistance v. temperature table, and soil moisture acquiring unit connects with the 3rd differential amplification unit
Connect, and it is poor according to the tertiary voltage after amplification, the soil moisture value of matching is obtained from resistance v. temperature table.
It is well known that have between the voltage difference at soil moisture content and transmission line both ends (first voltage after amplification is poor)
There is good linear relationship, mathematical modeling Y=K × X+B can be used to represent, wherein X represents that transmission line both end voltage is poor, and Y represents soil
Earth moisture content, K, B represent model parameter, can obtained by rating test.Voltage difference between soil conductivity and the probe of M, N two (is put
Tertiary voltage after big is poor) between there is good linear relationship, it is also possible to mathematical modeling Y=K*X+B represents, wherein X expressions
Voltage difference between the probes of MN two, Y represent soil conductivity, and K, B represent model parameter, can obtained by rating test.
In one embodiment, K, B calibration experiment can be prepared by the following：
Rating test
Hardware device：Quartz sand, standard earth pillar, cutting ring, electronic balance, drying baker, regulated power supply (DC0V~24V), ten thousand
Use table.
Software equipment：Excel forms.
Demarcate material：240 mesh quartz sands are taken, control the water of addition to obtain the demarcation earth pillar of different volumes water content：Contain
Each 1 part of the soil sample that water is about 5%, 10%, 20%, 30%, 40%；
Demarcating steps：
1) according to sensor interface define wiring (sensor red line connects the positive pole of power supply, and black line meets the negative pole GND of power supply,
The green line of sensor connects the positive pole of universal meter (paying attention to the negative pole of universal meter will be connected with the negative pole of power supply).
2) fetched earth with four cutting rings in earth pillar is demarcated, think to disturb to reduce, fetched earth in each earth pillar 4 parts, by four parts
Soil sample is put into baking box (105 DEG C, 12h), determines the soil sample volumetric(al) moisture content of its four repetitions, averages as standard value.
The standard value of five soil samples is inserted in table.
3) soil moisture detection module is inserted in 5 soil samples with different moisture content respectively, measured using universal meter
The output signal (i.e. magnitude of voltage) of soil moisture detection module, the magnitude of voltage measured is inserted in table.
4) calibration curve of soil moisture sensor is can obtain using least-squares algorithm linear fitting in Excel forms
(Y=KX+B).
5) K, B value of corresponding order setting sensor are combined by RS485 interfaces, demarcation is completed.
It should be noted that the acquisition process of voltage difference-soil conductivity model and voltage-soil moisture model with it is above-mentioned
Method is similar, and the present invention repeats no more.
On the basis of the various embodiments described above, in addition to memory module, obtained with soil moisture acquiring unit, soil conductivity
Unit and soil moisture acquiring unit is taken to connect, memory cell includes flash storage sections and SD card storage section；
Wherein, unique identification information, the voltage difference-soil of the soil parameters measurement apparatus of flash storages section storage contain
The running frequency of water rate model, resistance v. temperature table and processor is the lock-out pulse number that processor occurs in 1 second, this implementation
It is 72MHz in example.
SD card storage section storage soil moisture content, soil conductivity and soil moisture value.
It is described below by taking the processing procedure to soil moisture content as an example, the first differential amplification unit is by after amplification
One voltage difference sends the soil moisture acquiring unit into processor, and the flash storage sections in memory cell are by voltage difference-soil
Earth moisture content model is sent to soil moisture acquiring unit, soil moisture acquiring unit enters voltage difference-soil by first voltage difference band
In earth moisture content model, the soil moisture content of matching is obtained, then the soil moisture content of acquisition is sent to SD card and stores section,
And preserved with txt forms.
On the basis of the various embodiments described above, soil parameters measurement apparatus also includes：Clock module, it is connected with processor,
Clock module is used to provide time reference to processor；
Wherein, processor is also connected with energy supply control module, and processor is additionally operable to according to time reference, to power supply mould
Block send time sharing power supply instruction so that energy supply control module to soil moisture detection module, soil conductivity detection module with
And soil moisture detection module time sharing power supply.
It should be noted that time reference is extremely important for the soil parameters sensing device of the embodiment of the present invention, due to
The present apparatus needs to switch in 3 kinds of detection projects, if time entanglement, the accuracy to measurement is interfered, processor leads to
Cross acquisition time reference, it is possible to the instruction of time sharing power supply is sent to energy supply control module, energy supply control module according to the instruction,
3 detection modules are carried out with the control of time sharing power supply.Processor sends the letter at current time according to time reference to memory module
Breath, can introduce concept of time in the record of soil moisture content, soil conductivity and soil moisture value, be more beneficial for finding
Go out the situation of change of soil parameters at different moments.
Fig. 5 shows the fundamental diagram of energy supply control module, and processor provides 3 control letters to energy supply control module
Number, when control signal 1 is effective, energy supply control module gives soil moisture detection module for power supply, the power supply when control signal 2 is effective
Control module is powered to soil conductivity detection module, and when control signal 3 is effective, energy supply control module detects to the soil moisture
Module for power supply.
On the basis of the various embodiments described above, soil parameters measurement apparatus also includes：
Display module, it is connected with processor, display module is used to show soil moisture content, soil conductivity, the soil moisture
Value and current time.
In one alternate embodiment, display module includes 0.96 cun of 128*64 pixel OLED screen curtain, is shown with low-power consumption
Soil moisture content, soil conductivity and soil moisture value.
On the basis of the various embodiments described above, soil parameters measurement apparatus also includes：Communication module, it is connected with processor,
Communication module is used to rs 232 serial interface signal being converted into 485 signals, and to realize and external communication, while the later stage can join multiple soil
Number measurement apparatus is connected on any collector with 485 buses, is easy to data acquisition.
On the basis of above-described embodiment, soil parameters measurement apparatus also includes：12V lithium batteries power supply and Power convert
Module, power transfer module by 12V Power converts be+3.3V ,+5V, -5V power supplys, respectively to energy supply control module, processor,
Display module, communication module, memory module and clock module power supply.Specifically, energy supply control module needs+5V work electricity
Pressure, processor, memory module, display module, clock module and communication module needs+3.3V operating voltages, soil water go-on-go
Module, soil conductivity detection module and soil moisture detection module needs ± 5V power supplies are surveyed, wherein ﹣ 5V are by Power convert mould
Block is provided, and+5V is provided by energy supply control module.
Fig. 6 shows the functional block diagram of soil parameters measurement apparatus, and the energy conversion of lithium battery is by power transfer module
The operating voltage that each module needs, clock unit provide time reference to processor, and processor is according to time reference to power supply control
Molding block sends the instruction of time sharing power supply, and energy supply control module is according to the instruction to soil moisture detection module, soil conductivity
Detection module and soil moisture detection module time sharing power supply, soil moisture detection module, soil conductivity detection module and
Soil moisture detection module exports the data of the moisture for characterizing soil, electrical conductivity and temperature respectively, and processor counts according to these
According to the True Data of the moisture of acquisition soil, electrical conductivity and temperature, send to display module and shown, send to storage mould
Block is stored or sent to communication module and sent to the external world, and master-slave communication is generally adopted by RS485 communication networks
Mode, the i.e. multiple slaves of host tape, thus if user needs that a collector for carrying 485 buses can be designed,
Multiple soil parameters measurement apparatus can be articulated in above.
Finally, the present processes are only preferable embodiment, are not intended to limit the scope of the present invention.It is all
Within the spirit and principles in the present invention, any modification, equivalent substitution and improvements made etc., the protection of the present invention should be included in
Within the scope of.
Claims (10)
- A kind of 1. soil parameters measurement apparatus, it is characterised in that including：Soil moisture detection module, including double probes, double probes include the first probe and the second probe；Soil conductivity detection module, include four probes of Wenner configurations, wherein, four probes of the Wenner configurations In positioned at the probe in outside be second probe, the axially inside setting positioned at another probe in outside accommodates sky Between；AndSoil moisture detection module, include the proof armored platinum resistor for the four-wire system being arranged in the receiving space, the four-wire system Proof armored platinum resistor and another probe insulation positioned at outside.
- 2. soil parameters measurement apparatus as claimed in claim 1, it is characterised in that also include：Energy supply control module, mould is detected with the soil moisture detection module, soil conductivity detection module and the soil moisture Block connects, for the soil moisture detection module, soil conductivity detection module and soil moisture detection module timesharing Power supply.
- 3. soil parameters measurement apparatus as claimed in claim 1 or 2, it is characterised in that the soil moisture detection module is also Including：Signal source, for producing 100MHz electromagnetic wave；Coaxial transmission line, the signal source is connected with double probes, the coaxial transmission line is used for the electromagnetism Ripple transmits the electromagnetic wave being reflected back to double probes and transmission from double probes；Rf power measurement circuit, the both ends of the coaxial transmission line are connected, to detect the voltage at the coaxial transmission line both ends；First differential amplification unit, it is connected with the rf power measurement circuit, the differential amplification unit is described for obtaining The voltage difference at coaxial transmission line both ends, it is poor as first voltage, and output is amplified to the first voltage difference.
- 4. soil parameters measurement apparatus as claimed in claim 3, it is characterised in that the soil conductivity detection module also wraps Include：Sine wave emission source, for producing -0.5V~+0.5V sine waves；AC constant-current source：For using-the 0.5V~+0.5V sine waves as input, exporting stable 100uA constant-current sources；Precision resistance, the AC constant-current source is arranged on being located in four probes of Wenner configurations in two probes in outside Any one probe between；First voltage detection unit, positioned at the electricity of two middle probes in four probes for detecting the Wenner configurations Pressure difference, it is poor as second voltage；Second differential amplification unit, it is connected with the first voltage detection unit, second differential amplification unit is used to amplify And it is poor to export the second voltage.
- 5. soil parameters measurement apparatus as claimed in claim 4, it is characterised in that the soil moisture detection module also wraps Include：Current source, exported for producing direct current constant current, and to the proof armored platinum resistor of the four-wire system；Second voltage detection unit, the voltage difference at the proof armored platinum resistor both ends for detecting the four-wire system, as tertiary voltage Difference；3rd differential amplification unit, it is connected with the second voltage detection unit, the 3rd differential amplification unit is used for institute State tertiary voltage difference amplification output.
- 6. soil parameters measurement apparatus as claimed in claim 5, it is characterised in that also including processor, the processor bag Include：Soil moisture acquiring unit, obtain voltage difference-soil moisture content model, the soil moisture acquiring unit and described first Differential amplification unit connects, and poor according to the first voltage after amplification, is obtained from the voltage difference-soil moisture content model The soil moisture content of matching；Soil conductivity acquiring unit, obtain voltage difference-soil conductivity module, the soil conductivity acquiring unit with it is described Second differential amplification unit connects, and poor according to the second voltage after amplification, from the voltage difference-soil conductivity rate mould Type obtains the soil conductivity of matching；Soil moisture acquiring unit, obtain resistance v. temperature table, the soil moisture acquiring unit and the 3rd differential amplification list Member connection, and it is poor according to the tertiary voltage after amplification, the soil moisture value of matching is obtained from the resistance v. temperature table.
- 7. soil parameters measurement apparatus as claimed in claim 6, it is characterised in that also including memory module, with the soil Moisture acquiring unit, soil conductivity acquiring unit and the connection of soil moisture acquiring unit, the memory cell include flash Store section and SD card storage section；Wherein, unique identification information, the voltage of the described soil parameters measurement apparatus of the flash storages section storage Difference-soil moisture content model, the resistance v. temperature table, the operation frequency of the voltage difference-soil conductivity model and processor Rate；The SD card storage section stores soil moisture content, soil conductivity and the soil moisture value.
- 8. soil parameters measurement apparatus as claimed in claim 7, it is characterised in that also include：Clock module, it is connected with the processor, the clock module is used to provide time reference to the processor；Wherein, the processor is also connected with the energy supply control module, and the processor is additionally operable to according to the time reference, The instruction of time sharing power supply is sent to the energy supply control module, so that the energy supply control module is to the soil moisture detection mould Block, soil conductivity detection module and soil moisture detection module time sharing power supply.
- 9. soil parameters measurement apparatus as claimed in claim 8, it is characterised in that also include：Display module, be connected with the processor, the display module be used for show the soil moisture content, soil conductivity with And soil moisture value and current time；Communication module, it is connected with the processor, the communication module is used for the soil moisture content, the soil for obtaining processor Earth electrical conductivity and soil moisture value are converted into 485 signals by rs 232 serial interface signal, with realization and external communication.
- 10. soil parameters measurement apparatus as claimed in claim 9, it is characterised in that also include：Power transfer module, with institute Energy supply control module, processor, display module, communication module, memory module and clock module connection are stated, to be powered.
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| CN108872709A (en) * | 2018-08-13 | 2018-11-23 | 西南交通大学 | A kind of different moisture content lower leaf soil dynamic electric resistor characteristic test method |
| CN109030773A (en) * | 2018-06-28 | 2018-12-18 | 沈阳兴迪电子科技有限公司 | A kind of soil testing assemblies applied to smart city, system and method |
| CN110297071A (en) * | 2019-07-05 | 2019-10-01 | 上海交通大学 | Soil Parameters measurement method |
| CN111707803A (en) * | 2020-04-08 | 2020-09-25 | 中国科学院南京土壤研究所 | Portable soil multi-parameter in-situ measuring and calibrating device |
| CN115639408A (en) * | 2022-12-23 | 2023-01-24 | 中大智能科技股份有限公司 | High-precision soil conductivity self-adaptive monitoring system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108008198A (en) * | 2017-12-01 | 2018-05-08 | 广东电网有限责任公司佛山供电局 | A kind of impulse earthed resistance measuring method of meter and earth mat temperature |
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| CN108872709A (en) * | 2018-08-13 | 2018-11-23 | 西南交通大学 | A kind of different moisture content lower leaf soil dynamic electric resistor characteristic test method |
| CN110297071A (en) * | 2019-07-05 | 2019-10-01 | 上海交通大学 | Soil Parameters measurement method |
| CN111707803A (en) * | 2020-04-08 | 2020-09-25 | 中国科学院南京土壤研究所 | Portable soil multi-parameter in-situ measuring and calibrating device |
| CN111707803B (en) * | 2020-04-08 | 2022-07-01 | 中国科学院南京土壤研究所 | Use method of portable soil multi-parameter in-situ measurement and calibration device |
| CN115639408A (en) * | 2022-12-23 | 2023-01-24 | 中大智能科技股份有限公司 | High-precision soil conductivity self-adaptive monitoring system |
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