CN110411524A - PWM mode fertilzer sucking pipe road flow quantity detecting system and control method - Google Patents
PWM mode fertilzer sucking pipe road flow quantity detecting system and control method Download PDFInfo
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- CN110411524A CN110411524A CN201910698517.5A CN201910698517A CN110411524A CN 110411524 A CN110411524 A CN 110411524A CN 201910698517 A CN201910698517 A CN 201910698517A CN 110411524 A CN110411524 A CN 110411524A
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01C—PLANTING; SOWING; FERTILISING
- A01C23/00—Distributing devices specially adapted for liquid manure or other fertilising liquid, including ammonia, e.g. transport tanks or sprinkling wagons
- A01C23/04—Distributing under pressure; Distributing mud; Adaptation of watering systems for fertilising-liquids
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/582—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters without electrodes
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/05—Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
- G05B19/054—Input/output
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- Life Sciences & Earth Sciences (AREA)
- Automation & Control Theory (AREA)
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- Soil Sciences (AREA)
- Environmental Sciences (AREA)
- Electromagnetism (AREA)
- Fluid Mechanics (AREA)
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Abstract
The invention discloses a kind of PWM mode fertilzer sucking pipe road flow quantity detecting system and control methods, including water main, mixing chamber, EC/PH sensor, vacuum solenoid valve, the first fertilising pipeline, the second fertilising pipeline, venturi fat absorption device, solution bucket, filter, flowmeter, the fertile solenoid valve of suction, fertilizing pump, check valve and control system.The present invention needs the demand of precise measurement according to each interchannel flow, construct PWM mode fertilzer sucking pipe road flow quantity detecting system, according to the pulse characteristic of the Hall flow meter under venturi fat absorption device, solenoid valve and PWM control mode, different time sections flow detection and calculation method are devised, the flow value of each Cycle accurate has been obtained.This detection system is novel in design, and control system is accurately reliable, and detection quickly, has preferable economic value and social value, there is good application prospect.
Description
Technical field
The invention belongs to the Integration of Water into Fertilizer fields, and in particular to a kind of PWM mode fertilzer sucking pipe road flow quantity detecting system
And detection method.
Background technique
In recent years, since slight irrigation has many advantages, such as water-saving, irrigation uniformity is high, saving of labor, section fertilizer, volume increase, develop fast
Speed is widely used, it has also become the important technical in agricultural production, whole nation slight irrigation application area has reached at present
More than 5000 ten thousand mu.Slight irrigation is by pipe-line system and the special douche (water dropper, micro- spray that are mounted on tail portion (on final stage pipeline)
Head, infiltrating irrigation pipe and micro-pipe etc.), water and nutrient are transported to crop root with lesser flow, make soil conservation best water,
The irrigation method of fertilizer, gaseity.Since water and nutrient are directly delivered directly to crop root by slight irrigation, so utilizing irrigation system
Fertilising has very big advantage, thus water-fertilizer integral has also obtained generally using.
At present the fertilizing equipment product category in water-fertilizer integral system mainly have pressure differential tank, high pressure fertilizing pump,
Venturi fat absorption device, waterpower fertilizing pump etc., these equipment realize the purpose for fertilizer being applied pipeline, but cannot accurately control and apply
Concentration, the ratio entered, can not realize automation control, have been unable to meet the requirement of Tree Precise Fertilization, automatic fine fertilizer applicator
Appearance solves this problem, thus has obtained quick development.Automatic fine fertilizer applicator is by computer or small controller control
System, realize precision fertilizing, by pump auxiliary by solution continuous and quantitative inject slight irrigation pipeline, per be provided with all the way venturi fat absorption device and
Solenoid valve automatically adjusts fertilising concentration, EC and pH value by PWM mode.
Currently, automatic fine fertilizer applicator is adjusted according to EC, PH sensor value of feedback by controller automatically per dose all the way
Section, flow are determined by calibration, and suction fertilizer accurate flow each time can not be obtained by measurement.Due to inhale fertile flow by
The multifactor influences such as main pipe pressure, main conduit flow, EC, PH setting value, venturi inlet and outlet pressure are not determining value,
It thus needs accurately to measure suction fertilizer flow each time, can just obtain more accurately controlling.
Summary of the invention
Present invention aims at constructing a kind of PWM mode fertilzer sucking pipe road flow quantity detecting system, while providing corresponding detection
Method obtains accurate flow value, is precisely controlled for automatic fine fertilizer applicator and provides basis
The present invention is achieved by the following technical solutions:
A kind of PWM mode fertilzer sucking pipe road flow quantity detecting system, including water main, mixing chamber, EC/PH sensor, decompression electricity
Magnet valve, the first fertilising pipeline, the second fertilising pipeline, venturi fat absorption device, solution bucket, filter, flowmeter, inhale fertile solenoid valve,
Fertilizing pump, check valve and control system；
The mixing chamber is connected with water main, is located among water main, for irrigation water and solution to be sufficiently mixed；
The water outlet of the water main is connect by vacuum solenoid valve with the first fertilising pipeline, on the first fertilising pipeline
Equipped with multiple venturi fat absorption devices, the venturi fat absorption device includes entrance and outlet flow section, the water outlet of the first fertilising pipeline
Mouth is connect with the entrance of venturi fat absorption device, and the lower section of venturi fat absorption device is equipped with the second fertilising pipeline, venturi fat absorption device
Outlet flow section with second fertilising pipeline water inlet connect, it is described second apply fertilizer pipeline pass sequentially through fertilizing pump and check valve and master
The water inlet of water pipe connects；The fertile mouth of suction is additionally provided in the middle part of the venturi fat absorption device, the fertile mouth of the suction passes through solution pipe and fertilizer
The connection of liquid bucket, the solution pipe, which is equipped with, inhales fertile solenoid valve, flowmeter and filter, and the venturi fat absorption device inhales fertilizer electricity
Magnet valve, flowmeter, filter and solution bucket are sequentially connected；
The EC/PH sensor is applied between vacuum solenoid valve and venturi fat absorption device, through tee tube with first
Fertile pipeline is connected, for obtaining EC value and pH value in the first fertilising pipeline；
The control system is set to the side of solution bucket, respectively with inhale fertile solenoid valve, EC/PH sensor, flowmeter, fertilising
Pump and vacuum solenoid valve electrical connection, for controlling fertilization system operation.
The technical solution that the present invention further solves is that the control system includes station cabinet, touch screen, PLC control
Device, fertilizing pump frequency converter and irrigation pump frequency converter processed；The front installation touch screen of the station cabinet, the interior peace of station cabinet
Equipped with PLC controller, fertilizing pump frequency converter and irrigation pump frequency converter, the signal input part of the PLC controller respectively with EC/
PH sensor, flowmeter signal output end signal connection, the signal output end of the PLC controller respectively with touch screen, inhale
Fertile solenoid valve is connected with vacuum solenoid valve signal, and the signal output end of the fertilizing pump frequency converter is connect with fertilising pump signal.
The technical solution that the present invention further solves is that the flowmeter uses Hall flow meter, the Hall flow
Meter includes shell, impeller, screw rod, magnetic element, Hall element and acquisition system, during the screw rod is fixed in shell
Portion, it is parallel with the fluid inlet of shell；Screw rod is equipped with impeller, and the upside of the impeller is equipped with magnetic element, the magnetic member
Part is coaxial with impeller；The side of the magnetic element is equipped with Hall element, the signal input part of Hall element and acquisition system
The connection of signal output end signal, the signal input part signal of the PLC controller of the signal output end and control system of Hall element
Connection.
The technical solution that the present invention further solves is to be connected between multiple venturi fat absorption devices using parallel way
It connects.
The technical solution that the present invention further solves is that the filter uses laminated filter, and filtering accuracy is not small
In 80 mesh.
The technical solution that the present invention further solves is that the fertile solenoid valve of the suction uses high-frequency electromagnetic valve.
The present invention also protects the control method of the PWM mode fertilzer sucking pipe road flow quantity detecting system, with scheduled valve opening
Time is entire PWM cycle, generates pwm pulse waveform by control system, suction is adjusted by the duty ratio of the PWM waveform of output
The switch of fertile solenoid valve, and then the fluid flow by flowmeter is adjusted, flowmeter exports corresponding pulses according to the variation of flow
Signal feeds back to control system, and the suction fertilizer flow being calculated in PWM cycle, and steps are as follows for specific calculating:
Step 1: record is all during the fertile solenoid valve of suction inhales fertile solenoid valve to closing from opening in a PWM cycle
The time of number of pulses and each pulse experience；
Step 2: calculating first pulse flow according to the time of first pulse, calculation formula is as follows:
Wherein, V1Indicate the water of first pulse, V0Indicate single pulse water, t1Indicate first pulse experience
Time, t2Indicate the time of second pulse experience；
Step 3: correcting the last one pulse according to the time that the last one pulse and penultimate pulse are undergone
Flow, correction formula are as follows:
Vn=V0*tn/tn-1,
Wherein, VnIndicate the water of the last one pulse, V0Indicate single pulse water, tn-1Indicate penultimate pulse
The time of experience, tnIndicate the time of the last one pulse experience；
Step 3: according to step 2 and step 3 obtain as a result, calculate a PWM cycle in flow, calculation formula
It is as follows:
Wherein, q indicates the suction fertilizer flow of a PWM cycle, V1Indicate the water of first pulse, V0Indicate single pulse
Water, VnIndicate the water of the last one pulse, tiIndicate the time of i-th of pulse experience；
Step 4: electronic scale weighs the reduction amount of the solution bucket weight in a PWM cycle, it is denoted as Development of Venturi Fertilizer Applicator
Practical fertilizer-sucting quantity, and practical fertilizer-sucting quantity and the fertilizer-sucting quantity that step 3 is calculated are compared.
Further, the range of the duration of valve opening is 0.05~2s.
The invention has the benefit that
The present invention needs the demand of precise measurement according to each interchannel flow, constructs PWM mode fertilzer sucking pipe road flow detection
System devises difference according to the pulse characteristic of the Hall flow meter under venturi fat absorption device, solenoid valve and PWM control mode
Period flow detection and calculation method have obtained the flow value of each Cycle accurate.This detection system is novel in design, control system
System is accurate reliable, and detection quickly, has preferable economic value and social value, there is good application prospect.
Detailed description of the invention
Fig. 1 is overall structure of the present invention.
Fig. 2 is that fertile schematic diagram is inhaled in single channel of the invention.
Fig. 3 is Hall sensor structure chart of the invention.
Hall sensor state schematic diagram when Fig. 4 is valve opening of the invention.
Hall sensor state schematic diagram when Fig. 5 is pass valve of the invention.
Fig. 6 is pulse-time curve graph of the invention.
Fig. 7 is control system architecture schematic diagram of the invention.
Serial number in figure, 1- water main, 2- mixing chamber, 3-EC/PH sensor, 4- vacuum solenoid valve, 5- first apply fertilizer pipeline,
6- venturi fat absorption device, 7- solution bucket, 8- filter, 9- flowmeter, 10- inhale fertile solenoid valve, 11- fertilizing pump, 12- check valve,
13- control system, the fertilising of 14- second pipeline, 61- entrance, 62- outlet flow section, 63- inhale fertile mouth, 91- shell, 92- Hall member
Part, 93- acquisition system, 94- magnetic element, 95- impeller, 96- screw rod, 131- station cabinet, 132- touch screen, 133-PLC
Controller, 134- fertilizing pump frequency converter, 135- irrigation pump frequency converter.
Specific embodiment
Summary of the invention of the invention is further described with reference to the accompanying drawings and examples.
Referring to a kind of PWM mode fertilzer sucking pipe road flow quantity detecting system shown in Fig. 1-2, including water main 1, mixing chamber 2,
EC/PH sensor 3, vacuum solenoid valve 4, first apply fertilizer pipeline 5, second apply fertilizer pipeline 14, venturi fat absorption device 6, solution bucket 7,
Filter 8, flowmeter 9 inhale fertile solenoid valve 10, fertilizing pump 11, check valve 12 and control system 13；
The water main 1 irrigates required water and solution for conveying, and has an inlet and outlet, water (flow) direction is by figure
Shown in direction it is mobile；The mixing chamber 2 is connected with water main 1, be located at water main 1 among, inside have spiral water guide knot
Structure, for irrigation water and solution to be sufficiently mixed；
The water outlet of the water main 1 is connect by vacuum solenoid valve 4 with the first fertilising pipeline 5, the vacuum solenoid valve 4
It is connected by threeway with water main 1, positioned at the water outlet of water main 1, the pressure of controllable first fertilising pipeline 5 is not higher than setting
Value, vacuum solenoid valve 4 is also electrically connected with control system 13, can be opened or closed by control system；The first fertilising pipe
Road 5 is equipped with multiple venturi fat absorption devices 6, and the venturi fat absorption device 6 includes entrance 61 and outlet flow section 62, the first fertilising
The water outlet of pipeline 5 is connect with the entrance 61 of venturi fat absorption device 6, and the lower section of venturi fat absorption device 6 is equipped with the second fertilising pipe
Road 14, the outlet flow section 62 of venturi fat absorption device 6 are connect with the water inlet of the second fertilising pipeline 14, the second fertilising pipeline 14
It passes sequentially through fertilizing pump 11 and check valve 12 is connect with the water inlet of water main 1, fertilizing pump 11 is multistage anti-corrosion centrifugal pump, with control
System electrical connection processed, check valve 12 make water can only be from 1 water outlet of water main through applying fertilizer between fertilizing pump 11 and water main 1
Pipeline flows back to 1 water inlet of water main；The middle part of the venturi fat absorption device 6 is additionally provided with the fertile mouth 63 of suction, and the fertile mouth 63 of the suction passes through
Solution pipe 64 is connect with solution bucket 7, and the solution bucket 7 holds solution, and bucket is plastic material, can anti-corrosion；In the solution pipe 64
Equipped with inhaling fertile solenoid valve 10, flowmeter 9 and filter 8, the venturi fat absorption device 6, inhale fertile solenoid valve 10, flowmeter 9,
Filter 8 and solution bucket 7 are sequentially connected；
The EC/PH sensor 3 passes through tee tube and first between vacuum solenoid valve 4 and venturi fat absorption device 6
Fertilising pipeline 5 is connected, while being connect by signal wire with control system 13, for obtaining the EC value in the first fertilising pipeline 5
With pH value and feed back to control system 13, it is preferable that the EC/PH sensor used in the present embodiment is limited for the unusual science and technology in Nanjing
Company's S-EC/PH-A1 type；
The control system 13 is set to the side of solution bucket 7, respectively with inhale fertile solenoid valve 10, EC/PH sensor 3, flow
Meter 9, fertilizing pump 11 and vacuum solenoid valve 4 are electrically connected, for controlling fertilization system operation.
Referring to Fig. 7, in the present embodiment, the control system 13 includes station cabinet 131, touch screen 132, PLC control
Device 133, fertilizing pump frequency converter 134 and irrigation pump frequency converter 135；The front installation touch screen 132 of the station cabinet 131,
PLC controller 133, fertilizing pump frequency converter 134 and irrigation pump frequency converter 135, the PLC control are installed in station cabinet 131
The signal input part of device 133 processed is connect with the signal output end signal of EC/PH sensor 3, flowmeter 9 respectively, the PLC control
The signal output end of device 133 processed is connect with touch screen 132, the fertile solenoid valve 10 of suction and 4 signal of vacuum solenoid valve respectively, the fertilising
The signal output end of pump frequency conversion device 134 is connect with 11 signal of fertilizing pump.
Referring to Fig. 3, in the present embodiment, the flowmeter 9 uses Hall flow meter, and each fertilising interchannel need to be arranged not
Same ratio is unable to accurately control flow and ratio, therefore by every since there are many factor of each pass effect fertilizer-sucting quantity
The mode detection flows of a channel installation flowmeter, the Hall flow meter include shell 91, impeller 95, screw rod 96, magnetism
Element 94, Hall element 92 and acquisition system 93, the screw rod 96 are fixed at middle part, the fluid with shell 91 in shell 91
Entrance is parallel；Screw rod 96 is equipped with impeller 95, and the upside of the impeller 95 is equipped with magnetic element 94, the magnetic element 94 with
Impeller 95 is coaxial；The side of the magnetic element 94 is equipped with Hall element 92, and the signal input part of Hall element 92 and acquisition are
The signal output end signal connection of system 93, the letter of the PLC controller 133 of the signal output end and control system 13 of Hall element 92
The connection of number input end signal.After water enters flowmeter, driving impeller 95 rotates, and magnetic element 94 also follows rotation, Hall element
92 sense magnetic element 94, and acquisition system 93 generates a pulse signal, and each pulse signal represents certain flow.Impeller
95 revolving speeds change with changes in flow rate, and 92 output phase of Hall element answers pulse signal, feed back to control system 13, are by control
System 13 judges uninterrupted.
In the present embodiment, connected between multiple venturi fat absorption devices 6 using parallel way.
In the present embodiment, the filter 8 uses laminated filter, and filtering accuracy is not less than 80 mesh, was mainly used for
The impurity in solution is filtered, guarantees that system unit is unaffected.
In the present embodiment, the fertile solenoid valve 10 of the suction uses high-frequency electromagnetic valve, is electrically connected with control system 13, according to control
The PWM duty cycle high-speed switch that system 13 exports controls fertilizer-sucting quantity.
The detection system working principle is: iirigation water source is by water main, when water main pressure is greater than vacuum solenoid valve
When setting pressure, vacuum solenoid valve is opened, and water enters fertilising pipeline, and apply fertilizer pump operation, and water flows through venturi fat absorption device, is inhaling fertilizer
Mouth generates negative pressure, and when inhaling fertile solenoid valve opening, the solution in solution bucket is inhaled into fertilising pipeline, and into supervisor, in complex fertilizer
It is intracavitary to be mixed with water and irrigation water is applied to crop to accurate quantification together.The pressure of venturi fat absorption device throat is stablized not
When change, the fertile flow of suction is also just stablized constant.In the fertile situation of continuous suction, venturi fat absorption device generates stable negative pressure, inhales fertilizer stream
Substantially constant is measured, the flow of flowmeter acquisition is also relatively uniform.Fertilizer-sucting quantity size is by control system according to the Application Ratio of setting
Or EC/PH value, it is realized and is adjusted by the switch time that PWM mode controls solenoid valve.
Under PWM control mode, inhaling fertilizer is discontinuous, and when solenoid valve is opened, solution enters under the action of negative pressure inhales fertilizer
Pipe and Venturi tube, negative pressure become smaller from maximum value, are converted to the potential energy (height), kinetic energy (speed) and line loss of solution, this
In the case of kind, the negative pressure at trunnion is variation, and the peak suction at different valve opening, closing valve time trunnion is different, variation
Amplitude is also different；When duration of valve opening very in short-term, negative pressure value is reduced to 0 not yet, and valve is turned off, when duration of valve opening is longer, bear
Pressure value is reduced to 0 from maximum value, then keeps a stable state；When closing valve time very in short-term, at trunnion not yet generate most
Big negative pressure, valve have been opened, and negative pressure value decreases, and fertilizer-sucting quantity can also be reduced；When closing valve time is longer, generated most at trunnion
Big negative pressure, after valve is opened, fertilizer-sucting quantity is larger.
When solenoid valve is opened, water enters fertilzer sucking pipe, flows into Hall flow meter, impeller and magnet unit rotation, adopts
Collector generates pulse signal, and the flow velocity of solution increases to a stable value from 0, and the frequency of pulse signal is variation, often
The time of a pulse experience is also different.When solenoid valve is closed, negative pressure disappears in pipeline after solenoid valve, but part solution still has speed
Flow forward is spent, water hammer effect is generated, the impeller in flowmeter also will continue to roll, and generate pulse signal, and acquisition system still can
Flow is acquired and calculates, actually these pulse signals are all invalid, so needing to be distinguished and remove.Therefore flowmeter
Since the effective impulse of calculation be to terminate opening solenoid valve to closing solenoid valve.
Referring to fig. 4, the Hall flow meter detection process in a PWM cycle: there are 3 states when valve opening, Hall element is rigid
Fortunately at induction (a), a pulse is generated at once, and error is maximum, is more 1 pulse；Hall element has just been crossed at induction
(b), a pulse is generated after rotating a circle, error 0 is just 1 pulse after rotating a circle；Hall element is in centre
Position (c), error is between more 0~1 pulse.Referring to Fig. 5, also there are 3 states when closing valve, Hall element just arrives at induction
(a), a pulse, error 0 are generated at once；Hall element will just arrive at induction (b), and error is maximum, for few 1 pulse；
Hall element is in middle position (c), and error is few 0~1 pulse.
It can be seen that valve opening, Hall element present position is different when closing valve, the error of detection is also different, and error is when flow detection
More or few 0~1 pulse, fluctuation range are 2 pulses.Under PWM mode, duration of valve opening is generally 0.05s~2s, umber of pulse
Amount is 1~40 pulse, and 2 pulse pair measurement accuracy influence very big.
Can be seen that the 2nd to (n-1)th pulse from the above analysis and pulse-time curve is all to represent one completely
Pulse, and the variation of the 1st and n-th of pulse is very big, and flow is possible to from 0 to maximum value, thus needs to correct.By scheming
As can be seen that the 1st pulse elapsed-time standards longest (maximum elapsed-time standards), illustrates that flow is small, the 2nd pulse is minimum, explanation in 6
Flow is big, and then the time gradually rises, until steady, the last one pulse (maximum elapsed-time standards) and previous pulse basic one
It causes.
Based on above-mentioned test request, the control method of PWM mode fertilzer sucking pipe of the present invention road flow quantity detecting system,
With scheduled duration of valve opening for entire PWM cycle, pwm pulse waveform is generated by control system 13, passes through the PWM waveform of output
Duty ratio inhales the switch of fertile solenoid valve 10 to adjust, and then adjusts the fluid flow for passing through flowmeter 9, and flowmeter 9 is according to flow
Variation, output phase answers pulse signal, and pulse signal includes the time of number of pulses and each pulse experience, is then fed back to
The suction fertilizer flow in PWM cycle is calculated in control system 13, and steps are as follows for specific calculating:
Step 1: record is all during the fertile solenoid valve of suction inhales fertile solenoid valve to closing from opening in a PWM cycle
The time of number of pulses and each pulse experience；
Step 2: calculating first pulse flow according to the time of first pulse, calculation formula is as follows:
Wherein, V1Indicate the water of first pulse, L；V0Indicate single pulse water, L；t1Indicate first pulse warp
The time gone through, s；t2Indicate the time of second pulse experience, s；
Step 3: correcting the last one pulse according to the time that the last one pulse and penultimate pulse are undergone
Flow, correction formula are as follows:
Vn=V0*tn/tn-1,
Wherein, VnIndicate the water of the last one pulse, L；V0Indicate single pulse water, L；tn-1Indicate penultimate
The time of pulse experience, s；tnIndicate the time of the last one pulse experience, s；
Step 3: according to step 2 and step 3 obtain as a result, calculate a PWM cycle in flow, calculation formula
It is as follows:
Wherein, q indicates the suction fertilizer flow of a PWM cycle, L/s；V1Indicate the water of first pulse, L；V0Indicate single
A pulse water, L；VnIndicate the water of the last one pulse, L；tiIndicate the time of i-th of pulse experience, s；Step 4: with
Electronic scale weighs the reduction amount of the solution bucket weight in a PWM cycle, is denoted as the practical fertilizer-sucting quantity of Development of Venturi Fertilizer Applicator, and will
Practical fertilizer-sucting quantity is compared with the fertilizer-sucting quantity that step 3 is calculated.
For above calculating step, setting duration of valve opening is 1s, replaces solution using water, records effective impulse number and every
The time of a pulse experience, flow is calculated separately by correction algorithm, while electronic scale records each fertilizer-sucting quantity, is converted into arteries and veins
It rushes number and compares.
In the present embodiment, carry out calculating practical water of 2 groups of data in a PWM cycle using above-mentioned calculation method
It measures, wherein V0It is the performance parameter of flowmeter, is directly given by producer, value 1/60L.
2 groups of data of record are as follows:
1st group of calculating flow and measured discharge compare:
First according to t1/t2=5.83 >=4, therefore calculate V1=3V0/ 4=12.5L mL, then calculates V again17=V0*
t17/t16=14.8 mL；The V that will finally obtain1And V17Substituting into the formula of step 3 and q is calculated is 277.3mL/s, therefore
In the duration of valve opening of 1s, the volume that water passes through is 277.3mL, is by the quality that water can be calculated in the density of water
277.3g, the water of reduction is 273g in practical fertilizer bucket, therefore the water of water obtained by calculation and actual absorption
Percentage error is 1.6%.
2nd group of calculating flow and measured discharge compare:
First according to t1/t2=5.88 >=4, therefore calculate V1=3V0/ 4=12.5mL, then calculates V again18=V0*t18/
t17=0.3mL；The V that will finally obtain1And V18Substituting into the formula of step 3 and q is calculated is 279.5mL/s, therefore 1s's
In duration of valve opening, the volume that water passes through is 279.5mL, is 279.5g by the quality that water can be calculated in the density of water, practical
The water of reduction is 274g in fertilizer bucket, therefore the percentage error of the water of water obtained by calculation and actual absorption is
2%.
To sum up, the detection system and detection method and actual flow deviation that the present invention uses illustrate detection system less than 3%
It is feasible with method.
What has been described above is only a preferred embodiment of the present invention, it is noted that for those of ordinary skill in the art
For, without departing from the concept of the premise of the invention, various modifications and improvements can be made, these belong to the present invention
Protection scope.
Claims (8)
1. a kind of PWM mode fertilzer sucking pipe road flow quantity detecting system, it is characterised in that: including water main (1), mixing chamber (2), EC/
PH sensor (3), vacuum solenoid valve (4), the first fertilising pipeline (5), the second fertilising pipeline (14), venturi fat absorption device (6), fertilizer
Liquid bucket (7), flowmeter (9), inhales fertile solenoid valve (10), fertilizing pump (11), check valve (12) and control system at filter (8)
(13)；
The mixing chamber (2) is connected with water main (1), is located among water main (1), for irrigation water and solution is sufficiently mixed
It closes；
The water outlet of the water main (1) is connect by vacuum solenoid valve (4) with the first fertilising pipeline (5), first fertilising
Pipeline (5) is equipped with multiple venturi fat absorption devices (6), and the venturi fat absorption device (6) includes entrance (61) and outlet flow section
(62), the water outlet of the first fertilising pipeline (5) is connect with the entrance (61) of venturi fat absorption device (6), venturi fat absorption device (6)
Lower section be equipped with second fertilising pipeline (14), the outlet flow section (62) of venturi fat absorption device (6) with second fertilising pipeline (14) into
Mouth of a river connection, second fertilising pipeline (14) pass sequentially through the water inlet of fertilizing pump (11) and check valve (12) and water main (1)
Mouth connection；The fertile mouth (63) of suction is additionally provided in the middle part of the venturi fat absorption device (6), the fertile mouth (63) of the suction passes through solution pipe (64)
It is connect with solution bucket (7), the solution pipe (64), which is equipped with, inhales fertile solenoid valve (10), flowmeter (9) and filter (8), institute
Venturi fat absorption device (6), the fertile solenoid valve (10) of suction, flowmeter (9), filter (8) and solution bucket (7) is stated to be sequentially connected；
The EC/PH sensor (3) is located between vacuum solenoid valve (4) and venturi fat absorption device (6), passes through tee tube and
One fertilising pipeline (5) is connected, for obtaining EC value and pH value in the first fertilising pipeline (5)；
The control system (13) is set to the side of solution bucket (7), respectively with inhale fertile solenoid valve (10), EC/PH sensor
(3), flowmeter (9), fertilizing pump (11) and vacuum solenoid valve (4) electrical connection, for controlling fertilization system operation.
2. a kind of PWM mode fertilzer sucking pipe road according to claim 1 flow quantity detecting system, it is characterised in that: the control
System (13) includes station cabinet (131), touch screen (132), PLC controller (133), fertilizing pump frequency converter (134) and fills
Irrigate pump frequency conversion device (135)；Front installation touch screen (132) of the station cabinet (131), the interior peace of station cabinet (131)
Equipped with PLC controller (133), fertilizing pump frequency converter (134) and irrigation pump frequency converter (135), the PLC controller (133)
Signal input part is connect with the signal output end signal of EC/PH sensor (3), flowmeter (9) respectively, the PLC controller
(133) signal output end is connect with touch screen (132), fertile solenoid valve (10) and vacuum solenoid valve (4) signal of suction respectively, described
The signal output end of fertilizing pump frequency converter (134) is connect with fertilizing pump (11) signal.
3. a kind of PWM mode fertilzer sucking pipe road according to claim 2 flow quantity detecting system, it is characterised in that: the flow
It counts (9) and uses Hall flow meter, the Hall flow meter includes shell (91), impeller (95), screw rod (96), magnetic element
(94), Hall element (92) and acquisition system (93), the screw rod (96) is fixed at middle part in shell (91), with shell
(91) fluid inlet is parallel；Screw rod (96) is equipped with impeller (95), and the upside of the impeller (95) is equipped with magnetic element (94),
The magnetic element (94) and impeller (95) are coaxial；The side of the magnetic element (94) is equipped with Hall element (92), Hall member
The signal input part of part (92) is connect with the signal output end signal of acquisition system (93), the signal output end of Hall element (92)
It is connect with the signal input part signal of the PLC controller (133) of control system (13).
4. a kind of PWM mode fertilzer sucking pipe road according to claim 1 flow quantity detecting system, it is characterised in that: described is more
It is connected between a venturi fat absorption device (6) using parallel way.
5. a kind of PWM mode fertilzer sucking pipe road according to claim 1 flow quantity detecting system, it is characterised in that: the filtering
Device (8) uses laminated filter, and filtering accuracy is not less than 80 mesh.
6. a kind of PWM mode fertilzer sucking pipe road according to claim 1 flow quantity detecting system, it is characterised in that: the suction fertilizer
Solenoid valve (10) uses high-frequency electromagnetic valve.
7. a kind of control method of PWM mode fertilzer sucking pipe described in claim 1 road flow quantity detecting system, which is characterized in that with
Scheduled duration of valve opening is entire PWM cycle, generates pwm pulse waveform by control system (13), passes through the PWM waveform of output
Duty ratio inhales the switch of fertile solenoid valve (10) to adjust, and then adjusts the fluid flow for passing through flowmeter (9), flowmeter (9) root
According to the variation of flow, output phase answers pulse signal, feeds back to control system (13), and the suction fertilizer stream being calculated in PWM cycle
Amount, steps are as follows for specific calculating:
Step 1: recording in a PWM cycle and inhaling pulse all during fertilizer solenoid valve is inhaled in fertile solenoid valve to closing from opening
The time of quantity and each pulse experience；
Step 2: calculating first pulse flow according to the time of first pulse, calculation formula is as follows:
Wherein, V1Indicate the water of first pulse, V0Indicate single pulse water, t1Indicate the time of first pulse experience,
t2Indicate the time of second pulse experience；
Step 3: the last one pulse flow is corrected according to the time that the last one pulse and penultimate pulse are undergone,
Correction formula is as follows:
Vn=V0*tn/tn-1,
Wherein, VnIndicate the water of the last one pulse, V0Indicate single pulse water, tn-1Indicate penultimate pulse experience
Time, tnIndicate the time of the last one pulse experience；
Step 3: according to step 2 and step 3 obtain as a result, calculating the flow in a PWM cycle, calculation formula is as follows:
Wherein, q indicates the suction fertilizer flow of a PWM cycle, V1Indicate the water of first pulse, V0Indicate single pulse water,
VnIndicate the water of the last one pulse, tiIndicate the time of i-th of pulse experience；
Step 4: electronic scale weighs the reduction amount of the solution bucket weight in a PWM cycle, it is denoted as the reality of Development of Venturi Fertilizer Applicator
Border fertilizer-sucting quantity, and practical fertilizer-sucting quantity and the fertilizer-sucting quantity that step 3 is calculated are compared.
8. a kind of control method of PWM mode fertilzer sucking pipe road according to claim 7 flow quantity detecting system, feature exist
In: the range of the duration of valve opening is 0.05~2s.
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| CN112889448A (en) * | 2021-04-02 | 2021-06-04 | 西北农林科技大学 | Water and fertilizer machine actively regulated and controlled based on pipe network terminal information and use method thereof |
| CN112987556A (en) * | 2021-01-25 | 2021-06-18 | 河南锐利特计算机科技有限公司 | Constant-speed fertilization method based on variable frequency regulation |
| CN113412719A (en) * | 2021-06-21 | 2021-09-21 | 西北农林科技大学 | Fertilizer suction flow measurement and control integrated device and control method thereof |
| CN114514819A (en) * | 2022-02-16 | 2022-05-20 | 农业农村部南京农业机械化研究所 | Multi-path isobaric equal-pressure equal-quantity distribution device and method for liquid manure |
| CN114788449A (en) * | 2022-05-11 | 2022-07-26 | 福建省农业机械化研究所(福建省机械科学研究院） | Device and method for adjusting and controlling fertilizer suction amount of water and fertilizer all-in-one machine |
| CN117063686A (en) * | 2023-09-01 | 2023-11-17 | 中国农业科学院农业信息研究所 | Corn water and fertilizer integrated irrigation method |
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| CN112987556A (en) * | 2021-01-25 | 2021-06-18 | 河南锐利特计算机科技有限公司 | Constant-speed fertilization method based on variable frequency regulation |
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| CN117063686A (en) * | 2023-09-01 | 2023-11-17 | 中国农业科学院农业信息研究所 | Corn water and fertilizer integrated irrigation method |
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