温室环境监测和控制系统外文翻译文献.docx

温室环境监测和控制系统外文翻译文献.docx

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温室环境监测和控制系统外文翻译文献

温室环境监测和控制系统外文翻译文献

（文档含中英文对照即英文原文和中文翻译）

New Environment Parameters Monitoring AndControlSystem For Greenhouse Based On Master-slave Distributed

Abstract 

According to the actual need of monitoring and control of greenhouse environment parameters in rural areas,a master-slave distributed measurement and control system is designed,in which PC is taken as the host. The system consists of PC ,soil moisture measurement and control module,temperature and humidity, and 

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CO2monitoring andcontrolmodule.Inthesystem,PChaslargeamount ofdata storagewhichiseasytomakeuseoffuzzycontrolexpert  system,configuration software-KingViewisusedtodevelopsoftwareforPC,bywhichthedevelopment cycleis shortenand a friendly human-computerinteractionis provided.Each monitoring and  control module consists  of  STC12 series of microcontrollers,sensors,relays etc.Different modules are select based on the need if system to achieve control greenhouse in partition and block. 

I INTRODUCTION 

To modernindooragriculture,theautomaticmeasurementandcontrolof environment parameters is the key to achieve crop yield and quality of greenhouse.In recentyears,facilitiesagriculturedevelopsvigorouslyinourcountry,matchedwith it,themonitoringandcontrolinstrumentof greenhousehave alsomadecertain development.Afternearly10yearsofunremittinghardwork,ourresearchteamof measurement and control system of agriculture environment parameters,designed an intelligent measurement and control system of distribution combined of greenhouse whichcanbepopularizedinthevastruralareas.Thissystemismainlycontrolof temperature,humidity,CO2concentration,soil moisture and illumination of greenhouse.OF SCM,as the data storage is small,display interface is single,amount of information is limited,but its capability price ratio is high,so it is used as a front unit of data acquisition and control;and of PC,it has a large amount of data storage,rich software,convenienthuman-computerinteraction,andsoon.Ifweuseoutdatedand 

low-pricedPC,takingthe PCastheupper machine,takingthe different function control modules composed of multiple microcomputers as the lower machines,then a master-slavedistributedandintelligentcontrolsystembasesonmicrocomputeris made up,by which both better monitoring and control,display and data collection or management are achieved,but also lower cost of system is get according to the actual need. 

II SYSTEM STRUCTURE AND PRINCIPLE 

Themostmarkedfeatureofthedistributioncombinedandintelligentcontrolsystemgreenhouse isthat of incorporatingwithdata acquisition,controland managementas a whole,module combination, simple structure,convenient human-computerinteraction,and using technologyof intelligentexpertfuzzy 

control,which can adapt to a variety of crop management control in greenhouse.The basic structure of the system is shown in Fig.1.

The structure of the distributed system is composed of two layers:

the upper and 

lower.Inthe top-pricePC istakenas thehost tomakesystem managementand experts  fuzzy  operation in 

intelligent,and  to provide a friendly 

human-computer 

interface,and to  realize the united 

monitoring and  management  of 

greenhouse; the  lower is composed 

of a series of  modules of different 

function,and in  each  module,a 

single chip of  AT89C is adopted 

as the lower  machine,RS485 is 

usedto communicatePC with allAT89C,andthenthe collection,processingand control of the greenhouse parameters is achieved.Each function module is completely isolated in electrical,any failure on the nodule does not produce any effect on other modules.Thesystemcollectsseparatelywaysofenvironmentinformationthrough eachmonitoringandcontrol module,andsendsit tohostPC throughtheRS485 interface.AndinthePCconfigurationcontrolsystem,theacquiredparametersare comparedwith the values of setting,then according to a variety of expert intelligent fuzzy controlsystem of crops at different growth stages,the fuzzy control instructions ontheenvironmenttemperature,humidity,CO2concentration,soilwatercontentand the corresponding operation instructions or alarm are given. 

The system is applied in rural greenhouses in Qinhuangdao.Usually at 1/4 near East and West end in a greenhouse,and at the height of 1.5m from the ground in the middleinthenorthernhalf（nearthewetcurtain）andthesouthernhalf（nearthe fan ）,a module of air temperature and humidity ,C2cOoncentration and a module of soil moisture content are set;a module of soil moisture contentwill be added in the middle of the greenhouse according to the actual condition;at the height of 1.5m in the main entrance,awater tank is set,ofwhich the solenoid of drip tube should be set based on the need and controlled by module of soil moisture content;and the PC is placed in the main entrance to the greenhouse. 

III HARDWARE DESIGN 

A.The CP and communicationsystem Inthedistributedsystemofdataacquisitionandcontrol,asthemicrocontrol

unit is limited in data storage and slow in calculating of complex functions,so PC is used and the master-slave module is adopted in the system,that is a system of,taking PC as the host and taking the SCMsystems located in the scene as slave.

Inthis distributedsystem,communicationisthekeytoit.Generally,theserial portof PCisstandardRS232,ofwhichtransmissiondistance isshorter.Butin agriculture controlsystem.its communication distance is of tens of meters or several kilometers,soRS232/RS485converterisusedtoachievecommunicationbetween thePCandSCM.Toreduceinvestment,bothconsideringtheuserconvenienceand friendlyhuman-computerinteraction,low-pricePCofabove486andbelowPIVis adopted;andconsideringtheoperationofconfigurationsoftware,itisrequiredthat memory is 64M or above and hard disk is 10Gb or above. 

B. The control modules of temperature and humidity,illuminance and CO2 concentration 

Each control unit consists of SCM,sensors,signal processing circuit,RS485 interface and output circuit.The hardware structure of module of temperature and humidity,CO2 concentration is shown in Fig.2. 

CO2 

concentration is measured by sensor based on NDIR technology,measurement is of 0~2×103mol.Throughthe sensor,controlsystem,bysoftware of digital filter,linear interpolationandtemperaturecompensation,theCO2 concentrationis output as digital adhered to UART protocol,and then is input directly to the SCM.

The new intelligentsensor of SHT11 based on CMOSens technology is chosen in themeasurementof temperature andhumidity.InSHT11,thetemperature and humiditysensors,signal amplification,A/D,2IC bus are all integrated in a chip;it has full-scale calibration,second-linedigitaloutput,andhumiditymeasuring rangeof 

0~100% RH,temperature measurement range of -40℃~+123.8℃,humidity measurement accuracy of ±3.0% RH,temperature measurement accuracy of 

±0.4℃,the response time of <4s. 

The illuminancesensor of JY1-TBQ-6 of silicon photovoltaic detection is used Lightmeasuring.Its measurementrange is 0~200,000 Lux;spectralrange is 400~700（nm） visible light;measurement error is less than 2%; output is 4~20mA or 0~20mV;outputsignal canbe directly send to the A/Dof the SCM after being amplified to 0~4V.

ModulesaccepttheinstructionsformthetheUpper,andoutputviatheoutput circuit .The output circuit consists of optical isolation,thesignal driver and the output relays. 

C. The measurement and control modules of soil moisture Water is a polar medium, the dielectric constant of the soil containingwater is 

mainly determined by the water,whenwater content is different,thewave impedance isdifferent.Thesoilmoistureismeasuredbystandingwaveradiomethodinthis 

system. 

Based on the theory of Engineering ElectromagneticField,for lossy medium,the electromagneticwave impedance as follows:

Z0=√μ/ε（1+jλ/（ωε）） 

Where μ is medium permeability,and μ of soil is μ≈μ0 is the vacuum permeability;ε is medium dielectric constant;λ is medium conductivity;ω is electromagnetic wave frequency. 

In the very low audio（<2000Hz）,the loss tangent of dry soil dielectric is λ/ωε≈0.07,if you choose the frequency of the signal source at above 20MHz.then,ε≈ε∞,the imaginary part of the soil wave impedance is neglect,only the real part,which amounts to a pure resistance. 

Soilmoisturesensorconsistsof100MHzsignalsource,acoaxialtransmission line and a 4-pin stainless probe.The electromagneticwaves of signal transmit to the probe along the lines.As the probe impedance and line impedance are different,thesuperimposition of incidentwaves and reflected waves forms a standingwaves.

Taking the coaxial transmission line as a lossless uniform line,wave impedance is Z0,Zlis the load impedance.

Then the reflected coefficient of voltage wave at the probe is:

Γ= （ZL-Z0）/（ZL+Z0） 

Choosing the length of transmission line