【正文】 is neglect,only the real part,which amounts to a pure resistance. Soil moisture sensor consists of 100MHz signal source,a coaxial transmission line and a 4pin stainless electromagic waves of signal transmit to the probe along the the probe impedance and line impedance are different,the superimposition of incident waves and reflected waves forms a standing waves. Taking the coaxial transmission line as a lossless uniform line,wave impedance is Z0,Zl is the load impedance. Then the reflected coefficient of voltage wave at the probe is: Γ= （ ZLZ0） /(ZL+Z0) Choosing the length of transmission line is l=λ/4,the maximum and minimum of both ends of the line are Umax and Umin,Then the standing wave radio in the line can be expressed as: S=Umax /Umin =(1|Γ|)/(1+|Γ|) In the way,the soil moisture radio can be measured by measuring the standing wave rate of transmission line. 外文翻譯 6 As shown in .,soil moisture module consists of sensors and controllers,the sensors are subordinated to controllers,controllers can be omitted without the need of irrigation in greenhouse. To simplify the control,irrigation technology of nodetype in partition is adopted in the control soil moisture in this a certain extent,the parameters of upper and lower the ground can be decoupled by adopting this technology. IV CONTROL SYSTEM PROGRAMMING The software of PC is developed by KingView of Beijingcontrolled configuration software has high reliability,shorter development cycle,perfect capability of graphical interface generation,and friendly humanputer interaction。 output is 4~20mA or 0~20mV。% RH,temperature measurement accuracy of 177。at the height of in the main entrance,a water tank is set,of which the solenoid of drip tube should be set based on the need and controlled by module of soil moisture content。 中文 3730 字 本科畢業(yè)設(shè)計 （外文翻譯） 題 目 姓 名 專 業(yè) 自動化 學(xué) 號 指導(dǎo)教師 二○一四年五月外文翻譯 1 New Environment Parameters Monitoring And Control System For Greenhouse Based On Masterslave Distributed Abstract According to the actual need of monitoring and control of greenhouse environment parameters in rural areas,a masterslave 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 CO2 monitoring and control module. In the system,PC has large amount of data storage which is easy to make use of fuzzy control expert sys tem,configuration softwareKingView is used to develop software for PC,by which the development cycle is shorten and a friendly humanputer interaction is monitoring and control module consists of STC12 series of microcontrollers,sensors,relays modules are select based on the need if system to achieve control greenhouse in partition and block. I INTRODUCTION To modern indoor agriculture, the automatic measurement and control of environment parameters is the key to achieve crop yield and quality of recent years,facilities agriculture develops vigorously in our country,matched with it,the monitoring and control instrument of greenhouse have also made certain nearly 10 years of unremitting hard work,our research team of measurement and control system of agriculture environment parameters,designed an intelligent measurement and control system of distribution bined of greenhouse which can be popularized in the vast rural system is mainly control of temperature,humidity,CO2 concentration,soil moisture and illumination 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 un