New Environment Parameters Monitoring And Control System For Greenhouse Based On Master-slave DistributedAbstract-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 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 system,configuration software-KingView is used to develop software for PC,by which the development cycle is shorten and a friendly human-computer interaction is 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. INTRODUCTIONTo modern indoor agriculture, the automatic measurement and control of environment parameters is the key to achieve crop yield and quality of greenhouse.In recent years,facilities agriculture develops vigorously in our country,matched with it,the monitoring and control instrument of greenhouse have also made certain development.After 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 combined of greenhouse which can be popularized in the vast rural areas.This system is mainly control of temperature,humidity,CO2 concentration,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of PC,it has a large amount of data storage,rich software,convenient human-computer interaction,and so on.If we use outdated and low-priced PC,taking the PC as the upper machine,taking the different function control modules composed of multiple microcomputers as the lower machines,then a master-slave distributed and intelligent control system bases on microcomputer is 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 PRINCIPLEThe most marked feature of the distribution combined and intelligent control system greenhouse is that of incorporating with data acquisition, control and management as a whole,module combination, simple structure,convenient human-computer interaction,and using technology of intelligent expert fuzzy 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.In the top-price PC is taken as the host to make system management and 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 used to communicate PC with all AT89C,and then the collection,processing and 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.The system collects separately ways of environment information through each monitoring and control module,and sends it to host PC through the RS485 interface.And in the PC configuration control system,the acquired parameters are compared with the values of setting,then according to a variety of expert intelligent fuzzy control system of crops at different growth stages,the fuzzy control instructions on the environment temperature,humidity,CO2 concentration,soil water content and 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 middle in the northern half (near the wet curtain) and the southern half (near the fan ),a module of air temperature and humidity ,CO2 concentration and a module of soil moisture content are set;a module of soil moisture content will be added in the middle of the greenhouse according to the actual condition;at the height of 1.5m 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;and the PC is placed in the main entrance to the greenhouse.III . HARDWARE DESIGNA. The CP and communication systemIn the distributed system of data acquisition and control