Environment Monitoring System For Multi-span Greenhouse Based On 485-bus

Traditional multi-span greenhouse monitoring mainly relies on the accumulated experience of the producers and manual operation.Due to lacking of accurate access to obtain environmental information as well as convenient means of agricultural facilities controlling,multi-span greenhouse monitoring has a low efficiency and backward production technologies,which seriously restrict its development.Recently,as a kind of industrial data bus the fieldbus shows a rapidly trend in many research areas,which mainly solves problems such as digital communications between controllers in industrial fields and intelligent instrumentations,as well as information transmissions between these devices with advanced control systems.Agricultural environment,which is one of the important applications of fieldbus technology,is quite necessary to be carried a further study on.Based on the analysis of current situation of bus technologies,this paper designed and developed a multi-factor environmental monitoring system based on 485-bus for multi-span greenhouse.This paper mainly focused on two aspects: environmental monitoring nodes design and environmental main control nodes design,on this basis,this paper realized SMS based real-time greenhouse monitoring and warning system.The specific work and research results were as follows:(1)Hardware designing of Multi-span Greenhouse monitoring system.The hardware designing had three parts which included acquisitioncircuit,control circuit and power supply circuit.According to Multi-span Greenhouse monitoring demands,air temperature and humidity,soil temperature and humidity,light intensity and CO2 intensity were determined as the acquisition parameters.Selection and optimization designing between the air sensor,soil sensor andCO2 sensor with microcontroller were the work emphasizes of this part.Control circuit took the role of driving the whole system,through transforming weak control signals to large ones,to realize dropper equipment,ventilation equipment and rolling equipment,lighting equipment in Multi-span Greenhouse cooperating.Whole framework of hardware designing was illustrated at last of this part.(2)Software designing of Multi-span Greenhouse monitoring system based on Keil integrated development environment(IDE).First of all,MCU was initialized to execute related singlechip precompiled instructions;Secondly,main software program was developed,including communications between MCU and sensors mentioned above to accomplish environment information collection from hardware facilities;Thirdly,based on 485 bus protocol,communication signals was treated between the compiler microcontroller and PC,thus,sub-nodes were equipped with abilities to acquire distributed and real-time environment data;Finally,the implementation processing of the software compiler was utilized as an example for the overall operation of the system.(3)Designing of real-time warning based on SMS.By analyzing the key technologies and basic principles of message receiving and dispatching,this paper implemented a feasible way of adding SMS warning function on monitoring systemestablished in last part as an expand function.Based on an environment database,a real-time database with several functions including retrieval,early warning,condition management and matching,SMS alert and SMS inquiry was established.The system hardware consisted of a monitoring host and a GSM modem.C# language and Access database were adopted in software design.The results showed that the system had the advantages of reliable operation,friendly human-computer interaction,easy upgrading and transplantation.It also provided a solution for real-time early warning which could reduce the difficulty of developing complex monitoring system greatly and the work intensity of the personnel on duty effectively,thus had a good application promotion prospective.(4)Overall designing and debugging of Multi-span Greenhouse monitoring system.System hardware and software performances and real-time SMS alarm function were verified in this part.Underlying platform accomplished monitoring and controlling,while the upper platform took charge of data storage,querying,alarming and other operations.Hardware design wasdeveloped by Altium Designer to complete the circuit board and PCB circuit.Through well designed andclinched circuits,pre-compiled software program was burning in,which could make the database and computer program run at the same time.Byanalysis on the coordinated operation status between underlying platform and upper platform,system function and performance were verified.