The Research Of Remote Collecting And Controlling Card For Water Temperature And Water Level Based On GPRS

With the economic progress and social development, wireless communication technologyhas made rapid development and the application areas are more and more widely, such asmeasurement and controlling field, intelligent home field. In the measurement and controllingfield, a collecting and controlling card for water temperature and water level was designed,which uses wireless communications technology to solve the defects and deficiencies in thesolar hot water project currently. Deficiencies are that the system is a stand-alone workindependently or uses RS485,CAN bus etc, the above work is required on-site operation andcan not meet the new needs currently of hot water collecting and controlling. Therefore,remote data collecting and controlling becomes the new direction of the solar energy field andGPRS-based wireless communication is the focus of development. This paper designed acollecting and controlling card for water temperature and water level based on GPRS, whichcan be well used in solar hot water project and achieve the purpose of collecting data andcontrolling hot water.(1)The introduction part of this paper describes the design issues of the background andanalyzes the range of collecting and controlling water temperature and water level system inthe solar hot water project, mainly through three stages: stand-alone RS485bus,CAN buscontrol stage; By comparing with these three advantages and disadvantages, remote collectingand controlling water temperature will be the future direction of development based on GPRS.(2)The second part is the overall design of the system. Firstly, the overall structure of thesystem is expounded, which is mainly composed by a collecting and controlling card,awireless communication module, remote PC and GPRS network; Secondly, wirelesscommunication module based on GPRS is highlighted. The wireless communicationmodule-ATK-SIM900A module is selected from aspects of the definition, classification, functions, features to the advantages in terms of data transmission, the technical parameters，which is fit for the system designed. The second part of the system also draws an overallblock diagram of collecting and controlling card and introduce each part of the structurecollecting and controlling card briefly.(3)The third part is the core of this paper, named hardware design of collecting andcontrolling card. The collecting and controlling card hardware design is divided into two parts:one part is the hardware design of lower machine; the other part is hardware design of thewireless communication module SIM900A. The hardware design of the lower machineincludes a PIC18F458microcontroller and peripheral circuits, a key input circuit, a liquidcrystal display circuit, temperature measuring circuit, the water level measurement circuit, therelay control circuit and real-time clock circuit. Each circuit lists schematic in detail,especially water temperature measuring circuit and water level measuring circuit, we make adetailed exposition. The hardware design of wireless communication module SIM900Aincludes the power supply circuit design, switches circuit design, lights (power indicator andnetwork status indicator) circuit design, antenna interface circuit design, RS232serialinterface circuit design; in this section,the power supply circuit design，switches circuitdesign, antenna interface circuit design and RS232serial interface circuit design are described,the other are not introduced.(4)The fourth part is also the core part of the paper, named software design of collectingand controlling card. First, the development environment of the suitable system is listed, andthen by comparing with several emulators, Emulator-MAPLAB ICD2debugger is selectedfor the suitable system. In this part of software design, mainly on initialization procedure ofthe collecting and controlling card, sending procedure of the collecting and controlling cardand receiving procedure of wireless communication module SIM900A are elaborated mainly.The collecting and controlling card initialization procedure includes the initialization of lowermachine and the initialization of wireless communications module SIM900A. Theinitialization of lower machine includes the setting of relay control output port, the setting ofreal-time clock chip PCF8563，address, A/D module initialization of water temperature datacollected, the limited of water temperature and water level, LCD module initialization and data display, the settings of I2C bus and PCF8563.The initialization of the wirelesscommunication module SIM900A includes SIM card is whether inserted in the wirelesscommunication module, how the signal quality of SIM card, the current SIM card operators,work light is whether lifted, SIM900A network is whether normal, the network light iswhether blinking, reading and writing of the memory is whether normal. In the initializationof wireless communication module,we also used the serial debugging assistant as animportant tool for system debugging.(5)The fifth part of this paper deals with a summary and outlook for future work.Finally, the paper includes four parts such as references,appendix,master of articlespublished during the study and expressing thanks.