Research And Implementation Of Data Collecting And Transmitting Device In The Network Meter System

The using of embedded system is becoming a hot issue in meter reading system. The application of embedded operating system is the direction of embedded system developing.Embedded operating system is a system which sustaining embedded system application.It usually contains the bottom drive software,kernel, communication protocol and graphical user interface of the hardware.Embedded operating system takes charge of distributing,attempering and controlling work of all hardware and software,and can achieve function configuration by loading or unloading modules,in the person of character of the system.Data collecting and transmitting device is based on embedded real time operating systemμC/OS-Ⅱin the Network Meter System,The material framework is based on ARM7,the framework which runningμC/OS-Ⅱin ARM chip,can enhance the running speed and reliability if system.The memory on the board is large and capability compare price is high, reliability etc.The data collecting and transmitting device concentrates the user gas instrument's gas quantity information by the RS-485 bus line firstly,the through the GPRS network,the information will be given to the server,in order to achieve long-range wireless automatic meter reading function.The main work of this designing is to make a research on the development and realization of data collecting and transmitting device.The achievements are as follows:1.The design of data collecting and transmitting device,including the ARM7-based LPC2114 chip as main controller and peripheral hardware circuit,has been finished.The real-time,multi-task embeddedμC/OS-Ⅱoperating system has been transplanted to the microprocessor LPC2114 to create a follow-up development of software platform.2.In this thesis,we choose the RS-485 terminal network communication by comparing the advantages and disadvantages of various serial communications.Then, we design the communication data-frame between the gas meter and the data collecting and transmitting device.3.In allusion to the advantages of GPRS wireless communications,the thesis designs the communication data-frame of the server based on the research of GPRS Working Principle.In allusion to the disadvantage of GPRS wireless communications dropping easily,the thesis maintain the real-time online with the method of sending a heartbeat data-frame to the server.There are always frame-dropping and responding slowly in programming the communication interface using querying method,so we use interruption to resolve effectively the problem and ensure the stability of communication.4.This thesis storages the data on the E~2PROM for the security of data reading from gas meter by considering various factors,researches and experiments I~2C bus communication of the various modes,and programs the driver.In this thesis,data collecting and transmitting device has completed a series of the real-time and reliability experiments of RS-485,GPRS communications etc. The data collecting and transmitting device can complete accurately and reliably the function of data collection,procession and transmission etc,and meet fully the control requirements of the Net Meter System.