Gprs-based Instrument Data Acquisition And Monitoring System

This paper aims to solve the problems encountered when we structure a large wireless meters data acquisition and monitoring system based on GPRS communication technology. According to the requirements of solving the problem, this paper mainly researches serveral fields as follows: First studies and analyzes series of international GPRS protocols, puts forward technological difficulties and requirements during estabilishing GPRS data service channels, concludes the realizing ways about how to estabilish PPP link, makes certain the technical line and design idea to this subject; Second researches several means structuring the data acquisition networks based on GPRS networks, proves more reasonable to structure data acquisition system based on GPRS and Internet communication networks and works out its concrete realizing scheme, parses the principle and realization about two key technologies—Dynamic Domain Name and Port Mapping , which are often encountered when connecting the data center server to Internet; Third researches international Point-to-Point Protocol (PPP), exposes its essential and tidy programming-scheme, and also explains how to embed TCP/IP (including UDP and TCP) datagram into PPP datagram to exchange data; Finally expatiates on overall realization process of the data acquisition system based on GPRS by several chapters, from hardware and software design of GPRS terminal equipment to programming of data center server.This paper consists of seven chapters:The chapter 1 makes clear relative merits of the traditional ways about meter data acquisition and monitoring system, and then introduces the contents and the solved problems of this paper.The chapter 2 first presents the features of GPRS; then analyzes the functions and relationship of GPRS network cells and interfaces at detail; at last makes great efforts to conclude the interface protocols between the GPRS and external data networks from serials of GPRS international communication technology documents. The chaper parses the relation of connection between the GPRS and Internet networks, makes clear the data communication mechanism of GPRS, and works out the design scheme of the subject.The chapter 3 mainly discusses several means we structure the networks. Here more importance will be attached to the ones the data center server (DCS) accesses the Internet. Since the technologies of dynamic domain name and port mapping are important and usually used, here also gives detailed analyses, even describes how to carry out it.The chapter 4 works out the hardware design of GPRS terminal equipment, including the minimum system design based on the SumSung ARM7-core microcontroller S3C44B0X, and the hardware design adding the GPRS engine MC35i produced by Siemens and RS485 interface to the minimum system.The chapter 5, according to dial-up procedure, describes how to design the MC35i dial-up program. Here introduces some important subsets of AT command sets, and also describes how to use them to dial up MC35i; analyzes the principle of the point-to-point protocol, and also demonstrates how to establish the wireless link to GPRS by practical example.