Design Of The Embedded Data Acquisition System

With the popularity of higher education of China, the number of university students increases unceasingly, which results in difficulty increase in school electrical power management and arouses new problems frequently. The original management mode is no longer applicable. Colleges are actively searching for a new management mode, which can directly monitor the condition of electricity power use of every classroom and dormitory. At the same time, the energy consumption problem is more and more serious in our country, universities also hope that with the help of a new type of management mode, it can be achieved to reduce campus equipment’s electricity consumption, and fulfill the goal of energy conservation and emissions reduction. Therefore, in order to respond to national Twelfth Five-year Plan of energy-saving and environmental protection, and to seek an effective safety power supply mode, universities carry out the construction of campus energy saving platform. In the network structure of energy saving platform, the most critical part is the intelligent gateway which is responsible for the power consumption information data acquisition and transmission. The intelligent gateway is the core of the whole system.The embedded gateway of energy-saving platform is, first of all, to collect power consumption information(electric quantity, voltage, power, power factor etc.) of each room of the campus, and then Store the collected data to the server. The communication protocol between embedded gateway and measurement control-one box(intelligent distribution cabinets) follows the 645 protocol. Use the RS-485 bus to transport the communication protocol. Data transmission and control commands transmission between the embedded gateway and data server adopt the TCP/IP mode.In the embedded gateway system, this article adopts the ARM920 T kernel s3c2240 microprocessor as the core, extends gateway serial port to eight by using four pieces ST16C2550 serial extended chip, takes DM9000 as the Ethernet cards to achieve the Ethernet function of system. Transplant the Linux operating system and embedded Web server Boa to realize the gateway online configuration. Transplant the Libxml2 function library to store the configuration information. Design the gateway database structure, transplant the SQLite embedded database and complete collection data of the preservation of each pathway. This paper realizes the overall design of the gateway system in terms of hardware. The design includes the microprocessor minimum system, reset circuit, serial ports expand circuit, Ethernet circuit and RS-485 circuit etc. In the software aspect, this paper explains the transplantation of related software and the implement method of gateway configuration webpage, introduce the establishing of gateway database and the process of protocol conversion.