Based On The 1-wire Technology, Ground Meteorological Data Acquisition System

This paper introduces a system of ground meteorological parameters collected from the automatic weather station based on 1-Wire bus technology. The weather station is developed jointly by Dallas Semiconductor and Texas Weather Instruments, Inc.. of USA. 1-Wire bus technology transmits both power and bidirectional data over a single twisted-wire cable.An automatic measuring system of weather parameter is proposed. The function of collecting meteorological parameters is completed by 1-Wire sensors (DS1820,DS2423,DS2450), adapter(DS9097U) and computer. The package can be augmented with humidity, barometric pressure, and other weather sensors simply by connecting the sensor to the cable at the desired position and adding the appropriate software.This paper explains 1-Wire net, such as the hardware circuit and communication protocol, analyzes features of sensor chips (the 1-Wire devices) and 1-Wire?line-powered MicroLAN?networking technique. Three programmable sensor of 1-Wire devices,DS1820^ DS2450 and DS2423 are introduced, including the working principle and application in 1-Wire weather station, and circuit which connect the sensors and 1-Wire bus. In this paper, we discuss about the theory of cyclic redundancy checks and its application. We take DSI 820 for example to realize the hardware and software methods in Dallas's 1-Wire chips.We can access and control the 1-Wire devices, also read out the data of these sensors, using Visual C++ and TMEX DLL. The software we developed can access and control the 1-Wire devices. According to the current demand, the information of serial port of computer which is connected with 1 -Wire bus can be obtained, and the type of sensors and 64 bit ROM also are available. The data outputted from these sensors is converted to temperature, wind speed, wind direction and rainfall. Then the real time weather parameters are collected and saved to database automatically. The principle of the system, its hardware structure and software designing are also introduced in the paper.We established a Local Area Network. The meteorological data collected by PC are transmitted to Server on time, The database of Server updates timely, and other Clients access the new meteorological material which can be released on Internet.