Design And Development Of GPRS DTU For Automatic Data Acquisition Of Soil And Water Conservation

The automatic data mining system of conservation of soil and water is a multi subject technology, such as communication, electronics and micro computer. It is an automated system to measure and report the information of conservation of soil and water. The monitoring range of conservation of soil and water is widespread, most of the monitoring's points are in the field, the environment is very poor and no one on duty. Conservation of soil and water need real time return testing data from equipment to monitoring center, and testing equipment mostly use RS-232 serial communication protocols which the maximum transmission distance is less than 15 m,obviously can not meet the need that set up communication between conservation of soil and water monitoring equipment and data center site over a long distance. Therefore, it is necessary to design a set of system which can real-time and stable and transmit data from serial data to conservation of soil and water data center over a long distance.Based on the characteristics and requirements of the data transmission of conservation of soil and water in China, the paper chooses the GPRS communication mode, and design the GPRS DTU for automatic data mining system for conservation of soil and water. The characteristics of GPRS is wide coverage, always on line, low cost and so on. It is a reasonable choice for the remote data transmission of conservation of soil and water. The GPRS DTU can turn serial data from serial device into the TCP/IP data packet and return to the data center through the GPRS network, which can infinitely increase the transmission distance of the data. According to the ISO seven layer network model, the serial port actually contains only the physical layer and data link layer, while TCP/IP include transport layer and network layer. The essence of turn serial port to Ethernet network is the serial port data as the TCP/IP application layer data transport with TCP/IP package. After GPRS DTU achieve data of soil and water conservation monitoring facilities, namely send an application to establish a connection with monitoring center through the IP address and port number of monitoring center of soil and water conservation, monitoring center receive requests and then establish a TCP connection with GPRS DTU, soil and water conservation monitoring equipment can establish communication with center of soil and water conservation through GPRS DTU.Software testing shows that the GPRS DTU for conservation of soil and water designed by the paper can achieve the desired function: the device of conservation of water and soil send data to GPRS DTU, then successfully establish communication with data center from the GPRS DTU.