Design Of Automatic Meter Reading System Based On Power Line Carrier Communication

The technology of low-voltage power line carrier communication, by using the existing low-voltage as transmission channels,can achieve the data transmission and information exchange. It is a new means of communication which has significant advantages, such as no wiring, covering a wide range and convenient connected. However, in practical application process, the signal transmission effect is not very good in the low-voltage power line because of the strong noise jamming, signal attenuation and time-variation of communication. These hinder the development and popularization of the low-voltage power line carrier communication.Through the analysis of channel characteristics of the low-voltage power line, an automatic meter reading system is developed based on the low-voltage power line carrier communication. The system is consisted of power meters, data acquisition, concentrator, master station. The PSTN technology is applied in the upstream channel, and the power line carrier communication technology is adopted in the downstream channel. The subjects of accomplished include the following aspects:1. The carrier communication modules is developed based on ST7538, including the circuit and software designing, the hardware anti-jamming technology (the filter circuit and protect circuit, etc.), and the software anti-jamming technology (setting software trap, filtering software, instruction redundancy, etc.) implementing. The module has been proved to be powerful anti-jamming, stable and reliable of communication.2. The circuit and its related function modules in the data acquisition, such as pulse acquisition module, relay module, memory module, clock module and etc. are completed in the project. The circuit of telephone modem interface module, serial port expansion module and its related functions module in the concentrator are implemented. The communication protocols between the data acquisition and concentrator, the concentrator and the master station are formulated.3. According to the network transmission structure of the low voltage power line carrier communication reading system, the dynamic routing algorithm is proposed. The establishment and maintenance of the routing table can improve the effective in maintaining power line communication transmission path, and enhance the reliability of remote meter reading data transmission. These can ensure the properly of the system running.The project of the meter reading system has been debugged successful in lab, and applied to a district, and the system design goal has been achieved. The automatic meter reading system has the merits of economical and practical, anti-interference ability, reliable, and high precision.