Design And Implementation Of The Concentrator In Low-voltage Automatic Meter Reading System

With the development of construction conditions, people's requirements on the intelligence of electrical meter have been improved daily. Meantime, the needs from electrical power administration department on data statistics and charge management also request reform on traditional manual meter reading methods. With the development of modern electrical technology, the communication technology and computer network technology both have rapid progress, furthermore, advancement of sensor technology, and all of them have fastened the appearance of kinds of intelligent meters, which have provided complete terms for the actualization of the automatic meter reading system.The paper analyzes the development status and trends of automatic meter reading system, discusses popular data transmission methods in the meter reading system. Based on the technical standards of low-voltage electrical power meter reading system regulations declared by Guangdong Electrical Power Network Company, it proposes the meter reading system applying RS-485 bus technology.The system applies 4-layer structure. The first layer is master station system, consisting of locale application server and database server, it is responsible of storing data and providing human-machine interface; the second layer is concentrator, it is responsible of collecting as well as storing data from multi-function meters and collectors; the third layer is the collector and multi-function meters, the collector is responsible of the data exchange from concentrators to the measured points; the forth layer is the measured point, which is RS-485 meter . In this system, it applies PSTN or GPRS channel to communicate between the first layer and the second layer; while the communication between the other layers is processed through RS-485 bus.The paper primarily researches the software and hardware realization of the concentrator in the system, in order to satisfy its performance requirements, it applies W77E516 as the micro-processor of concentrator. In order to improve the anti-jamming capability and observe the standard of Electro Magnetic Compatibility of China Electric Power Research Institute, it adds anti-jamming design into the power circuit and RS-485 communication circuit; the Rtx51 Tiny version is introduced to the software to improve the concurrency and the response time of the system. In software design, it also applies watchdog timer, software trap, as well as adds summation check in the communication protocol to improve the system performance.Currently, the system has got through experimental testing and approved by EMC certification. It has been put into operation in one community in Nanhai City GuangDong Province. The operation has proven that, the meter reading system could achieve functions of reading in turn backup daily date backup monthly date and etc. The meter reading accurate could be above 99%, which has achieved the design aim.