| With the rapid rising of student's number, many universities have built student's multi-layer apartment. Under the circumstances, guaranteeing the security of student's daily electricity, preventing the abnormal power consuming, and to realize the scientific and intelligent electric energy management is necessary. In order to meet these demands, a kind of cheap pre-paid power-measuring system with novel structure is designed, which can realize centralized measuring, centralized management and real-time control.The system is composed of the parts on the host computer and the slave microprocessor. The host computer can process all the uploaded data which could be showed and analyzed, the slave microprocessor is used to collect data, measure energy and monitor load, and the IC card is the carrier of information between the host and slave computer. The most important part is measuring and controlling in this design. So, power measuring, power controlling, data transmitting of multi-user is focused on this paper. The structure charts, program flow-charts and circuits are given.On the premise of guaranteeing accuracy of measuring, in order to raise the whole system's security, we adopted the design methods of measuring alone, multi-zone supervision, top controlling, bus communication,and the measuring system was divided into three layers, that is main board (MB) .secondary board (SB) and user board (UB) ,carrying on the communication through the data bus between each layer. According to the real-time requirement and the CPU selection,we confirmed RS-485 bus communication between main board and secondary board, SPI bus communication between secondary board and user board ,and has defined the corresponding communication agreement in the software. Following the structure of system, we finished designing hardware and software, and finally, through debugging respectively and uniting and adjusting passing systematically, can realize the design objective, meet user's request. |
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