关键词：自动抄表系统，ZigBee，采集终端，MSP430F149，CC2430
Abstract
On the one hand, because of the rapid development of Chinese power industry, power supply enterprises and users are urgently needed in modern management method, on the other hand, the computer technology and communication technology continues to mature and progress. In the two aspects of technology and management to the urgent needs of reform, the various automatic meter reading technology gradually developed. Currently popular automatic meter reading methods have IC card prepayment way, power line carrie way, GPRS cellular network way and so on. Each way has certain shortcoming, but does not have the wide range promotion.
This paper presents a scheme for wireless automatic meter reading system design by ZigBee wireless network and GPRS cellular networks, in order to copy user’s data safely with lowest cost. ZigBee is an emerging at close range, low power, low speed, low-cost wireless network technology, suitable for not amount of data communication, small range but many points, safe and reliable data transger but low rate, and low cost and power consumption. GPRS is a new network designed for high-speed data communication based on GSM network in existing. User data packet to send and receive by GPRS network, with real-time online, billing according to the flow, fast sign, high-speed transmission, switching, etc. It can reduce service costs and improve service quality quickly.
The terminal is the key hardware of the automatic meter reading system, which is the data processing, receiving and sending embedded system based on MSP430F149 microprocessor. It communicates with the collector through the chip of CC2430, and communicates with the energy meter through the RS-485 bus. MSP430F149 microprocessor is a 16-bit ultra-low power RISC structure of mixed-signal processors produced by Texas Instruments, which has rich components on-chip and ultra-low power consumption.The chip of CC2430 is a 2.4GHz RF System-on-Chip in line with the ZigBee specification produced by Chipcon, which needs only few peripheral parts to receive and send data.
This paper discusses the design process of the terminal, which is composed by central processor, calendar clocking circuit, memory circuits, RS-485 interface circuit and wireless communication circuit, etc. Through the analysis of the terminal’s function, we select right device for the various parts of the circuit and make the terminal’s schematic and PCB layout. The terminal’s software mainly introduces the protocol and process communicating with energy meter and CC2430. Because MSP430F149 does not have IIC bus, this paper presents a software simulating IIC bus program, for communicating with memory chip and calendar chip.
This paper also simply introduces the design process of the collector and management software, and give some ways to improve the automatic meter reading system.
