摘 要:目前，我国一部分城乡居民用户依旧采用的是人工读表的计量方式。人工读表是比较落后的，因为它需要很多的人力和物力，同时，人工读表要花费很长的时间，容易出错，准确率不高。这也就直接导致了数据处理的滞后，不能及时发现、解决问题。人工读表阻碍了电力行业向智能电网发展，要突破这一瓶颈就需要采用较为先进的读表系统。
本文主要介绍了一种基于单片机的读表系统研究。本次所研究的读表系统功能设计有实时时钟显示，电能表数据的显示。其中，实时时钟显示功能的实现是对DS1302芯片进行编程，在LCD1602上显示时间。本次研究最重要的部分就是AT89S52单片机与单相电子式多费率电能表DDSF211之间的RS485通信。它们之间的通信是建立在DL/T645-1997多功能电能表通信协议上的。AT89S52单片机为主站，通过一个RS232/RS485转换器与电能表连接，电能表为从站。主站发出读数据命令，从站正常应答，主站接收数据然后将其显示在LCD1602上。
关键词：单片机 电能表 RS485通信
ABSTRACT:Currently, part of the urban and rural residents in China still uses manual meter reading method. This way is slow, not only wasted a lot of manpower, material and caused large time span of data collection, low accuracy, human error, but also led directly to a data processing lag, so the problems can not be found in time to solve. Manual meter reading has hindered the development of the power industry to the smart grid, to break through this bottleneck needs to adopt more advanced meter reading system.
This paper describes the study of a microcontroller-based meter reading system. The meter reading system designed has some functions, such as the display of real time clock and the power meter data. The programming of a DS1302 chip achieves real-time clock display functions, LCD1602 will display time finally. In this study, the most important part is the RS485 communication of AT89S52 microcontroller and single-phase electronic multi-rate the energy meter DDSF211. Their communication satisfies DL/T645-1997 multifunction energy meter communication protocol. As a master, The AT89S52 microcontroller connected with energy meter via an RS232/RS485 converter, energy meter is the station. The Master sends a read data command to the station, the station will response normally. The main station receives the data and then displays them on the LCD1602.
Keywords: MCU；energy meter；RS485 communication
