摘要:剩余电流就是低压配电线路中各相(含中性线)电流矢量和不为零的电流。当今，单片机的技术已经非常成熟了，它集成度高、功能强、存储量大、速度快、抗干扰性强和指令丰富等的优点，使它的应用遍及各个领域。本文设计的系统就是单片机应用于火灾监控的一个例子。本系统是一种高精度、测控速度快的应用性比较强的剩余电流式火灾智能监控系统。

　　　本系统以AT89S52单片机为控制核心，通过硬件电路的制作和软件程序的编制，实现一个火灾监控系统。本系统主要包括信号采集模块、温度采集调理模块、A/D转换模块、外部显示模块、时钟模块、报警模块和存储模块。在前向通道一路通过热敏电阻（PT100）对温度进行采集，另一路用剩余电流互感器测电流，转化成直流电压，这两路采集到的数据通过A/D转换模块转换成数字信号，通过单片机处理，显示屏显示电流值和温度值，当电流超过设定值时蜂鸣器将报警。

　　　本系统的软件采用C语言进行模块化编程。本系统响应速度比较迅捷，还具有功耗低，可靠性好的特点。所以本系统具有很强的应用性，适合建筑电气火灾监控。

关键词：单片机；剩余电流；A/D转换；热敏电阻（PT100）

Abstract:Residual current of each phase in the low-voltage distribution lines (including neutral) current vector sum of the current is not zero. Nowadays, computer technology is already very mature, of its high integration, strong function, large storage capacity, fast speed, strong anti-interference and rich in instruction and other advantages, it is applied widely in various fields. The system is designed in single chip microcomputer application in fire monitoring as an example. This system is a kind of high precision, fast speed control in the application of relatively strong residual current fire monitoring system.

　　　The design uses the AT89S52 single-chip microcomputer as the control core, through the production of the hardware circuits and software programming, the realization of a fire control system. The system includes a signal acquisition module, the temperature acquisition conditioning module, A / D conversion module, an external display module, clock module, the alarm module and storage module.In the forward channel through a thermistor ( PT100) on the temperature of the collection. Another way, the residual current mutual inductor current to be measured, is converted into DC voltage. The two road collected data into a digital signal converted by the A/D converter module, single-chip processing, the display shows the current value and temperature value, the buzzer will alarm when the current exceeds the set value.

　　　The system software uses C language modular programming. The response speed of the system is relatively quick, but also has the advantages of low power consumption, good reliability. So this system has very strong application, suitable for building electric fire monitor.

Key words：single-chip microcomputer, residual current, A/D convert, thermistor(PT100)