【摘要】 提出对传统报警系统改进的办法:用PC机作为主机,用AT89S52单片机作为从机,采用RS485总线型网络系统。该系统的特点:(1)不仅主机可以呼叫从机,从机在必要时可以主动呼叫主机,避免了从机只能等待主机轮询访问的弊端,从而提高了系统实时性和可靠性;(2)由于报警的时间毕竟很少,因此没有必要让主机无休止地轮询访问各个从机。而且轮询的方式效率很低,主机未必能从多台从机中立刻定位到报警的那台从机。更多还原

【Abstract】 This paper puts forward a way to better the traditional warning system.This system is a net system through RS485 bus,PC used as the master computer,single-chip microcomputer AT89S52 used as the slave computer.There are two characteristics in this paper.One is that master computer can call slave computer,in addition,slave computers also can call the master computer in order to avoid the limitation that slave computer only wait for the master computer to call,so as to improve the real time and the reliability of the system.The other is that the master computer unnecessarily call all slave computers continually one by one.The way that master computer call all slave computers one by one is inefficient,also,the master computer can not find the slave computer that gives a alarm accurately.更多还原