【摘要】 研究PLC网络及其通信方法 ,以建立一个网络化的远程监控系统。Omron可编程控制器 (PLC)对各换热站和给水泵房进行现场的实时监控 ;借助企业已存的电话网络作为上位监控计算机和下位PLC之间的通信介质 ,根据上位机链接命令的帧格式和Modem的AT指令 ,使用VB编写通信程序 ;并且 ,利用PLC网络的无协议通信方式进行下位机的主动拨号报警。该系统实现了换热站和泵房的无人值守。更多还原

【Abstract】 PLC network and its communication method were researched to build a network remote monitoring system. Omron Programmable Controller (PLC) monitored the heat exchanging stations and water supply stations in the field. The internal telephone network was communication medium of monitor computer and PLCs, the communication program was written by VB based on frame format and AT instruction. The PLCs can call up to alarm in non-protocol communication method. The system realizes nobody is on duty in stations.更多还原