Plc system is composed of manage computer , master device and i / o modules . programme software runs in windows - based manage computer system and it has many functions , such as hardware configuration , editing with ladder diagram , simulated running of control programs , communications with master device , and so on . this software is a necessary tool of editing control programs , debugging control programs and real monitoring for plc system designer Plc系统由上位机、主控制器和i / o模块等组成,编程软件运行于上位机系统windows2000平台,具有系统硬件配置、梯形图程序编辑、控制程序仿真运行以及与主控制器通信等功能,是plc系统设计人员编制、编辑、调试plc控制程序以及实时监测现场运行状况的必备工具。