摘要:本文介绍了S7-200 小型PLC的工作原理及在彩灯控制中的应用，设计了一种基于PLC的循环彩灯的亮灭、闪烁及流动方向的PLC控制程序，经模拟仿真，达到预期的控制要求。

关键字：PLC；循环彩灯；梯形图程序

Abstract:This paper introduces the working principle of S7-200 PLC and its application in lantern’s controlling , a corresponding program had been designed based on PLC to control the lanterns’ turning on and turning off, the flash and the flow direction had also been accomplished, the desired control requirements had achieved successfully after simulation.

Key words: PLC; lanterns; ladder diagram program

　　采用PLC来控制彩灯循环，提高了系统运行的可靠性，其梯形图程序简单直观，利用PLC的定时功能、计数功能、步进功能，可灵活地编写、增减和修改程序。PLC具有很强的自诊断功能。迅速方便的检查判断出故障，缩减了检修时间，不需要很多配套的外围设备和大量复杂的接线。大大缩减了设计和施工周期。