Design of Traffic Lights Controlling System Based on PLC and Configuration Technology

A kind of traffic lights controlling system by using PLC was designed, and the automatic control of the traffic lights was performed by software. In the system, the original relay wiring was replaced by the program, and the hardware and software resources of PLC were used reasonably. The normally running and emergency transport were introduced in detail, and that the emergencies from the east-west and from the south-north can interlock. The traffic lights signal system was displayed with two seven-segment digital tubes in countdown order; meanwhile the wiring of hardware and PLC ladder diagram was discussed in details. The remote monitoring system of traffic lights at the crossroads was designed with configuration software MCGS, which monitored traffic lights in real-time and improved the reliability greatly. At the same time, we can change the states of the traffic lights by the configuration picture.