ABSTRACT
INTRODUCTION
Since the birth of the traffic lights, which has internal circuit control system is constantly
improved, design method also began varied, so that the traffic lights appear more intelligent.
Especially in recent years, along with the electronics and the rapid development of computer
technology, electronic circuit analysis and design method has greatly improved, electronic
design automation has become a modern electronic system indispensable tool and means, and
now PLC technology fast development, used more and more widely in industrial automation,
the position is very important and widely used in various industries. With the development of
science and technology, the programmable controller function is increasingly perfect, plus the
miniaturization, low price, high reliability, the role in modern industry more outstanding. At
the same time traffic control is to intelligent direction development, LED traffic light in
continuous luminous, rain, dust, etc of bad weather conditions, can still maintain a good
working performance, and the price is much lower. This paper mainly through the Siemens
PLC control traffic traffic lights.
KEYWORDS: Siemens S7-200; The traffic lights; PLC, ladder diagram
II