Implementing a TRAFFIC LIGHT CONTROLLER using a PLC

This book is about programming a S7-300 PLC to function as a traffic light controller. This book has been prepared for those who are already familiar with basic PLC instructions and now wish to challenge their knowledge by writing more complex industrial PLC programs: in this case, preparing a control program for a PLC to control a 4 intersection traffic light and its related 8 timing counters and 24 stop lights.
When you either write a PLC program similar to the one defined in the text, or read my solutions and understand the code, you will be able to write additional programs with the even more complexity on your own. You even can expand these programs to have more features if you wish. When you can accomplish that, it means that you definitely have the entry level skills required to succeed in a competitive PLC programming market. PLC programmers must be able to develop logical thinking skills, problem solving skills and trouble shooting skills in order to be successful in today’s market. Therefore, successfully completing this project verifies that you have taken those steps, fulfilled these requirements and achieved those goals.
The main control program on PLC controls 5 input signal and 41 outputs as following:
1- 8 x 2 digits countdown timers plus 3 traffic signals on each PCB installed on each 4 intersection (and Main Street).
2- 1 x 6 digits seven segment display PCB plus 2 sets of LEDs to display current TIME and DATE
3- 1 x 2 digits seven segment display PCB + 2 LED indicators to show the speed of passing car on main street (between two secondary intersections).
4- MAIN PCB which is feeding data to all PCBs and also connected to input signals such as 3 pushbuttons + 2 IR sensors
Ladder Logic program developed for this phase has consisted of 177 networks that most of time each network is consisting of more than 5 to 10 application of simple instructions such as AND, OR ,Timers, counters... etc. So to develop a PLC control program to control all these numerical displays and stop signal lights in harmony is not easy! And when you do something like this own your own, that is the time that you can tell your future employer "YES I CAN DO IT" with lot's of confidence.
And since application of HMI devices nowadays in processes is de facto standard, I have developed two more program software to allow system operator to monitor all activities related to this automated Traffic lights system project on a HMI device and on a PC's monitor as well.
PLC Technicians involved in design or repair of industrial control equipment generally work in clean, well-lighted, air-conditioned surroundings such as in offices or testing and repair facilities. Prior to all of this happening, you must show your future employer that you are the best candidate for the job rather than someone just out of school. Having gone through this text and rewriting a PLC control program similar to the one developed in the text enables you to perform more complicated PLC programming skills. The main control PLC program will be provided to you if you email me proof of your purchase of Kindle version of the text from Amazon as you are directed in the 'Notice to the reader' section of the text.
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