history of plc s7

hello !
i want to know PLC's date of invention , ameliorations between each categories...

can anyone help me !

Hello,

For the whole SIMATIC,you can try Milestones in automation:

http://www.amazon.com/Milestones-Automation-Arnold-Zankl/dp/3895782599

unknown user

This story of the concept of Totally Integrated Automation extends from the beginning of Simatic, the world's most successful programmable controller family, to modern-day technology, with the documentation backed by specific solution examples and a brief look into the future.

Easy to read and creatively designed, the book offers technicians, engineers and managers a profound look into the development history and possibilities for the use of a technology that has left its mark like no other on industrial processes and a huge range of technical systems.

I hope this helps,

Hamid Hosseini

the book seems important but i can't buy it 

there's no free thing to download ?

mamadou13

the book seems important but i can't buy it 

there's no free thing to download ?

 This is an official publication on the topic.It is published by the same company, perhaps you can find other materials from independent sources/individuals but for sure they are not accurate for your work.

Also you have option of checking important keywords in search engines and Wikipedia to get some general/rough ideas.