Guys,
Just register here(yes..as student...but its fine) its free, you'll receive rewards while learning!
Its about Data communication (profibus, foundation fieldbus...etc), Wiring,...etc....they have white papers, which are downloadable...you'll learn!..for short....
http://plantweb.emersonprocess.com/University/login.asp?redir=http://plantweb.emersonprocess.com/University/my_profile.asp?
Freebies
