Much as you may enjoy drooling over the Opto22 training videos, you may like to checkout an excellent comprehensive system specification guide hidden away on the Opto22 website, suitable for design engineers, systems integrators and end users alike.
1696 PAC System Specification Guide
http://www.opto22.com/site/documents/drilldown.aspx?aid=3325
After an initial introduction aimed at defining a suitable architecture for your project requirements, the guide then delves into the fine detail of defining system components, networking options, I/O specifications, installing and field wiring modules.
It really brings together a number of separately available documents and presents PAC as a system solution. I would recommend including it as standard documentation for any turnkey project.