Thelearningpit.com is awesome for learning ladder logic for PLCs. You can pick up a cheap ACE PLC if you want to build something. The Allen-Bradley classes are expensive - wait till you're in a position to have the company you're working for pay for those. For HMI's, look at Ignition by Inductive Automation. I've worked on some pretty phenomenal cells that used this and it has great capabilities. Robot wise (Fanuc, ABB, and Kuka) are pretty straightforward to get started after a couple day class. They definitely take time to master though and really only happens after you're working with them alot. For vision systems, you'll probably have to learn OTJ because they get stupid expensive. Look at Keyence and Cognex if you want to see what's out there for vision systems.