You might consider contacting the local AB distributor. Our local contact has demo units for all the PLC lines. MicroLogix, SLC500, PLC5, and Control Logix 5000. They also put on training courses, maybe they would let you sneak in on a student pass. We just recently purchased a complete SLC504 system on EBAY for a very cheap price. AB also sells a starter kit which included a SLC500 with Digital inputs and outputs.
