Steve,

I don't know what the budget for this project is, but I would recommend using a PLC with off the shelf motor drives. Use an Allen-Bradley Micrologix, SLC-50X, etc. This project may seem too simple for PLC control, but PLC's are the most bulletproof control platform on the planet. Then the controller can be connected to the motor drive using Ethernet, ControlNet, DeviceNet, FieldBus, etc. In the US, PLC's are the standard for controlling processes where human safety is important. Why reinvent the wheel? I know, because it's more fun. This way, your time is spent in software development. RLL is a great control language.

My rule is:

OEM = Microcontroller
One timer --> 10's or 100's = PLC and/or PC

Cory Spackman