Control systems Engineering
Those are very practical hands-on type things. If you already know how to program in a few radically different computer languages (especially object-oriented for the HMI and an HDL (VHDL or Verilog) and perhaps assembly language of some kind) you'll pick it up very quickly. 

PLCs often use ladder-logic programming, which is sort of an HDL, but it's implemented with sequential processing (which has implications for the way the programs behave).

I would think that for less than the cost of tuition for a University-level course you could pick up a commercial PLC, an HMI and the requisite software and run through a few simple projects. For example you could automate watering and nutrient dispensing of your garden, fish out that old bread maker from the closet and re-implement the logic in it, automate lights and animatronics for Halloween or Christmas etc.