Comment by schlauerfox

Microcontrollers and PLC are historically different fields that have some overlap as the fields converge somewhat. PLC come from relay logic and so learning Ladder Logic and playing with a cheaper Automation Direct PLC might be good if you're looking to do control systems like industrial machines and those robotics. RPi series micros are good to learn embedded electronics, servo controls and Realtime OS. Computer Engineering and Control System Engineering are treated differently even in the California State Engineering License Exams, so they tend to be different paths but the skills have some overlap. My degree was in computer engineering and didn't cover any PLC, but I contract and PLC comes up a lot in one-off things that need to be reliable.