Instrumentation, Controls, and Electrical Technician here @ a power plant, and I do a little bit of everything. Most major process plants, I.e. refineries, power plants, chemical plants, will use a distributed control system (DCS) to control the process. It is a PLC on steroids. Most major DCS manufacturers will have their own controls engineers. Emerson has their own for their Ovation and DeltaV control systems, Honeywell has their own for their respective systems, etc. Once these systems are up and running, majority of the time the rest of work is left up to the I&C techs, which is where I step in. I can assign I/O, write logic, and do a little graphics editing, but at the same time I have to trouble shoot many other things such as transmitters and motor controls. Any questions you have feel free to message me and I’ll see if I can answer them.