Process control distributed control systems are becoming more computer/network reliant. Therefore, engineers are required to not only know how to tune loops, create drawings (Loop sheets, P&IDs), and program PLCs, but also how to carry out various IT related tasks. IT tasks normally include- patching computers, managing, accounts, group policies, network switch management, network documentation and much more. In many plants there is a variety of PLCs or DCS.
It is not uncommon for a plant to be using process control technology with an age range of over 40 years.
This site will in no way answer all of your questions. Its a place for people to share ideas, code and practices.