Hi Hoai Nam Tang,

I am really sorry for my late response here. Currently for industry I think having a good working knowledge of PID control is very important.

In my opinion getting theory is another thing and trying to implement these algorithms in real world is a whole another challenge, so try to work on a project where you implement these algorithms on real hardware. This will give you an insight into controls like never before and you will be able to ace any interview in the future.

Hope this helps.