Hi f1r4z,
There are a few versions of the generic term called a single loop and multiple loop. Do you happen to know which area this deals with (just to help me understand it a little more). You mention the term "controller", which could mean electrically speaking, or of a fluid process flow loop. Does it depend on the feedback mechanism, or can you think of some other terms which could help me answer your question?
I wish you the best.
Sincerely,
Eugene