Editing Proportional–integral–derivative controller (section)

===Applications===
In theory, a controller can be used to control any process that has a measurable output (PV), a known ideal value for that output (SP), and an input to the process (MV) that will affect the relevant PV. Controllers are used in industry to regulate [[temperature]], [[pressure]], [[force]], [[feed rate]],<ref name="Kebriaei et al. 2013">{{cite journal|last=Kebriaei|first=Reza|author2=Frischkorn, Jan |author3=Reese, Stefanie |author4=Husmann, Tobias |author5=Meier, Horst |author6=Moll, Heiko |author7= Theisen, Werner |title=Numerical modelling of powder metallurgical coatings on ring-shaped parts integrated with ring rolling|journal=Material Processing Technology|volume=213|issue=1|pages=2015–2032|doi=10.1016/j.jmatprotec.2013.05.023|year=2013}}</ref> [[Volumetric flow rate|flow rate]], chemical composition (component [[concentration]]s), [[weight]], [[position (vector)|position]], [[speed]], and practically every other variable for which a measurement exists.