This course manuscript is an introduction to supervision and dependability of mechatronic systems. It is intended for master students. Indeed, for the study of mechatronic systems, we can use external functional analysis methods that illustrate the relationships between a system and its external environment. We thus present the Safe-SADT method and the GRAFCET which allow the representation of the mechatronic system. A general model of analysis of the safety of operation and supervision of operation is proposed and validated by a case study of a paint mixer.