System Engineering, Plant Engineering and Functional Models

System Engineering, as defined in the IEEE 1220 [4], promotes a model-driven process for designing complex systems. This approach comprises three main activities: the requirement analysis, the definition of the functional architecture and the allocation to the design architecture; all of these together lead to the system architecture. The result is a system specification that defines subsystems, components and interfaces. Interfaces and components are finally linked to discipline specific specifications. One of the central ideas in system engineering is the duality between the functional architecture and the design architecture [5]. These models serve as interdisciplinary description of “means” in the system design process; the functional model not only bridges the gap between operational requirements and solutions, but is also important for intent analysis and interface specifications. This paper considers system engineering methods and especially functional models in two ways: Firstly, how a functional model must be defined to describe the intent of a system as postulated in [6], and secondly, how this can be used in plant engineering.