Functional Classification

Functional classification is suitable for fault-finding in systems whose normal and defective structures can be described by materials and components with states, and whose normal and abnormal behavior can be derived from the description of the behavior of the components. A functional model describes how the input materials are converted into the output materials in a system. Examples are the gasoline engine, which converts air and gasoline into motive power and exhaust gases (Fig. 18.1), the blood circulation for supplying oxygen to the body (Fig. 18.2) and a circuit for addition and multiplication, which has numbers as input and output (Fig. 18.3).