Human–machine function allocation: a functional modelling approach

Function allocation between humans and systems is an important factor regarding safety, reliability and efficiency of industrial processes. One should allocate functions in order to maximise the operatorʹs situation understanding and ability to handle unexpected events. Functional models can be used to study function allocation in a process control environment, because they explicitly describe functions and tasks of both the plant and the operator. The Halden Reactor Project is currently engaged in such a project called function allocation methods (FAME), aimed specifically at the work in a nuclear power plant control room. This paper describes the main features of the approach, and discusses how functional modelling can be used to address the issue of how much information is necessary for the operator, and thereby give a basis for how functions should be allocated.