Human computer interaction in complex process control: developing structured mental models that allow operators to perform effectively

One of the distinguishing features of humans is the ability to modify the environment in which they live, through the creation of artifacts or tools. The physical realisation of this is evident in process plants in the profusion of electric drives, pumps, actuators and instrumentation which reduces the physical effort required of humans, whilst extending the range of tasks of which they are capable. The nature and purpose of cognitive artifacts are more subtle, but include any item or device that aids the human cognitive process, and as such can range from a pencil and paper, a check list or form, through to a computerised control system with human computer interaction (HCI) facilities to enable people to control complex processes. Those cognitive artifacts have to be developed and engineered to maximise their utility to the human operator and to optimise human performance. The objectives of the paper are to outline the underlying principals of HCI engineering, and to provide guidance on the methods and tools available for evaluating and modelling HCI and the associated cognitive structures and processes upon which human performance depends. The paper concludes with heuristic methods to utilise those models to enhance human performance, and maximise the system performance by using an engineering approach. The paper is presented in the context of a supervisory control and data acquisition (SCADA) system, but the underlying principles are applicable to other forms of human and system interaction.