Establishing timing requirements for control loops in real-time systems

Advances in scheduling theory have given designers of control systems greater flexibility over their choice of timing requirements. This could lead to systems becoming more responsive and more maintainable. However, experience has shown that engineers find it difficult to exploit these advantages due to the difficulty in determining the ‘real’ timing requirements of systems and therefore the techniques have delivered less benefit than expected. Part of the reason for this is that the models used by engineers when developing systems do not allow for emergent properties such as timing. The paper presents an approach and framework for addressing the problem of identifying an appropriate and valid set of timing requirements in order that the best use can be made of the advances in scheduling theory by the use of modelling techniques that allow for emergent properties such as timing behaviour.