Discrete event modelling and simulation in Omola

The author describes how discrete event and combined discrete event and continuous-time models are represented in Omola, an object-oriented, equation-based language for representing structured dynamic models. Discrete event behavior is represented by events with state conditions. Events can also be scheduled. The main formalism for representing discrete behavior is difference equations, which are executed in response to events. The formalism also contains an event-propagation mechanism that makes it possible synchronize-events defined in different submodels. The concepts are illustrated by an example of a chemical process with a sampled and sequential control system