This paper presents a unified approach to the modelling and simulation of parallel real-time systems using event-driven nets. A new paradigm of the modelling and simulation based on the utilization of knowledge-based systems is introduced. The simulation process is analyzed and the steps in simulation model design and evaluation, where knowledge-based systems can be successfully used, are indicated. The problem of required knowledge representation is also elaborated. To highlight the facilities of the proposed approach, a model of a small production cell is studied.