Modeling a continuous system always faces with complexities and uncertainties. Therefore, attempting to use Petri Nets approach causes a sensible complexity reduction. In this article a heuristic method entitled speed control arcs is introduced to accompany Petri Nets in continuous system modeling. To do so, first by employing speed control arcs concept in Petri Nets, the corresponding model of continuous systems is obtained. Speed control arcs are a newly introduced concept in Petri Nets method which can control the firing speeds associated with transitions. Using these concepts, differential equations can be modeled. Then, for the obtained Petri Nets model, a PID controller is designed based on speed control arcs. Simulation results are provided to illustrate the effectiveness of the proposed method. It was observed that this method runs faster than the classic approach. The authors believe that the devised scheme can facilitate the design procedure for multi-mode controllers in industrial systems.