This paper proposes a Petri Nets based modeling of discrete event systems (DESs) that includes complex temporal constraints. State evolution in DESs depends on the occurrence of discrete events over the time and consequently on temporal information between tasks. The contributions of the paper are to transform Business Process Modeling (BPM) that deal with such constraints into PNs and to propose a systematic way to include inter-tasks constraints in PN formalisms. Such model enables the analysis of incomplete temporal sequences of events, which is a key feature when dealing with diagnostic issues.