TEMPORAL ANALYSIS OF DATA-FLOW CONTROL-SYSTEMS

Due to their distributed/parallel and data-driven nature, control syst ems can easily be modeled according to a data flow approach. Control s ystems are very often real-time systems; therefore, a formalism able t o capture timing is required. In this paper we introduce a data flow m odel that includes time and priority for specifying real-time control systems and we give its formal semantics. The control system is specif ied by a data flow network which, beside the controller, may include t he model of the plant at some abstraction level. Time is associated to any computational activity and time accounting is made directly in th e model and not as a separate issue. Priorities allow to deal with eve nts, as alarm signals, which cannot be delayed. A general framework fo r the indirect evaluation of the model is introduced, and a data flow network to timed Petri net transformation is defined allowing the util ization of the automatic tools of Petri nets for analyzing the tempora l properties of the data how network. The approach is illustrated by a n example in which, after the application of the transformation, selec ted performance measures are computed. (C) 1998 Elsevier Science Ltd. All rights reserved.