In the context of Model Driven Engineering, models are the primary artifacts of the system development cycle. In order to manage the complexity of systems, models are decomposed into models of simpler subsystems. A major difficulty is to handle the heterogeneity of the different models of computation used for modeling the subsystems. Through the example of a power window system, this article presents an approach to the specification of the semantic adaptation of data, time and control between models of computation. The approach is supported by ModHel'X, a heterogeneous modeling and simulation environment. The example is simple enough to be completely described in the article, but rich enough to illustrate the matters of (a) defining models of computation, and (b) specifying the semantic adaptation between models of computation.