Simulation of LET Models in Simulink and Ptolemy

This paper describes two different approaches of simulating embedded control software whose real-time requirements are explicitly specified by means of the Logical Execution Time (LET) abstraction introduced in the Giotto project. As simulation environments we chose the black-box MATLAB/Simulink product and the open-source project Ptolemy II. The paper first sketches the modeling of LET-based components with the Timing Definition Language (TDL). As the LET abstraction allows the platform-independent modeling of the timing behavior of embedded software, a correct simulation of TDL components is equivalent to the behavior on a specific platform. We integrated TDL with both MATLAB/Simulink and Ptolemy and highlight the differences and similarities of the particular TDL simulation.