A method, system, and computer readable article of manufacture for simulating a mechanism system controlled by a plurality of electronic control units operating at different clock rates. The simulation system includes a mechanism system simulator; a plurality of electronic control unit emulators for electronically emulating the respective plurality of electronic control units, each thereby receiving an input signal with a time and giving an output signal with a time; and a scheduler for receiving and storing the output signals with the times from the plurality of electronic control unit emulators, and for providing, in response to a change in the output signal coming from the electronic control unit emulator and having a relatively late time, the output signal with a time preceding the relatively late time to the mechanism system simulator.