Model-based development of CPS is based on the capability of early verification of system properties on a model of the controls and the controlled physical system, and the capability of producing automatically an implementation of the model. Unfortunately, in the development of complex distributed or highly concurrent systems, the scheduling and communication delays may significantly affect the behavior of the controls. We present a framework for adding the model of schedulers, tasks and messages to Simulink models and to verify by simulation the impact of scheduling and execution times delays on the performance of the controls. Our toolset is highly modular and extensible and allows application to existing models with limited changes and even the automatic synthesis of the task and message model from an external specification.