We provide models of safe controllers both for potentially blocking and non blocking controlled systems. To obtain algorithms for these problems, we make the use of abstract interpretation techniques which provide over-approximations of the transitions set to be disabled. To our knowledge, with the hypotheses taken, the improved version of our algorithm provides a better solution than what was previously proposed in the literature. Our tool SMACS allowed us to make an empirical validation of our methods to show their feasibility and usability.