This paper highlights the benefits of formal methods to improve the quality and efficiency of process control engineering, according to two key aspects: the definition of a formal engineering framework which allows the re-usability of specifications at a high level of abstraction and the ability to prove some properties of the process control models. An introductory example presents a formal structuring framework using the B method and highlights the main temporal requirements for modelling and proving control systems in this framework. Taking into account these temporal modalities requires an extension of the B model. An attempt using \textsc{TLA} is suggested and discussed.