This article describes the general theory of determining the time response characteristics of different component parts of modern automated control systems (ACS) and the method of calculating constraints on the time response characteristics of information security systems (ISS) used in ACS as real-time systems. For an arbitrary manufacturing process (both under development and existing) ACS, this method enables to perform calculations and set requirements, relating to timing constraints of processing information signals of the ACS, for various elements, including ISS.