Many mission-critical systems today have stringent timing requirements. Especially for cyber-physical systems that directly interact with real-world entities, violating correct timing may cause accidents, damage, or endanger life, property, or the environment. To ensure the timely execution of time-sensitive software, a suitable system architecture is essential. This paper proposes a novel conceptual system architecture based on well-established technologies, including transition systems, process algebras, Petri Nets, and time-triggered communications. This architecture for time-sensitive software execution is described as a conceptual model backed by an extensive list of references and opens up several additional research topics. This paper focuses on the conceptual level and defers implementation issues to further research and subsequent publications.