What does Level 0 in the ISA 62443 Reference Model define?

Level 0 in the ISA 62443 Reference Model specifically defines the actual physical processes that are being controlled within an industrial automation and control system (IACS). This level focuses on the real-world activities and mechanical systems that produce tangible outcomes in manufacturing or process environments.

Understanding this is essential because Level 0 serves as the foundation for all other levels within the ISA 62443 model, which build upon the physical operations to address higher-level concerns such as cybersecurity controls, management policies, and system assessments. By characterizing the physical processes at Level 0, organizations can gain insight into potential risks and vulnerabilities that may originate from the operational aspects of their systems, which is fundamental for implementing effective cybersecurity measures throughout the entire IACS environment.

The focus on physical processes at this level emphasizes the importance of understanding the underlying operations before layering on cybersecurity considerations.