What is the main function of a safety instrumented system (SIS)?

The main function of a safety instrumented system (SIS) is to ensure safety measures and prevent accidents. An SIS is designed specifically to monitor and control processes where there is a potential for hazardous events, acting as a critical layer of protection to manage risks associated with industrial operations. It consists of sensors, logic solvers, and actuators that work together to automatically bring the system to a safe state in the event of a fault or abnormal condition.

This capability is vital in industries such as oil and gas, chemical processing, and manufacturing, where the consequences of failure can lead to catastrophic outcomes, including injuries or environmental harm. While improving efficiency, optimizing signal processing speed, or extending equipment lifespan are important elements in control systems and automation, they do not define the primary objective of an SIS, which focuses specifically on the protection of personnel, the environment, and assets from hazards.