The objective of this paper is to demonstrate through a practical example how an end-user should deal with functional safety while designing a safety instrumented function and implementing it in a safety instrumented system. The paper starts with explaining the problems that exist inherently in safety systems. After understanding the problems the paper takes the reader from the verbal description of a safety function through the design of the architecture, the process for the selection of safety components, and the role of reliability analysis. After reading this paper the end-users understands the practical process for implementing the design of safety instrumented systems without going into detail of the requirements of the standard.
HIMA (2006) Functional Safety A Practical Approach