Functional safety, as defined basically in IEC 61508 and in ISO 26262 for automotive systems, clearly describes actions to take and methods to use to develop a safe system. "Safe" actually can include the presence of faults and bugs. This implies the detection of malfunctions and taking proper actions before any harm is done. So it's all about timing: Before a hazard occurs, the system has to put itself, in time, into a safe state involving automated mechanisms and the driver.
Precisely defining the safety requirements, including time intervals the system has to respond to faults, is mandatory. And it is crucial for project success to evaluate early in the development process if these requirements are met.
This article introduces the reader to the timing aspects of functional safety. A model-based methodology based on a matured tool suite will be described to help design embedded systems having the correct dynamic behavior and robustness to changes and unexpected system states.
For the complete article, including five steps to functional safety (with design of a seat position memory system as an example), click here, courtesy of Automotive Designline Europe.