System level error models for safety critical control systems

The problem of verifying the functional integrity of control system in a range of operating conditions is a key issue in the design and development of safety critical systems. The integrity can be compromised by a variety of source, these include hardware faults, design errors, and electromagnetic disturbances. In the past, the prime method for demonstrating the functional integrity of a control system in the presence of faults has been fault injection. Most of fault injection methodologies are fraught with a host of limitations with respect to modeling the effects of EMI upsets. This paper presents a system level error model for a generic control computing platform. Errors are modeled from a high level system perspective without consideration for the actual physical failures and the implementation details. This error model serves to classify error patterns which may occur in the information flow during EMI exposure