Читать книгу Design for Excellence in Electronics Manufacturing - Cheryl Tulkoff - Страница 31

Fault injection testing consists of a systematic series of evaluations where hardware and/or software elements are purposefully disrupted or disabled to test and grow the robustness of the whole system to deal with abnormalities and exception faults. The goal is to verify that a device is tolerant of potential system abnormalities. The fault injection procedures focus on functional stability during abnormalities. This requires that:

1 The device will not be physically damaged by an abnormal input or output,

2 The program can recognize fault conditions and abnormal I/O and automatically compensate via alternative operating or graceful degradation operating modes to continue to remain stable and ensure safe system operation to the highest degree possible while issuing fault alerts and logging appropriate diagnostic fault codes.

3 If the abnormality or disruption is removed, the device resumes its normal operating mode.

Before performing this procedure, a mechanization review of the device's internal and external hardware and software is required to organize the device into logical functional subsystems of related input and outputs and to identify the type of fault conditions appropriate to each I/O. This data is to be used to develop a detailed fault injection test script. When function‐critical parameters come from digital values, delivered over a data link, the denial or disruption of this data should be included as items in the fault tolerance evaluation plan.