Tech Briefs

The Extended Testability Analysis (ETA) Tool is a software application that supports fault management (FM) by performing testability analyses on the fault propagation model of a given system. Fault management includes the prevention of faults through robust design margins and quality assurance methods, or the mitigation of system failures. Fault management requires an understanding of the system design and operation, potential failure mechanisms within the system, and the propagation of those potential failures through the system.

The purpose of the ETA Tool software is to process the testability analysis results from a commercial software program called TEAMS Designer in order to provide a detailed set of diagnostic assessment reports. The ETA Tool is a command- line process with several user-selectable report output options. The ETA Tool also extends the COTS testability analysis and enables variation studies with sensor sensitivity impacts on system diagnostics and component isolation using a single testability output. The ETA Tool can also provide extended analyses from a single set of testability output files.

The following analysis reports are available to the user: (1) the Detectability Report provides a breakdown of how each tested failure mode was detected, (2) the Test Utilization Report identifies all the failure modes that each test detects, (3) the Failure Mode Isolation Report demonstrates the system’s ability to discriminate between failure modes, (4) the Component Isolation Report demonstrates the system’s ability to discriminate between failure modes relative to the components containing the failure modes, (5) the Sensor Sensitivity Analysis Report shows the diagnostic impact due to loss of sensor information, and (6) the Effect Mapping Report identifies failure modes that result in specified system-level effects.

The ETA Tool provides iterative assessment analyses for conducting sensor sensitivity studies, as well as a command-line option that allows the user to specify the component isolation level. The tool accesses system design information from the diagnostic model to generate detailed diagnostic assessment reports, and command- line processing enables potential batch mode processing of TEAMS Designer models. The tool also features user-specified report options that include internal source calls and access to system environmental variables – features that enable automation of the previously laborintensive manipulation of input files. The software generates detailed, readable diagnostic assessment reports that can be viewed in an Internet browser or imported into either Microsoft Word or Excel programs. Procedural C code provides fast, consistent, and efficient processing of the diagnostic model information.

This work was done by Kevin Melcher of Glenn Research Center, and William A. Maul and Christopher Fulton of QinetiQ North America.

Inquiries concerning rights for the commercial use of this invention should be addressed to NASA Glenn Research Center, Innovative Partnerships Office, Attn: Steven Fedor, Mail Stop 4–8, 21000 Brookpark Road, Cleveland, Ohio 44135.

This Brief includes a Technical Support Package (TSP).

Extended Testability Analysis Tool (reference LEW-18795-1) is currently available for download from the TSP library.

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