Testability

The testability tab of the FMECA Manager allows you to make use of the FMECA product tree structure and data, and provides a means to enter fault detection/isolation and false alarm rate information for failure modes. You can easily build the isolation list from a dropdown list of items that are applicable for each ambiguity group, and order them by failure rate or other criteria. Normally, this information is entered only at the lowest level of the product tree structure, and all intermediate values are calculated by ASENT.

ASENT’s powerful Library Editor allows you to define detection/ isolation groups (IBIT, PBIT, visual, test points, etc.) and populate the test code library. Test codes can be organized into categories (hardware, software, etc.) for easy reference, and default false alarm rates can be specified for each test code. ASENT will quickly calculate fault detection/ fault isolation percentages, and false alarm rates for each group. You can easily see how test coverage stacks up in comparison to your design or customer requirements.

The above screen shows where Test Points J1-62/J1-20 on the SRA are used to detect a LOSS OF 5 VOLTS A AND B failure, isolating the failure cause to components C0003 and F0001.
 

This screen shows how you might set up detection/isolation groups. Here, various flavors of BIT are listed along with a VISUAL group and test points for both WRAs and SRAs.

Also you can define Isolation Group Sizes. For example, group 6 represents test points on the SRA. This example shows groups that isolate to 4 or fewer components, 8 or fewer components, or 10 or fewer components. Below shows a Test Coverage Summary report. You can turn on or off a wide variety of options when generating testability reports, so that only information that interests you is output.

ASENT’s testability completeness checker will identify any missing or incomplete data. This saves time and effort, and provides extra assurance that the results are accurate and complete. You will appreciate the wide range of available reports. Whether you need a quick summary of test coverage for a certain group, or a detailed report that slices the data a certain way, ASENT has it covered. ASENT allows you to copy testability data from one failure mode to one or more failure modes with only a few mouse clicks. This can save considerable time when performing analysis on areas of your design with similar detection/isolation criteria. Alternate tests can be defined in order to perform trade studies.
 

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ASENT’s Testability Analysis capability is an integral part of its R&M tool suite. The product tree structure and failure rates are readily available, along with FMEA/FMECA data. Whether it is your Testability Group or your Maintainability Group that is interested in analyzing your design’s test coverage, they will enjoy the benefits of ASENT’s integrated solution. Its client/server architecture supplies additional benefits by providing concurrent access to project data for a wide range of engineering disciplines. This reduces cycle time by allowing many of the analyses to be performed in parallel.