Detect Critical Malfunctions

Feature Description

What is the purpose of this algorithm?

The Detect Critical Malfunctions fault detection algorithm attempts to provide the most direct path to a critical failure. The first eight Test Weightings are set up so that the tests that are most likely to detect the most severe failures (that is, the failures with the highest end item effect severity) are selected first. The second eight Test Weightings are identical to those defined for the algorithm Detect Malfunctions with Fewest Tests, as are the Test Candidate Groupings. This means that, if two tests cover equally critical failures, the test that is most likely to fail is selected first. Also, if failure effects are not defined for the given design (or if all failures are equally severe), this algorithm will produce the same detection order as the algorithm Detection Malfunctions with Fewest Tests.

Note: With sixteen test weightings, this algorithm is one of the most computationally complex of eXpress's predefined diagnostic algorithms. It is recommended that the Analyst review these weighting definitions and remove any that are not applicable to the current design (if, for example, the design were only to test for failure modes, the eight weighting definitions based on a functional domain could be deleted). This will help speed up diagnostic processing for larger systems.

How was this algorithm implemented?

The following outline describes the full set of test selection criteria defined by this algorithm.

A. Test Candidate Groupings (4)

1. Test Candidate Grouping 1 of 4: Non-Intrusive Tests

a) Candidate Test Types (4)

1) All Operational Tests

2) All User-Initiated Tests

3) All Signature Tests

4) Non-intrusive Inspection Tests

b) Weightings: uses algorithm defaults

c) Cutoffs: uses algorithm defaults

2. Test Candidate Grouping 2 of 4: Intrusive Tests

a) Candidate Test Types (2)

1) All Probe Tests

2) Intrusive Inspection Tests

b) Weightings: uses algorithm defaults

c) Cutoffs: uses algorithm defaults

3. Test Candidate Grouping 3 of 4: Individual Net Functions

a) Candidate Test Types (1)

1) All Net Functions

b) Weightings: uses algorithm defaults

c) Cutoffs: uses algorithm defaults

4. Test Candidate Grouping 4 of 4: Output Flags

a) Candidate Test Types (1)

1) All Output Flags

b) Weightings: uses algorithm defaults

c) Cutoffs: uses algorithm defaults

B. Default Test Weightings (16)

1. Test Weighting 1 of 16: Max Severity (End Item Effects)

a) Priority: 150