Intrusiveness is a test feature that can be used to influence the order of testing during diagnostics. Test intrusiveness has no fixed meaning—it is simply a way of specifying that some tests or test types are relatively more disruptive than others and should therefore be postponed during diagnostics until after less intrusive tests have been performed.
How is Test Intrusiveness Established?
Test intrusiveness can be established in three different ways: 1) within Test Candidate Groupings that include only certain types of tests, 2) within Test Candidate Groupings that refer to built-in test settings, and within Test Weightings that refer to a special Analyst-defined test Attribute. In each of these cases, test intrusiveness will only contribute to diagnostic optimization if the selected diagnostic algorithm explicitly takes it into consideration.
First of all, test intrusiveness can be inferred from the candidacy rules in the Test Candidate Groupings of a selected Diagnostic Algorithm. For example, the groupings may be set up so that tests that can be performed without interrupting normal system operation are selected before more intrusive tests. This method assumes that intrusiveness is a fundamental criterion for diagnostic optimization, since test groupings take precedence over weightings during test selection. Furthermore, this method is most profitably employed when the same relative intrusiveness can be assumed for all tests of a particular type.
The second way in which test intrusiveness can be established applies only to Inspection tests. Unlike other tests, for which intrusiveness applies to all tests of the given type, individual Inspection tests can be either intrusive or non-intrusive. Relatively intrusive Inspection tests might include procedures that involve opening up an enclosure in order to examine an element or removing a part to be tested using external equipment. Relatively non-intrusive Inspection tests might include those that can be performed with little or no impact upon system operation (such as looking at a system-level indicator, listening for an expected or unexpected sound, or witnessing normal or aberrant system behavior).
The third way of establishing test intrusiveness requires that a unique test Attribute be created to represent the relative intrusiveness of each test. This Attribute must then be used in a Test Weighting in the selected diagnostic algorithm . Although this method requires additional work to set up, it has several advantages over the other to more automatic approaches. It allows a different intrusiveness setting for each test, regardless of test type. It allows for degrees of intrusiveness to be represented using different numeric Test limits, rather than simply classifying tests as being intrusive or non-intrusive. Finally, this approach allows intrusiveness to be treated as one criterion among several that must be weighted (with different priorities) during test selection.
