A Test Prerequisite is a condition placed up a test to determine how it is to be used in diagnostics. The test must pass the prerequisite in order to be used
For each prerequisite, the analyst may select other test(s) from the test sets as (passed/failed/performed/not performed) condition of the prequisite.
For each prerequisite, the analyst may select from one of the following three Operator settings:AND, OR, NAND, NOR
For each prerequisite, , the analyst may select from one of the following three usage settings:
1
? Always Require Prerequisite –the test prerequisite must always be satisfied before the target test will be performed.
2
? Require if Prerequisite is Candidate – the test prerequisite must be satisfied if the prerequisite test is both in a candidate test set (that is, a test set that has been explicitly selected on the Detection or Isolation Options panel) and is allowed by the selected Fault Detection or Fault Isolation algorithm (which is also selected on the Detection or Isolation Options panel).
3
? Requisite if Prerequisite Can be Used – the test prerequisite must be satisfied if the prerequisite test is a candidate test (see description for the previous usage type) and is also capable of being used by the diagnostics. If, for any reason, the prerequisite test is determined to be not useful (due, for example, to its having redundant coverage with a previous utilized test), then that prerequisite need not be satisfied. Note: if this usage option is selected for a prerequisite of a given test, then that test will either not be used (in the case where the prerequisite can be neither satisfied nor eliminated) or will be postponed until after the prerequisite has been eliminated (this will happen when the entire coverage of the prerequisite test has been proven or detected by another test(s)). Because of this postponement, it is possible for the test that contains that prerequisite to be selected in an order that is not in keeping with its defined weightings (since, at the point where the weightings would normally cause that test to be selected, the prerequisite may not have yet been eliminated).
How to setup a test Prequisite
Select a Test to have a prerequisite and Select the Test Prerequisite tab in the Context Panel as shown below.
1) Then select the Operator. Here "AND" (default) was used.
2) Open the Applicable test set and select the Test
.
Here the test Lift D2 lead and verify resistance between J1::+28V and J1::GND > 500 OHM was selected.
How to set the Conditions for a Prerequisite
Use at right of Condition: to select Condition
Use at right of Usage: to select usage
Also a filter was here to aid in finding the applicable test.
More than one Prerequisite (condition) can be placed upon the same test as shown below
at right of Condition: to select Condition
