Diagnostics consists of two distinct phases Fault Detection and Fault Isolation. Although these phases may be separately calculated and optimized using different criteria, a diagnostic strategy will always account for both phases.
+
Scope Options [Detail] Operating modes [Subsets of the model]
Hierarchy Options
Prognostic Options
Detection Options - Detection Algorithms - Detection Test Candidates
The Fault Detection phase of a diagnostic session consists of all tests up to and including the first failed test. In a static diagnostic strategy, the Fault Detection Sequence consists of the set of tests that would be performed if every test were to pass (this is sometimes referred to as the "go chain"). Fault detection may be optimized to verify that no faults exist using the fewest tests, to detect a failure using the fewest tests, or even to postpone detecting a failure until as much of the system has been proven good as possible. Fault Detection can also attempt to first detect the presence of certain critical faults or reduce the time of testing by privileging tests that can quickly detect a large number of failures.
The Fault Isolation phase of a diagnostic session consists of all tests subsequent to the first failed test. In a static diagnostic strategy, all tests not in the fault detection order ("go chain") can be thought of as fault isolation tests. Fault isolation is typically optimized using different criteria than for fault detection. One of the most commonly-used optimization techniques for fault isolation is the binary half-split, which attempts to reduce the overall number of tests performed.
The Flow diagram Settings allow the Analyst to control those items to show in the flow diagram.
Threaded Isolation - Detection requires Tests to be run sequentially, yielding a series of detected faults which represent an ambiguity set for each detected fault. Threaded isolation allows these ambiguity sets to be broken down and isolated in a parallel fashion dependent on the number of threads the processor is capable of running. Running Threaded isolation reduces the isolation time by the number of threads used.
A new Desktop Fault Insertion feature has replaced the Strategy Automation dialog that appeared in earlier versions of eXpress. Although similar in concept, this new capability consists of a dialog and report that can be used separately or in tandem to address a variety of Diagnostic Validation scenarios, including:
“Sanity Check” explorations of diagnostics in the process of being developed
In-house reviews and validation of calculated diagnostic procedures
Customer demonstrations of diagnostic strategy deliverables
Troubleshooting of diagnostic issues identified during maintenance demos
Isolation and resolution of problems that arise with fielded diagnostics
+ 