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Total Probability Detected Algorithmn

Description
The Total Probability Detected is the probability that a fault will be proven / detected by the detection sequence in the given diagnostic study. Although two Test limits are calculated for this metric (see minimum and maximum fault detection), only one number is used when both Test limits are the same (otherwise, this metric is presented as a range). The minimum Test limit for this is metric (which is based on the sequence's detection coverage) is frequently used to satisfy the fault detection component of contracted testability requirements. The non-probability-weighted equivalent of this metric is the Total Functions Detected.
 
Calculation
This Test limit is calculated by summing the relative failure probability of all functions/failure modes in the specified Diagnostic Scope that are proven / detected by tests in the detection sequence.
When fault detection is calculated across the entire design (i.e., the Diagnostic Scope is set to <Entire Design>), this metric can be calculated using the following equation:
where
N
=
the total number of used functions
Xi
=
1 if the ith function is proven / detected (partially or fully) by the set of detection tests (this will only happen for functions in the specified Diagnostic Scope); 0 otherwise
Rfpi
=
the relative failure probability of the ith function
 
Note: When calculating the total probability detected for a diagnostic sequence that utilizes hybrid diagnostics, the corresponding partial failure probabilities are summed for each detected element (function or failure mode), the failure probabilities for each object having been adjusted based on the selected failure probability calculation method.
When fault detection is calculated with the Diagnostic Scope restricted to a specific Operating Mode, then this metric is calculated as follows:
where
N
=
the total number of used functions
Xi
=
1 if the ith function is proven / detected (partially or fully) by the set of detection tests (this will only happen for functions in the specified Diagnostic Scope); 0 otherwise
Rfpi
=
the relative failure probability of the ith function
Si
=
1 if the ith function is in the Operating Mode specified by the Diagnostic Scope or if the Scale Statistics to Scope option has been disabled; 0 otherwise
 
Standards, Handbooks and Publications
 
The following Standards, Handbooks and Publications provide information about this and/or similar metrics:
 
Metric
Standard
Expected Percentage of Detection
IEEE 1522 (2004)
Percent BIT Fault Detection
Fraction of Faults Detectable
RAC-MKIT (2000)
Hit Rate
Fraction of Faults Detected
RL-TR-91-200 (1991)
Fraction of Faults Detected
Fraction of Critical Faults Detected
Fault Coverage
BIT Fault Detection Level
Percent Detection