ASIL accuracy

A conceptually simple implementation incorporates a fully redundant measurement.

A fault in the primary measurement can be detected by comparing the primary and diagnostic measurements, and signaling a fault if the difference is outside the expected operating range.

The fault detection limit, however, should not be confused with ASIL accuracy.

Consider the case of a single point fault in which the primary measurement drifts to an incorrect value.

ASIL accuracy describes the maximum such drift before the fault is flagged.

To detect single point faults, two measurements can be compared.
Illustration of overlapping measurements with different accuracy, and correspondingly chosen fault detection limit.
Illustration of how to calculate ASIL accuracy given the fault detection limit VLIM and the diagnostic accuracy V2.