Diagnostic coverage

In a safety-related use of the brake in a safe brake system, the diagnostic coverage (DC) is relevant for the final determination of the safety integrity, e.g. performance level (PL). The DC value is a characteristic value for the brake test. This value is determined as the ratio of the number of detectable dangerous failures of a brake to the total number of dangerous failures of that brake. The DC value is a indicator for which hazardous faults on a brake are detected by the brake test. A brake test is required from a system architecture of category 2 and higher in accordance with EN ISO 13849-1.

The originator of a brake test determines the DC value that is valid for the test, which is then used as part of the determination of the performance level (PL) achieved for the safe brake system.