“Qualifier bits” allow the SafetyProvider to indicate the correctness of values on a fine-grained level. It is good practice to attach a qualifier bit to each individual value sent within an SPDU. The qualifier bits are part of the SafetyData and hence not within the scope of this part.

[RQ5.1] However, whenever qualifier bits are used, the values shown in Table 5 shall be used, i.e. 0x1 for a valid value (“good”), and 0x0 for an invalid value (“bad”).

Table 4 – Example “Application Variables with qualifier”




0x1 (= good)

not valid

0x0 (= bad)

Checking the qualifier is done in the safety application.