Search for:
Mechatronic paths without reliable error detection
Explanation:
The MSR form will be searched in section 5 (Risk Analysis) for error detections and in section 6 (Optimization) for detection actions for which the assigned DC or M values are not reliable enough for a reduced AP rating.
To be considered reliable, a DC value must be minimum 99.99%, and an M value must be maximum 1.
Example:
Abbreviations:
- The example demonstrating how the described quality rule (QR) works has the structure shown above. The contained failures and safety mechanisms are linked with each other as shown in the following failure net. By selecting the suitable display options (e.g., Functional safety parameters, Evaluation), the parameters that are relevant to execute the QR can be shown in both the Structure Editor and the Failure Net Editor
- The described QR searches the MSR form for error detections (Risk Analysis section) and detection actions (Optimization section) for which the assigned DC or M values are not reliable enough to reduce the AP rating. For such values to be considered reliable, the DC value must be minimum 99.99%, and the M value must be maximum 1.
- The following conditions must be met for the Risk Analysis section so that an error detection is included in the search result of the QR:
1. At least one of the two parameters DC or M must be determined, i.e., assigned a value.
2. One of the determined parameters must violate the reliability condition defined above.
- For the Optimization section, the following conditions must be met for a detection action to be included in the search result of the QR:
1. The parameter M must be determined, i.e., assigned a value.
2. The determined parameter M must violate the reliability condition defined above.
- The considered QR can only be executed in the MSR form, which is why the QR search result is also displayed in the MSR form. In our example, the form, which has the focus failure BF, looks as follows after the QR search run:
Search result: 
Thus, after the QR search, four hits are shown in the Risk Analysis section and one hit in the Optimization section. In the Risk Analysis section, Er Det 2 and Er Det 5 are marked as hits because the DC values assigned are <99.99%. Er Det 1 and Er Det 6 are also marked as hits in the Risk Analysis section because the M values assigned are >1. Finally, in the Optimization section, the detection action DA(6) is marked as a hit because its M value is also >1.
Er Det 3 and Er Det 4, are not included in the QR search result, because none of their defined parameters violates the reliability condition.