Editing an FTA
- Tino Pförtner
The FTA can be edited at document, module, key-value pair, and object levels.
In the Repository view, right-click an FTA document.
Choose Document properties. - Outcome: the Properties for dialog with the entries "FTA Document", "FTA module", and “Key-Value Pairs” will open.
Document
In this dialog the Mission Time in hours can be changed. The default value is 1.0E9 from the FIT
calculation. If safety goals have been created, they can be assigned here or in the Safety Goals view.
Module
The changes will be active for every FTA document.
In this dialog the general FTA module properties can be changed.
Key-Value Pairs
Object
Right-click on a gate/event and choose Properties.
Outcome: the gate dialog will open.
Outcome: the event dialog will open.
Paste and Paste Reference Features
Paste Reference
Use of these commands may be required if a given structure replicates somewhere else in the failure tree. Our example case is based on replicating the MF13/GA2 objects:
What is the best approach to achieving this objective depends on your purpose. Use of the “conventional” Paste command would have the side-effect of creating new gates/notes and updating the counters accordingly. If you wish to avoid this, Paste reference is the implement to choose. As the name suggests, this command will create new references only, as opposed to new objects.
To use Paste reference as suggested in our example scenario, perform the following activities:
Select the MF13/GA2 structure (left-click).
Right-click on your selection and choose Copy from the context menu.
Select your target structure, MF14/GA3.
Right-click on your selection and choose Paste reference from the context menu.
Outcome: the selected reference will be pasted onto your target, which SOX will indicate with the symbolism highlighted below:
Paste
As noted before, use of the “conventional” Paste command will result in the addition to your failure tree of the objects copied. The first three steps involved are identical to the Paste reference method:
Select the MF13/GA2 structure (left-click).
Right-click on your selection and choose Copy from the context menu.
Select your target structure, MF14/GA3.
Right-click your target and select Paste.
Outcome: a dialog giving you two alternative options will pop up.
As the label suggests, the first option is more conservative in that it copies nodes but references the existing Malfunctions. Alternatively, it is possible to copy the Malfunctions involved also.
Outcome of copying nodes only:
SOX created a new node, GA9 but references MF13 as before.
Outcome of copying “everything” (second option):
SOX created a new malfunction, MF59, a new gate and events.