Sydvest offers user focused, R&D based tools for
analysis and management of safety and reliability

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[CARA-
FaultTree]

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information]

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A quick tour through drawing a new fault tree, enter input data and run a simple analysis is given below.

If you have downloaded the Demo version but didn't download the Start-up Guide, you may download the guide now instead (The downloaded file is a self-extracting file containing an Acrobat PDF-file, filesize appr. 0.6MB). Note that the guide also includes the quick tour described below.

The CARA-FaultTree window has a menu, a toolbar for menu shortcuts, a symbol palette and an area for fault trees and reports, see below:

The procedure to create a new fault tree, enter some data and run an analysis is described in detail below:

1. Create a new fault tree using the File | New command (or simply start with the new fault tree opened when the program is started).

2. Add an OR-gate as TOP event in your new fault tree as follows: Click the mouse on the OR-gate button in the Fault Tree Symbol Palette. The mouse pointer is now "loaded", this is indicated by an OR-gate shown at the side of the cursor. Drop the OR-gate on the fault tree page by clicking on the position where you want the gate to be drawn (preferably near the top of the fault tree page).

3. Add two Basic events below the OR-gate you have inserted as follows: Load the cursor with a Basic event symbol by clicking the Basic event-button in the Fault Tree Symbol Palette. Try moving the cursor around the fault tree page. Observe that as long as you are pointing outside the OR-gate, the cursor will be accompanied by a stop sign , and you are not able to add the Basic event. If you move the cursor over the OR-gate, however, the cursor again shows the Basic event symbol. Drop the Basic event on the OR-gate by simultaneously pressing the Shift key and clicking on the OR-gate. The Basic event is automatically connected to the gate, and given the default name "Basic 1". The reason for pressing down the Shift key is that the cursor then remains loaded with the Basic event symbol. Click on the OR-gate once more, but this time do not hold the Shift key. A new Basic event (named "Basic 2") is inserted below the OR-gate. Since you did not hold down the Shift key this time, the cursor is reset and loaded with the pointer.

4. The fault tree should now look like this:
   

5. To edit the input data, double-click on the Basic event "Basic 1". A property dialog is opened, where you may enter an event ID (set by default to "Basic 1", "Basic 2", etc.), a description, as well as Failure data see below:



6. Enter an appropriate set of failure data into the Event data tab of the dialog.

7. While leaving the property dialog open, click on the Basic event named "Basic 2". The property dialog is updated to display information about the new active component "Basic 2". Enter some failure data for this component as well. If you removed the property dialog by accident, just double-click on "Basic 2" to create it again.

8. The fault tree page and the OR-gate both have "properties" as well. By double-clicking on a blank part of the page, you are allowed to enter a page id and a description as well as determining the page layout. In the description field you may add text as you like, or enter one of the supported codes, e.g. ^Date to print the current date or ^Page to print the name of the page

9. By clicking the right mouse button on a gate or an event, a quick menu is available. This menu change depending on the type of component selected. E.g. if you add a Transfer down-symbol to your tree you can, by right-clicking this transfer symbol create a new page to which the transfer symbol is connected. Further, you can connect it to an already existing page, or (if the transfer symbol is already linked to a page) move to the connected page.

10. Select the Look-at tool from the Symbol Palette, and move the cursor over one of the components. All the failure data is displayed in a yellow sticker on the screen. This utility, which is also available in tree overview, makes it quick to view and verify the data input.

11. Run an analysis, e.g. by selecting Analysis | Failure frequency distribution.... You will be prompted to enter some settings to run the analysis, then press OK to perform the calculations. A result window is displayed. This report may be saved in RTF-format (readable for all standard word processors running under Windows). You can also mark text or graphics in the result window, copy the text to the clipboard (e.g. using the standard Windows Ctrl+C key) and paste it into your word processor (e.g. using the standard Windows Ctrl+V key).

12. To run a new analysis, you must first make the fault tree the active window, e.g. by selecting Fault tree 1 in the Window menu. Then all analyses options are again available.

13. Now, select the Tree | Overview command or press the Overview button in the toolbar. In the Overview window all pages of your fault tree are displayed tied together (here, having only one fault tree page, only this single page is shown). If you select the Look-at tool from the Symbol Palette, and place the cursor over a fault tree page, the structure of that page is displayed.

14. Use the zoom scrollbar on the bottom of the window to increase the zoom factor. Zoom up to 15%. Now, the structure of the fault tree is displayed within the overview window, and the Look-at tool will display properties for all gates and events. If you want to, you can even edit the fault tree in this view (add or remove components, utilise drag and drop etc.). Go to a different page by selecting Edit | Goto Page ( in the toolbar, or Ctrl+G) and select the desired page from the displayed list.

Sydvest, Trondheim, Norway
E-mail: post@sydvest.com
Contact details: see "Contact us"
Last modified: 14.10.2005 by jrv