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1. 77 View Openk ues 78 ZOOM E es istituti Deo a notet OD nn nt da ne 79 ZOOM OU pect eae ce 80 Appendix Analysis Methods 81 Se 81 Numerical Probability Analysis share bre ri sane 81 Monte Carlo SU 82 The P model and the Modeles can nn 83 Appendix The Three Motor Example sse 84 Bal T P 84 Three Motor EXaImpIB 84 Tibe Level ae 86 The Transterred Fault Tree 88 The Qualitative Analysis Report eeessseeeessreeseeresseresesressessrssressersterreesrestrsereseesee 89 The Probability Analysis 93 The Monte Carlo S OR 97 Th Primary Event Database Reporting d 104 3 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Lid Chapter 1 Introduction Chapter 1 Introduction Overview This manual describes how OpenFTA is used for the drawing and analysis of fault trees It includes a step by step tutorial and a reference section describing each of the tool s facilities What is OpenFTA is a sophisticated engineering tool for drawing analysin
2. RR gt Figure 2 Components of the OpenFTA window The menubar consists of a number of menus of options that can be applied to the fault tree being drawn The toolbar consists of shortcuts in the form of icon buttons to frequently used menu options When the mouse cursor is placed over an icon button a small description a Tool Tip is displayed to provide a hint about the function of the button Tool tips are also provided on the controls of dialog boxes Many frequently used menu options also have accelerators and mnemonics The symbol palette on the left of the OpenFTA window presents the drawable elements of a fault tree If any symbol is not permitted e g AND gate if a gate is selected on the canvas area the symbol button is greyed out Thus only syntactically valid fault trees can be drawn using OpenFTA The canvas area of OpenFTA is a scrollable area on which a fault tree is drawn Note that only one tree may be drawn at a time The top level intermediate event of the fault tree is always present at the top centre of the canvas with all child symbols laid out automatically by OpenFTA This ensures that the fault tree is laid out in an efficient and aesthetic manner The OpenPED window allows access to the primary events database capability of OpenFTA The provision of a separate capability to handle the management of primary events allows fault trees to be 6 OpenFTA Version 1 0 User Manual Copyrig
3. 2 112164E 006 0 13 91 51 T2 4 3 3 658376 006 2 112164 006 0 13 92 Tlinc T2 3 3 658376 006 2 112164 006 0 13 93 K5 T2 3 3 658376 006 2 112164E 006 0 13 94 K1 K5 Tlinc 3 3 658376E 006 2 112164 006 0 13 95 K5 T1 3 3 658376 006 2 112164E 006 0 13 96 K5 T1 T3inc 3 3 658376E 006 2 112164E 006 0 13 97 K1 K5 KTlinc 3 3 658376 006 2 112164 006 0 13 98 K5 T3 3 3 658376 006 2 112164E 006 0 13 99 K5 51 T3 3 3 658376E 006 2 112164E 006 0 13 100 K5 T3 T3inc 3 3 658376 006 2 112164 006 0 13 101 K1 KT3 T2 T4 2 2 438917E 006 1 724575E 006 0 09 102 K1 KT2inc T2 2 2 438917E 006 1 724575E 006 0 09 103 K1 K5 T3inc 2 2 438917 006 1 724575E 006 0 09 104 K2 K5 KT2inc 2 2 438917 006 1 724575E 006 0 09 105 K2 K5 KT3 2 2 438917E 006 1 724575E 006 0 09 106 K5 KT2 S1 T4 2 2 438917E 006 1 724575E 006 0 09 107 K5 KTlinc KT2inc T1 2 2 438917E 006 1 724575E 006 0 09 108 K5 T 2 2 438917E 006 1 724575E 006 0 09 109 5 KT2inc T1 T4inc 219459 006 1 219459 006 04 110 K5 51 219459 006 1 219459 006 04 111 K5 Tlinc T3 T4inc 219459 006 1 219459 006 04 112 KT2inc KT3 51 T2 219459 006 1 219459E 006 04 113 2 51 2 T4inc 219459 006 1 219459 006 04 114 2 KT3inc T2 219459
4. E Use minitial CE Wominima an tile Ol C Limit minimal cut set order to i Cancel Help OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Figure 11 Minimal Cut Sets Dialog On activation of the OK button OpenFTA displays a working dialog and carries out the minimal cut set generation using the parameters requested The Stop button on the working dialog may be pressed to abort the generation of the minimal cut sets Note that the generation of minimal cut sets may take a long time for very large trees when large order minimal cut sets are required On activation of the Cancel button the operation is aborted and the dialog is removed On activation of the Help button context sensitive help information is displayed On completion of the operation a Qualitative Report is generated to a named lt fault tree name gt mcs and displayed in a dialog The report consists of the directory path to the file used to store the fault tree analysed in this report the date and time of the report s creation the method used to calculate the minimal cut sets the number of unique primary events in the fault tree including those in any transfer trees the range of cut set orders possible for the fault tree a list of the minimal cut sets separated into the orders that have been located a
5. T1 KT2 T1 K5 T4 T4inc K5 T2 KT3inc T4inc KT1 KT3 T4 Tl T3 T4inc K5 T3 T4inc KTlinc KTZ T2 KT3 KT3inc 51 T2 KT3 Tlinc T2 KTlinc KT2 51 T2 71 T2 51 T3 T4ine K5 T2 T2inc K5 T2 T4inc K5 KT2 T3 T3inc 81 Tlinc T2inc K5 KT1 T1 K5 Tlinc T2inc K2 K5 KTlinc K5 KT3 T1 T4inc K5 KT2 T4 KT2 KT2inc 1 K5 T2 219459E 006 219459E 006 219459E 006 219459E 006 219459E 006 219459E 006 219459E 006 219459E 006 219459E 006 219459E 006 1 219459E 006 219459E 006 219459E 006 219459E 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 Chapter 3 OpenFTA Reference 1 1 f 1 1 1 f 1 Rf 1 T 1 Ls f 1 1 1 y T 1 1 1 t 1 1 t 1 1 1 t 1 1 1 1 tf 1 1 Ty T Tf 1 tf 1 1 1 1 ds OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd
6. 009 200000 009 200000 009 200000 009 280000 012 L 280000E 012 280000 012 1 280000 012 280000 012 280000 012 280000 012 46 47 48 49 50 51 52 53 54 Chapter 3 OpenFTA Reference KTlinc KT3 T2 T3inc T4 4 1 2 2 2 T4inc KT1 KT2 T3inc KT1 KT2 4inc T2inc T4 T4inc TA 4 2 2 KT2inc T2 T2inc KT3 KT3inc T2 T2inc T2 T2inc T3inc KT2inc KT3 KT3inc T2 KT2inc KT3 T2 T2inc T4 KT1 KT3 KT3inc T2 T2inc T3inc KT1 KT3 T2 T2inc T3inc T4 280000 012 280000 012 280000 012 280000 012 280000 012 280000 012 280000 012 280000 012 280000 012 Probability of top level event minimal cut 1 term 2 terms 3 terms 2 824405 003 1 072849 004 3 382002 006 Primary Event Analysis Event Failure contrib 000000 004 080256 004 000320 003 264205 007 841023 008 632102 007 841023 008 264205 007 2 824405E 003 2 717120E 003 2 720502 003 29 I5 73 sets up to order 18 used upper bound lower bound upper bound Importance OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference KT3inc 3 841023E 008 0 00 51 8
7. Chapter 2 OpenFTA Tutorial Chapter 2 OpenFTA Tutorial Overview This chapter introduces key concepts and provides a guide to the facilities offered by OpenFTA For more detailed information on any particular facility of OpenFTA refer to Chapter 3 This tutorial describes e how to start OpenFTA e getting on line help from OpenFTA e how to create and modify fault tree drawings e how to specify primary event definitions e how to analyse fault trees e exporting data to other packages Starting OpenFTA OpenFTA is started by selecting OpenFTA from the windows Start menu The default location for this is inside a group called Formal Software Construction gt OpenFTA OpenFTA Tree Untitled Database Untitled Begs File Edit View Analysis Report Help ane X RR a Tree Untitled Database Untitled gt gt 0200 Apply Clear Help Figure 1 OpenFTA s Initial Display l OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial Figure 1 shows the windows displayed when OpenFTA is first started i e and OpenPED The OpenFTA window and the OpenPED window provide facilities for constructing fault trees and are discussed in more detail in the following sections The OpenFTA window consists of the following four elements fie Eot Wow arasi Remote Hop
8. Chapter 3 OpenFTA Reference KT2inc T2 T4inc KT3inc T2 T3inc T2 T3inc T4inc KT3inc T2 T2inc T2 T2inc 4 T2 T2inc T3inc c T3inc T4inc 3 Tline T2 inc T2 T4 ine KT3inc Tl T2 inc KT3inc T2 inc T1 T2 4 inc T2 T3 T4inc Tl T2 T3ine ine T2 T3 T3inc KTlinc KTlinc KT2inc KT2inc T1 T2 T3inc 4 T2 T3inc 4 KT3inc T1 T2 T2inc KT3inc TZ 2 KT2inc T1 KT2inc T2 KT3inc T1 KT3inc TZ T1 T2 T2in T2 T2inc KIline KT3inc T2 KIlime 4 1 T3ine KT1 KTlinc 4 KTlinc T2 T4 KTlinc 4 KT1 KTlinc 4 2 2 T4inc 2 4 T2 T2inc T3ine T2inc T3 T3inc c T3inc T4inc 3 T3inc T4inc KT2 KT2inc KT3 KT2 KT2inc KT3 T2 KT2 KT3 KT3inc T2 KT2 KT3 T2 T3inc KT2inc KT3 KT3inc KT2inc KT3 T2 T4 KT3 KT3inc T2 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd 200000E 009 200000E 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000E 009 200000 009 200000E 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000 009 200000
9. Sets the paper size and orientation Location Invoked from Page Setup OpenFTA Page Setup OpenPED and Page Setup Print Preview Operation The dialog consists of e a Paper panel allowing the Size and Source of the paper to be specified Orientation panel that sets the output to be either Landscape or Portrait e a Margin panel where the Left Right Top and Bottom margin distances can be adjusted On activation of the OK button the settings are confirmed and the dialog is removed from the screen On activation of the Cancel button the procedure is aborted and the dialog is removed from the screen Cross References Page Setup Print Print Dialog Print Preview Printer Setup OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Paste OpenFTA Control Type Menu Option Function Places the clipboard contents as a child of the currently selected fault tree symbol Location OpenFTA menubar gt Edit gt Paste Shortcuts Accelerator Ctrl V Toolbar Pre conditions A symbol in the drawing area is selected Operation A copy of the clipboard contents usually a sub tree of gates and events is added as a child of the currently selected fault tree symbol If this operation would cause the fault tree to become invalid then an error dialog is displayed and the operation is aborted The Paste operation can be repeat
10. Shortcuts Accelerator Ctrl X Toolbar ie Pre conditions A symbol on the canvas is selected Operation Used to remove the current selection and sub tree below it from the displayed fault tree and copies it to the clipboard Selections copied to the clipboard are available for the Paste operation Any information previously held on the clipboard is lost when a Cut operation is carried out Cross References Copy Paste and Undo OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Cut OpenPED Control Type Menu Option Function Removes the current selected text from the ID Probability or Description fields and copies it to the clipboard Location OpenPED menubar gt Edit gt Cut Shortcuts Accelerator Ctrl X Toolbar gt Pre conditions Text is selected in one of the text fields Operation Removes the current selected text from the ID Probability or Description fields and copies it to the clipboard Selections copied to the clipboard are available for the Paste operation Any information previously held on the clipboard is lost when a Cut operation is carried out Cross References Copy and Paste OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Database Control Type Menu Option Function Creates an association between a fault tree and a primary e
11. Ww Ww w Ww 097513E 005 755669E 006 755669E 006 755669E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 536211E 006 6752E 006 6752E 006 6752E 006 6752E 006 6752E 006 6752E 006 316752 006 316752 006 316752 006 6752 006 316752 006 316752 006 316752E 006 316752 006 316752E 006 316752 006 316752E 006 316752 006 316752 006 097293E 006 097293E 006 097293E 006 097293E 006 Chapter 3 OpenFTA Reference t t 3 Ss 3 3 35 35 35 Ba 3 3 3 32 3 2 2 2 2 2 2 2 2 2 2 2 24 2 2 2 2 2 2 OpenFTA Version 1 0 User Manual 658376 006 449150 006 449150 006 449150 006 226384 006 226384 006 226384 006 226384 006 226384 006 226384 006 226384 006 226384 006 226384 006 226384 006 226384 006 226384 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 98
12. file with a different name and or directory location Cross References File Selection Dialog Save OpenFTA OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Save As OpenPED Control Type Menu Option Function Stores the current primary events database to a named file Location OpenPED menubar gt File gt Save As Shortcuts Accelerator None Toolbar None Pre conditions None Operation Used to store the open primary events database to a named file The file name is of the form name of database gt ped On activation a selection dialog titled Save is displayed For more details on the use of this dialog read the section titled File Selection Dialog Note that on activation of the OK button the database is stored to the currently selected file and the Save dialog is removed If no file is selected then an error dialog is displayed If the output file does not have write access then an error dialog is displayed In order to save the database the permissions must be changed or the Save As operation must be used to store the database to a file with a different name and or directory location Cross References File Selection Dialog Save OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Selected Control Type Menu Option Function Dis
13. ue 12 Analysing The Fault e nets seas 12 Decomposing Fault 14 Chapter 3 OpenFTA RETRO 16 16 PRIMAL SUS T een ne 17 Apply Oper PED Een e 18 Clear ODenPED 19 Copy OPen ETA o es ey Ot nent ue nce tren ne us 20 rid UP MT V dew ete 21 Constant Failure Rate Unit Fe uico ire te teer tei B nine 22 C t Bros Eo T H 23 EE curb T td aE 24 P H 25 BS a Open a bibe 26 RO nSsconSi ings b 27 E nsn MR T 28 lo udis e 29 Edit OEY EC 30 lo D r I EN 31 EDO E e eee 32 Export Text US dt tn nice 33 File Bog 34 File CORRE 35 Fil Selection LUA OB C 36 ER ecw eee eerste 37 CT TR TERRIER RN 38 SUS X P 39 Monte Carlo Simulation eio Gert o eot uti Leid nte na ep a uM rani 41 IVS Rigo LR ann 44 lr Rigo ius P 45 N me
14. 000000 004 29 41 1 4 080256 004 15 00 2 400640 005 0 88 T2 8 240832 004 30 29 2 3 841023 008 0 00 T3 4 080256E 004 15 00 3 841023E 008 0 00 T4 1 632102E 007 0 01 T4inc 3 841023E 008 0 00 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference The Monte Carlo Report This report shows an example of the results obtained when a Monte Carlo Simulation is performed upon a fault tree The simulation produces the probability of at least one component failing the probability of the top level event occurring and the cut sets of the fault tree It does this using the method detailed in Appendix A The number of tests simulations is user definable but the calculation time of the probabilities will increase as the number of tests is increased A primary event analysis is carried out and the failure contribution and importance of each primary event is displayed Monte Carlo Simulation Tree Three Motor Example Motor 2 Only fta Time Thu Feb 28 13 22 20 2002 Note Only runs with at least one component failure are simulated Number of primary events 18 Number of tests 250000 Unit Time span used 1 000000 Number of system failures 2288 Probability of at least 3 048647E 001 exact one component failure Probability of top event 2 790121E 003 5 833042 005 Rank Failure mode Fail
15. 006 1 219459 006 04 115 KT3inc Tlinc 219459E 006 1 219459E 006 04 T2 116 K1 K2 2 T3 219459E 006 1 219459E 006 04 117 51 2 2 4 219459 006 1 219459 006 04 118 K5 KTlinc KT2 219459 006 1 219459 006 04 119 K2 K5 KT3inc T2inc 219459E 006 1 219459E 006 04 120 K1 K5 KT2inc T4 219459 006 1 219459 006 04 121 K5 KT2inc Tlinc T3 219459 006 1 219459 006 04 122 51 Tlinc 2 T4inc 219459 006 1 219459 006 04 123 K5 T3 T3inc 219459 006 1 219459 006 04 124 K2 K5 KTlinc 219459E 006 1 219459E 006 04 125 K1 K2 K5 T2 219459 006 1 219459 006 04 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd 100 126 127 128 129 130 1731 132 133 134 135 136 137 138 139 142 143 144 145 147 148 150 151 152 154 155 156 157 158 159 K1 K1 S1 K5 K2 K5 K5 K5 K5 K2 K5 K5 K2 K1 K5 K5 K5 K2 K1 K5 K2 K5 K5 K2 K1 K5 K2 K2 K2 K5 K2 KT3inc 51 T2 K5 KT2 1 KT2inc T2 T3 Tline T2 T3inc KT2 KT3 S1 K5 Sl Tline K5 KTlinc KT2inc K5 KT3 S1 KT3inc Tl T2 T2 T2inc T3 T1 T4 K5 2 T3inc KT2inc 4 Tline 2 KT2inc
16. 182 K2 183 K1 184 K1 185 K2 186 K5 187 K2 188 K1 189 K1 Compressed Rank Fai 1 K5 2 K5 3 K2 4 S1 5 K5 6 K1 7 K1 8 K2 Tline T2 Chapter 3 OpenFTA Reference Failures 358 356 343 348 318 317 311 11 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 9459 006 19459 006 19459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 1 219459 006 Estimated Probability 4 365662 004 4 341273E 004 4 182743E 004 4 243716E 004 3 877879E 004 3 865684E 004 3 792516E 004 1 341405E 005 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 4 OpenFTA Version 1 0 User Manual 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459 006 219459E 006 219459 006 219459 006 2194
17. Control Type Pulldown Menu Function Provides access to facilities for manipulating primary events databases Location OpenPED menubar gt File Shortcuts Accelerator None Toolbar None Pre conditions None Operation Used to invoke the following operations New Open Save Save As Export Text File Printer Setup Page Setup and Print Cross References Export Text File New OpenPED Open OpenPED Page Setup Page Setup Dialog Print OpenPED Print Dialog Printer Setup Save OpenPED and Save As OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference File Selection Dialog Control Type Dialog Function Provides a means to open or store a file Location Invoked for all File operations Shortcuts Accelerator None Toolbar None Pre conditions None Operation The dialog consists of e a Files of Type drop down list this shows the filter currently in use A filter is a way of limiting the types of files displayed in the dialog The default filter is currently displayed which means that only files with the specified extension will be displayed in the dialog e a scrollable list of Directories and Files lists the files and directories below the current working directory Movement between directories is performed by multi clicking on any directory in the list e a File name te
18. Copyright 2005 Formal Software Construction Ltd
19. Cut Sets Tree Three Motor Example Motor 2 Only fta Time Thu Feb 28 13 19 13 2002 Method Algebraic No of primary events 18 Minimal cut set order 1 to 18 Order 1 Order 2 1 2 Ki 3 K2 4 K5 5 5 6 K5 7 81 Order 3 1 K2 2 TL K5 T2 K5 S1 T1 T3 T2 Tline T2 Tlinc T2 3 TZ T3 1 5 KT2 KT3 2 K5 4 Order 5 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Order 6 Order 7 Chapter 3 OpenFTA Reference K2 KTlinc KT2inc KT3inc T2 K2 KTlinc KT2inc T2 T4inc K2 KTlinc KT3inc T2 T3inc K2 KTlinc T2 T3inc T4inc K2 KT2inc KT3inc T2 T2inc K2 KT2inc T2 T2inc 4 K2 KT3inc T2 T2inc T3inc K2 T2 T2inc T3inc T4inc 1 KT2 KT3 Tlinc T2 KT1 KT3 Tlinc T2 T4 KTlinc KT2inc KT3inc T1 T2 KTlinc KT2inc KT3inc T2 T3 KTlinc KT2inc Tl T2 T4inc KTlinc KT2inc T2 T3 T4inc KTline KT3ine Tl 2 T3ine KTlinc KT3inc T2 T3 T3inc KTlinc T1 T2 T3inc 4 KTlinc T2 T3 T3inc T4inc KT2inc KT3inc T1 T2 T2inc KT2inc KT3inc T2 T2inc T3 KT2inc T1 T2 T2inc T4inc KT2inc T2 T2inc T3 T4inc KT3ine Tl T2 Taine Tsine KT3inc T2 T2inc T3 T3inc T2 Tino T3inc T4inc T2 T2inc T3 T3ine T ine KTlinc KT2 KT2inc KT3inc 2 KT1 KTlinc KT2 KT2inc KT3 T2 T4inc KT1 KTlinc KT2 KT3 KT3inc T2 T3inc KT1 KTlinc KT2 KT3 T2 T3inc T4inc KTlinc KT2inc KT3 KT
20. OpenFTA window The tree will now display the event ID next to the symbol together with its probability and any descriptive text within the symbol Validation Once the fault tree is considered complete it can be validated Validation ensures that the tree is syntactically and semantically correct g all events have been linked to valid defined primary events A fault tree is validated by selecting Analysis gt Validate which produces an on screen report This report will list all the errors that prevent the tree being considered valid together with any warnings The most common error is that an event is not found in a database either because the link has never been made between the tree event and the database event because the linked primary event has been deleted from the primary events database or because the incorrect database has been associated with the tree Analysing The Fault Tree When a fault tree is valid a full analysis of the fault tree can be performed With OpenFTA this can be performed in two ways A deterministic analysis may be achieved by a qualitative analysis to generate minimal cut sets This enables a quantitative evaluation to be performed on a logically reduced tree represented by the minimal cut sets Alternatively a statistical analysis may be performed using the Monte Carlo Simulation facility OpenFTA implements an algebraic generation of minimal cut sets which is very quick for most developed trees Minimal
21. Provides an empty primary events database Location OpenPED menubar gt File gt New Shortcuts Accelerator None Toolbar Pre conditions None Operation Used to create an empty primary events database If the database currently on display has been modified and not saved then confirmation is requested before OpenPED proceeds with the New operation Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Numerical Probability Control Type Menu Option Function Calculates the probability of occurrence of the top level event of the displayed fault tree and generates and displays an associated analysis report Location OpenFTA menubar gt Analysis gt Numerical Probability Shortcuts Accelerator None Toolbar None Pre conditions Fault tree has been saved is valid and the minimal cut sets have been generated Operation Calculates the minimal cut set probabilities for the fault tree and the probability of the top level event occurring system failure On activation a OpenFTA Probabilities dialog is displayed containing e a statement of the total number of unique primary events in the displayed fault tree including those in any transfer in trees e atext field containing the directory path to the generated minimal cut sets file e description of the file consisting of the number
22. View gt Zoom Out Shortcuts Accelerator None Toolbar 2 Pre conditions None Operation Decreases the zoom value of the OpenFTA canvas by 10 Cross References Set Zoom Zoom In OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Appendix A Analysis Methods Appendix A Analysis Methods Overview This appendix describes the analysis methods used to e out the numerical probability calculations e out Monte Carlo Simulations It then briefly details the Pmodel and model used to define the probability of occurrence of a primary event Numerical Probability Analysis This is calculated using a method of direct computation from the probabilities of the primary events which are independent in OpenFTA The method depends upon the logically reduced tree but the precision of the result does not This relies on the number of terms calculated in the expression for the top level probability see below Note that the same information is generated stochastically by the Monte Carlo method The complexity of this calculation arises because the same primary event may occur in several places in a fault tree or in other words the component probabilities in the tree are not independent If the minimal cut sets are Mb Mn then the tree is logically equivalent to the expression M OR OR M It is this expression that is evaluated Note t
23. a cost of precision In practice the terms used get smaller rapidly and it is rarely necessary to go past the third term in the calculations for a large tree See Appendix B for more details e Unit Time text field This text field stipulates unit time for which the numerical probability is to be calculated This is required if there are primary events whose probabilities have been entered into the primary events database as a function of time model rather than as an absolute probability P model A default value will be displayed but can be altered to suit experimental needs See Appendix B for more details Estimated run time statement This is an estimate of how long the calculation will take depending upon the parameters stipulated in the dialog On activation of the OK button a working dialog is displayed and the numerical probabilities calculation is initiated The Stop button on the dialog may be pressed to abort the process at any time On activation of the Cancel button the procedure will be aborted and the OpenFTA Probabilities dialog will be removed from the screen On activation of the Help button a dialog containing context sensitive help information will be displayed On completion of the operation the OpenFTA Probabilities dialog is removed a Probability Report is generated to a file named lt fault tree name gt prp and displayed in a dialog The report consists of e the directory path to the file
24. closed after this time all three timers KT1 KT2 KT3 open de energizing the coil of K1 thus shutting down the system Suppose opens properly after the 60 seconds but K4 fails closed In that case opens to denergize and Motor 1 stops KT2 and KT3 act similarly to stop Motor 2 or Motor 3 should either 5 or K7 fail closed Now it can be seen that the main concern is the application of ElectroMotive Force EMF to the motors overrunning the 60 seconds For this problem we will concentrate on the failures of relays and switches pertaining to Motor 2 Thus the top level event for the fault tree will be EMF applied to Motor 2 for t gt 60 seconds OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference The Top Level Fault Tree OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Tree Three Motor Example Motor 2 Database Three Motor Example Motor 2 Only ped Chapter 3 OpenFTA Reference E1 applied to motor 2 fort gt 60 sec ANDI E2 K5 relay contacts es relay onan H remain closed for t gt 60 open when KS relay sec contacts closed for t gt 60 sec OR2 5 not removed from K2 relay remains on 5 when K5 reli coil for 1 gt 60 sec K5 relay K2 relay en K5
25. copyright notice OpenFTA help is context sensitive The help topics may be accessed from within the application s dialogs by using the Help button where available Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Link Control Type Menu Option Function Connects the currently selected event symbol in the fault tree to the selected primary event in the database Location OpenFTA menubar gt Edit gt Link Shortcuts Accelerator Ctrl I Toolbar Pre conditions A primary event is selected on the OpenFTA canvas area The database displayed in the OpenPED window is associated with the fault tree depicted on the canvas and an event in the Primary Events list is selected Operation On activation the currently selected event in the fault tree is linked to the selected primary event in the database This causes the JD Probability value and Description for the selected fault tree event symbol to be displayed on the canvas If the Type of event in the database differs from that of the selected event in the tree then confirmation is requested before the action is completed On completion the symbol on the canvas is changed to the type held within the database Note that a Link operation cannot be undone using the Undo option Cross References Database OpenFTA Version 1 0 User Manual Copyright 2005 Formal
26. cut set generation is performed by selecting Analysis gt Minimal Cut Sets Pressing OK on the resulting dialog displays a report file associated with the fault tree which is valid until the tree is next edited The report contains a list of all the minimal cut sets identified for the tree OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial OpenFTA Minimal Cut Sets Algebraic Method minimal cursets on OTM ial Figure 8 Minimal Cut Set Generation Dialog When minimal cut sets for a tree have been generated the quantitative analysis of the tree is performed by selecting Analysis gt Numerical Probability This displays the numerical probabilities dialog OpenFTA Probabilities Program Files Formal FTA Example Treesiliftuift mes Figure 9 Numerical Probabilities Dialog Pressing OK on the dialog displays a report file associated with the fault tree which is valid until the tree is next edited The report contains the calculated probability of the top level event occurring together with the probabilities for each of the minimal cut sets occurring and the contribution that each 13 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial of the primary events makes to the top level failure The top level event calculation uses the appropriate P
27. model or model according to how each primary event probability is defined The Monte Carlo Simulation allows a statistical determination of the cut sets for a tree and an approximation of the system failure by randomly failing events and determining the probability of overall system failure The Monte Carlo Simulation provides a statistical approximation and although it does not guarantee that all minimal cut sets will be found the likelihood is that the approximation will be adequate for very large trees for which even the algebraic generation of cut sets is too time consuming The report generated gives statistical information on the accuracy of the result The more simulations run at a time the more accurate the result will be but at the expense of processing time The Monte Carlo Simulation analysis of the tree is performed by selecting Analysis gt Monte Carlo Simulation OpenFTA Monte Carlo x There are 14 basic events in the tree Number of simulations fioooo Unit Time fi 0 Estimated run time 05 Cancel Help Figure 10 Monte Carlo Dialog Pressing OK on the resulting dialog displays a report file associated with the fault tree which is valid until the tree is next edited At any later time reports can be viewed and printed This is achieved through the options of the Report menu Decomposing Fault Trees The transfer in facility supports the splitting of large
28. printed FTA canvas Cross References Print Preview Dialog OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Print Preview Dialog Control Type Dialog Function Controls the layout of the printed FTA canvas Location Invoked from Print Preview Operation The dialog consists of e atoolbar containing 3 buttons o A Printer Setup button that launches the Print Dialog allowing the selection of the current printer A Page Setup button that launches the Page Setup Dialog allowing the specification of the paper size orientation o A Print button that launches the Print Dialog allowing the FTA Canvas to be sent to the selected printer awindow previewing what the output will look like using the current settings e a Horizontal Pages spin button that adjusts the number of horizontal pages required e a Vertical Pages spin button that adjusts the number of vertical pages required e Zoom spin button that adjusts the scale of the preview window On activation of the OK button the current setting are confirmed and the dialog is removed from the screen On activation of the Cancel button the current settings are discarded and the dialog is removed from the screen On activation of the Help button a dialog containing context sensitive help information is displayed Cross References Page Setup Dialog Print Dialog and Print Preview OpenF
29. same as any other primary event with the exception that the symbol on the canvas is drawn with a double line Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Edit OpenFTA Control Type Pulldown Menu Function Provides access to facilities for manipulation and alteration of the currently displayed fault tree Location OpenFTA menubar gt Edit Shortcuts Accelerator None Toolbar None Pre conditions None Operation Used to invoke the operations that alter the fault tree displayed on the main OpenFTA canvas area Cross References OpenFTA Cut OpenFTA Delete OpenFTA Link Paste OpenFTA Preferences Selected Shift Left Shift Right and Undo OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Edit OpenPED Control Type Pulldown Menu Function Allows access to the facilities for editing the primary events database Location OpenPED menubar gt Edit Shortcuts Accelerator None Toolbar None Pre conditions None Operation This menu is used to access the Cut Copy and Paste operations used to manipulate data between the ID Probability and Description fields It also provides the facility to Delete Primary Events from the Primary Event Database Cross References Copy OpenPED Cut Ope
30. selected fault tree symbol and the sub tree below it one position to the left Location OpenFTA menubar gt Edit gt Shift Left Shortcuts Accelerator Ctrl L Toolbar None Pre conditions A symbol on the canvas is selected Operation On activation the selected fault tree symbol and the sub tree below it are shifted one place to the left The layout of the fault tree is handled automatically The operation is available for purely aesthetic reasons and has no effect upon the analysis of the tree Note that Conditioning Events may not be shifted and if this operation is attempted an error dialog is displayed Cross References Shift Right and Undo OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Shift Right Control Type Menu Option Function Shifts the currently selected fault tree symbol and the sub tree below it one position to the right Location OpenFTA menubar gt Edit gt Shift Right Shortcuts Accelerator Ctrl R Toolbar None Pre conditions A symbol on the canvas is selected Operation On activation the selected fault tree symbol and the sub tree below it are shifted one place to the right The layout of the fault tree is handled automatically The operation is available for purely aesthetic reasons and has no effect upon the analysis of the tree Note that Conditioning Events may not be shifted and if this is a
31. 194 194 194 194 194 194 194 194 194 194 194 194 194 94 94 94 94 94 94 94 94 94 94 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 59 006 04 04 04 04 04 04 04 04 04 04 04 04 101 KTlinc 1 Tline inc S1 T2 T2inc K5 KT1 T3 K5 S1 T4 K5 KT2 4 KT3 T1 T2 S1 T2 T2inc inc Tlinc T2 Tlinc T2 T4 KT3ine 81 T3 S1 T2 T4 1 T2inc 4 KT3inc Tline T2 K5 KT3inc K5 K2 K5 T1 KT3 T4 2 51 T2 KT2inc Tl T2 K5 Tlino T3inc K5 Tlinc T2inc SL Ti T3 KT2 Tline T2 K5 KTlinc T2inc K2 K5 Tlinc lure mode T3 S1 K5 T2 TL K5 T2 165 K5 166 KT1 167 K2 168 Kl 169 K2 170 K1 171 K1 172 KT3 173 K2 174 K5 175 K2 176 K5 177 K1 178 K2 179 K1 180 K1 181 K5
32. 3inc T2 T4 KTlinc KT2inc T2 4 T4inc KTlinc KT3 KT3inc T2 T3inc TA KTlinc T2 T3inc 4 T4inc KT1 KT2 KT2inc KT3 KT3inc T2 T2inc OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Order Order Order Order Order Order Order Order Order Order Order 103 11 121 13 14 153 16 17 18 KT1 KT1 Chapter 3 OpenFTA Reference KT2 KT2inc KT3 T2 T2inc T4inc KT2 KT3 KT3inc 2 2 T3inc KT2 KT3 T2 T2inc T3inc T4inc KT2inc KT3 KT3inc T2 T2inc T4 KT2inc T2 T2inc 4 4 KT3inc 2 TZinc T3inc T4 KT3 T2 T2inc T3inc T4 T4inc Qualitative Importance Analysis OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd ALL Chapter 3 OpenFTA Reference 26 16 54 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference The Probability Analysis Report This report shows an example of the results obtained when a quantitative evaluation is performed upon the minimal cut sets of a fault tree The evaluation produces the minimal cut set probabilities according to the defined primary event probabilities A series expansion is then performed to calculate the probability of occurrence of the top level event of the fault tree for the given minimal cut sets This ser
33. 4 877835E 006 2 438917E 006 1 KT2 T2 4 4 877835E 006 2 438917E 006 1 K2 K5 4 4 877835E 006 2 438917E 006 K5 T1 T3 4 4 877835E 006 2 438917E 006 KTlinc S1 T2 4 4 877835E 006 2 438917E 006 1 K5 KT3 4 4 877835E 006 2 438917E 006 1 5 4 4 877835E 006 2 438917E 006 K2 K5 KTlinc 4 4 877835E 006 2 438917E 006 K5 S1 T2inc 4 4 877835E 006 2 438917E 006 K1 T2 T4inc 4 4 877835E 006 2 438917E 006 K5 T2 T3 4 4 877835E 006 2 438917E 006 K2 K5 KT2 4 4 877835E 006 2 438917E 006 K2 K5 T2 3 3 658376E 006 2 112164E 006 K1 T2 I3 3 3 658376E 006 2 112164E 006 KT1 S1 T2 3 3 658376E 006 2 112164E 006 K1 K5 KT3inc 3 3 658376E 006 2 112164E 006 K2 S1 T2 3 3 658376E 006 2 112164E 006 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd N N N N N w w w w w Chapter 3 OpenFTA Reference 88 K2 K5 Tlinc 3 3 658376E 006 2 112164 006 0 13 89 51 2 3 3 658376E 006 2 112164 006 0 13 90 K1 K5 T4inc 3 3 658376E 006
34. 59 006 219459 006 219459 006 219459 006 Importance 307324 005 300870E 005 258469 005 274871 005 174606 005 171184 005 150539E 005 044487 006 Copyright 2005 Formal Software Construction Ltd 1 3 15 14 12 L3 12 13 04 04 04 04 04 e e n 04 04 e n e n e n o o e e e n oe 04 04 04 102 Chapter 3 OpenFTA Reference 9 Tlinc T2 T3 6 7 316752E 006 2 987051E 006 10 Tlinc T2 4 4 877835E 006 2 438917 006 11 K5 KT3 4 1 1 219459 006 1 219459E 006 Primary Event Analysis Event Failure contrib Importance K1 7 658200 004 27 45 K2 4 316884 004 15 47 K5 2 064544 003 73 99 KT1 1 219459 006 0 04 KTlinc 0 000000E 000 0 00 KT2 0 000000E 000 0 00 KT2inc 0 000000E 000 0 00 KT3 1 219459 006 0 04 0 000000E 000 0 00 5 8 584989 004 30 77 3 926657 004 14 07 Tlinc 2 560863E 005 0 92 T2 8 292320 004 29 72 2 0 000000E 000 0 00 T3 4 438829E 004 15 91 T3inc 0 000000E 000 0 00 T4 1 219459 006 0 04 T4inc 0 000000E 000 0 00 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd 103 Chapter 3 OpenFT
35. 7051 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 987051 006 726792 006 126792 006 726792 006 726792 006 Copyright 2005 Formal Software Construction Ltd w w Ww w w w w Chapter 3 OpenFTA Reference K2 K5 T3 5 6 097293E 006 2 726792 006 Ki T2 5 6 097293E 006 2 726792 006 K1 Tlinc T2 5 6 097293E 006 2 726792 006 K5 KT2 T3 5 6 097293E 006 2 726792 006 K5 KT2inc T1 9 6 097293E 006 2 726792 006 K2 K5 5 6 097293E 006 2 726792 006 1 K5 5 6 097293E 006 2 726792 006 K5 51 Tlinc 5 6 097293E 006 2 726792 006 K5 T3 T4 5 6 097293E 006 2 726792 006 51 Tlinc T2 5 6 097293 006 2 726792 006 K1 T2 T3inc 4 4 877835E 006 2 438917E 006 K5 KT2inc T3 4 4 877835E 006 2 438917E 006 K5 51 11 4 4 877835E 006 2 438917E 006 T2 4 4 877835 006 2 438917 006 K1 K2 T2 4 4 877835E 006 2 438917E 006 K5 T1 Tlinc 4 4 877835E 006 2 438917E 006 K1 K5 T2inc 4 4 877835E 006 2 438917E 006 K5 S1 T4inc 4 4 877835E 006 2 438917E 006 K1 5 51 4 4 877835E 006 2 438917E 006 K2 K5 51 4 4 877835E 006 2 438917E 006 5 Tlinc T3 4 4 877835E 006 2 438917E 006 K5 KT3inc 51 4 4 877835E 006 2 438917 006 2 51 T2 4
36. A Reference The Primary Event Database Report This report shows an example of the primary events in a primary events database It details the Jd Type Description Probability of each and every event in the database Primary Events Database Database Filename Three Motor Example Motor 2 Only ped IDs T3 Probability 0 02 Type Undeveloped Dormant No Description Reset signal inadvertently applied or not removed from switch S1 ID 51 Probability 0 02 Type Basic Dormant No Description 51 switch inadvertently closes or fails to open ID T4 Probability 0 02 Type Undeveloped Dormant No Description KT2 timer does not time time out due to improper installation setting ID KT2 Probability 0 02 Type External Dormant No Description KT2 timer reset ID Probability 0 02 Type External Dormant No OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd or 104 Description ID Probability Chapter 3 OpenFTA Reference KT3 timer reset 0 02 Type External Dormant No Description ID T1 Probability timer reset 0 02 Type Undeveloped Dormant No Description ID K2 Probability Type Basic Dormant No Description ID T2 Probability EMF to K2 coil through S1 KT1 KT2 amp KT3 circuits 0 02 K2 relay contacts fail to open 0 02 Type Undeveloped Dormant No De
37. Formal Software Construction Limited CBTC Senghenydd Road Cardiff CF24 4AY Wales UK Tel 44 0 29 2064 6080 Fax 44 0 29 2064 7009 Web www fsc co uk Email fta fsc co uk OpenFTA Version 1 0 User Manual Disclaimer Formal Software Construction FSC Ltd provides this User Manual as is and free of charge It assumes no responsibility for its correctness or for maintaining its correctness and assumes no liability whatsoever for any losses resulting directly or indirectly from its use Copyright 2005 Formal Software Construction Ltd Chapter I Introduction Chapter 4 Dra 4 What is OpenFTA T PH 4 165 MM 4 This Manual pp 4 Chapter 2 OpenFTA eth ea P ota eeu S bb 5 lcu MT 5 SACS pe Ma E 5 Getting e 7 Drawing A Fault Tres nai 7 lusti MR c 8 File Storage E 8 PANUNG me c 9 Providing Primary Event Information sensuel nt 10 Connecting Trees With Databases uni Ya Erben 12
38. OpenFTA Reference Apply OpenPED Control Type Push Button Function Provides a means to accept a new or modified entry into the primary events database Location OpenPED gt Apply Shortcuts Accelerator None Toolbar None Pre conditions None Operation On activation the data in the ID Probability and Description text fields the Type radio buttons and the Constant Failure Rate Unit Time and Dormant toggle buttons are validated If the ID is valid and an event with that JD does not already exist in the database a new entry with the supplied data is added to the database and the Primary Events list updated accordingly If the ZD is valid and an event with that JD does exist in the database then if the Type of event has been altered OpenFTA requests confirmation before overwriting the existing database entry with the supplied data Cross References Clear OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Clear OpenPED Control Type Push Button Function Provides a means to clear the fields in the primary events database window Location OpenPED gt Clear Shortcuts Accelerator None Toolbar None Pre conditions None Operation On activation this causes the JD and Description text fields to be cleared the Type radio buttons to be deselected and the Constant Failure Rate Unit Time and Dormant to
39. Software Construction Ltd Chapter 3 OpenFTA Reference Minimal Cut Sets Control Type Menu Option Function Calculates the minimal cut sets for the currently displayed fault tree Location OpenFTA menubar gt Analysis gt Minimal Cut Sets Shortcuts Accelerator None Toolbar None Pre conditions The fault tree has been saved and is logically valid Operation This menu option is used to initiate the generation of the minimal cut sets for a fault tree When invoked a minimal cut sets dialog with the title OpenFTA Minimal Cut Sets is presented This dialog is used to specify whether or not to use the minimal cut sets already on file and to specify which orders of minimal cut sets should be generated If a minimal cut sets file already exists then the Use minimal cut sets on file toggle button is selected and the directory path to the minimal cut sets file is displayed as well as the number and order of the available minimal cut sets If the Generate all minimal cut sets toggle button is selected all orders of minimal cut sets for the fault tree will be calculated If the Limit minimal cut set order to toggle button is selected only minimal cut sets up to a specific order will be generated The required maximum cut set order is specified using the stepper the two back to back arrows OpenFTA Minimal Cut Sets Algebraic Method x There are 14 basic events in the tree r Minimal cut sets file
40. TA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial OpenFTA Database lift ped OT x File Edit Help Deas d Be gt Primary Events Probability CP_1 DMS 1 DMS 2 Constant Failure Rate Unit Time DM_1 DOD_1 r Type DOD 2 DPD 1 Basic C External Undeveloped Conditional not analysed D_1 Conditional analysed LMD_1 LMD_1_1 LMD_2 LPD 1 PS 1 Dormant Description 14 Apply Clear Help Figure 7 OpenPED Window Adding an event to a database requires a minimum amount of information for that event Every event must have a unique ID within the primary events database it must have a probability of failure and it must have a type In practice the events will include a textual description to distinguish them or provide further information The probabilities are applied by one of two models probability model P model or lambda model model The P model is used to state the probability of a primary event failing as an absolute value The model is used to state the probability that a primary event will fail within a unit time period i e as a function of time Each event s probability can be set according to the model that is appropriate See Appendix A for more details An event is added to the database by filling in the m
41. TA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Printer Setup Control Type Menu Option Function Allows the selection of the target printer Location OpenFTA and OpenPED menubar gt File gt Printer Setup Print Preview dialog toolbar Shortcuts Accelerator None Toolbar Print Preview dialog only za Pre conditions None Operation Invokes the print dialog that allows the target printer to be selected Cross References Print Print Dialog Print Preview Page Setup OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Report Control Type Pulldown Menu Function Provides access to the analysis reports generated by OpenFTA Location OpenFTA menubar gt Report Shortcuts Accelerator None Toolbar None Pre conditions None Operation Used to access the analysis reports generated by the OpenFTA application Cross References Minimal Cut Sets Monte Carlo Simulation Numerical Probability Print OpenFTA Report Validate and View OpenFTA Report OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Save OpenFTA Control Type Menu Option Function Stores the current fault tree to a file Location OpenFTA menubar gt File gt Save Shortcuts Acc
42. al Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Print Dialog Control Type Dialog Function Prints an image to a printer Location Invoked from Print OQpenFTA Printer Setup OpenFTA Print OpenPED Printer Setup OpenPED and Print OpenFTA Report Operation The dialog consists of e aPrinter Name list allowing the destination printer to be specified e a Properties button that invokes the properties dialog specific to the currently selected printer e a Print Range panel allowing a subset of pages to be selected for printing e Copies panel where the number of required copies can be set On activation of the OK button the document is sent to the selected printer and the dialog is removed from the screen On activation of the Cancel button the procedure is aborted and the dialog is removed from the screen On activation of the Help button a dialog containing context sensitive help information is displayed Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Print Preview Control Type Menu Option Function Invokes the Print Preview Dialog Location OpenFTA menubar gt File gt Print Preview Shortcuts Accelerator None Toolbar None Pre conditions None Operation Invokes the Print Preview Dialog that controls the layout of the
43. annotated but this is not obligatory OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Chapter 3 OpenFTA Reference Overview This reference section describes each of the user interface controls provided by OpenFTA For each control brief descriptions of form and function are followed by an explanation of usage and effect OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Analysis Control Type Pulldown Menu Function Provides access to facilities for analysing fault trees Location OpenFTA menubar gt Analysis Shortcuts Accelerator None Toolbar None Pre conditio ns None Operation This menu provides the following options e Validate determines if the fault tree currently displayed is valid and hence ready for further analysis e Minimal Cut Sets displays a dialog from which minimal cut set generation is initiated e Numerical Probability displays a dialog from which a deterministic qualitative analysis of the fault tree is initiated e Monte Carlo Simulation displays a dialog from which a statistical analysis of the fault tree is initiated Cross References Minimal Cut Sets Monte Carlo Simulation Numerical Probability and Validate OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3
44. are Construction Ltd Chapter 3 OpenFTA Reference Appendix B The Three Motor Example Overview This appendix briefly describes an example of a system suitable for analysis by OpenFTA and presents the results of such an analysis The data files generated are included in the OpenFTA delivery package Three Motor Example Test Sional 1 1 cl 1 Batterv 1 S1 T 4 m Ratterv 2 Figure 14 Power Distribution Box The above figure displays a power distribution box With contacts KT1 KT2 and KT3 normally closed a momentary depression of button 51 applies power from Battery 1 to the coils of relays and K2 and 2 close and remain electrically latched Next a 60 second signal is passed through K3 in order to test the operation of Motors 1 2 and 3 Once K3 has closed power from Battery 1 is applied to the coils of relays 4 and 5 The closure of K4 starts Motor 1 The closure of K5 applies power from Battery 2 to the coil of and also starts Motor 2 Finally the closure of K6 applies power from Battery 1 to the coil of K7 Closure of K7 starts Motor 3 This example is based on one presented in the Fault Tree Handbook U S Nuclear Regulatory Commission NUREG 0492 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference After 60 seconds K3 is supposed to open shutting down all three motors Should K3 fail
45. around large fault trees Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Undo Control Type Menu Option Function Undoes the last edit action carried out upon the fault tree Location OpenFTA menubar gt Edit gt Undo Shortcuts Accelerator Ctrl U Toolbar None Pre conditions One of the edit actions Copy Cut Delete Paste Shift Left or Shift Right has been carried out or a symbol has been added to the fault tree Operation On activation the last edit action or symbol addition to the fault tree is undone Note that if the Undo option is selected twice in a row it undoes the first undo action Cross References Copy Cut Delete OpenFTA Paste Shift Left Shift Right and Symbol Palette OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Validate Control Type Menu Option Function Verifies that the current fault tree is logically correct and ready for analysis Location OpenFTA menubar gt Analysis gt Validate Shortcuts Accelerator None Toolbar None Pre conditions The fault tree displayed on the canvas has been associated with a primary events database and been saved Operation On selection of this option a validation report is produced and displayed The report contains any warnings or errors found with
46. cted printer or to a file On activation a dialog titled Print is displayed For more details read the section entitled Print Dialog Cross References Print Dialog OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Print OpenFTA Report Control Type Menu Option Function Prints any of the three generated reports Qualitative Report Probability Report and Monte Carlo Report Location OpenFTA menubar gt Report gt Print Shortcuts Accelerator None Toolbar None Pre conditions None Operation On activation a slide right menu is displayed containing three options Qualitative Report Probability Report and Monte Carlo Report By choosing any one of the available reports a dialog titled Print is displayed For more details on the use of this dialog read the section titled Print Dialog Note that if the appropriate analyses that generate the reports have not been performed then the relevant options are greyed out For the Qualitative Report to be available for printing the minimal cut sets must have been generated For the Probability Report the Numerical Probability analysis must have been carried out and for the Monte Carlo Report the Monte Carlo Simulation must have been performed Cross References Minimal Cut Sets Monte Carlo Simulation Numerical Probability and Print Dialog OpenFTA Version 1 0 User Manu
47. ds such as the estimated probability are adjusted accordingly a table titled Basic Event Analysis This contains a list of all of the primary events in the fault tree and their failure contribution towards the top level event occurring This contribution is als o stated as a percentage importance value for each primary event Cross References Analysis Minimal Cut Sets Print OpenFTA Report Validate and View OpenFTA Report OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd New OpenFTA Control Type Menu Option Function Provides a blank canvas area for the drawing of a new fault tree in the OpenFTA window Location Chapter 3 OpenFTA Reference OpenFTA menubar gt File gt New Shortcuts Accelerator Ctrl N Toolbar A Pre conditions None Operation Used to create a canvas displaying a single empty intermediate top level event The application is then ready for the drawing of a new fault tree If the fault tree currently on display has been modified and not saved then confirmation is requested before OpenFTA proceeds with the New operation Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference New OpenPED Control Type Menu Option Function
48. e mode the list of primary events which occurred to cause the top event OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference The data is then used to obtain both the top level probability and the probabilities of individual cut sets For example for N trials resulting in F failures the probability would be estimated as F vF N One refinement of this scheme is made Consider a tree with 30 primary events with probabilities of the order of 10 In this case in approximately 97 of trials no primary event would occur and the fault tree would be evaluated with no faults All these runs would be effectively useless and therefore a waste of computational time To avoid this only trials in which at least one primary event occurs are simulated The probability P of at least one primary event occurring is evaluated exactly Thus the probability of the top event occurring is estimated as P F F N It should be noted that the failure modes generated by this method are not minimal For example if A and BC are minimal cut sets the Monte Carlo method will report A AB AC BC and ABC separately To deal with this the Monte Carlo Report generated by OpenFTA provides a Compressed list of cut sets in which supersets of other cut sets are removed These compressed cut sets are likely to be but are not guaranteed to be minimal When a set is removed its failure count
49. e has not been stored previously then the Save operation acts in the same way as the Save As operation If the output file does not have write access then an error dialog is displayed In order to save the database the permissions must be changed or the Save As operation must be used to store the database to a file with a different name and or directory location Cross References Save As OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Save As OpenFTA Control Type Menu Option Function Stores the current fault tree to a named file Location OpenFTA menubar gt File gt Save As Shortcuts Accelerator Ctrl A Toolbar None Pre conditions None Operation Used to store the open fault tree to a named file The file name is usually of the form lt name of tree gt fta On activation a file selection dialog titled Save is displayed For more details on the use of this dialog read the section titled File Selection Dialog Note that on activation of the OK button the fault tree is stored to the currently selected file and the Save dialog is removed If no file is selected then an error dialog is displayed If the output file does not have write access then an error dialog is displayed In order to save the fault tree the permissions must be changed or the Save As operation must be used to store the fault tree to a
50. ed several times since the clipboard retains its contents until they are overwritten by a Copy or Cut operation Cross References Copy OpenFTA Cut OpenFTA and Undo OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Paste OpenPED Control Type Menu Option Function Places the clipboard contents to the place marked by the cursor into the Id Probability or Description fields Location OpenPED menubar gt Edit gt Paste Shortcuts Accelerator Ctrl V Toolbar Pre conditions Text has previously been Cut or Copied onto the clipboard or to paste into the Probability fields data in a decimal or exponential format has previously been Cut or Copied onto the clipboard Operation A copy of the clipboard contents is added into one of the text fields where the cursor is currently situated If text is currently highlighted the clipboard contents replace the highlighted text If non numerical data is pasted into the Probability field white space will be pasted instead The Paste operation can be repeated several times since the clipboard retains its contents until they are overwritten by a Copy or Cut operation Cross References OpenPED Cut OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Preferences Control Type Menu Option Function Invoke
51. eferences None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Export Text File Control Type Menu Option Function Exports the OpenPED database as a text file Location OpenPED menubar gt File gt Export Text File Shortcuts Accelerator Ctrl E Toolbar None Pre conditions None Operation Exports the OpenPED database as a text file A file selection dialog is posted allowing the target file to be specified Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference File Open FTA Control Type Pulldown Menu Function Provides access to facilities for manipulating fault tree files Location OpenFTA menubar gt File Shortcuts Accelerator None Toolbar None Pre conditions None Operation Used to invoke the following operations New Open Save Save Export Image Printer Setup Page Setup Print Preview Print Database and Exit Cross References Database Exit Export Image New OpenFTA Open OpenFTA Page Setup Page Setup Dialog Print OpenFTA Print Dialog Print Preview Printer Setup Save OpenFTA and Save As OpenFTA OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference File Open PED
52. elerator Ctrl S Toolbar Pre conditions None Operation Used to store the currently displayed fault tree to a file On activation if the fault tree has been previously stored then the tree is stored to the same file This overwrites any previous contents held within the file The file name is of the form lt name of tree gt fta If the tree has not been stored previously then the Save operation acts in the same way as the Save As operation If the output file does not have write access then an error dialog is displayed In order to save the fault tree the permissions must be changed or the Save As operation must be used to store the fault tree to a file with a different name and or directory location Cross References Save As OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Save OpenPED Control Type Menu Option Function Stores the current primary events database to a file Location OpenPED menubar gt File gt Save Shortcuts Accelerator Ctrl S Toolbar Pre conditions None Operation Used to store the currently displayed primary events database to a file On activation if the database has been previously stored then it is stored to the same file This overwrites any previous contents held within the file The file name is of the form lt name of database gt ped If the databas
53. elete Event OpenPED Control Type Menu Option Function Removes the currently selected primary event from the primary events database displayed in the OpenPED window Location OpenPED menubar gt Edit gt Delete Shortcuts Accelerator Ctrl D Toolbar M Pre conditions An item in the Primary Events list is selected Operation Used to remove the currently selected primary event from the database Confirmation is requested before this action is completed since no Undo operation is available Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Dormant Control Type Check Box Function Provides a means to depict a primary event as being dormant Location OpenPED gt Dormant Shortcuts Accelerator None Toolbar None Pre conditions None Operation If set on activation of the Apply button the current event will be entered into the primary events database as a dormant event Dormant events are special case primary events They may fail with no visible external effects An example is the failure of a filament in a warning lamp if the light is not on then it would normally be assumed that the system which it is monitoring does not require a warning to be issued However it could be that both the lamp filament and the subsystem it monitors have failed In OpenFTA the dormant event is treated the
54. fault trees into more manageable chunks Because each tree transferred in exists as a fault tree in its own right all of the OpenFTA operations including analyses can be applied to that tree individually Any tree may be transferred into any other tree any number of times Trees may be broken up to support team working to reflect redundancy in the systems or maybe to defer working on a little known area of a system Transfer in trees make large trees easier to manage but have no impact on the analysis Each sub tree can be analysed in isolation or the analysis may be performed on the top level tree OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial To include a transferred in tree add a transfer in symbol at the required position in the tree and multi click on the transfer in symbol This displays a dialog to add an JD This ID is equivalent to a tree name and is displayed on the tree with a ft a extension to reinforce this concept If a sub tree has been identified as a candidate for converting into a transfer in tree the sub tree can be cut or copied the File gt New option selected and the sub tree pasted onto the canvas area and saved in the normal manner A transfer in symbol with the ID of the newly created tree can then be added to the original tree If a tree is used as a transfer in tree the top level intermediate event may have a transfer out symbol added and
55. fied The toolbar provides access to the Printer and Page Setup dialogs along with a button to print the tree el OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial Horizontal Pages F6 7 Vertical Pages b D EP pene is OK Cancel Help Figure 6 Print Preview Dialog Providing Primary Event Information To complete the drawing of a fault tree information on the primary events within the tree must be supplied This is achieved either by retrieving the events from an existing primary events database or by creating a new database Databases are accessed through the OpenPED window This window has a menubar and toolbar akin to those found on the OpenFTA window a scrolled list of the primary events within the open database and the details of the selected primary event Separating the primary events from the fault tree drawing allows many benefits including the partitioning of work and allowing multiple trees to share a single database It decouples the process of producing a fault tree for a system from the mechanics of describing the individual events that influence the system This separation also allows a single primary event to appear in a tree or in many trees without the need to duplicate the primary event details for every occurrence Primary event details can exist in a database without appearing in a tree OpenF
56. g and printing fault trees The task of the analyst is aided by the tool s many facilities and features which include e a point and click graphical user interface enabling rapid drawing of fault trees e support for the full set of fault tree symbols in accordance with NUREG 0492 e a database for storing primary event definitions e qualitative analysis of fault trees to determine minimal cut sets e quantitative analysis of fault trees including a Monte Carlo Simulation facility Pre Requisites This manual assumes that the user is familiar with modern software packages that have graphical user interfaces GUIs This manual is not intended to be a textbook on fault tree analysis It is assumed that the user is familiar with the methodologies involved in the drawing and analysis of fault trees and the terminology employed in the discipline This Manual This manual is divided into two main sections e OpenFTA Tutorial introduces the facilities offered by OpenFTA by working through the process of drawing and analysing a fault tree e the OpenFTA Reference provides a comprehensive description of each of the facilities and functions provided by OpenFTA Throughout the document when a new term is introduced in the text it is highlighted in a bold font Text that is in an italic font is text that is displayed by the OpenFTA user interface Al OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd
57. ggle buttons to be deselected and the probability set to zero Cross References Apply OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Copy OpenFTA Control Type Menu Option Function Copies the current selection and the entire sub tree below it from the fault tree displayed in the OpenFTA window to the clipboard Location OpenFTA menubar gt Edit gt Copy Shortcuts Accelerator Ctrl C Toolbar 45 Pre conditions A symbol on the canvas is selected Operation Used to place a copy of the current selection and the sub tree below it to the clipboard Selections copied to the clipboard are available for the Paste operation Any information previously held on the clipboard is lost when a Copy operation is carried out Cross References Cut Paste and Undo OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Copy OpenPED Control Type Menu Option Function Copies the current selected text from the Id Probability or Description fields to the clipboard Location OpenPED menubar gt Edit gt Copy Shortcuts Accelerator Ctrl C Toolbar Pre conditions Text in one of the text fields is selected Operation Used to place copy of the currently selected text from the ID Probability or Description text fields onto the clipboard Selections c
58. hat the minimal cut sets are neither mutually exclusive nor independent The general expression for the probability of the OR of n arbitrary events is P M U M U UM P M 1 1 2 j l n il j l OAM OM i 3 j 2 k l 1 P M AM m M This is a sum of terms each of which is the probability of the AND of minimal cut sets The probability of the AND of several minimal cut sets is not simply the product of their individual probabilities as they may share primary events Assuming the primary events are independent it is the product of the probabilities of all the primary events that occur in any cut set taking each one only once This series however has 2 terms where N is the number of minimal cut sets In general it would take a prohibitively long time to evaluate all the terms in this series even for fairly small trees For example a tree with 20 basic events could have 100 minimal cut sets which would imply more than 10 terms In Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference fact it is not necessary to evaluate all the terms The following series gives ever closer approximations to the exact result Y PM n id i 2 j l n i l jd P M n M nM k 3 UN N i 3 j The series has N terms each of which has NCr sub terms giving 2N terms in all The first term is simply the sum of probabilit
59. ht 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial constructed with emphasis on how the system decomposes without knowledge of the details behind the primary events The OpenPED window will be discussed in more detail later in this chapter Getting Help OpenFTA assists the user by providing help screens Overall help for OpenFTA is available under the Help menu option Context sensitive help is available from the Help buttons on the dialogs Tool tips are also provided on menu options and dialog controls To display help on a particular topic select Help gt Index to popup the help index list and click on any item to display its help screen Drawing A Fault Tree The basic mode of operation when drawing a fault tree with OpenFTA is to select a parent symbol on the canvas then select a control to manipulate that symbol The insertion of fault tree symbols is achieved by such a mechanism Selecting one of the available symbols from the symbol palette inserts that symbol below the selected symbol As usual if any symbol is inapplicable it is greyed out As the fault tree is extended it may become too large to be viewed on the canvas Hidden areas of the fault tree can be viewed by using the scrollbars to navigate around or by selecting the View gt Tree Overview option This presents a resizeable window which contains a scaled version of the fault tree Selecting a symbol within the overview causes the corresponding sy
60. ies expansion is detailed in Appendix A The number of terms is user definable but the calculation time of the series will increase quickly as the number of terms is increased with only a relatively small gain in precision A primary event analysis is carried out and the failure contribution and importance of each primary event is displayed Probabilities Analysis Tree Three Motor Example Motor 2 Only fta Time Thu Feb 28 13 19 37 2002 Number of primary events 18 Number of minimal cut sets 54 Order of minimal cut sets 18 Unit time span 1 000000 Minimal cut set probabilities 1 1 5 4 000000 004 2 K1 T2 4 000000 004 3 2 K5 4 000000E 004 4 5 51 4 0000 00E 004 5 5 4 000000 004 6 K5 T3 4 000000 004 7 51 2 4 000000 004 8 K2 Tlinc T2 8 000000E 006 9 T1 Tlinc T2 8 000000 006 10 Tlinc T2 T3 8 000000 006 11 K5 2 KT3 1 600000 007 12 K5 KT3 4 1 600000 007 13 K2 KTlinc 2 KT3inc T2 3 200000 009 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd 14 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 a 38 39 40 41 42 43 44 45 K2 KTlinc K2 KTlinc K2 KTlinc K2 KT2inc K2 KT2inc K2 KT3inc K2 T2 T2in KT1 KT2 KT KT1 KT3 1 KTlinc KT2 KTlinc KT2 KTline KT2 KTline KT2 KTlinc KT3 KTlinc KT3
61. ies of the minimal cut sets The increments in the series alternate in sign and it can be shown that the terms always bracket the answer i e the first term is an upper bound the second a lower bound the third a better upper bound etc Thus the result can be made arbitrarily accurate by specifying a sufficient number of terms i e Vxdn P P lt x Vi gt n where P P M UM v UM In practice the terms get smaller rapidly and it is rarely necessary to go past the third term for a large tree For 100 minimal cut sets the first term has 100 sub terms the second 4950 the third 161 700 and the fourth 3 921 225 It is safest to calculate the default two terms first progressing to higher terms one at a time if necessary Monte Carlo Simulation The principle behind the Monte Carlo methodology is to simulate occurrences of the primary events component failures using a random number generator For each trial each primary event is simulated by generating a pseudo random real number in the range 0 to 1 inclusive If this number is less than equal to the probability of the primary event the event is deemed to have occurred and its value is set to TRUE Otherwise it is deemed not to have occurred and its value is set to FALSE The fault tree is then evaluated with these values for the primary events to see if the top event occurs system failure The number of top event occurrences is stored together with the corresponding failur
62. iew option a slide right menu is displayed containing three options Qualitative Report Probability Report and Monte Carlo Report By choosing any one of the available reports a OpenFTA View Report dialog containing the associated information is displayed Note that for the Qualitative Report to be available for viewing the minimal cut sets must have been generated For the Probability Report the Numerical Probability analysis must have been performed and for the Monte Carlo Report the Monte Carlo Simulation must have been performed If the appropriate analyses that generate the reports have not been done then the relevant options are greyed out Cross References Minimal Cut Sets Monte Carlo Simulation and Numerical Probability OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Zoom In Control Type Menu Option Function Increases the zoom value of the OpenFTA canvas Location OpenFTA menubar gt View gt Zoom In Shortcuts Accelerator None Toolbar Pre conditions None Operation Increases the zoom value of the OpenFTA canvas by 10 Cross References Set Zoom Zoom Out OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Zoom Out Control Type Menu Option Function Decreases the zoom value of the OpenFTA canvas Location OpenFTA menubar gt
63. inimum information in the details area of the OpenPED window and pressing Apply If the information supplied is valid the event JD is added to the list of events in the database An event may be modified by selecting it in the Primary Events list which causes its details to be displayed modifying the required information and selecting Apply If the details are invalid the database is unaffected and if the changes cannot be corrected or should be discarded Clear can be pressed The OpenPED window provides similar File options to the OpenFTA window OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial Connecting Trees With Databases When a primary events database has been saved it can be associated with the fault tree This is performed by selecting the File gt Database option on the OpenFTA window Note that a fault tree may be associated with only one database Opening a saved fault tree automatically opens the associated primary events database in the OpenPED window Associating a database with a fault tree is only the first step in preparing the fault tree for analysis Every primary event symbol on the fault tree must be linked to a primary event definition in the database This is performed by selecting a primary event on the tree selecting the required primary event in the primary events database and selecting Edit gt Link or the corresponding toolbar icon on the
64. is added to each of its subsets Consider the previous example a failure ABC would count as both A and BC Note that the sum of failures for all the compressed cut sets will therefore be greater than the total number of failures This is consistent with the probabilities generated in the numerical probability analysis The P model and the model OpenFTA supports the P model or model definition of the probability of a primary event occurring A P model definition is used to state the probability of an event occurring when the time to failure event occurring is unknown or unpredictable model definition is used to state the probability that a primary event will occur within a given period of time A model definition is appropriate for events within systems that are continuously operating and have a known probability of failure during a unit time period Each event defined in terms of the model has a probability of failure given by 1 where t unit time to event occurring and 1 constant Events defined in terms of the P model do not have to be modified for time The probability of a cut set is the multiplication of the probabilities of the events within it as determined by the P or models For more details see the Fault Tree Handbook U S Nuclear Regulatory Commission NUREG 0492 and Introduction to Reliability Engineering E E Lewis 83 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Softw
65. losed for 160 sec ORI E2 EMF nol removed from relay coil when K3 contacts K1 relay closed for 60 sec contacts fall to open oR CA EMF lo K1 coil through timer circuit when K3 a KT1 timer does not time out due los KT1 timer contacts fall to open KT2 timer contacts falto opon KT2 timer does no time due to contacts viosed for 1260 sec AND1 E5 E KT1 timer contacts fll KT2 timer contacts fail KTS timer contacts fail to open when K3 to open when K3 to open when K3 contacts closed for contacts closed for contacts closed for P60 sec 160 sec 1260 sec ons KT3 timer does nol ime out due to KT3 timer contacts fall to open OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd E4 EMF to K1 coil through 51 contacts when K3 contacts viosed for 160 sec S1 switch inadvertently closes or fails to open Resel signal inadvertently applied or Chapter 3 OpenFTA Reference The Qualitative Analysis Report This report shows an example of the results obtained by generating minimal cut sets for a fault tree The minimal cut sets for each order and the distribution of minimal cut sets to orders is displayed Minimal
66. may be longer than that which can be displayed within a symbol s boundary In this case the text is truncated and ended with a continuation indicator to show that more text exists NI OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial Primary event IDs and details are entered in a different manner consistent with their characteristics within OpenFTA Multi clicking on a primary event symbol does not popup a dialog but selects the primary event in the database This will be described later in this chapter If the cursor falls outside the boundary of any symbol a dialog allowing free format descriptive text for the whole tree is displayed This text is always displayed in the top left of the canvas area and on any hardcopy of the tree The gate dialog provides the ability to change a gate s type if necessary Preferences The preferences dialog allows the colours of the FTA canvas to be specified This can be invoked by selecting Edit gt Preferences View Colur Biroo Cour Highilght Colour Background Colour come Figure 3 preferences dialog The two radio buttons switch the canvas between colour and monochrome views Clicking on any of the symbol or colour buttons launches a selection dialog that changes the colour of the selected item Clicking the OK button applies
67. mbol of the fault tree to be selected and centred on the main canvas area Thus large trees can be easily navigated When drawing a fault tree mistakes will be made or changes will be required from time to time OpenFTA supports standard editing operations and some application specific ones Any symbol on a fault tree can be viewed as the parent of a sub tree even a symbol on its own Thus as a fault tree is made up of smaller sub trees the smaller trees can be cut copied and pasted to other parts of the fault tree drawing Obviously there are some restrictions e g the top level intermediate event cannot be cut from the drawing but OpenFTA provides warnings to prevent the tree becoming syntactically invalid and an Undo option that can revert a tree to a previous state In addition OpenFTA allows some manipulation of the fault tree for aesthetic reasons It is possible to change the order in which symbols are drawn below their parents with Edit gt Shift Left and Edit gt Shift Right This has no impact on the analysis of the tree only on how it is displayed As symbols are added they can be annotated All symbols can be given an ID as well as other information according to their type To enter the annotations for all but the primary events multi click the left mouse button with the cursor mywhere within the boundary of a symbol This causes the symbol to become selected and displays an associated dialog The descriptive text entered
68. n On activation of the Help button context sensitive help information is displayed On completion of the simulation the OpenFTA Monte Carlo dialog is removed from the screen a Monte Carlo Report is generated to a file named lt fault tree name gt mrp and displayed ina dialog The report consists of the directory path of the file used to store the fault tree analysed in this report the date and time of the report s creation the number of unique primary events in the displayed fault tree including any transfer in trees the number of Monte Carlo Simulation runs that have been performed upon the displayed fault tree the number of unit times simulated for each run the number of system failures that occurred occurrences of the top level event due to primary events being failed during the calculations the probability of at least one component in the tree failing during the simulation the probability of the top level event occurring a table of the cut sets found during the simulations Each row of the table consists of the cut set the number of failures attributed to it in the simulations the estimated probability of one of the events in that cut set occurring and the percentage imp ortance of the cut set in comparison to the other cut sets found a table titled Compressed This is the same as the previous table but those cut sets which are less minimal versions of others are subsumed by the more minimalistic ones The other fiel
69. nPED Delete OpenPED and Paste OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Exit Control Type Menu Option Function Shuts down OpenFTA Location OpenFTA menubar gt File gt Exit Shortcuts Accelerator Ctrl Q Toolbar None Pre conditions None Operation Used to terminate the OpenFTA application If neither the primary events database nor the fault tree have been modified without saving then the execution of the application is terminated and OpenFTA is removed from the display If the fault tree has been modified and not saved then confirmation is requested before OpenFTA proceeds with the termination of the application If the database has been modified and not saved then the operator is informed and the operation is aborted Cross References Save OpenFTA Save OpenPED Save As OpenFTA and Save As OpenPED OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Export Image Control Type Menu Option Function Exports the OpenFTA canvas as a JPEG image Location OpenFTA menubar gt File gt Export Image Shortcuts Accelerator Ctrl E Toolbar None Pre conditions None Operation Exports the OpenFTA canvas as a JPEG image A file selection dialog is posted allowing the target file to be specified Cross R
70. o specify a failure event that is expected to occur and is therefore not directly a failure The event can only have a probability attached to it of 0 Failed or 1 Working C P Conditioning Event Used to specify certain conditions upon any logic gate There are two 72 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference states for this type of event Analysed a probability is assigned to the event and it forms part of the analysis of the tree Not Analysed no probability is assigned to the event and it s role is to add pertinent comments This type of event is mainly used in conjunction with the Priority And and Inhibit gates and is displayed to the right of a gate Logic Gate Symbols C And Gate Used to show that the output fault will only happen if all of the inputs occur Or Gate Used to show that the output fault will only occur if one or more of the input faults take place Priority And Gate The output only occurs if the input faults take place in a certain order The sequence of events is usually stated in a conditioning event situated to the right of the gate Inhibit Gate The output fault only occurs if the single input happens and the attached Conditioning Event is satisfied The gate is in effect a special case And gate A N Exclusive Or Gate The output only occurs if exactly one of the input faults happens Transfer Symbols These symbols are
71. of minimal cut sets their maximum order and the date and time of file generation Use all minimal cut sets radio button If this is selected then all the generated minimal cut sets are used in the numerical probabilities calculation OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference OpenFTA Probabilities x There are 14 basic events in the tree Minimal cut sets file c1Program Files Formal FTA Example TreesWiftlift mcs 12 Minimal cut sets Max order 14 Date Mon Apr 15 14 52 24 2002 amp Generate all minimal cut sets C Limit minimal cut set order Maximum order f d Number oftermsfi2 E Unit Time fi 0 Estimated run time 05 Lox Figure 13 Numerical Probabilities Dialog e a Limit minimal cut set order radio button This is only available if the Use all minimal cut sets radio button is not selected This limits the order of the minimal cut sets used in the calculation to the value chosen using the stepper the two back to back arrows e a Number of terms option which is altered through the use of a stepper The option is provided in order to limit the number of terms used in the probability calculation This uses a series expansion in which there are n terms each with C sub terms making a total number of possible terms By limiting the number of terms used the calculation is speeded up at
72. opied to the clipboard are available for the Paste operation Any information previously held on the clipboard is lost when a Copy operation is carried out Cross References Cut and Paste OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Constant Failure Rate Unit Time Control Type Toggle Button Function Provides a means to state a primary event s failure rate in terms of the probability that it will fail within a given time period i e as a function of time model rather than as an absolute probability P model Location OpenPED gt Constant Failure Rate Unit Time Shortcuts Accelerator None Toolbar None Pre conditions None Operation If set on activation of the Apply button the probability of the current event will be entered into the primary events database as a function of time model rather than as a function of probability P model For more details please refer to Appendix B Cross References Apply OpenPED Monte Carlo Simulation and Numerical Probability OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Cut OpenFTA Control Type Menu Option Function Removes the current selection and sub tree below it from the fault tree displayed in the OpenFTA window and copies it to the clipboard Location OpenFTA menubar gt Edit gt Cut
73. plays the selected fault tree symbol s associated information Location OpenFTA menubar gt Edit gt Selected Shortcuts Accelerator None Toolbar None Pre conditions A symbol on the canvas is selected Operation On activation the selected fault tree symbol s details are displayed For a chosen intermediate event transfer symbol or logic gate a dialog is displayed containing the pertinent information about the symbol For a primary event the relevant database entry in the OpenPED window is highlighted and information is displayed The operation can also be activated by multiclicking within the boundary of the required symbol in the fault tree Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Set Zoom Control Type Menu Option Function Set s the zoom value of the OpenFTA canvas Location OpenFTA menubar gt View gt Set Zoom Shortcuts Accelerator None Toolbar None Pre conditions None Operation Invokes a dialog that allows the current zoom to be set The zoom can be entered manually or a preset value selected from the drop down list Cross References Zoom In Zoom Out OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Shift Left Control Type Menu Option Function Shifts the currently
74. pyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Open OpenFTA Control Type Menu Option Function Opens a previously stored fault tree for display and possible modification Location OpenFTA menubar gt File gt Open Shortcuts Accelerator Ctrl O Toolbar gx Pre conditions None Operation Used to open a fault tree that has been previously stored On activation a file selection dialog titled Open is displayed For more details on the use of this dialog read the section titled File Selection Dialog Note that on activation of the OK button the currently selected file is opened and the Open dialog is removed If no file or non existent or inaccessible files are selected then an error dialog is displayed If a fault tree has been modified without saving then confirmation is requested before OpenFTA proceeds with the Open Operation On successful completion of the operation the newly chosen fault tree is displayed Cross References File Selection Dialog OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Open OpenPED Control Type Menu Option Function Opens a previously stored primary events database for display and possible modification Location OpenPED menubar gt File gt New Shortcuts Accelerator Ctrl O Toolbar am Pre conditions None Operation Used to open a primary e
75. r generator is used in this method if the number of simulations is increased the accuracy of the results obtained will increase but with the penalty of a longer execution time for the calculations Unit Time text field This text field stipulates the number of unit times for which each Monte Carlo Simulation run is to simulate This is only required if there are primary events whose probabilities have been entered into the primary events database as a function of time model rather than as a function of probability P model A default value will be displayed but can be altered to suit experimental needs See Appendix B for more details e an Estimated run time statement This is an estimate of how long the calculation will take depending upon the parameters stipulated in the dialog OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference OpenFTA Monte Carlo x There are 14 basic events in the tree Number of simulations 0000 Unit Time 0 Estimated run time 05 Cancel Help Figure 12 Monte Carlo Dialog On activation of the OK button a working dialog is displayed and the Monte Carlo Simulation is executed The Stop button on the dialog may be pressed to abort the simulation at any time On activation of the Cancel button the procedure is aborted and the OpenFTA Monte Carlo dialog removed from the scree
76. relay contacts fail to contacts fail to contacts closed for open open 1 gt 60 sec AND2 ORS E6 E7 E8 relay contacts fail K1 relay contacts fail K3 relay contacts remain eee for t gt 60 to open when K3 relay to open when K5 relay EMF to K2 coil um contacts closed for contacts closed for through S1 KT1 1 gt 60 sec 1 gt 60 sec KT2 amp ORS E9 Ka 0 02 EMF not removed from K1 relay coil remains K3 K5 relay when K5 relay K1 relay oll for t gt 60 sec contacts fall to contacts closed for Ronde ral te open 1 gt 60 sec open 10 E11 EMF to K1 coil through EMF to K1 coll through timer circuit when K5 51 contacts when K5 contacts closed for contacts closed for 160 sec 1560 sec AND3 OR E12 ET 0 02 2 timer contacts fail to open when K5 relay 1 switch Reset signal contacts closed for inedvartenty inadvertenty KT timer reset eae timer reset PUEROS s open ORB KT2 timer does not time time out due KT2 timer reset OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference The Transferred Fault Tree Tree fla Database Three Motor Example Motor 2 Only ped KA relay contacts fail to open when K3 contacts c
77. ri al Probability quee 46 2 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter I Introduction Open Open PTA ee 49 Open L8 221551 b Es ME 50 ESSOR A A E R 51 Page Setup E AE a 52 Paste Open FTA sieis eerie eien EE EER 53 Paste R E E A MER 54 PRC ROTC Bf Re de 53 Print Open FTA SL 56 Print CORP 57 Print OpenFTA Report ueni ipo tet aereo be ein bipes edem ueste isina 58 Print PIT o T dee 59 Print PG a eT e 60 Print Preview Dial Oe p H 61 Printer SOU M c EO 62 Repor ee ER 63 Saye Open FTA AA E none 64 Saye CSI END os sre ioeie E EEE EAE OA EEEE 65 Save Asa Open FTA dun 66 Save As OpenPED 67 Selected 22 68 Wrap 69 SUAE SM Tn 70 PASS c M 71 Symbol Palette x 72 MEY CE UW PP e 74 Enn eta I 75 Validate e a nn 76 bil
78. s the preferences dialog Location OpenFTA menubar gt Edit gt Preferences Shortcuts Accelerator None Toolbar None Pre conditions None Operation Invokes the preferences dialog that allows the colours of the OpenFTA canvas to be changed The colour of all the symbols can be specified along with the pen background and highlight colurs Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Print OpenFTA Control Type Menu Option Function Prints the currently displayed fault tree either to a printer or to a file Location OpenFTA menubar gt File gt Print Shortcuts Accelerator Ctrl P Toolbar Pre conditions None Operation Used to print the fault tree On activation a dialog titled Print is displayed For more details on the use of this dialog read the section entitled Print Dialog Cross References Print Dialog OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Print OpenPED Control Type Menu Option Function Prints the currently displayed primary events database either to a printer or to a file Location OpenPED menubar gt File gt Print Shortcuts Accelerator None Toolbar Pre conditions None Operation Used to print the primary events database either to a conne
79. scription ID KS Probability Type Basic Dormant No Description ID Probability Type Basic Dormant No Description ID KTlinc Test signal remains on K3 coil for t gt 60 sec K5 relay contacts fail to open relay contacts fail to open OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd 105 Chapter 3 OpenFTA Reference Probability 0 02 Type Basic Dormant No Description timer contacts fail to open ID KT2inc Probability 0 02 Type Basic Dormant No Description KT2 timer contacts fail to open ID KT3inc Probability 0 02 Type Basic Dormant No Description KT3 timer contacts fail to open ID Tlinc Probability 0 02 Type Undeveloped Dormant No Description Reset signal inadvertently applied or not removed from switch 51 ID T2inc Probability 0 02 Type Undeveloped Dormant No Description timer does not time out due to improper installation or setting ID T3inc Probability 0 02 Type Undeveloped Dormant No Description KT2 timer does not time out due to improper installation or setting ID T4inc Probability 0 02 Type Undeveloped Dormant No 106 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Description KT3 timer does not time out due to improper installation or setting 107 OpenFTA Version 1 0 User Manual
80. table titled Qualitative Importance Analysis The table represents the distribution of the number of minimal cut sets found per order of cut sets that are possible for the fault tree Cross References Analysis Print OpenFTA Report Report Validate and View OpenFTA Report OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Monte Carlo Simulation Control T ype Menu Option Function Calculates the probability of occurrence of the top level event of the displayed fault tree and generates and displays an associated analysis report Location OpenFTA menubar gt Analysis gt Monte Carlo Simulation Shortcuts Accelerator None Toolbar None Pre conditions The fault tree has been saved and is valid Operation Determines the probability of the top event occurring by using a Monte Carlo Simulation statistical algorithm Also determines statistically the cut sets and minimal cut sets but note that not all cut sets may be determined On activation a OpenFTA Monte Carlo dialog is displayed containing astatement of the total number of unique primary events in the displayed fault tree including those in any transfer in trees Number of simulations text field This contains the number of Monte Carlo Simulations that will be performed upon the fault tree A default value will be displayed but can be altered Since a random numbe
81. the changes and closes the dialog Clicking the Cancel button aborts the changes and closes the dialog Clicking the Defaults button reverts back to the original colours set when OpenFTA was first installed Clicking the Help button brings up the context sensitive help for the preferences dialog File Storage Fault trees can be saved or opened from the File menu or via the toolbar The File operations provide a degree of protection e g from destroying unsaved trees by opening an existing tree All fault trees are stored in files with the extension ft a When using the file selection dialog to access fault trees the fta extension may be omitted from the selection field OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 2 OpenFTA Tutorial Open x OpenFTA 8 amp EJ Example Trees HTMLHelp UninstallerData a Figure 4 File Selection Dialog Printing Fault trees can be printed to any printer via File gt Print The destination printer and the details of the required paper size and orientation can be changed by selecting the File gt Printer Setup and File gt Page Setup menu items Figure 5 Print and Page Setup Dialogs It is possible to print fault trees over multiple pages Choosing File gt Print Preview launches the Print Preview dialog This allows the number of pages both horizontally and vertically to be speci
82. the fault tree and states if the tree is logically correct The report is stored in the file named fault tree name gt vrp Ifthe output file does not have write access then an error dialog is displayed The permissions for the file or directory must be changed before activating this option again Cross References Analysis Minimal Cut Sets Monte Carlo Simulation and Numerical Probability OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference View Control Type Pulldown Menu Function Provides access to facilities for displaying different views of the fault tree Location OpenFTA menubar gt View Shortcuts Accelerator None Toolbar None Operation Tree Overview shows the entire tree in a window Zoom facilities allow inspection of an area of the tree in greater or lesser detail Pre conditions None Cross References Set Zoom Tree Overview Zoom In and Zoom Out OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference View OpenFTA Report Control Type Menu Option Function Provides a means to view any of the three generated reports Qualitative Report Probability Report and Monte Carlo Report Location OpenFTA menubar gt Report gt View Shortcuts Accelerator None Toolbar None Pre conditions None Operation On selection of the V
83. ttempted an error dialog is displayed Cross References Shift Left and Undo OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Symbol Palette Control Type Push Buttons Function The set of symbols available to draw a fault tree Location Left hand side of the OpenFTA window Shortcuts Accelerator None Toolbar None Pre conditions A symbol on the canvas is selected Operation Selecting a symbol from the palette adds the chosen symbol as the right most child of the symbol selected on the canvas Note that the tree layout is managed automatically and that the symbol palette is context sensitive and thus prevents illogical additions to the tree by greying out inappropriate symbols The Symbol Palette is made up of events gates and transfer symbols Event Symbols Intermediate Event Used to specify a failure event that occurs due to one or more causes acting through logic gates below it in the fault tree Basic Initiating Event Used to specify a failure event that does not require any further development i e it is a leaf of the fault tree and has no gates or events below it in the tree o Undeveloped Event Used to specify a failure event that is not developed as far as it could be either because the event is of no importance in this fault tree or because there is not enough information available External Event Used t
84. ures Estimated Probability Importance 1 K5 T3 267 3 255955 004 1 992612E 005 11 67 2 K5 51 261 3 182787E 004 1 970096E 005 11 41 3 K2 K5 257 3 134009 004 1 954941E 005 11 23 4 S1 T2 252 3 073036 004 1 935831E 005 11 01 5 K5 Tl 235 2 865728 004 1 869395E 005 10 27 6 K1 K5 231 2 816949 004 1 853417E 005 10 10 7 T2 217 2 646225 004 1 796375E 005 9 48 8 1 2 2 rL 1 341405E 005 4 044487E 006 0 48 9 1 KTlinc T2 9 1 097513E 005 3 658376E 006 0 39 OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 K1 K5 4 K5 KTlinc T1 KT3 S1 TZ K2 K5 T4inc K2 Tlinc T2 KI 5 T3 K1 K5 KT2 K5 KTlinc S1 Ki KTS T2 K5 51 5 3 Si T2 T3inec K5 S1 T2 K5 Ti T2inc 51 T2 2 K2 5 2 K5 T2ine T3 KI Si T2 S1 T2 T3 51 T2 4 K2 K5 T3inc K1 T2 T4 KT2inc 51 T2 K2 K5 KTSine T2 K5 T3 T4inc K5 XTlinc T3 K5 S1 T3inc S1 T1 T2 K5 KT3inc T1 K5 KT2 S1 KE I3 K5 KT2inc K5 S1 T4 K5 KT3 S1 K5 KT2inc S1 K2 K5 T4 Tlinc T2 T3 K5 T4inc Ww Ww WwW
85. used to modularise a fault tree For example if there is a sequence of events that occurs in more than one place in the fault tree then it can be removed and placed into a separate sub tree and just referenced by the main fault tree Transfer In Used to depict a sub tree that has been stored in a separate ta file The name of the file is used as the identifier for the transfer in symbol Note that the t a suffix is added automatically to the file name Transfer Out Used to depict that the tree shown below a transfer out symbol is a sub tree of a fault tree that is stored in a different file The name of the sub tree may be used as the identifier for the transfer out symbol Note that the t a suffix is added automatically to the file name Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Tree Overview Control Type Menu Option Function Displays the entire fault tree in a resizeable window Location OpenFTA menubar gt View gt Tree Overview Shortcuts Accelerator None Toolbar None Pre conditions None Operation On activation a resizeable dialog entitled OpenFTA Tree is displayed The dialog contains a scaled image of the fault tree currently displayed on the OpenFTA canvas area Symbols can be selected on the overview causing them to become centered on OpenFTA s canvas area This aids navigation
86. used to store the fault tree analysed in this report e the date and time of the report s creation e the number of unique primary events in the displayed fault tree including those in any transfer in trees OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference the number of minimal cut sets available for the fault tree the maximum order of the minimal cut sets available for use in the probability calculations for the displayed fault tree a statement of the order of minimal cut sets utilised in the probability calculations if less than the maximum order available is used the unit time span used for the calculations a table titled Minimal cut set probabilities This consists of a list of all the minimal cut sets and the probabilities of each and every event in a minimal cut set failing in order to cause the top level event to occur system failure the probability of the top level event occurring given the cut set probabilities calculated previously a table titled Basic Event Analysis This contains a list of all the primary events in the fault tree and their failure contribution towards the top level event occurring This contribution is also stated as a percentage importance value for each primary event Cross References Analysis Minimal Cut Sets Print Dialog Print OpenFTA Report Report Validate and View OpenFTA Report OpenFTA Version 1 0 User Manual Co
87. vents database Location OpenFTA menubar gt File gt Database Shortcuts Accelerator None Toolbar None Pre conditions The fault tree and primary events database have been saved Operation Associate the events database displayed in the OpenPED window with that currently displayed on the OpenFTA canvas Any existing association between a tree and a database is overridden As a consequence of forming an association between a tree and a database the data displayed in the tree s primary events will be updated to be consistent with the database i e each primary event will display the description and probability corresponding to the event s ID Cross References Link OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Delete OpenFTA Control Type Menu Option Function Removes the current selection and sub tree below it from the fault tree displayed in the OpenFTA window Location OpenFTA menubar gt Edit gt Delete Shortcuts Accelerator Ctrl D Toolbar Pre conditions A symbol on the canvas is selected Operation Used to remove the current selection and sub tree below it from the displayed fault tree Unlike Cut the deleted sub tree is not placed on the clipboard Cross References Cut Undo OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference D
88. vents database that has been previously stored On activation a file selection dialog titled Open is displayed For more details on the use of this dialog read the section titled File Selection Dialog Note that on activation of the OK button the currently selected file is opened and the Open dialog is removed If no file or non existent or inaccessible files are selected then an error dialog is displayed If a database has been modified without saving then confirmation is requested before OpenFTA proceeds with the Open Operation On successful completion of the operation the newly chosen database is displayed in the OpenPED window Cross References File Selection Dialog OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Page Setup Control Type Menu Option Function Invokes the page setup dialog Location OpenFTA and OpenPED menubar gt File gt Page Setup Print Preview dialog toolbar Shortcuts Accelerator None Toolbar Print Preview dialog only T Pre conditions None Operation Invokes the page setup dialog that allows the paper size orientation to be selected Cross References Page Setup Dialog Print Print Dialog Print Preview Printer Setup OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Page Setup Dialog Control Type Dialog Function
89. xt field contains the filename of the currently selected file File selection takes place by either e multi clicking on the required file e selecting the file and activating the Open Save button e completing the selection text field and activating the Open Save button On activation of the Open Save button the required file operation is attempted and if successful the dialog is removed from the screen On activation of the Cancel button the file operation is aborted and the dialog is removed from the screen Cross References None OpenFTA Version 1 0 User Manual Copyright 2005 Formal Software Construction Ltd Chapter 3 OpenFTA Reference Help Control Type Pulldown Menu Function Provides access to the online help facility Location OpenFTA and OpenPED menubars gt Help Shortcuts Accelerator None Toolbar None Pre conditions None Operation Used to access information on any aspect of the OpenFTA application The categories of help provided are Help on Help Index User Support and Copyright The Help on Help option provides information on the help facility The ndex option opens a scrollable window which contains a list of all the help topics available By selecting one and pressing the Ok button the information on that subject is displayed The User Support option details how to get technical support The Copyright option displays the version of the application and a

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