Missing entries in the Variants Transition Matrix

Search:

Explanation:

A search will be made for variants for which entries may have to be made in the Variants Transition Matrix. This is the case:

a) if, in the IQ-document (fme file), structure-spanning nets exist and/or form sheets should be created,

b) if a structure has been defined as the main structure via the project administration, which also must have at least one variant,

c) if there is more than one structure with variants and

d) if at least one of these variants has remained unallocated in the Variants Transition Matrix.

Example:

Abbreviations

ASIL = Automotive safety integrity level
BF = Base failure of a base function
BFn = Base function of a base structure element
BSE = Base structure element
Cl Prc = Classification for process characteristic
Cl Prd = Classification for product characteristic
Cl Req = Classification for requirement
CM = Control method
DA = Detection action
DC = Diagnostic coverage
DSCF = Dangerous safety critical failure
Er Det = Error detection
Er Resp = Error response
F = Failure
FIT = Failure in time
Fn = Function
FSM = Functional safety management
IE = Inspection equipment
LF = Latent fault
LFM = Latent fault metric
OC = Operating condition
PA = Preventive action
PE = Process element
PFH = Probability of failure per Hour
PMHF = Probabilistic metric for random hardware failures
PrcC = Process characteristic
PrdC = Product characteristic
QM = Quality method
QR = Quality rule
Req = Requirement
RMR = Risk Matrix Ranking
RP = Reaction plan
SE = Structure element
SE ErDet = Structure element for error detections
SE ErResp = Structure element for error responses
SFF = Safe failure fraction
SG = Safety Goal
SIL = Safety integrity level
SM = Organisational-SE for “safety mechanisms”
SPF = Single point fault
SPFM = Single point fault metric
TF = Top failure of a top function
TFn = Top function at root element
TS = Test sample

The two parent structures A and B shown above in the Structure Editor, which are deliberately simple in design and limited at the functional level, together with their two variants A1 and A2 as well as B1 and B2 form the “Quality rule 082” project. Information on this can be found in the Project Management.

Mother structure A has been defined using the context menu in the project management as the main structure. This is marked in bold. Mother structure A is connected to mother structure B via function links, resulting in structure-spanning function nets. These nets look like this:

The variants belonging to the parent structures were created by removing functions. Thus, the variants A1 and A2 were created from mother structure A by eliminating the functions Fn2-A and Fn1-A, respectively. This is how they look in the FFA Editor:

Variants B1 and B2 of the mother structure B were created by removing the functions Fn2-B and Fn1-B respectively:

Since both function and failure nets are linked via the parent structures – and not via the variants – the Variants Transition Matrix must be used to determine which variants are connected (associated) with each other. To do this, make sure that the Variant Transition Matrix is activated beforehand via Tools | Workstation Settings | Settings | Application components.
If the display option “Show NULL variants” is not active, the matrix will look like the following image. This is because there are only four variants in the project “Quality rule 082” and two of them belong to the main structure (here: Mother structure A):

The following three examples briefly illustrate how the function net for variant A1 changes according to linked information contained in the Variants Transition Matrix. The second image shows how this is displayed in the Project Management.

The results from this Quality Rules are dependent on how the Variant Transition Matrix is filled out. In this example, the Quality Rule identifies seven variant-transition-matrix cases whereby matrix entries are missing. These results are identified from their columns and rows whereby entries need to be made. Using the IQ Explorer, the seven cases are shown below: