merge to work laptop

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Robin Clark 2013-04-02 14:59:08 +01:00
parent 7ee1203c09
commit 52ff945161
2 changed files with 15 additions and 4 deletions

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@ -3,7 +3,7 @@
\label{sec:chap2}
The generic and statistical European Safety Standard, EN61508:6\cite{en61508}[B.6.6]
describes FMEA as:
describes Failure Mode Effect Analysis (FMEA) as:
\begin{quotation}
``To analyse a system design, by examining all possible sources of failure
of a system's components and determining the effects of these failures
@ -262,8 +262,9 @@ is significantly reduced, enough for some standards to exclude it~\cite{en298}~\
\paragraph{Resistor failure modes according to EN298.}
EN298, the European gas burner safety standard, tends to
provide failure modes more directly usable for performing FMEA than FMD-91.
EN298, the European gas burner safety standard,
tends to be give failure modes more directly
usable for performing FMEA than FMD-91.
%
EN298 requires that a full FMEA be undertaken, examining all failure modes
of all electronic components~\cite{en298}[11.2 5] as part of the certification process.
@ -441,7 +442,7 @@ that we got from FMD-91, listed in equation~\ref{eqn:opampfms}.
FS8: PIN 8 OPEN & & (Vcc) disconnected & & $NOOP_A$ and $NOOP_B$ \\ \hline
& & & & \\
& & & & \\
submission_thesis/CH2_FMEA/copy.tex submission_thesis/CH2_FMEA/copy.tex.03APR2012
& & & & \\ \hline
FS9: PIN 1 $\stackrel{short}{\longrightarrow}$ PIN 2 & & A -ve 100\% Feed back, low gain & & $LOW_A$ \\ \hline

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@ -347,3 +347,13 @@ we thus reveal design deficiencies.
%in the hardware/software interface.
In Safety Integrity Level (SIL)~\cite{en61508} terms, by identifying undetectable faults and fixing them, we raise
the safe failure fraction (SFF).
\section{Conclusion}
It is the authors belfief that the practise of FMEA would be imporoved by taking a modular approach
and that it is necessary that software and hardware should be included n the same failure mode models.
%
The proposed methodology, FMMD, provides the means to do this, and it is the authors hope that this
or a variant thereof is taken up and used to improve system safety.