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FMEA types now sub-sections---still have to think more about the conclusions...

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Robin Clark 2012-08-02 19:42:14 +01:00
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2 changed files with 26 additions and 17 deletions
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15
mybib.bib
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@ -29,17 +29,21 @@
YEAR = "2012"
}
@INPROCEEDINGS{sfmeainterface,
@ARTICLE{sfmeainterface,
author={Ozarin, N.W.},
booktitle={Reliability and Maintainability Symposium, 2009. RAMS 2009. Annual}, title={Applying software failure modes and effects analysis to interfaces},
booktitle={Reliability and Maintainability Symposium, 2009. RAMS 2009. Annual},
journal={Reliability and Maintainability Symposium, 2009. RAMS 2009. Annual},
title={Applying software failure modes and effects analysis to interfaces},
year={2009},
month={jan.},
pages={533 - 538},
volume={},
number={},
pages={533 -538},
keywords={mission-critical system;safety-critical system;software failure mode and effect analysis;software variable;system recovery;},
doi={10.1109/RAMS.2009.4914732},
ISSN={0149-144X},}
ISSN={0149-144X}}
%%#%%
@ARTICLE{sfmea,
AUTHOR = "Chris Price, Neal Snooke",
@ -199,11 +203,10 @@ publisher = {John Wiley & Sons, Ltd},
issn = {2047-7481},
url = {http://dx.doi.org/10.1002/smr.580},
doi = {10.1002/smr.580},
pages = {n/a--n/a},
keywords = {integrated design, FMEA, safety standards},
year = {2012},
}
%%pages = {n/a--n/a},
@ARTICLE{fafmea,
AUTHOR = "Zigmund Bluvband, Pavel Grabov",

26
papers/fmea_software_hardware/software_fmea.tex
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@ -226,7 +226,8 @@ and determining what system level failure modes could be caused.
FMEA has its roots in the previous century where simple electro-mechanical systems were the norm.
Modern control systems nearly always have a significant software/firmware element,
and not being able to model software with current FMEA methodologies
is a cause for criticism~\cite{safeware}[Ch.12].
is a cause for criticism~\cite{safeware}[Ch.12]. Similar difficulties in integrating mechanical and electronic/software
failure models are discussed in ~\cite{SMR:SMR580}.
%Software FMEA techniques have been proposed
@ -340,7 +341,7 @@ current signal into a voltage that we can read with an ADC.%
\begin{figure}[h]
\centering
\includegraphics[width=200pt]{./ftcontext.png}
\includegraphics[width=250pt]{./ftcontext.png}
% ftcontext.png: 767x385 pixel, 72dpi, 27.06x13.58 cm, bb=0 0 767 385
\caption{Context Diagram for {\ft} loop}
\label{fig:ftcontext}
@ -386,7 +387,7 @@ value representing the voltage read (see code sample in figure~\ref{fig:code_rea
%%{\vbox{
\begin{figure}[h+]
\tiny
\footnotesize
\begin{verbatim}
/***********************************************/
/* read_4_20_input() */
@ -443,7 +444,7 @@ voltage value.
%{\vbox{
\begin{figure}[h+]
\tiny
\footnotesize
\begin{verbatim}
/***********************************************/
/* read_ADC() */
@ -510,7 +511,12 @@ the base components in this design.
We now apply FMMD starting with the hardware.
\section{Hardware FMEA}
\section{Failure Mode effects Analysis}
Four emerging and current techniques are now used to
alpply FMEA to the hardware, the software, the software medium and the software hardware insterface.
\subsection{Hardware FMEA}
The hardware FMEA requires that for each component we consider all failure modes
and the putative effect those failure modes would have on the system.
@ -550,8 +556,8 @@ the multiplexer and the analogue to digital converter.
The last two failures both lead to the system failure of $VAL\_ERROR$ .
They could lead to low or high reading as well, but we would only be able to determine this
from knowledge of the software systems criteria for these.
\section{Software FMEA - variables in place of components}
\clearpage
\subsection{Software FMEA - variables in place of components}
For software FMEA, we take the variables used by the system,
and examine what could happen if they are corrupted in various ways~\cite{procsfmea, embedsfmea}.
@ -607,8 +613,8 @@ We must now determine putative system failure modes for these variables becoming
\end{tabular}
\end{table}
}
\section{Software FMEA - failure modes of the medium ($\mu P$) of the software}
\clearpage
\subsection{Software FMEA - failure modes of the medium ($\mu P$) of the software}
Microprocessors/Microcontrollers have sets of known failure modes, these include RAM, ROM
EEPROM failure\footnote{EEPROM failure is not applicable for this example.} and
@ -653,7 +659,7 @@ oscillator clock timing
}
\clearpage
\section{Software FMEA - The software/hardware interface}
\subsection{Software FMEA - The software/hardware interface}
As FMEA is applied separately to software and hardware
the interface between them is an undefined factor.