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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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17
mybib.bib
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@ -29,17 +29,21 @@
YEAR = "2012" YEAR = "2012"
} }
@INPROCEEDINGS{sfmeainterface, @ARTICLE{sfmeainterface,
author={Ozarin, N.W.}, 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}, year={2009},
month={jan.}, month={jan.},
pages={533 - 538},
volume={}, volume={},
number={}, number={},
pages={533 -538},
keywords={mission-critical system;safety-critical system;software failure mode and effect analysis;software variable;system recovery;}, keywords={mission-critical system;safety-critical system;software failure mode and effect analysis;software variable;system recovery;},
doi={10.1109/RAMS.2009.4914732}, doi={10.1109/RAMS.2009.4914732},
ISSN={0149-144X},} ISSN={0149-144X}}
%%#%%
@ARTICLE{sfmea, @ARTICLE{sfmea,
AUTHOR = "Chris Price, Neal Snooke", AUTHOR = "Chris Price, Neal Snooke",
@ -191,7 +195,7 @@ Publication:
} }
@article {SMR:SMR580, @article{SMR:SMR580,
author = {Bachmann, Volker and Messnarz, Richard}, author = {Bachmann, Volker and Messnarz, Richard},
title = {Improving safety and availability of complex systems by using an integrated design approach in development}, title = {Improving safety and availability of complex systems by using an integrated design approach in development},
journal = {Journal of Software: Evolution and Process}, journal = {Journal of Software: Evolution and Process},
@ -199,11 +203,10 @@ publisher = {John Wiley & Sons, Ltd},
issn = {2047-7481}, issn = {2047-7481},
url = {http://dx.doi.org/10.1002/smr.580}, url = {http://dx.doi.org/10.1002/smr.580},
doi = {10.1002/smr.580}, doi = {10.1002/smr.580},
pages = {n/a--n/a},
keywords = {integrated design, FMEA, safety standards}, keywords = {integrated design, FMEA, safety standards},
year = {2012}, year = {2012},
} }
%%pages = {n/a--n/a},
@ARTICLE{fafmea, @ARTICLE{fafmea,
AUTHOR = "Zigmund Bluvband, Pavel Grabov", 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. 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, Modern control systems nearly always have a significant software/firmware element,
and not being able to model software with current FMEA methodologies 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 %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] \begin{figure}[h]
\centering \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 % ftcontext.png: 767x385 pixel, 72dpi, 27.06x13.58 cm, bb=0 0 767 385
\caption{Context Diagram for {\ft} loop} \caption{Context Diagram for {\ft} loop}
\label{fig:ftcontext} \label{fig:ftcontext}
@ -386,7 +387,7 @@ value representing the voltage read (see code sample in figure~\ref{fig:code_rea
%%{\vbox{ %%{\vbox{
\begin{figure}[h+] \begin{figure}[h+]
\tiny \footnotesize
\begin{verbatim} \begin{verbatim}
/***********************************************/ /***********************************************/
/* read_4_20_input() */ /* read_4_20_input() */
@ -443,7 +444,7 @@ voltage value.
%{\vbox{ %{\vbox{
\begin{figure}[h+] \begin{figure}[h+]
\tiny \footnotesize
\begin{verbatim} \begin{verbatim}
/***********************************************/ /***********************************************/
/* read_ADC() */ /* read_ADC() */
@ -510,7 +511,12 @@ the base components in this design.
We now apply FMMD starting with the hardware. 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 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. 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 $VAL\_ERROR$ . 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 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. from knowledge of the software systems criteria for these.
\clearpage
\section{Software FMEA - variables in place of components} \subsection{Software FMEA - variables in place of components}
For software FMEA, we take the variables used by the system, 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}. 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{tabular}
\end{table} \end{table}
} }
\clearpage
\section{Software FMEA - failure modes of the medium ($\mu P$) of the software} \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 Microprocessors/Microcontrollers have sets of known failure modes, these include RAM, ROM
EEPROM failure\footnote{EEPROM failure is not applicable for this example.} and EEPROM failure\footnote{EEPROM failure is not applicable for this example.} and
@ -653,7 +659,7 @@ oscillator clock timing
} }
\clearpage \clearpage
\section{Software FMEA - The software/hardware interface} \subsection{Software FMEA - The software/hardware interface}
As FMEA is applied separately to software and hardware As FMEA is applied separately to software and hardware
the interface between them is an undefined factor. the interface between them is an undefined factor.