From 90e385545f84efa25b0c054f720c7be8f5881352 Mon Sep 17 00:00:00 2001 From: Robin Clark Date: Mon, 1 Apr 2013 11:11:13 +0100 Subject: [PATCH] ... --- submission_thesis/CH3_FMEA_criticism/copy.tex | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/submission_thesis/CH3_FMEA_criticism/copy.tex b/submission_thesis/CH3_FMEA_criticism/copy.tex index 7e3a453..6ca9ef3 100644 --- a/submission_thesis/CH3_FMEA_criticism/copy.tex +++ b/submission_thesis/CH3_FMEA_criticism/copy.tex @@ -131,7 +131,17 @@ Although this would give a better picture of the failure mode behaviour, it is by no means a rigorous approach to tracing errors that may occur in hardware through to the top (and therefore ultimately controlling) layer of software. +% +With the increasing use of micro-controllers in place of analogue electronics +for most new designs of electronic product, the poor integration capabilities of FMEA +are now being seen as deficiencies. +This apparent then in the dilemma now faced +by organisations dealing with highly safety critical systems, and having rely on `smart~instruments' +that they can no longer validate using FMEA. +Smart instruments are dealt with in the section below. +Distributed real time systems, which rely on micro-controllers connected in a network +using a communications protocol, are also impossible to be meaningfully analysed by FMEA. \subsection{The rise of the smart instrument} %% AWE --- Atomic Weapons Establishment have this problem.... @@ -228,10 +238,14 @@ utterly anachronistic in the distributed real time system environment. \item Difficult to re-use previous analysis work \item Very Difficult to model simultaneous failures. \item Software and hardware models are separate. - \item Distributed real time systems are very difficult to meaningfully analyse with FMEA. + \item Distributed real time systems are very difficult to analyse with FMEA because they typically involve many hardware/software interfaces. \end{itemize} -FMEA is no longer fit for purpose! +Traditional forms of FMEA are no longer % fit for purpose! +of meaningful use for modern systems incorporating programmatic elements. +They were designed to analyse simple electro-mechanical systems +and even the commonplace large integrated analogue circuits (that are physically small), are +getting to complicated for meaningful analysis using FMEA. % % % \section{Conclusions on current FMEA Methodologies}