another trudge through the snows of stalingrad...

This commit is contained in:
Robin P. Clark 2012-05-09 19:55:30 +01:00
parent 2a4e5510bb
commit 6d0ba7a6df
6 changed files with 161 additions and 32 deletions

View File

@ -149,7 +149,7 @@ and determine how they affect the operation of the potential divider.
For this example we look at single failure modes only. For this example we look at single failure modes only.
For each failure mode in our {\fg} `potential~divider' For each failure mode in our {\fg} `potential~divider'
we can assign a {\fc} number (see table \ref{pdfmea}). we can assign a {\fc} number (see table \ref{tbl:pdfmea}).
Each {\fc} is analysed to determine the `symptom' Each {\fc} is analysed to determine the `symptom'
of the potential dividers' operation. For instance of the potential dividers' operation. For instance
if resistor $R_1$ was to go open, then the circuit would not be grounded and the if resistor $R_1$ was to go open, then the circuit would not be grounded and the
@ -175,7 +175,7 @@ gives a high voltage output.%We can now consider the {\fg}
FS4: $R_2$ OPEN & LOW & LowPD \\ \hline FS4: $R_2$ OPEN & LOW & LowPD \\ \hline
\hline \hline
\end{tabular} \end{tabular}
\label{pdfmea} \label{tbl:pdfmea}
\end{table} \end{table}
} }

View File

@ -5,7 +5,7 @@ PNG_DIA = blockdiagramcircuit2.png bubba_oscillator_block_diagram.png circuit1
poss1finalbubba.png poss2finalbubba.png pt100.png pt100_doublef.png pt100_singlef.png \ poss1finalbubba.png poss2finalbubba.png pt100.png pt100_doublef.png pt100_singlef.png \
pt100_tc.png pt100_tc_sp.png shared_component.png stat_single.png three_tree.png \ pt100_tc.png pt100_tc_sp.png shared_component.png stat_single.png three_tree.png \
tree_abstraction_levels.png vrange.png sigma_delta_block.png ftcontext.png ct1.png hd.png \ tree_abstraction_levels.png vrange.png sigma_delta_block.png ftcontext.png ct1.png hd.png \
sigdel1.png sigdel1.png sdadc.png

View File

@ -1656,9 +1656,9 @@ The more we can modularise, the more we decimate the $O(N^2)$ effect
of complexity comparison. of complexity comparison.
\section{Sigma Delta Analogue to Digital Converter ($\Sigma \Delta $ADC)} \section{Sigma Delta Analogue to Digital Converter.} %($\Sigma \Delta ADC$)}
The following example shows the analysis of a mixed analogue and digital circuit. The following example is used to demonstrate FMMD analysis of a mixed analogue and digital circuit (see figure~\ref{fig:sigmadelta}).
\begin{figure}[h] \begin{figure}[h]
\centering \centering
\includegraphics[width=200pt]{./CH5_Examples/circuit4004.png} \includegraphics[width=200pt]{./CH5_Examples/circuit4004.png}
@ -1684,7 +1684,7 @@ The following example shows the analysis of a mixed analogue and digital circuit
\paragraph{How the circuit works.} \paragraph{How the circuit works.}
The diagram in~\ref{fig:sigmadeltablock} shows the signal path used The diagram in~\ref{fig:sigmadeltablock} shows the signal path used
by this configuration for a $\Sigma \Delta $ADC. by this configuration for a \sd.
% %
It works by placing the analogue voltage to be read into It works by placing the analogue voltage to be read into
a mixed analogue and digital feedback circuit. a mixed analogue and digital feedback circuit.
@ -1695,16 +1695,16 @@ signal with the input.
The output of the integrator is digitally cleaned-up by IC2 (i.e. output is TRUE or FALSE for digital logic) The output of the integrator is digitally cleaned-up by IC2 (i.e. output is TRUE or FALSE for digital logic)
which acts as a comparator, and fed to the D type flip flop. which acts as a comparator, and fed to the D type flip flop.
% %
The output of the flip flop is a digital representation The output of the flip flop forms a bit pattern representing the value
of the input voltage. of the input voltage.
% %
The output of the flip flop, is now cleaned as an analogue signal The output of the flip flop, is now level converted to an analogue signal
(i.e. a digital 0 becomes a -ve voltage and a digital 1 becomes a +ve voltage) (i.e. a digital 0 becomes a -ve voltage and a digital 1 becomes a +ve voltage)
and fed into the summing integrator completing the negative feedback loop. and fed into the summing integrator completing the negative feedback loop.
\subsection{FMMD analysis of $\Sigma \Delta $ADC} \subsection{FMMD analysis of \sd }
The partslist for the $\Sigma \Delta $ADC The partslist for the \sd :
$$\{ IC1, IC2, IC3, IC4, R1, R2, R3, R4, C1 \} $$. $$\{ IC1, IC2, IC3, IC4, R1, R2, R3, R4, C1 \} $$.
@ -1729,12 +1729,15 @@ $$ fm ( C ) = \{OPEN, SHORT\} $$
\subsubsection{Summing Junction} \subsubsection{Summing Junction}
We now need to choose {\fgs}. The signal path is circular, but we can start We now need to choose {\fgs}. The signal path is circular, but we can start
with the input voltage, which is applied to $R2$, we can term this voltage $V_{in}$. with the input voltage, which is applied via $R2$, we term this voltage $V_{in}$.
$R2$ and $R1$ form a summing junction to IC1. %
$R1$ supplies the feedback voltage for the ADC, we can term this voltage as $V_{fb}$ The feedback voltage for the ADC is supplied via $R1$, we term this voltage as $V_{fb}$.
This can be our first {\fg}. For the symptoms, we have to think in terms of the effect %The input voltage is supplied via $R2$ and we term this voltage as $V_{in}$.
on its performance as a summing junction and not be $R2$ and $R1$ form a summing junction to IC1: they thus work to fulfil this specific function.
distracted by the integrator formed by $C_1$ and $IC1$. This can be our first {\fg} and we analyse it in table~\ref{tbl:suml=j}.
%For the symptoms, we have to think in terms of the effect
%on its performance as a summing junction and not be
%distracted by the integrator formed by $C_1$ and $IC1$.
$$G^0_1 = \{R1, R2 \}$$ $$G^0_1 = \{R1, R2 \}$$
@ -1757,17 +1760,19 @@ $$G^0_1 = \{R1, R2 \}$$
\end{table} \end{table}
From the analysis in table~\ref{tbl:sumj}, we can now create a derived component From the analysis in table~\ref{tbl:sumj} we collect symptoms.
$SUMJ$ which has the failure modes from collecting its symptoms. We can create the derived component
We can state $SUMJ$.% which has the failure modes from collecting its symptoms.
We now state:
$$ fm(SUMJ) = \{ V_{in} DOM, V_{fb} DOM \} $$ $$ fm(SUMJ) = \{ V_{in} DOM, V_{fb} DOM \} .$$
\subsubsection{Buffered Integrator} \subsubsection{Buffered Integrator}
Following the signal path, the next functional group is the integrator. Following the signal path, the next functional group is the integrator.
This integrator is formed by $C$ by $IC2$\cite{aoe}[ch.4]. %
The output of the integrator is fed into IC2, which acts as a buffer. This integrator is formed by placing $C1$ in the negative feedback loop of $IC2$\cite{aoe}[p.222].
The output of the integrator is fed into IC2, which acts as a buffer,
%performing the function of %performing the function of
isolating the integrator from any load on its output. isolating the integrator from any load on its output.
These three components work together to form a buffered integrator, These three components work together to form a buffered integrator,
@ -1822,7 +1827,7 @@ The potential divider provides a mid rail reference voltage
to the inverting input of IC3. to the inverting input of IC3.
\paragraph{Potential divider Formed by R3,R4.} \paragraph{Potential divider Formed by R3,R4.}
We re-use the analysis from section~\ref{sec:pd}, and used the derived component $PD$ We re-use the analysis from table~\ref{tbl:pdfmea}, and used the derived component $PD$
to represent the potential divider formed by R3 and R4. Because PD is a derived component, we can denote this to represent the potential divider formed by R3 and R4. Because PD is a derived component, we can denote this
by super-scripting it with its abstraction level of 1, thus $PD^1$. by super-scripting it with its abstraction level of 1, thus $PD^1$.
$$ $$
@ -1840,6 +1845,7 @@ We now form a {\fg} from $PD^1$ and $IC3$.
$$ G^1_0 = \{ PD^1, IC3 \} $$ $$ G^1_0 = \{ PD^1, IC3 \} $$
We now analyse the {\fg} $G^1$ in table~\ref{tbl:DS2AS}. We now analyse the {\fg} $G^1$ in table~\ref{tbl:DS2AS}.
%$$ fm (BFINT) = \{ HIGH, LOW, NO\_INTEGRATION , LOW\_SLEW \} $$
\begin{table}[h+] \begin{table}[h+]
\caption{$PD^1, IC3$ Digital level to analogue level converter: Failure Mode Effects Analysis} % title of Table \caption{$PD^1, IC3$ Digital level to analogue level converter: Failure Mode Effects Analysis} % title of Table
@ -1898,19 +1904,139 @@ IC4 is as yet unused, the signal path connects IC4 and DL2AL. These seem natural
for the next {\fg}. for the next {\fg}.
BFINT and SUMJ are adjacent in the signal path and these are chosen as a {\fg} as well. BFINT and SUMJ are adjacent in the signal path and these are chosen as a {\fg} as well.
\clearpage
\subsubsection{{\fg} BFINT and SUMJ}
\subsubsection{{\fg} IC4 and DL2AL}
\subsubsection{{\fg} $BFINT^1$ and $SUMJ^1$}
We now form a {\fg} with the two derived components $BFINT^1$ and $SUMJ^1$.
This forms a buffered integrating summing junction which we analyse in table~\ref{tbl:BISJ}.
$$ G^1_0 = \{ BFINT^1, SUMJ^1 \} $$
%$$ fm (BFINT) = \{ HIGH, LOW, NO\_INTEGRATION , LOW\_SLEW \} $$
%$$ fm(SUMJ) = \{ V_{in} DOM, V_{fb} DOM \} .$$
\begin{table}[h+]
\caption{ $BFINT^1, SUMJ^1$ buffered integrating summing junction: Failure Mode Effects Analysis} % title of Table
\label{tbl:DS2AS}
\begin{tabular}{|| l | l | c | c | l ||} \hline
\textbf{Failure Scenario} & & \textbf{failure result } & & \textbf{Symptom} \\
& & & & \\
\hline \hline
FS1: $SUMJ^1$ $V_{in} DOM$ & & output integral of $V_{in}$ & & $OUTPUT STUCK$ \\
FS2: $SUMJ^1$ $V_{fb} DOM$ & & output integral of $V_{fb}$ & & $OUTPUT STUCK$ \\ \hline
%\hline
FS3: $BFINT^1$ $HIGH$ & & output perm. high & & $OUTPUT STUCK$ \\
FS4: $BFINT^1$ $LOW$ & & output perm. low & & $OUTPUT STUCK$ \\ \hline
FS5: $BFINT^1$ $ NO\_INTEGRATION$ & & no current drive & & $OUTPUT STUCK$ \\
FS6: $BFINT^1$ $LOW\_SLEW$ & & delayed signal & & $REDUCED\_INTEGRATION$ \\ \hline
\hline
\end{tabular}
\end{table}
We now collect symptoms $\{ OUTPUT STUCK , REDUCED\_INTEGRATION \}$, and create a {\dc}
called $BISJ^2$.
\subsubsection{{\fg} $IC4$ and $DL2AL$}
%$$ fm (DL2AL^2) = \{ LOW, HIGH, LOW\_SLEW \} $$
%$$ fm ( CD4013B) = \{ HIGH, LOW, NOOP \} $$
The functional group formed by $IC4$ and $DL2AL$ takes the flip flop clocked and buffered
value, and outputs it at analogue voltage levels for the summing junction.
$ G^2_1 = \{ IC4^0, DL2AL^2 \} $
We analyse the buffered flip flop circuitry in table~\ref{tbl:FFB}.
\begin{table}[h+]
\caption{ $IC4^0,DL2AL^2$ flip flop buffered: Failure Mode Effects Analysis} % title of Table
\label{tbl:FFB}
\begin{tabular}{|| l | l | c | c | l ||} \hline
\textbf{Failure Scenario} & & \textbf{failure result } & & \textbf{Symptom} \\
& & & & \\
\hline \hline
FS1: $IC4^0$ $HIGH$ & & output stuck high & & $OUTPUT STUCK$ \\
FS2: $IC4^0$ $LOW$ & & output stuck low & & $OUTPUT STUCK$ \\
FS3: $IC4^0$ $NOOP$ & & output stuck low & & $OUTPUT STUCK$ \\ \hline
%\hline
FS4: $DL2AL^2$ $LOW$ & & output perm. high & & $OUTPUT STUCK$ \\
FS5: $DL2AL^2$ $HIGH$ & & output perm. low & & $OUTPUT STUCK$ \\ \hline
FS6: $DL2AL^2$ $LOW\_SLEW$ & & no current drive & & $LOW\_SLEW$ \\
\hline
\end{tabular}
\end{table}
We now collect symptoms $\{OUTPUT STUCK, LOW\_SLEW\}$ and create a {\dc} at the third level of symptom abstraction
called $FFB^3$.
\subsection{Final, top level {\fg} for sigma delta Converter} \subsection{Final, top level {\fg} for sigma delta Converter}
We now have two {\dcs}, $FFB^3$ and $BISJ^2$: we form a final functional group with these:
$$ G^3_0 = \{ FFB^3, BISJ^2 \} .$$
We analyse the buffered {\sd} circuit in table~\ref{tbl:FFB}.
%
% FFB^3 $\{OUTPUT STUCK, LOW\_SLEW\}$
% BISJ^2 $\{ OUTPUT STUCK , REDUCED\_INTEGRATION \}$
%
\begin{table}[h+]
\caption{ $FFB^3, BISJ^2$ \sd : Failure Mode Effects Analysis} % title of Table
\label{tbl:sd}
\begin{tabular}{|| l | l | c | c | l ||} \hline
\textbf{Failure Scenario} & & \textbf{failure result } & & \textbf{Symptom} \\
& & & & \\
\hline \hline
FS1: $FFB^3$ $OUTPUT STUCK$ & & value max high or low & & $OUTPUT\_OUT\_OF\_RANGE$ \\
FS2: $FFB^3$ $LOW\_SLEW$ & & values will appear larger & & $OUTPUT\_INCORRECT$ \\
% FS3: $IC4^0$ $NOOP$ & & output stuck low & & $OUTPUT STUCK$ \\ \hline
%\hline
FS3: $BISJ^2$ $OUTPUT STUCK$ & & value max high or low & & $OUTPUT\_OUT\_OF\_RANGE$ \\
FS4: $BISJ^2$ $REDUCED\_INTEGRATION$ & & values will appear larger & & $OUTPUT\_INCORRECT$ \\ \hline
\hline
\end{tabular}
\end{table}
%\clearpage
We now collect the symptoms for the \sd $ \;
\{OUTPUT\_OUT\_OF\_RANGE, OUTPUT\_INCORRECT\}$.
We can now create a {\dc} to represent the analogue to digital converter, $SADC^4$.
$$fm(SADC^4) = \{OUTPUT\_OUT\_OF\_RANGE, OUTPUT\_INCORRECT\}$$
We now show the final hierarchy in figure~\ref{fig:sdadc}.
\begin{figure}[h]
\centering
\includegraphics[width=400pt]{./CH5_Examples/sdadc.png}
% sdadc.png: 886x1134 pixel, 72dpi, 31.26x40.01 cm, bb=0 0 886 1134
\caption{FMMD Analysis hierarchy for the {\sd}}
\label{fig:sdadc}
\end{figure}
\clearpage
% ] % ]
% into % into
% %
@ -1963,11 +2089,11 @@ BFINT and SUMJ are adjacent in the signal path and these are chosen as a {\fg} a
% $$fm(SUMJUNCT) = \{ R1\_IN\_DOM, R2\_IN\_DOM \} $$. % $$fm(SUMJUNCT) = \{ R1\_IN\_DOM, R2\_IN\_DOM \} $$.
The D type flip flop %The D type flip flop
%\subsection{FMMD Process applied to $\Sigma \Delta $ADC}. %\subsection{FMMD Process applied to $\Sigma \Delta $ADC}.
T%he block diagram in figure~\ref{fig %T%he block diagram in figure~\ref{fig
\clearpage \clearpage
@ -1983,7 +2109,7 @@ This section
% These failure symptoms are used to define % These failure symptoms are used to define
% a derived component. % a derived component.
% %
demonstrates FMMDs ability to model multiple {\fms}, and shows demonstrates FMMDs ability to model multiple simultaneous {\fms}, and shows
how statistics for part {\fms} can be used to determine the statistical likelihood of failure symptoms. how statistics for part {\fms} can be used to determine the statistical likelihood of failure symptoms.

Binary file not shown.

View File

@ -28,7 +28,10 @@
\setlength{\oddsidemargin}{0mm} \setlength{\evensidemargin}{0mm} \setlength{\oddsidemargin}{0mm} \setlength{\evensidemargin}{0mm}
% %
\newcommand{\permil}{\ensuremath{0/{\!}_{00}}} \newcommand{\permil}{\ensuremath{0/{\!}_{00}}}
\newcommand{\emp}{} %% do nothing, all the italics are unnecessary %\newcommand{\emp}{ELECTRO MAGNETIC FUKING PULSE}
\newcommand{\emp}{} %% was italics
%\newcommand{\sd}{\ensuremath{\Sigma \Delta ADC}}
\newcommand{\sd}{\ensuremath{Sigma\;Delta\;ADC}}
\newcommand{\derivec}{{D}} \newcommand{\derivec}{{D}}
\newcommand{\abslev}{\ensuremath{\alpha}} \newcommand{\abslev}{\ensuremath{\alpha}}
\newcommand{\oc}{\ensuremath{^{o}{C}}} \newcommand{\oc}{\ensuremath{^{o}{C}}}