From 2cf2630edffe4cb81a01b383126e41b479db6f17 Mon Sep 17 00:00:00 2001 From: Robin Clark Date: Sat, 14 Aug 2010 11:25:58 +0100 Subject: [PATCH] PT100 papaer now uses bib iles in thesis directory --- .../component_failure_modes_definition.tex | 2 +- introduction/introduction.tex | 2 +- millivoltamp/Makefile | 22 + millivoltamp/millivoltamp.tex | 833 ++++++++++++++++++ millivoltamp/paper.tex | 34 + mybib.bib | 274 ++++++ pt100/Makefile | 4 + pt100/mybib.bib | 68 -- pt100/paper.tex | 2 +- pt100/pt100.tex | 8 +- thesis.tex | 6 +- 11 files changed, 1178 insertions(+), 77 deletions(-) create mode 100644 millivoltamp/Makefile create mode 100644 millivoltamp/millivoltamp.tex create mode 100644 millivoltamp/paper.tex diff --git a/component_failure_modes_definition/component_failure_modes_definition.tex b/component_failure_modes_definition/component_failure_modes_definition.tex index d7c118a..384726c 100644 --- a/component_failure_modes_definition/component_failure_modes_definition.tex +++ b/component_failure_modes_definition/component_failure_modes_definition.tex @@ -188,7 +188,7 @@ We can represent this using a UML diagram in figure \ref{fig:cfg}. Using the symbol $\bowtie$ to indicate the analysis process that takes a functional group and converts it into a new component. -$$ \bowtie ( FG ) \mapsto DerivedComponent $$ +\[ \bowtie ( FG ) \mapsto DerivedComponent \] \begin{figure}[h] diff --git a/introduction/introduction.tex b/introduction/introduction.tex index 74abc74..0fd7f6a 100644 --- a/introduction/introduction.tex +++ b/introduction/introduction.tex @@ -41,7 +41,7 @@ of this process however, is `static testing'. This involves looking at the desig from the perspective of environmental stresses, natural input fault conditions\footnote{For instance in a burner controller, the gas supply pressure reducing}, components failing, and the effects on safety this could have. Some static testing involves checking that the germane `EN' standards have -been complied with\footnore{for instance protection levels of enclosure, or down rating of electrical components}. +been complied with\footnote{for instance protection levels of enclosure, or down rating of electrical components}. Failure Mode Effects Analysis (FMEA) was also applied. This involved looking in detail at selected critical sections of the product and proposing component failure scenarios. diff --git a/millivoltamp/Makefile b/millivoltamp/Makefile new file mode 100644 index 0000000..c356d15 --- /dev/null +++ b/millivoltamp/Makefile @@ -0,0 +1,22 @@ + +# +# Make the propositional logic diagram a paper +# + + +paper: paper.tex millivoltamp_paper.tex + #latex paper.tex + #dvipdf paper pdflatex cannot use eps ffs + pdflatex paper.tex + mv paper.pdf millivoltamp_paper.pdf + okular millivoltamp_paper.pdf + + +# Remove the need for referncing graphics in subdirectories +# +millivoltamp_paper.tex: millivoltamp.tex + cat millivoltamp.tex | sed 's/millivoltamp\///' > millivoltamp_paper.tex + + +bib: + bibtex paper diff --git a/millivoltamp/millivoltamp.tex b/millivoltamp/millivoltamp.tex new file mode 100644 index 0000000..8865be0 --- /dev/null +++ b/millivoltamp/millivoltamp.tex @@ -0,0 +1,833 @@ +% +% Make the revision and doc number macro's then they are defined in one place +\ifthenelse {\boolean{paper}} +{ +\begin{abstract} +\paragraph{NOT WRITTEN YET USES PT100 DOC AS FRAME WORK: DO NOT READ} +This paper analyses the example ciruit with an added safety component, given in the introduction chapter. + +The analysis is performed using Propositional Logic +diagrams to assist the reasoning process. +This chapter describes taking +the failure modes of the components, analysing the circuit using FMEA +and producing a failure mode model for the circuit as a whole. +Thus after the analysis the Milli Volt Amplifier circuit, may be viewed +from an FMEA perspective as a component itself, with a set of known failure modes. + +\end{abstract} +} +{ +\section{Overview} + +\paragraph{NOT WRITTEN YET USES PT100 DOC AS FRAME WORK: DO NOT READ} +The analysis is performed using Propositional Logic +diagrams to assist the reasoning process. +This chapter describes taking +the failure modes of the components, analysing the circuit using FMEA +and producing a failure mode model for the circuit as a whole. +Thus after the analysis the Milli Volt Amplifier circuit, may be viewed +from an FMEA perspective as a component itself, with a set of known failure modes. +} + +%\begin{figure}[h] +% \centering +% \includegraphics[width=400pt,bb=0 0 714 180,keepaspectratio=true]{./milli volt amplifier/milli volt amplifier.jpg} +% % milli volt amplifier.jpg: 714x180 pixel, 72dpi, 25.19x6.35 cm, bb=0 0 714 180 +% \caption{Milli Volt Amplifier four wire circuit} +% \label{fig:milli volt amplifier} +%\end{figure} +% + +\section{General Description of Milli Volt Amplifier four wire circuit} + +The Milli Volt Amplifier four wire circuit uses two wires to supply small electrical current, +and returns two sense volages by the other two. +By measuring voltages +from sections of this circuit forming potential dividers, we can determine the +resistance of the platinum wire sensor. The resistance +of this is directly related to temperature, and may be determined by +look-up tables or a suitable polynomial expression. + + +%\begin{figure}[h] +% \centering +% \includegraphics[width=150pt,bb=0 0 273 483,keepaspectratio=true]{./milli volt amplifier/vrange.jpg} +% % milli volt amplifier.jpg: 714x180 pixel, 72dpi, 25.19x6.35 cm, bb=0 0 714 180 +% \caption{Milli Volt Amplifier expected voltage ranges} +% \label{fig:milli volt amplifiervrange} +%\end{figure} +% + +The voltage ranges we expect from this three stage potential divider\footnote{ +two stages are required for validation, a third stage is used to measure the current flowing +through the circuit to obtain accurate temperature readings} +are shown in figure \ref{fig:milli volt amplifiervrange}. Note that there is +an expected range for each reading, for a given temperature span. +Note that the low reading goes down as temperature increases, and the higher reading goes up. +For this reason the low reading will be referred to as {\em sense-} +and the higher as {\em sense+}. + +\subsection{Accuracy despite variable \\ resistance in cables} + +For electronic and accuracy reasons a four wire circuit is preferred +because of resistance in the cables. Resistance from the supply + causes a slight voltage +drop in the supply to the Milli Volt Amplifier. As no significant current +is carried by the two `sense' lines, the resistance back to the ADC +causes only a negligible voltage drop, and thus the four wire +configuration is more accurate\footnote{The increased accuracy is because the voltage measured, is the voltage across +the thermistor and not the voltage across the thermistor and current supply wire resistance.}. + +\subsection{Calculating Temperature from \\ the sense line voltages} + +The current flowing though the +whole circuit can be measured on the PCB by reading a third +sense voltage from one of the load resistors. Knowing the current flowing +through the circuit +and knowing the voltage drop over the Milli Volt Amplifier, we can calculate its +resistance by Ohms law $V=I.R$, $R=\frac{V}{I}$. +Thus a little loss of supply current due to resistance in the cables +does not impinge on accuracy. +The resistance to temperature conversion is achieved +through the published Milli Volt Amplifier tables\cite{eurothermtables}. +The standard voltage divider equations (see figure \ref{fig:vd} and +equation \ref{eqn:vd}) can be used to calculate +expected voltages for failure mode and temperature reading purposes. + +%\begin{figure}[h] +% \centering +% \includegraphics[width=100pt,bb=0 0 183 170,keepaspectratio=true]{./milli volt amplifier/voltage_divider.png} +% % voltage_divider.png: 183x170 pixel, 72dpi, 6.46x6.00 cm, bb=0 0 183 170 +% \caption{Voltage Divider} +% \label{fig:vd} +%\end{figure} +%%The looking at figure \ref{fig:vd} the standard voltage divider formula (equation \ref{eqn:vd}) is used. + +\begin{equation} +\label{eqn:vd} + V_{out} = V_{in}.\frac{Z2}{Z2+Z1} +\end{equation} + +\section{Safety case for 4 wire circuit} + +This sub-section looks at the behaviour of the Milli Volt Amplifier four wire circuit +for the effects of component failures. +All components have a set of known `failure modes'. +In other words we know that a given component can fail in several distinct ways. +Studies have been published which list common component types +and their sets of failure modes, often with MTTF statistics \cite{mil1991}. +Thus for each component, an analysis is made for each of its failure modes, +with respect to its effect on the +circuit. Each one of these scenarios is termed a `test case'. +The resultant circuit behaviour for each of these test cases is noted. +The worst case for this type of +analysis would be a fault that we cannot detect. +Where this occurs a circuit re-design is probably the only sensible course of action. + + + +\subsection{Single Fault FMEA Analysis \\ of Milli Volt Amplifier Four wire circuit} + +\label{fmea} +This circuit simply consists of three resistors. +Resistors according to the DOD Electronic component fault handbook +1991, fail by either going OPEN or SHORT circuit \cite{mil1991}. +%Should wires become disconnected these will have the same effect as +%given resistors going open. +For the purpose of this analyis; +$R_{1}$ is the \ohms{2k2} from 5V to the thermistor, +$R_3$ is the Milli Volt Amplifier thermistor and $R_{2}$ connects the thermistor to ground. + +We can define the terms `High Fault' and `Low Fault' here, with reference to figure +\ref{fig:milli volt amplifiervrange}. Should we get a reading outside the safe green zone +in the diagram we can consider this a fault. +Should the reading be above its expected range this is a `High Fault' +and if below a `Low Fault'. + +Table \ref{ptfmea} plays through the scenarios of each of the resistors failing +in both SHORT and OPEN failure modes, and hypothesises an error condition in the readings. +The range {0\oc} to {300\oc} will be analysed using potential divider equations to +determine out of range voltage limits in section \ref{ptbounds}. + +\begin{table}[ht] +\caption{Milli Volt Amplifier FMEA Single Faults} % title of Table +\centering % used for centering table +\begin{tabular}{||l|c|c|l|l||} +\hline \hline + \textbf{Test} & \textbf{Result} & \textbf{Result } & \textbf{General} \\ + \textbf{Case} & \textbf{sense +} & \textbf{sense -} & \textbf{Symtom Description} \\ +% R & wire & res + & res - & description +\hline +\hline + $R_1$ SHORT & High Fault & - & Value Out of Range Value \\ \hline +$R_1$ OPEN & Low Fault & Low Fault & Both values out of range \\ \hline + \hline +$R_3$ SHORT & Low Fault & High Fault & Both values out of range \\ \hline + $R_3$ OPEN & High Fault & Low Fault & Both values out of range \\ \hline +\hline +$R_2$ SHORT & - & Low Fault & Value Out of Range Value \\ + $R_2$ OPEN & High Fault & High Fault & Both values out of range \\ \hline +\hline +\end{tabular} +\label{ptfmea} +\end{table} + +From table \ref{ptfmea} it can be seen that any component failure in the circuit +should cause a common symptom, that of one or more of the values being `out of range'. +Temperature range calculations and detailed calculations +on the effects of each test case are found in section \ref{milli volt amplifierrange} +and \ref{milli volt amplifiertemp}. + + + +\subsection{Range and Amplifier Calculations} +\label{milli volt amplifiertemp} +Milli Volt Amplifier resistors are designed to +have a resistance of \ohms{100} at {0\oc} \cite{aoe},\cite{eurothermtables}. +A suitable `wider than to be expected range' was considered to be {0\oc} to {300\oc} +for a given application. +According to the Eurotherm Milli Volt Amplifier +tables \cite{eurothermtables}, this corresponded to the resistances \ohms{100} +and \ohms{212.02} respectively. From this the potential divider circuit can be +analysed and the maximum and minimum acceptable voltages determined. +These can be used as bounds results to apply the findings from the +Milli Volt Amplifier FMEA analysis in section \ref{fmea}. + +As the Milli Volt Amplifier forms a potential divider with the \ohms{2k2} load resistors, +the upper and lower readings can be calculated thus: + + +$$ highreading = 5V.\frac{2k2+milli volt amplifier}{2k2+2k2+milli volt amplifier} $$ +$$ lowreading = 5V.\frac{2k2}{2k2+2k2+milli volt amplifier} $$ +So by defining an acceptable measurement/temperature range, +and ensuring the +values are always within these bounds we can be confident that none of the +resistors in this circuit has failed. + +To convert these to twelve bit ADC (\adctw) counts: + +$$ highreading = 2^{12}.\frac{2k2+milli volt amplifier}{2k2+2k2+milli volt amplifier} $$ +$$ lowreading = 2^{12}.\frac{2k2}{2k2+2k2+milli volt amplifier} $$ + + +\begin{table}[ht] +\caption{Milli Volt Amplifier Maximum and Minimum Values} % title of Table +\centering % used for centering table +\begin{tabular}{||c|c|c|l|l||} +\hline \hline + \textbf{Temperature} & \textbf{Milli Volt Amplifier resistance} & +\textbf{Lower} & \textbf{Higher} & \textbf{Description} \\ +\hline +% {-100 \oc} & {\ohms{68.28}} & 2.46V & 2.53V & Boundary of \\ +% & & 2017\adctw & 2079\adctw & out of range LOW \\ \hline + {0 \oc} & {\ohms{100}} & 2.44V & 2.56V & Boundary of \\ + & & 2002\adctw & 2094\adctw & out of range LOW \\ \hline + {+300 \oc} & {\ohms{212.02}} & 2.38V & 2.62V & Boundary of \\ + & & 1954\adctw & 2142\adctw & out of range HIGH \\ \hline +\hline +\end{tabular} +\label{ptbounds} +\end{table} + +Table \ref{ptbounds} gives ranges that determine correct operation. In fact it can be shown that +for any single error (short or opening of any resistor) this bounds check +will detect it. + + +\section{Single Fault FMEA Analysis \\ of Milli Volt Amplifier Four wire circuit} + +\subsection{Single Fault Modes as PLD} + +The component~failure~modes in table \ref{ptfmea} can be represented as contours +on a PLD diagram. +Each test case, is defined by the contours that enclose +it. The test cases here deal with single faults only +and are thus enclosed by one contour each. + + +%\begin{figure}[h] +% \centering +% \includegraphics[width=400pt,bb=0 0 518 365,keepaspectratio=true]{./milli volt amplifier/milli volt amplifier_tc.jpg} +% % milli volt amplifier_tc.jpg: 518x365 pixel, 72dpi, 18.27x12.88 cm, bb=0 0 518 365 +% \caption{Milli Volt Amplifier Component Failure Modes} +% \label{fig:milli volt amplifier_tc} +%\end{figure} +% +%ating input Fault +This circuit supplies two results, the {\em sense+} and {\em sense-} voltage readings. +To establish the valid voltage ranges for these, and knowing our +valid temperature range for this example ({0\oc} .. {300\oc}) we can calculate +valid voltage reading ranges by using the standard voltage divider equation \ref{eqn:vd} +for the circuit shown in figure \ref{fig:vd}. + +% +%\begin{figure}[h] +% \centering +% \includegraphics[width=100pt,bb=0 0 183 170,keepaspectratio=true]{./milli volt amplifier/voltage_divider.png} +% % voltage_divider.png: 183x170 pixel, 72dpi, 6.46x6.00 cm, bb=0 0 183 170 +% \caption{Voltage Divider} +% \label{fig:vd} +%\end{figure} +%%The looking at figure \ref{fig:vd} the standard voltage divider formula (equation \ref{eqn:vd}) is used. +% +%\begin{equation} +%\label{eqn:vd} +% V_{out} = V_{in}.\frac{Z2}{Z2+Z1} +%\end{equation} +% + + +\subsection{Proof of Out of Range \\ Values for Failures} +\label{pt110range} +Using the temperature ranges defined above we can compare the voltages +we would get from the resistor failures to prove that they are +`out of range'. There are six test cases and each will be examined in turn. + +\subsubsection{ TC 1 : Voltages $R_1$ SHORT } +With milli volt amplifier at 0\oc +$$ highreading = 5V $$ +Since the highreading or sense+ is directly connected to the 5V rail, +both temperature readings will be 5V.. +$$ lowreading = 5V.\frac{2k2}{2k2+100\Omega} = 4.78V$$ +With milli volt amplifier at the high end of the temperature range 300\oc. +$$ highreading = 5V $$ +$$ lowreading = 5V.\frac{2k2}{2k2+212.02\Omega} = 4.56V$$ + +Thus with $R_1$ shorted both readings are outside the +proscribed range in table \ref{ptbounds}. + +\subsubsection{ TC 2 : Voltages $R_1$ OPEN } + +In this case the 5V rail is disconnected. All voltages read are 0V, and +therefore both readings are outside the +proscribed range in table \ref{ptbounds}. + + +\subsubsection{ TC 3 : Voltages $R_2$ SHORT } + +With milli volt amplifier at 0\oc +$$ lowreading = 0V $$ +Since the lowreading or sense- is directly connected to the 0V rail, +both temperature readings will be 0V. +$$ lowreading = 5V.\frac{100\Omega}{2k2+100\Omega} = 0.218V$$ +With milli volt amplifier at the high end of the temperature range 300\oc. +$$ highreading = 5V.\frac{212.02\Omega}{2k2+212.02\Omega} = 0.44V$$ + +Thus with $R_2$ shorted both readings are outside the +proscribed range in table \ref{ptbounds}. + +\subsubsection{ TC 4 : Voltages $R_2$ OPEN } +Here there is no potential divider operating and both sense lines +will read 5V, outside of the proscribed range. + + +\subsubsection{ TC 5 : Voltages $R_3$ SHORT } + +Here the potential divider is simply between +the two 2k2 load resistors. Thus it will read a nominal; +2.5V. + +Assuming the load resistors are +precision components, and then taking an absolute worst case of 1\% either way. + +$$ 5V.\frac{2k2*0.99}{2k2*1.01+2k2*0.99} = 2.475V $$ + +$$ 5V.\frac{2k2*1.01}{2k2*1.01+2k2*0.99} = 2.525V $$ + +These readings both lie outside the proscribed range. +Also the sense+ and sense- readings would have the same value. + +\subsubsection{ TC 6 : Voltages $R_3$ OPEN } + +Here the potential divider is broken. The sense- will read 0V and the sense+ will +read 5V. Both readings are outside the proscribed range. + +\subsection{Summary of Analysis} + +All six test cases have been analysed and the results agree with the hypothesis +put in Table \ref{ptfmea}. The PLD diagram, can now be used to collect the +symptoms. In this case there is a common and easily detected symptom for all these single +resistor faults : Voltage out of range. + +A spider can be drawn on the PLD diagram to this effect. + +In practical use, by defining an acceptable measurement/temperature range, +and ensuring the +values are always within these bounds we can be confident that none of the +resistors in this circuit has failed. + + +%\begin{figure}[h] +% \centering +% \includegraphics[width=400pt,bb=0 0 518 365,keepaspectratio=true]{./milli volt amplifier/milli volt amplifier_tc_sp.jpg} +% % milli volt amplifier_tc.jpg: 518x365 pixel, 72dpi, 18.27x12.88 cm, bb=0 0 518 365 +% \caption{Milli Volt Amplifier Component Failure Modes} +% \label{fig:milli volt amplifier_tc_sp} +%\end{figure} +% + +\subsection{Derived Component : The Milli Volt Amplifier Circuit} +The Milli Volt Amplifier circuit can now be treated as a component in its own right, and has one failure mode, +{\textbf OUT\_OF\_RANGE}. It can now be represnted as a PLD see figure \ref{fig:milli volt amplifier_singlef}. + +%\begin{figure}[h] +% \centering +% \includegraphics[width=100pt,bb=0 0 167 194,keepaspectratio=true]{./milli volt amplifier/milli volt amplifier_singlef.jpg} +% % milli volt amplifier_singlef.jpg: 167x194 pixel, 72dpi, 5.89x6.84 cm, bb=0 0 167 194 +% \caption{Milli Volt Amplifier Circuit Failure Modes : From Single Faults Analysis} +% \label{fig:milli volt amplifier_singlef} +%\end{figure} +% + +%From the single faults (cardinality constrained powerset of 1) analysis, we can now create +%a new derived component, the {\emmilli volt amplifiercircuit}. This has only \{ OUT\_OF\_RANGE \} +%as its single failure mode. + + +%Interestingly we can calculate the failure statistics for this circuit now. +%Mill 1991 gives resistor stats of ${10}^{11}$ times 6 (can we get special stats for milli volt amplifier) ??? +\clearpage +\subsection{Mean Time to Failure} + +Now that we have a model for the failure mode behaviour of the milli volt amplifier circuit +we can look at the statistics associated with each of the failure modes. + +The DOD electronic reliability of components +document MIL-HDBK-217F\cite{mil1992} gives formulae for calculating +the +%$\frac{failures}{{10}^6}$ +${failures}/{{10}^6}$ % looks better +in hours for a wide range of generic components +\footnote{These figures are based on components from the 1980's and MIL-HDBK-217F +can give conservative reliability figures when applied to +modern components}. + +Using the MIL-HDBK-217F\cite{mil1992} specifications for resistor and thermistor +failure statistics we calculate the reliability of this circuit. + + +\subsubsection{Resistor FIT Calculations} + +The formula for given in MIL-HDBK-217F\cite{mil1992}[9.2] for a generic fixed film non-power resistor +is reproduced in equation \ref{resistorfit}. The meanings +and values assigned to its co-efficients are described in table \ref{tab:resistor}. + +\begin{equation} +% fixed comp resistor{\lambda}_p = {\lambda}_{b}{\pi}_{R}{\pi}_Q{\pi}_E +resistor{\lambda}_p = {\lambda}_{b}{\pi}_{R}{\pi}_Q{\pi}_E + \label{resistorfit} +\end{equation} + +\begin{table}[ht] +\caption{Fixed film resistor Failure in time assessment} % title of Table +\centering % used for centering table +\begin{tabular}{||c|c|l||} +\hline \hline + \em{Parameter} & \em{Value} & \em{Comments} \\ + & & \\ \hline \hline + ${\lambda}_{b}$ & 0.00092 & stress/temp base failure rate $60^o$ C \\ \hline + %${\pi}_T$ & 4.2 & max temp of $60^o$ C\\ \hline + ${\pi}_R$ & 1.0 & Resistance range $< 0.1M\Omega$\\ \hline + ${\pi}_Q$ & 15.0 & Non-Mil spec component\\ \hline + ${\pi}_E$ & 1.0 & benign ground environment\\ \hline + +\hline \hline +\end{tabular} +\label{tab:resistor} +\end{table} + +Applying equation \ref{resistorfit} with the parameters from table \ref{tab:resistor} +give the following failures in ${10}^6$ hours: + +\begin{equation} + 0.00092 \times 1.0 \times 15.0 \times 1.0 = 0.0138 \;{failures}/{{10}^{6} Hours} + \label{eqn:resistor} +\end{equation} + +While MIL-HDBK-217F gives MTTF for a wide range of common components, +it does not specify how the components will fail (in this case OPEN or SHORT). {Some standards, notably EN298 only consider resistors failing in OPEN mode}. +FMD-97 gives 27\% OPEN and 3\% SHORTED, for resistors under certain electrical and environmental stresses. This example +compromises and uses a 90:10 ratio, for resistor failure. +Thus for this example resistors are expected to fail OPEN in 90\% of cases and SHORTED +in the other 10\%. +A standard fixed film resistor, for use in a benign environment, non military spec at +temperatures up to 60\oc is given a probability of 13.8 failures per billion ($10^9$) +hours of operation (see equation \ref{eqn:resistor}). +This figure is referred to as a FIT\footnote{FIT values are measured as the number of +failures per Billion (${10}^9$) hours of operation, (roughly 114,000 years). The smaller the +FIT number the more reliable the fault~mode} Failure in time. + +The formula given for a thermistor in MIL-HDBK-217F\cite{mil1992}[9.8] is reproduced in +equation \ref{thermistorfit}. The variable meanings and values are described in table \ref{tab:thermistor}. + +\begin{equation} +% fixed comp resistor{\lambda}_p = {\lambda}_{b}{\pi}_{R}{\pi}_Q{\pi}_E +resistor{\lambda}_p = {\lambda}_{b}{\pi}_Q{\pi}_E + \label{thermistorfit} +\end{equation} + +\begin{table}[ht] +\caption{Bead type Thermistor Failure in time assessment} % title of Table +\centering % used for centering table +\begin{tabular}{||c|c|l||} +\hline \hline + \em{Parameter} & \em{Value} & \em{Comments} \\ + & & \\ \hline \hline + ${\lambda}_{b}$ & 0.021 & stress/temp base failure rate bead thermistor \\ \hline + %${\pi}_T$ & 4.2 & max temp of $60^o$ C\\ \hline + %${\pi}_R$ & 1.0 & Resistance range $< 0.1M\Omega$\\ \hline + ${\pi}_Q$ & 15.0 & Non-Mil spec component\\ \hline + ${\pi}_E$ & 1.0 & benign ground environment\\ \hline + +\hline \hline +\end{tabular} +\label{tab:thermistor} +\end{table} + + +\begin{equation} + 0.021 \times 1.0 \times 15.0 \times 1.0 = 0.315 \; {failures}/{{10}^{6} Hours} + \label{eqn:thermistor} +\end{equation} + + +Thus thermistor, bead type, non military spec is given a FIT of 315.0 + +Using the RIAC finding we can draw up the following table (table \ref{tab:stat_single}), +showing the FIT values for all faults considered. + + + +\begin{table}[h+] +\caption{Milli Volt Amplifier FMEA Single // Fault Statistics} % title of Table +\centering % used for centering table +\begin{tabular}{||l|c|c|l|l||} +\hline \hline + \textbf{Test} & \textbf{Result} & \textbf{Result } & \textbf{MTTF} \\ + \textbf{Case} & \textbf{sense +} & \textbf{sense -} & \textbf{per $10^9$ hours of operation} \\ +% R & wire & res + & res - & description +\hline +\hline +TC:1 $R_1$ SHORT & High Fault & - & 1.38 \\ \hline +TC:2 $R_1$ OPEN & Low Fault & Low Fault & 12.42\\ \hline + \hline +TC:3 $R_3$ SHORT & Low Fault & High Fault & 31.5 \\ \hline +TC:4 $R_3$ OPEN & High Fault & Low Fault & 283.5 \\ \hline +\hline +TC:5 $R_2$ SHORT & - & Low Fault & 1.38 \\ +TC:6 $R_2$ OPEN & High Fault & High Fault & 12.42 \\ \hline +\hline +\end{tabular} +\label{tab:stat_single} +\end{table} + +The FIT for the circuit as a whole is the sum of MTTF values for all the +test cases. The Milli Volt Amplifier circuit here has a FIT of 342.6. This is a MTTF of +about 360 years per circuit. + +A Probablistic tree can now be drawn, with a FIT value for the Milli Volt Amplifier +circuit and FIT values for all the component fault modes that it was calculated from. +We can see from this that that the most likely fault is the thermistor going OPEN. +This circuit is around 10 times more likely to fail in this way than in any other. +Were we to need a more reliable temperature sensor this would probably +be the fault~mode we would scrutinise first. + + +%\begin{figure}[h+] +% \centering +% \includegraphics[width=400pt,bb=0 0 856 327,keepaspectratio=true]{./milli volt amplifier/stat_single.jpg} +% % stat_single.jpg: 856x327 pixel, 72dpi, 30.20x11.54 cm, bb=0 0 856 327 +% \caption{Probablistic Fault Tree : Milli Volt Amplifier Single Faults} +% \label{fig:stat_single} +%\end{figure} + + +The Milli Volt Amplifier analysis presents a simple result for single faults. +The next analysis phase looks at how the circuit will behave under double simultaneous failure +conditions. + +\clearpage +\section{ Milli Volt Amplifier Double Simultaneous \\ Fault Analysis} + +In this section we examine the failure mode behaviour for all single +faults and double simultaneous faults. +This corresponds to the cardinality constrained powerset of +the failure modes in the functional group. +All the single faults have already been proved in the last section. +For the next set of test cases, let us again hypothesise +the failure modes, and then examine each one in detail with +potential divider equation proofs. + +Table \ref{tab:ptfmea2} lists all the combinations of double +faults and then hypothesises how the functional~group will react +under those conditions. + +\begin{table}[ht] +\caption{Milli Volt Amplifier FMEA Double Faults} % title of Table +\centering % used for centering table +\begin{tabular}{||l|l|c|c|l|l||} +\hline \hline + \textbf{TC} &\textbf{Test} & \textbf{Result} & \textbf{Result } & \textbf{General} \\ + \textbf{number} &\textbf{Case} & \textbf{sense +} & \textbf{sense -} & \textbf{Symtom Description} \\ +% R & wire & res + & res - & description +\hline +\hline + TC 7: & $R_1$ OPEN $R_2$ OPEN & Floating input Fault & Floating input Fault & Unknown value readings \\ \hline + TC 8: & $R_1$ OPEN $R_2$ SHORT & low & low & Both out of range \\ \hline +\hline + TC 9: & $R_1$ OPEN $R_3$ OPEN & high & low & Both out of Range \\ \hline + TC 10: & $R_1$ OPEN $R_3$ SHORT & low & low & Both out of range \\ \hline +\hline + + TC 11: & $R_1$ SHORT $R_2$ OPEN & high & high & Both out of range \\ \hline +TC 12: & $R_1$ SHORT $R_2$ SHORT & high & low & Both out of range \\ \hline +\hline + TC 13: & $R_1$ SHORT $R_3$ OPEN & high & low & Both out of Range \\ \hline +TC 14: & $R_1$ SHORT $R_3$ SHORT & high & high & Both out of range \\ \hline + +\hline + TC 15: & $R_2$ OPEN $R_3$ SHORT & high & Floating input Fault & sense+ out of range \\ \hline +TC 16: & $R_2$ OPEN $R_3$ SHORT & high & high & Both out of Range \\ \hline +TC 17: & $R_2$ SHORT $R_3$ OPEN & high & low & Both out of Range \\ \hline +TC 18: & $R_2$ SHORT $R_3$ SHORT & low & low & Both out of Range \\ \hline +\hline +\end{tabular} +\label{tab:ptfmea2} +\end{table} + +\subsection{Verifying complete coverage for a \\ cardinality constrained powerset of 2} + + + +It is important to check that we have covered all possible double fault combinations. +We can use the equation \ref{eqn:correctedccps2} +\ifthenelse {\boolean{paper}} +{ +from the definitions paper +\ref{pap:compdef} +, +reproduced below to verify this. + +\indent{ + where: + \begin{itemize} + \item The set $SU$ represents the components in the functional~group, where all components are guaranteed to have unitary state failure modes. + \item The indexed set $C_j$ represents all components in set $SU$. + \item The function $FM$ takes a component as an argument and returns its set of failure modes. + \item $cc$ is the cardinality constraint, here 2 as we are interested in double and single faults. + \end{itemize} +} +\begin{equation} + |{\mathcal{P}_{cc}SU}| = {\sum^{k}_{1..cc} \frac{|{SU}|!}{k!(|{SU}| - k)!}} +- \sum^{p}_{2..cc}{{\sum^{j}_{j \in J} \frac{|FM({C_j})|!}{p!(|FM({C_j})| - p)!}} } + \label{eqn:correctedccps2} +\end{equation} + +} +{ +\begin{equation} + |{\mathcal{P}_{cc}SU}| = {\sum^{k}_{1..cc} \frac{|{SU}|!}{k!(|{SU}| - k)!}} +- \sum^{p}_{2..cc}{{\sum^{j}_{j \in J} \frac{|FM({C_j})|!}{p!(|FM({C_j})| - p)!}} } + %\label{eqn:correctedccps2} +\end{equation} +} + + +$|FM(C_j)|$ will always be 2 here, as all the components are resistors and have two failure modes. + +% +% Factorial of zero is one ! You can only arrange an empty set one way ! + +Populating this equation with $|SU| = 6$ and $|FM(C_j)|$ = 2. +%is always 2 for this circuit, as all the components are resistors and have two failure modes. + +\begin{equation} + |{\mathcal{P}_{2}SU}| = {\sum^{k}_{1..2} \frac{6!}{k!(6 - k)!}} +- \sum^{p}_{2..2}{{\sum^{j}_{1..3} \frac{2!}{p!(2 - p)!}} } + %\label{eqn:correctedccps2} +\end{equation} + +$|{\mathcal{P}_{2}SU}|$ is the number of valid combinations of faults to check +under the conditions of unitary state failure modes for the components (a resistor cannot fail by being shorted and open at the same time). + +Expanding the sumations + + +$$ NoOfTestCasesToCheck = \frac{6!}{1!(6-1)!} + \frac{6!}{2!(6-2)!} - \Big( \frac{2!}{2!(2 - 2)!} + \frac{2!}{2!(2 - 2)!} + \frac{2!}{2!(2 - 2)!} \Big) $$ + +$$ NoOfTestCasesToCheck = 6 + 15 - ( 1 + 1 + 1 ) = 18 $$ + +As the test case are all different and are of the correct cardinalities (6 single faults and (15-3) double) +we can be confident that we have looked at all `double combinations', of the possible faults +in the milli volt amplifier circuit. The next task is to investigate +these test cases in more detail to prove the failure mode hypothesis set out in table \ref{tab:ptfmea2}. + + +\subsection{Proof of Double Faults Hypothesis } + +\subsubsection{ TC 7 : Voltages $R_1$ OPEN $R_2$ OPEN } +\label{milli volt amplifier:bothfloating} +This double fault mode produces an interesting symptom. +Both sense lines are floating. +We cannot know what the {\adctw} readings on them will be. +In practise these would probably float to low values +but for the purpose of a safety critical analysis +all we can say is the values are `floating' and `unknown'. +This is an interesting case, because it is, at this stage an undetectable +fault that must be handled. + + +\subsubsection{ TC 8 : Voltages $R_1$ OPEN $R_2$ SHORT } + +This cuts the supply from Vcc. Both sense lines will be at zero. +Thus both values will be out of range. + + +\subsubsection{ TC 9 : Voltages $R_1$ OPEN $R_3$ OPEN } + +Sense- will be floating. +Sense+ will be tied to Vcc and will thus be out of range. + +\subsubsection{ TC 10 : Voltages $R_1$ OPEN $R_3$ SHORT } + +This shorts ground to the +both of the sense lines. +Both values thuis out of range. + +\subsubsection{ TC 11 : Voltages $R_1$ SHORT $R_2$ OPEN } + +This shorts both sense lines to Vcc. +Both values will be out of range. + + +\subsubsection{ TC 12 : Voltages $R_1$ SHORT $R_2$ SHORT } + +This shorts the sense+ to Vcc and the sense- to ground. +Both values will be out of range. + + + + + + + + + +\subsubsection{ TC 13 : Voltages $R_1$ SHORT $R_3$ OPEN } + +This shorts the sense+ to Vcc and the sense- to ground. +Both values will be out of range. + +\subsubsection{ TC 14 : Voltages $R_1$ SHORT $R_3$ SHORT } + +This shorts the sense+ and sense- to Vcc. +Both values will be out of range. + +\subsubsection{ TC 15 : Voltages $R_2$ OPEN $R_3$ OPEN } + +This shorts the sense+ to Vcc and causes sense- to float. +The sense+ value will be out of range. + + +\subsubsection{ TC 16 : Voltages $R_2$ OPEN $R_3$ SHORT } + +This shorts the sense+ and sense- to Vcc. +Both values will be out of range. + + + + + +\subsubsection{ TC 17 : Voltages $R_2$ SHORT $R_3$ OPEN } + +This shorts the sense- to Ground. +The sense- value will be out of range. + + +\subsubsection{ TC 18 : Voltages $R_2$ SHORT $R_3$ SHORT } + +This shorts the sense+ and sense- to Vcc. +Both values will be out of range. + +\clearpage +\subsection{Double Faults Represented on a PLD Diagram} + +We can show the test cases on a diagram with the double faults residing on regions +corresponding to overlapping contours see figure \ref{fig:plddouble}. +Thus $TC\_18$ will be enclosed by the $R2\_SHORT$ contour and the $R3\_SHORT$ contour. + + +%\begin{figure}[h] +% \centering +% \includegraphics[width=450pt,bb=0 0 730 641,keepaspectratio=true]{milli volt amplifier/plddouble.jpg} +% % plddouble.jpg: 730x641 pixel, 72dpi, 25.75x22.61 cm, bb=0 0 730 641 +% \caption{Milli Volt Amplifier Double Simultaneous Faults} +% \label{fig:plddouble} +%\end{figure} + +The usefulnes of equation \ref{eqn:correctedccps2} is apparent. From the diagram it is easy to verify +the number of failure modes considered for each test case, but complete coverage for +a given cardinality constraint is not visually obvious. + +\subsubsection{Symptom Extraction} + +We can now examine the results of the test case analysis and apply symptom abstraction. +In all the test case results we have at least one an out of range value, except for +$TC\_7$ +which has two unknown values/floating readings. We can collect all the faults, except $TC\_7$, +into the symptom $OUT\_OF\_RANGE$. +As a symptom $TC\_7$ could be described as $FLOATING$. We can thus draw a PLD diagram representing the +failure modes of this functional~group, the milli volt amplifier circuit from the perspective of double simultaneous failures, +in figure \ref{fig:dubsim}. + + +%\begin{figure}[h] +% \centering +% \includegraphics[width=450pt,bb=0 0 730 641,keepaspectratio=true]{milli volt amplifier/plddoublesymptom.jpg} +% % plddouble.jpg: 730x641 pixel, 72dpi, 25.75x22.61 cm, bb=0 0 730 641 +% \caption{Milli Volt Amplifier Double Simultaneous Faults} +% \label{fig:plddoublesymptom} +%\end{figure} + + +\clearpage +\subsection{Derived Component : The Milli Volt Amplifier Circuit} +The Milli Volt Amplifier circuit again, can now be treated as a component in its own right, and has two failure modes, +{\textbf{OUT\_OF\_RANGE}} and {\textbf{FLOATING}}. +It can now be represented as a PLD see figure \ref{fig:milli volt amplifier_doublef}. + +%\begin{figure}[h] +% \centering +% \includegraphics[width=100pt,bb=0 0 167 194,keepaspectratio=true]{./milli volt amplifier/milli volt amplifier_doublef.jpg} +% % milli volt amplifier_singlef.jpg: 167x194 pixel, 72dpi, 5.89x6.84 cm, bb=0 0 167 194 +% \caption{Milli Volt Amplifier Circuit Failure Modes : From Double Faults Analysis} +% \label{fig:milli volt amplifier_doublef} +%\end{figure} + +\subsection{Statistics} + +%% +%% Need to talk abou the `detection time' +%% or `Safety Relevant Validation Time' ref can book +%% EN61508 gives detection calculations to reduce +%% statistical impacts of failures. +%% + +If we consider the failure modes to be statistically independent we can calculate +the FIT values for all the failures. The failure mode of concern, the undetectable {\textbf{FLOATING}} condition +requires that resistors $R_1$ and $R_2$ fail. We can multiply the MTTF +together and find an MTTF for both failing. The FIT value of 12.42 corresponds to +$12.42 \times {10}^{-9}$ failures per hour. Squaring this gives $ 154.3 \times {10}^{-18} $. +This is an astronomically small MTTF, and so small that it would +probably fall below a threshold to sensibly consider. +However, it is very interesting from a failure analysis perspective, +because here we have found a fault that we cannot detect at this +level. This means that should we wish to cope with +this fault, we need to devise a way of detecting this +condition in higher levels of the system. + + + +\vspace{20pt} + +%typeset in {\Huge \LaTeX} \today diff --git a/millivoltamp/paper.tex b/millivoltamp/paper.tex new file mode 100644 index 0000000..ca479af --- /dev/null +++ b/millivoltamp/paper.tex @@ -0,0 +1,34 @@ + +\documentclass[a4paper,10pt]{article} +\usepackage{graphicx} +\usepackage{fancyhdr} +\usepackage{tikz} +\usepackage{amsfonts,amsmath,amsthm} + +\usepackage{ifthen} +\newboolean{paper} +\setboolean{paper}{true} % boolvar=true or false + + + +\input{../style} + +%\newtheorem{definition}{Definition:} + +\begin{document} +\pagestyle{fancy} + +%\outerhead{{\small\bf PT100 FMMD analysis}} +%\innerfoot{{\small\bf R.P. Clark } } + % numbers at outer edges +\pagenumbering{arabic} % Arabic page numbers hereafter +\author{R.P.Clark} +\title{Milli-Volt Amplifier FMMD analysis} +\maketitle +\input{millivoltamp_paper} + +\bibliographystyle{plain} +\bibliography{../vmgbibliography,../mybib} + +\today +\end{document} diff --git a/mybib.bib b/mybib.bib index 8c702ca..edca07f 100644 --- a/mybib.bib +++ b/mybib.bib @@ -182,3 +182,277 @@ year = "2000" } + +@Manual{tlp181, + title = {TLP 181 Datasheet}, + key = {TOSHIBA Photocoupler GaAs Ired and Photo−Transistor}, + author = {Toshiba inc.}, + OPTorganization = {}, + address = {http://www.toshiba.com/taec/components2/Datasheet\_Sync//206/4191.pdf}, + OPTedition = {}, + OPTmonth = {}, + year = {2009}, +OPTnote = {}, + OPTannote = {}, + OPTurl = {}, + OPTdoi = {}, +OPTissn = {}, + OPTlocalfile = {}, + OPTabstract = {}, +} + + + + +@Manual{pic18f2523, + title = {PIC18F2523 Datasheet}, + OPTkey = {}, + author = {Microchip inc}, + OPTorganization = {}, + address = {http://ww1.microchip.com/downloads/en/DeviceDoc/39755c.pdf}, + OPTedition = {}, + OPTmonth = {}, + year = {2009}, + OPTnote = {}, + OPTannote = {}, + OPTurl = {}, + OPTdoi = {}, + OPTissn = {}, + OPTlocalfile = {}, + OPTabstract = {}, +} + + +@Book{wt, + title = {Water Treatment Essentials for Boiler Plant Operation}, + publisher = {Mc Graw Hill ISBN 0-07-048291-5}, + year = {1997}, + author = {Robert G Nunn}, + ALTALTeditor = {}, + OPTkey = {}, + OPTvolume = {}, + OPTnumber = {}, + OPTseries = {}, + OPTaddress = {}, + OPTedition = {}, + OPTmonth = {}, + OPTnote = {}, + OPTannote = {}, + OPTurl = {}, + OPTdoi = {}, + OPTissn = {ISBN 0-07-048291-5}, + OPTlocalfile = {}, + OPTabstracts = {}, +} + + +@TechReport{spiraxsarco, + author = {Spirax Sarco}, + title = {http://www.spiraxsarco.com/resources/steam-engineering-tutorials.asp}, + institution = {Spirax Sarco}, + year = {2010}, + OPTkey = {}, + OPTtype = {}, + OPTnumber = {}, + OPTaddress = {}, + OPTmonth = {}, + OPTnote = {}, + OPTannote = {}, + OPTurl = {}, + OPTdoi = {}, + OPTissn = {}, + OPTlocalfile = {}, + OPTabstract = {}, +} + +@Book{aoe, + title = {The Art of Electronics}, + publisher = {Cambridge}, + year = {1989}, + author = {Paul Horowitz, Winfield Hill}, + OPTkey = {}, + OPTvolume = {}, + OPTnumber = {}, + OPTseries = {}, + OPTaddress = {}, + OPTedition = {2nd}, + OPTmonth = {}, + OPTnote = {}, + OPTannote = {}, + OPTurl = {}, + OPTdoi = {}, + OPTissn = {ISBN 0-521-37095-7}, + OPTlocalfile = {}, + OPTabstracts = {}, +} + +@TechReport{eurothermtables, + author = {Alan Brown}, + title = {Thermocouple Emf TABLES and PLATINUM 100 RESISTANCE THERMOMETER TABLES}, + institution = {Eurotherm, UK}, + year = {1973}, + OPTkey = {}, + OPTtype = {}, + OPTnumber = {}, + OPTaddress = {}, + OPTmonth = {June}, + OPTnote = {Bulletin TT-1}, + OPTannote = {}, + OPTurl = {}, + OPTdoi = {}, + OPTissn = {}, + OPTlocalfile = {}, + OPTabstract = {}, +} + + +@Book{ldd, +author = {Jonathon Corbet}, +ALTeditor = {Alessandro Rubini}, +ALTeditor = {Greg Kroah-Hartman}, +title = {Linux Device Drivers}, +publisher = {O'Reilly ISBN 0-596-00590-3}, +year = {1998}, +OPTkey = {ISBN 0-596-00590-3}, +OPTvolume = {}, +OPTnumber = {}, +OPTseries = {linux}, +OPTaddress = {}, +OPTedition = {3rd}, +OPTmonth = {}, +OPTnote = {}, +OPTannote = {}, +OPTurl = {www.oreilly.com}, +OPTdoi = {}, +OPTissn = {}, +OPTlocalfile = {}, +OPTabstract = {} +}; + + +@Book{bash, +author = {Carl Albing}, +title = {Bash Cookbook}, +publisher = {O'Reilly ISBN 0-596-52678-4}, +year = {2007}, +OPTkey = {ISBN 0-596-52678-4}, +OPTvolume = {}, +OPTnumber = {}, +OPTseries = {unix/linux}, +OPTaddress = {}, +OPTedition = {}, +OPTmonth = {}, +OPTnote = {}, +OPTannote = {}, +OPTurl = {www.oreilly.com}, +OPTdoi = {}, +OPTissn = {}, +OPTlocalfile = {}, +OPTabstract = {} +}; + +@Book{sedawk, +author = {Dale Dougherty, Arnold Robbins}, +title = {Sed and Awk}, +publisher = {O'Reilly ISBN 1-56592-225-5}, +year = {1997}, +OPTkey = {ISBN 1-56592-225-5}, +OPTvolume = {}, +OPTnumber = {}, +OPTseries = {unix/linux}, +OPTaddress = {}, +OPTedition = {}, +OPTmonth = {}, +OPTnote = {}, +OPTannote = {}, +OPTurl = {www.oreilly.com}, +OPTdoi = {}, +OPTissn = {}, +OPTlocalfile = {}, +OPTabstract = {} +}; + +@Book{bels, +author = {Karim Yaghmour}, +title = {Building Embedded LINUX systems}, +publisher = {O'Reilly ISBN ISBN 0-596-00222-X}, +year = {2003}, +OPTkey = {ISBN 0-596-00222-X}, +OPTvolume = {}, +OPTnumber = {}, +OPTseries = {linux}, +OPTaddress = {}, +OPTedition = {3rd}, +OPTmonth = {}, +OPTnote = {}, +OPTannote = {}, +OPTurl = {www.oreilly.com}, +OPTdoi = {}, +OPTissn = {}, +OPTlocalfile = {}, +OPTabstract = {} +}; + +@Book{can, +author = {Olaf Pfeiffer}, +ALTeditor = {Andrew Ayre}, +ALTeditor = {Christian Keydel}, +title = {Embedded networking with CAN and CANopen}, +publisher = {RTC ISBN 0-929392-78-7}, +year = {2003}, +OPTkey = { }, +OPTvolume = {}, +OPTnumber = {}, +OPTseries = {Embedded Systems}, +OPTaddress = {}, +OPTedition = {1st}, +OPTmonth = {}, +OPTnote = {}, +OPTannote = {}, +OPTurl = {www.rtcbooks.com}, +OPTdoi = {}, +OPTissn = {}, +OPTlocalfile = {}, +OPTabstract = {} +}; + +@Article{article, +author = {dd}, +title = {dd}, +journal = {dd}, +year = {2008}, +OPTkey = {}, +OPTvolume = {}, +OPTnumber = {}, +OPTpages = {1,2}, +OPTmonth = {JAN}, +OPTnote = {}, +OPTannote = {}, +OPTurl = {}, +OPTdoi = {}, +OPTissn = {}, +OPTlocalfile = {}, +OPTabstract = {} +}; + +@Book{sqlite, +author = {Micheal Owens}, +title = {The definitive guide to SQLite}, +publisher = {Apres ISBN 1-59059-673-0}, +year = {2006}, +OPTkey = {}, +OPTvolume = {}, +OPTnumber = {}, +OPTseries = {Databases/SQLite}, +OPTaddress = {}, +OPTedition = {}, +OPTmonth = {}, +OPTnote = {}, +OPTannote = {}, +OPTurl = {}, +OPTdoi = {}, +OPTissn = {}, +OPTlocalfile = {}, +OPTabstract = {} +}; + diff --git a/pt100/Makefile b/pt100/Makefile index c1396bd..410f972 100644 --- a/pt100/Makefile +++ b/pt100/Makefile @@ -16,3 +16,7 @@ paper: paper.tex pt100_paper.tex # pt100_paper.tex: pt100.tex cat pt100.tex | sed 's/pt100\///' > pt100_paper.tex + + +bib: + bibtex paper diff --git a/pt100/mybib.bib b/pt100/mybib.bib index 150c845..544948d 100644 --- a/pt100/mybib.bib +++ b/pt100/mybib.bib @@ -1,27 +1,3 @@ -% -% -% $Id: mybib.bib,v 1.5 2008/12/18 17:05:23 robin Exp $ -% -% - -@TechReport{db, - author = {R Clark, D Legge}, - title = {ETC6000 Daughterboard Design notes}, - institution = {ETC HR221850}, - year = {2004}, - key = {}, - OPTtype = {}, - OPTnumber = {}, - OPTaddress = {}, - OPTmonth = {}, - OPTnote = {}, - OPTannote = {}, - OPTurl = {}, - OPTdoi = {}, - issn = {HR221850}, - OPTlocalfile = {}, - OPTabstract = {}, -} @TechReport{mil1991, author = {U.S. Department of Defence}, @@ -104,24 +80,6 @@ OPTissn = {}, OPTabstracts = {}, } -@TechReport{pcbAI222562, - author = {C Talmay}, - title = {Circuit Schematic TDS Daughterboard AI222562}, - institution = {ETC}, - year = {2010}, - OPTkey = {}, - OPTtype = {}, - OPTnumber = {AI222562}, - OPTaddress = {}, - OPTmonth = {}, - OPTnote = {}, - OPTannote = {}, - OPTurl = {}, - OPTdoi = {}, - OPTissn = {}, - OPTlocalfile = {}, - OPTabstract = {}, -} @TechReport{spiraxsarco, author = {Spirax Sarco}, @@ -147,7 +105,6 @@ OPTissn = {}, publisher = {Cambridge}, year = {1989}, author = {Paul Horowitz, Winfield Hill}, - %author = {}, OPTkey = {}, OPTvolume = {}, OPTnumber = {}, @@ -218,31 +175,6 @@ http://www.xfree86.org/ } -@misc{ touchscreenprod, - author = "M. Thirsk", - title = "Touchscreen Production Procedure : HR~222165", - howpublished = "Internal ETC Document", - year = "2008" }; - - -@misc{ touchscreensoftware, - author = "ETC Software Dept.", - title = "Touchscreen Software released to Production : HR~222162", - howpublished = "Internal ETC Software (medium: 2 MMC cards)", - year = "2008" }; - -@misc{ touchscreengui, - author = "D.J. Legge, R.P.Clark", - title = "Touchscreen GUI Design Document : HR~222163", - howpublished = "Internal ETC Document", - year = "2008" }; - - -@misc{ gumstix, - author = "Gumstix Inc", - title = "Gumstix Home Page", - howpublished = "WEB http://www.gumstix.com/", - year = "2008" }; @misc{ fltk, diff --git a/pt100/paper.tex b/pt100/paper.tex index a370658..83242f2 100644 --- a/pt100/paper.tex +++ b/pt100/paper.tex @@ -28,7 +28,7 @@ \input{pt100_paper} \bibliographystyle{plain} -\bibliography{vmgbibliography,mybib} +\bibliography{../vmgbibliography,../mybib} \today \end{document} diff --git a/pt100/pt100.tex b/pt100/pt100.tex index 3ac5ece..7366406 100644 --- a/pt100/pt100.tex +++ b/pt100/pt100.tex @@ -408,7 +408,7 @@ Now that we have a model for the failure mode behaviour of the pt100 circuit we can look at the statistics associated with each of the failure modes. The DOD electronic reliability of components -document MIL-HDBK-217F\cite{mil1992} gives formulae for calculating +document MIL-HDBK-217F\cite{mil1991} gives formulae for calculating the %$\frac{failures}{{10}^6}$ ${failures}/{{10}^6}$ % looks better @@ -417,13 +417,13 @@ in hours for a wide range of generic components can give conservative reliability figures when applied to modern components}. -Using the MIL-HDBK-217F\cite{mil1992} specifications for resistor and thermistor +Using the MIL-HDBK-217F\cite{mil1991} specifications for resistor and thermistor failure statistics we calculate the reliability of this circuit. \subsubsection{Resistor FIT Calculations} -The formula for given in MIL-HDBK-217F\cite{mil1992}[9.2] for a generic fixed film non-power resistor +The formula for given in MIL-HDBK-217F\cite{mil1991}[9.2] for a generic fixed film non-power resistor is reproduced in equation \ref{resistorfit}. The meanings and values assigned to its co-efficients are described in table \ref{tab:resistor}. @@ -472,7 +472,7 @@ This figure is referred to as a FIT\footnote{FIT values are measured as the numb failures per Billion (${10}^9$) hours of operation, (roughly 114,000 years). The smaller the FIT number the more reliable the fault~mode} Failure in time. -The formula given for a thermistor in MIL-HDBK-217F\cite{mil1992}[9.8] is reproduced in +The formula given for a thermistor in MIL-HDBK-217F\cite{mil1991}[9.8] is reproduced in equation \ref{thermistorfit}. The variable meanings and values are described in table \ref{tab:thermistor}. \begin{equation} diff --git a/thesis.tex b/thesis.tex index ddeff97..e007828 100644 --- a/thesis.tex +++ b/thesis.tex @@ -10,8 +10,7 @@ \newboolean{paper} \setboolean{paper}{false} % boolvar=true or false \input{style} - -%\usepackage{hyperref} +\usepackage{hyperref} \begin{document} \pagestyle{fancy} @@ -137,6 +136,9 @@ Software documentation for fmmd tool. \chapter{Algorithms and Mathematical Relationships Discovered} \input{fzd/fzd} +\chapter{Milli Volt Amp with Safety Resistor} +\input{millivoltamp/millivoltamp} + \chapter{A detailed look at the safety systems required by industrial burner controller} \input{burner/burner}