CH5 AF comments

submission_thesis/CH2_FMEA/copy.tex

@@ -429,8 +429,11 @@ investigations.
 \fmmdglossOPAMP
 The symptom for this is given as a low slew rate. 
 %
+Slew rate for a circuit/component is the rate at which it changes an output voltage level (i.e.  $\frac{\delta V}{\delta t} $).
+%
 This means that the op-amp will not react quickly to changes on its input terminals.
 %
+%
 This is a failure symptom that may not be of concern in a slow responding system like an
 instrumentation amplifier. However, where higher frequencies are being processed,
 a signal may  be lost entirely.

submission_thesis/CH5_Examples/copy.tex

@@ -78,9 +78,7 @@ A valid range for the output value of this circuit is assumed.
 %and voltages higher than a given threshold considered as  HIGH.
 %
 Because the amplifier inverts and the input is guaranteed positive any 
-output voltage above or equal to zero  would be erroneous.
-%
-This would be an `$AMP_{HIGH}$' failure symptom. 
+output voltage above or equal to zero  would be erroneous i.e. an `$AMP_{HIGH}$' failure symptom. 
 %
 A threshold would be determined for an `$AMP_{LOW}$' failure symptom (i.e. the output voltage more negative than expected). % error given the expected input range.
 %
@@ -183,7 +181,8 @@ The final stage of analysis for this amplifier, is made by
 by forming a {\fg} with the OpAmp and the new {\dc} $IPD$.
 %
 \begin{table}[h+]
-\caption{Inverting Amplifier: Single failure analysis using the $PD$ {\dc}}
+\centering
+\caption{Inverting Amplifier: Single failure analysis using the $IPD$ {\dc}}
 \begin{tabular}{|| l | l | c | c | l ||} \hline
  %\textbf{Failure Scenario} & &  \textbf{Inverted Amp Effect}  &   & \textbf{Symptom}          \\ \hline
  \textbf{Failure} & &  \textbf{Inverted Amp. Effect}  &   & \textbf{Symptom}          \\ 
@@ -460,7 +459,10 @@ This means R3 R4 is not a fixed potential divider, with R4 being on the positive
 %
 It could be at either polarity. % (i.e. the other way around R4 could be the negative side). 
 %
-Here it is more intuitive to model the resistors not as a potential divider, but individually.
+Here, even though R3 and R4 are used as a potential divider,
+it could be either inverted or non-inverted according to the voltages on the inputs.
+Therefore the resistors cannot modelled  as a potential divider, but must be placed in the {\fg}
+with the OpAmp and analysed.
 %This means we are either going to
 %get a high or low reading if R3 or R4 fail.
 
@@ -661,6 +663,7 @@ The first order low pass filter is analysed in table~\ref{tbl:firstorderlpass}.\
 
  
 \begin{table}[h+]
+\centering
 \caption{FirstOrderLP: Failure Mode Effects Analysis: Single Faults} % title of Table
 \label{tbl:firstorderlpass}
 
@@ -821,7 +824,7 @@ and these are marked on the circuit schematic in figure~\ref{fig:circuit2002_FIV
  \label{fig:circuit2002_FIVEPOLE}
 \end{figure}
 %
-\pagebreak[4]
+%\pagebreak[4]
 %
 So the final {\fg} will consist of the derived components $\{ LP1, SKLP_1, SKLP_2 \}$.
 %
@@ -1214,7 +1217,7 @@ increases the potential for re-use. % of pre-analysed {\dcs}.
 %
 A finer grained model---with potentially more hierarchy stages---also means  that 
 %more work, or 
-more reasoning stages have been used in the analysis.
+more reasoning stages, i.e. FMMD analysis stages with their associated analysis reports, have been used in the analysis.
 % HTR The more we can modularise, the more we decimate the $O(N^2)$ effect
 % HTR of complexity comparison.
 %
@@ -1227,7 +1230,7 @@ However, it involves a large reasoning distance, the final stage
 having 24 failure modes to consider against each of the other seven {\dcs}.
 A finer grained approach produces more potentially re-usable {\dcs} and 
 involves several stages with lower reasoning distances.
-The lower reasoning distances, or complexity comparision figures are given in the metrics chapter~\ref{sec:chap7}
+The lower reasoning distances, or complexity comparison figures are given in the metrics chapter~\ref{sec:chap7}
 at section~\ref{sec:bubbaCC}.
 These show that the finer grained models also benefit from lower reasoning distances for the failure mode model.
 
@@ -1731,7 +1734,7 @@ expected voltages for failure mode and temperature reading purposes.
 
 \begin{equation}
 \label{eqn:vd}
- V_{out} = V_{in}.\frac{Z2}{Z2+Z1}
+ V_{out} = V_{in}.\frac{Z_2}{Z_2+Z_1}
 \end{equation}
 
 \subsection{Safety case for 4 wire circuit: Detailed calculations}
@@ -1843,8 +1846,8 @@ As the voltage over $R_3$ is relative (a design feature to eliminate resistance
 the current can be calculated by reading
 the voltage over the known resistor 
 $R2$.\footnote{To calculate the resistance of the Pt100 we need the current flowing though it.
-This can be determined via Ohms law applied to $R_2$, $V=IR$, $I=\frac{V}{R_2}$, 
-and then using $I$, with $I$, $R_{3} = \frac{V_{R3}}{I}$.}
+This can be determined via Ohms law applied to $R_2$, $V=I R_2$, $I=\frac{V}{R_2}$, 
+and then using $I$, $R_{3} = \frac{V_{R3}}{I}$.}
 As these calculations are performed by Ohms law, which is linear, the accuracy of the reading
 will be determined by the accuracy of $R_2$ and $R_{3}$. 
 %It is reasonable to