robin/Robin_PHD
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

refs + comments

Browse Source
This commit is contained in:
Robin Clark 2010-06-18 08:45:22 +01:00
parent 376e20401a
commit 770c27d88f
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
pt100/pt100.tex
View File

@ -807,7 +807,8 @@ in figure \ref{fig:dubsim}.
\clearpage \clearpage
\subsection{Derived Component : The PT100 Circuit} \subsection{Derived Component : The PT100 Circuit}
The PT100 circuit again, can now be treated as a component in its own right, and has two failure modes, The PT100 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:pt100_doublef}. {\textbf{OUT\_OF\_RANGE}} and {\textbf{FLOATING}}.
It can now be represented as a PLD see figure \ref{fig:pt100_doublef}.
\begin{figure}[h] \begin{figure}[h]
\centering \centering
@ -819,6 +820,13 @@ The PT100 circuit again, can now be treated as a component in its own right, and
\subsection{Statistics} \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 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 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 requires that resistors $R_1$ and $R_2$ fail. We can multiply the MTTF