exjobb/rapport/introduction.tex

% !TeX root = main.tex
\chapter{Introduction}\label{cha:intro}
The standards ISO~7637, \emph{Road vehicles -- Electrical disturbances from conduction and coupling}, and ISO~16750, \emph{Road vehicles -- Environmental conditions and testing for electrical and electronic equipment}, are international standards that apply to equipment in road vehicles with a nominal supply voltage of \SI{12}{\volt} or \SI{24}{\volt}. The standards states, here put in a very condensed form, that the product shall withstand a sufficient amount of disturbances applied to its power supply. The reason for this is that there can be voltage surges and noise in a vehicle's power supply lines. In general, the source of disturbances and noise in a vehicle origins from inductance in other devices connected to the power line, the cables and the vehicles alternator in combination with switching of loads or the supply. \cite{iso_7637_2, iso_16750_2}

To test if a product comply with this standard, there is equipment that simulates different events on the power supply. The standard defines the different scenarios, raise and fall times of test pulses, repetition times etc. It also defines the functional requirements of the equipment during these tests for what is considered a passed or a failed test. \cite{iso_7637_2, iso_16750_2}

\section{Motivation}
The standard defines all the timing requirements that must be met, and also specifies the load conditions for which the requirements apply \cite{iso_7637_2}. From time to time the standards are revised, which may alter the requirements form the previous versions of the standard. New equipment is guaranteed by its manufacturer to do the tests according to the latest standard, as long as all the maintenance instructions are followed which might include sending the equipment in for calibration and service. New equipment might not be affordable by smaller test labs, and can thus inhibit labs from performing tests for this standard.

An appealing alternative would be the possibility to reuse the test equipment that was used along with the older revision of the standard, as long as it is capable of performing the tests reliably. For this to be possible, the test equipment must be verified in some way to be able to guarantee that the tests are performed according to the new standard.

\section{Aim}

The main goal of this work is to investigate the potential of reusing test equipment made for an old standard for testing with the newer version of that standard, and how to assure that the test results are reliable.

If the above goal is met, the verification of the system is desired to be automated.

\section{Research questions}

The following questions will be answered in this paper:

\begin{itemize}
    \item{Can test equipment made for ISO 7637-2:2004, be used for testing compliance against ISO 7637-2:2011, the newer version of the standard?}
    \item{If it can; What considerations must be made to allow for automating the test and verification process?}
    \item{If it can't; What causes the failure, and what possible fixes can be made to make the equipment usable for the newer standard?}
\end{itemize}

\section{Delimitations}
This paper only compares the standard ISO 7637-2:2004 to ISO 7637-2:2011 and ISO~16750-2:2012, because these are the most recent versions of the standards.

This paper only considers Pulse 1, Pulse 2a, Pulse 3a, Pulse 3b and Load dump A. The main reason being that these are the pulses that the available equipment can generate, but also that these pulses share many properties and the method of analysing them will probably be very similar.

This paper only considers the available test equipment for ISO~7637-2, presented in \autoref{tab:used_equipment}, in the pratical tests.
\begin{table}[H]
    \centering
    \begin{tabularx}{0.7\textwidth}{|l|l|X|}
        \hline
        \textbf{Brand} &\textbf{Model} &\textbf{Description}\\
        \hline
        EMTEST		& EFT 200A    &Burst generator\\
        \hline
        EMTEST		&MPG 200B    &Micropulse generator\\
        \hline
        EMTEST		&LD 200B    &Load dump generator\\
        \hline
        EMTEST		&CNA 200B    &Coupling network\\
        \hline
    \end{tabularx}    
    \caption{The test equipment available for the project}
    \label{tab:used_equipment}
\end{table}

\section{Report structure}

\todo[fyll i upplägg när det väl är klart]