242 lines
9.3 KiB
TeX
242 lines
9.3 KiB
TeX
%! TEX root = ../thesis.tex
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\chapter{Experiments}
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<contains the experimental observations defined in th theory>
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\section{Characterization}
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\subsection{sampling time}
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The first experiment needed to run was selecting an optimal number of cycles for which the adc will probe the to it at that moment connected pin.
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The ADC Sampling works by connecting one of the internal 12bit ADCs to a given Pin and then taking a sample value and disconnecting from the Pin, this proceure repeats fo all given pins and is bound to a Timer, whose Interrupts define the number of Ticks an ADC has to process the connected Voltage on a Pin.
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In this case the uncalibrated measurement of our input voltage was taken as example, and repeated with each of the possible 8 settings of the in Firmware used value.
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The resulting errors can be seen in figures \ref{sampleticks1} and \ref{sampleticks2}
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\begin{figure}[H]
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\centering
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\hspace*{-.175\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./data/m04_cycledepends/cycledepends_20180529.pdf}
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\caption{plotted difference from set input voltage, and fitted linearly, May 29th 2018, $\approx$32\si\degree C}
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\label{sampleticks1}
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\end{figure}
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Both figures \ref{sampleticks1} and \ref{sampleticks2} contain the relative error of the measured voltage compared to the theoretical , set input voltages. therefore the reference measurements (yellow), taken with an external multimeter, are not at 0.
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Also shown are the calculated gain erors which would need to be corrected for in case of all 8 settings.
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Important in figure \ref{sampleticks1} is the relative error in only the 0th case, here the cycleTime-Setting was set to 0 and therefore the smallest available sampletime. All other measurements are within errormargin of each other.
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The secondary plots confirm the
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\begin{figure}[H]
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\centering
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\hspace*{-.175\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./data/m04_cycledepends/cycledepends_20180530.pdf}
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\caption{plotted difference from set input voltage, and fitted linearly, May 30th 2018, $\approx$25\si\degree C}
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\label{sampleticks2}
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\end{figure}
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\subsection{Voltages}
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These Measuremts are expected to be relatively inaccurate, the more components are contained in their respective measurement circuit.
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\subsubsection{48V Input}
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\begin{figure}[H]
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\centering
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\hspace*{-.16\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180809/calib_V48.pdf}
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\caption{TODOF}
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\label{v48_precalib}
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\end{figure}
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When looking at calibrating the input voltage (fig. \ref{v48_precalib}), we can clearly see a relatively constand offset of $\approx$1V which can be the influence of inaccurate voltage division and later amplification. The resulting calibrated polnomial coefficients (fig. \ref{pitdb}, line 8) are show not only a offset, but also some deviation in the incline and curve of our polynomial fit.
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\subsubsection{9.6V Output}
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\begin{figure}[H]
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\centering
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\hspace*{-.16\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180809/calib_v10.pdf}
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\caption{TODOF}
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\label{v10_precalib}
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\end{figure}
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The 9.6V Calibration shows only a slight deviation of the internal values and the reference measurement, which results in a list of coefficients (fig. \ref{pitdb}, line 7), very similar to those set in the theoretical defaults.
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\begin{align}
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\sigma_{9.6V} = %TODO%
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\end{align}
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this difference is explained by the simple voltage division used for our circuitry, and no amplification, as seen in the circuit for input voltage.
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\subsubsection{1.8V Output}
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%\begin{figure}[H]
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% \centering
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% \hspace*{-.16\columnwidth}
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% \includegraphics[width=1.3\columnwidth]{./data/m02_adccalib_48/adccalib_v18ana.pdf}
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% \caption{}
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% \label{1v8anabefore}
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%\end{figure}
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%\begin{figure}[h]
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% \centering
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% \hspace*{-.16\columnwidth}
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% \includegraphics[width=1.3\columnwidth]{./data/m02_adccalib_48/adccalib_v18digi.pdf}
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% \caption{}
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% \label{1v8digibefore}
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%\end{figure}
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\begin{figure}[H]
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\centering
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\hspace*{-.15\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./data/m03_poticalib/adccalib_02.pdf}
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\caption{TODOF}
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\label{fig:v18_precalib}
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\end{figure}
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\subsection{Currents}
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\subsubsection{48V Input}
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%TODO: 19.6 and 20.6 unusable
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% \begin{figure}[h]
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% \centering
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% \includegraphics[width=\textwidth]{./pitstop/20180619/i48.pdf}
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% \caption{Calibration of input current adcs 19.06.2018}
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% \label{}
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% \end{figure}
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% \begin{figure}[h]
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% \centering
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% \hspace*{-.16\columnwidth}
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% \includegraphics[width=1.3\columnwidth]{./pitstop/20180620/i48.pdf}
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% \caption{Calibration of input current adcs 20.06.2018}
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% \label{}
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% \end{figure}
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\begin{figure}[H]
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\centering
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\hspace*{-.16\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180809/calib_i48.pdf}
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\caption{Calibration of input current adcs 21.06.2018}
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\label{}
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\end{figure}
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\subsubsection{9.6V Output}
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\subsubsection{1.8V Output}
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\begin{figure}[H]
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\centering
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\hspace*{-.15\columnwidth}
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%\vspace*{-.02\paperheight}
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%\includegraphics[width=\columnwidth]{pitstop/20180702/i18ana_nocalib.pdf}
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%\includegraphics[width=\columnwidth]{pitstop/20180702/i18digi_nocalib.pdf}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180809/calib_i18.pdf}
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\caption{Pre Calibration Measurement of Output Current at the 1.8V Analog and Digital Terminal (2.7.2018)}
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\label{precalib18iana}
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\end{figure}
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\section{after Calibration}
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\minty[minted options={lastline=10}, label={pitdb}]{yaml}{./pitstop/pitdb.yaml}
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\subsection{Voltages}
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\subsubsection{48V Input}
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\subsubsection{9.6V Output}
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\subsubsection{1.8V Output}
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\subsection{Currents}
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\subsubsection{48V Input}
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\subsubsection{9.6V Output}
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\subsubsection{1.8V Output}
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\begin{figure}[H]
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\centering
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\hspace*{-.16\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180702/i18ana_postcalib.pdf}
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\caption{Post Calibration Measurement of Output Current at the 1.8V Analog Terminal (29.06.2018}
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\label{postcalib18iana}
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\end{figure}
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\section{1.8V Regulation}
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\subsection{Characterization of Dropoff}
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Wanting to observe and characterize the voltage drop, happening between the PowerIt output terminal and the HICANN Chips, first the in figure \ref{1v8dip} monitored behavior can be seen.
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\begin{figure}[H]
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\centering
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\hspace*{-.16\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180807/ret_vdip.pdf}
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\caption{Voltage dip observed between PowerIt and HICANN, each point represents the state after enabling additional Reticles on the PowerWafer ()}
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\label{1v8dip}
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\end{figure}
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\subsection{after Numerical-Correction}
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The initial approach is a numerical. Through derivation from figures \ref{1v8dip} and \ref{v18_precalib} we can plot a function which maps the measured output current to a corresponding potentiometer setting (fig. \ref{numericalreg}) for which the observed dropoff will be mitigated (or at least near that). Also important is that it is not possible to use non interger values for the potentiometer setting.
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\begin{figure}[H]
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\centering
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\hspace*{-.16\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180807/ret_regulation.pdf}
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\caption{Potentiometer Setting (discrete integer), derived from ouput current (discrete floating point). }
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\label{numericalreg}
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\end{figure}
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Fitting these values, with a polynomial of 2nd degree, we obtain:
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\begin{align}
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P_{val} =& \lfloor m_2 \cdot I_{ana}^2 + m_1 \cdot I_{ana} + m_0 \rceil\\
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m_2 =& 51.390262 \frac 1 A\\
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m_1 =& -0.263850\frac 1 A\nonumber\\
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m_0 =& 0.000258\frac 1 A\nonumber
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\end{align}
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Which is the numeraical solution if the only desired voltage on HICAN Chips is 1.8V. But if we want to change these, we need a more general solution.
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Assuming the 2nd order Term to be small enough, we can assume a linear proportionality between the current and voltage:
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\begin{align}
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I_{ana, eff} = I_{ana} - \frac{V_{out}-1.8V}{c}
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\end{align}
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where c is obtained from the linear fit (incline) in figure \ref{1v8dip}
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\begin{align}
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c = 71.6978\cdot 10^{-3} \frac V A
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\end{align}
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\begin{figure}[H]
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\centering
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\hspace*{-.1\columnwidth}
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\includegraphics[width=1.2\columnwidth]{./pitstop/20180807/reticle_pic}
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\caption{ret5wafer}
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\label{fig:wafer-ret5}
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\end{figure}
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\begin{figure}[H]
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\centering
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\hspace*{-.15\columnwidth}
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\includegraphics[width=1.3\columnwidth]{./pitstop/20180807/reticle_corr}
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\caption{ret5}
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\label{fig:ret5}
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\end{figure}
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\begin{align}
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\pyval{r0_from_neighbor}\\
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\pyval{r0_from_farthest}\\
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\pyval{r0mean}\\
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\pyval{r0meancorr}
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\end{align}
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\begin{align}
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\pyval{r1_from_neighbor}\\
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\pyval{r1_from_farthest}\\
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\pyval{r1mean}\\
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\pyval{r1meancorr}
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\end{align}
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\section{Pitfalls}
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