diff --git a/temperature-measurement-error/temperature-measurement-error.pdf b/temperature-measurement-error/temperature-measurement-error.pdf index 3130710..40e81fb 100644 Binary files a/temperature-measurement-error/temperature-measurement-error.pdf and b/temperature-measurement-error/temperature-measurement-error.pdf differ diff --git a/temperature-measurement-error/temperature-measurement-error.tex b/temperature-measurement-error/temperature-measurement-error.tex index 522f5a2..28389ec 100644 --- a/temperature-measurement-error/temperature-measurement-error.tex +++ b/temperature-measurement-error/temperature-measurement-error.tex @@ -32,7 +32,7 @@ \begin{document} \begin{wrapfigure}{l}{0.4\textwidth} - \includegraphics[width=1\linewidth]{./Pictures/NTC-schematic.png} + \includegraphics[width=1\linewidth]{./Pictures/NTC-schematic.png} \caption{NTC Voltage Divider and Filter} \label{fig:NTC-schematic} \end{wrapfigure} @@ -48,23 +48,23 @@ The output voltage is then passed through an RC filter before being fed to an AD To estimate the error, we calculate the highest possible measured voltage at \SI{60}{\celsius}. According to the design of the voltage divider, the lower the temperature, the higher the output voltage. -As shown in Fig. \ref{fig:vref2}, the supply voltage VREF2 for the voltage divider can reach a maximum value of \SI{3.006}\volt. +As shown in Fig. \ref{fig:vref2}, the supply voltage $V_{REF2}$ for the voltage divider can reach a maximum value of \SI{3.006}\volt. Additionally, the total measurement error of the GPIO is $\pm\SI{0.0028}{\volt}$ (as shown in Fig. \ref{fig:aux}). Lastly, the maximum resistance of the NTC at \SI{60}{\celsius}, according to the LUT (Tab. \ref{tab:lut}), is \SI{3086.8}{\ohm}. The maximum possible voltage measurement can then be calculated as such: \begin{align} - V_{worstcase} &= V_{REF2} \cdot \frac{R_{NTC}}{R_{NTC}+R_1} + V_{err} \\ - &= \SI{3.006}\volt \cdot \frac{\SI{3086.8}{\ohm}}{\SI{3086.8}{\ohm}+\SI{9990}{\ohm}} + \SI{0.0028}{\volt} \\ - &\approx \SI{0.7124}{\volt} + V_{worstcase} & = V_{REF2} \cdot \frac{R_{NTC}}{R_{NTC}+R_1} + V_{err} \\ + & = \SI{3.006}\volt \cdot \frac{\SI{3086.8}{\ohm}}{\SI{3086.8}{\ohm}+\SI{9990}{\ohm}} + \SI{0.0028}{\volt} \\ + & \approx \SI{0.7124}{\volt} \end{align} To find the largest possible error, the lowest possible matching temperature should be calculated, which theoretically can produce the same voltage output. The calculation is as follows: \begin{align} - V_{worstcase} &= V_{REF2} \cdot \frac{R_{NTC}}{R_{NTC}+R_1} + V_{err} \\ - \SI{0.7124}{\volt} &= \SI{2.994}{\volt} \cdot \frac{R_{NTC}}{R_{NTC}+\SI{10010}{\ohm}} - \SI{0.0028}{\volt} \\ - R_{NTC} &\approx \SI{3141.6}{\ohm} + V_{worstcase} & = V_{REF2} \cdot \frac{R_{NTC}}{R_{NTC}+R_1} + V_{err} \\ + \SI{0.7124}{\volt} & = \SI{2.994}{\volt} \cdot \frac{R_{NTC}}{R_{NTC}+\SI{10010}{\ohm}} - \SI{0.0028}{\volt} \\ + R_{NTC} & \approx \SI{3141.6}{\ohm} \end{align} Since the LUT is used to match the voltage to the temperature, and the nominal resistance from the LUT is used for the calculation, the closest matching temperature is \SI{58.7}{\celsius}. @@ -128,7 +128,7 @@ Since the LUT is used to match the voltage to the temperature, and the nominal r \bibitem{ADBMS6830B datasheet} \textit{Table 3 Data Sheet ADBMS6830B Rev.0 page 6}. \hyperlink{https://www.analog.com/media/en/technical-documentation/data-sheets/adbms6830b.pdf}{www.analog.com}, 01.2024 \bibitem{ADBMS6830B datasheet} \textit{Table 5 Data Sheet ADBMS6830B Rev.0 page 7}. \hyperlink{https://www.analog.com/media/en/technical-documentation/data-sheets/adbms6830b.pdf}{www.analog.com}, 01.2024 \bibitem{vishay website} \textit{NTC RT Calculation Tool}. \hyperlink{https://www.vishay.com/en/thermistors/ntc-rt-calculator/}{www.vishay.com}, 03.2025 - + \end{thebibliography} \end{document}