Insert the enclsure figure + numerous word fixes

master
Peter Babič 8 years ago
parent 917cbc2cbf
commit 364756170b
  1. 8
      analytical.tex
  2. BIN
      figures/enclosure.pdf
  3. 4
      glossaries.tex
  4. 2
      introduction.tex
  5. 14
      mainpart.tex
  6. 48
      problemexpres.tex
  7. 7
      tukethesis.bib
  8. BIN
      tukethesis.pdf
  9. 2
      tukethesis.tex

@ -1,5 +1,5 @@
\section{Requirements}
The device under test will be referred to as \textbf{appliance}. The requirements for the final \textbf{measuring device} are grouped to the three categories. Mandatory requirements are bound to be met at any cost. Some of the high importance requirements can be skipped or slightly modified, if unpredictable obstacles are found. However, they are all assumed to be completed for well being of the project. Optional requirements will be completed only if the resources allow it.
The device under test will be referred to as \textbf{appliance}. The requirements for the final \textbf{measuring device} are grouped to the three categories. Mandatory requirements are bound to be met at any cost. Some of the high importance requirements can be skipped or slightly modified, if unpredictable obstacles are found. However, they are all assumed to be completed for well being of the project. Optional requirements will be completed only if the resources allow for it.
They are also divided to a hardware part and software part. Software is easier to change than hardware and requires hardware to be run on. Software is also limited by the resources provided by the hardware. Therefore, hardware needs to be logically completed first and are also highlighted in figures \ref{f:client_node} and \ref{f:serv_node}.
@ -85,9 +85,9 @@ The measuring devices, from now on called \textbf{client nodes}, will consist of
\subsection{Hardware components breakdown} \label{ss:hw}
For the \textbf{server node}, a complete working solution already exists, ready to be employed. The \textbf{GL.inet board}, described in more detail in the chapter \ref{s:glinet}, is greatly sufficient in all required aspects, and thus is used for this purpose.
Luckily, a particular part of the required functionality for the client node (displayed as a simplified schematic in \ref{f:schem_block}) is already integrated as an ESP-8266 module, described in more detail in the chapter \ref{s:esp8266}. The module contains the \gls{tcpip} stack, micro-controller (application processor) running the user program, \gls{wlan} and light indication, all in one piece, so this greatly simplifies the design process and allows for more focus on the actual measurement circuitry. The ESP-12E has been chosen as an actual module, because of the available certification\cite{online:2ADUIESP-12}, which allows it to be introduced on the market later. It was already shown in the figure \ref{f:esp-12e}. The \gls{pwm} is present there too, so sound indication requires just a sound emitting device.
Luckily, a particular part of the required functionality for the client node (displayed as a simplified schematic in \ref{f:schem_block}) is already integrated as an ESP-8266 module, described in more detail in the chapter \ref{s:esp8266}. The module contains the \gls{tcpip} stack, micro-controller (application processor) running the user program, \gls{wlan} and light indication, all in one piece, so this greatly simplifies the design process and allows for more focus on the actual measurement circuitry. The ESP-12E has been chosen as an actual module, because of the available certification\cite{online:2ADUIESP-12}, which allows it to be introduced to the market later. It was already shown in the figure \ref{f:esp-12e}. The \gls{pwm} is present there too, so sound indication requires just a sound emitting device.
Talking about the measurement circuitry, the viable candidate is MAX78615 \cite{online:MAX78615} with the companion \gls{ic} MAX78700 \cite{online:MAX78700}. The couple \ref{f:schem_block} should be used, because it provides multiple ways of same voltage level communication with the processor, galvanic isolation via the pulse transformer for improved circuitry protection, great precision, accuracy and utility. The shunt resistor is utilised as a way of obtaining measurements, described in the sub-chapter \ref{ss:pmic}.
Talking about the measurement circuitry \ref{f:schem_block}, the viable candidate is MAX78615 \cite{online:MAX78615} with the companion \gls{ic} MAX78700 \cite{online:MAX78700}. The couple should be used, because it provides multiple ways of same voltage level communication with the processor, galvanic isolation via the pulse transformer for improved circuitry protection, great precision, accuracy and utility. The shunt resistor is utilised as a way of obtaining measurements, described in the sub-chapter \ref{ss:pmic}.
\begin{figure}[ht!]
\centering
@ -101,7 +101,7 @@ Choosing the voltage level for the digital electronics (the output voltage of th
Talking about the measurement circuitry, the candidate is MAX78615 \cite{online:MAX78615}, working on nominal 3.3V level, along with the companion \gls{ic} MAX78700 \cite{online:MAX78700}. The couple has been chosen, because it provides multiple ways of communication with the processor (buses/serial interfaces), galvanic isolation via a pulse transformer for improved circuitry protection, great precision, accuracy and utility. The resistor network, including the shunt resistor is utilised as a way of obtaining measurements. The shunt resistor is also briefly described in the sub-chapter \ref{ss:pmic}.
The remaining part of the client node block diagram \ref{f:client_node} not yet mentioned is switching. Either a mechanical relay or a semiconductor device, such as a thyristor or a \gls{ssr} isolated by an opto-coupler\cite{trzynadlowski2015introduction} will do. Mechanical relays tend to be larger and produce sound noise, have slow response time, but have inbuilt separate isolation and are capable of switching higher currents without additional thermal issues than their semiconductor counterparts\cite{blume2008electric}. The disadvantages of the mechanical relay are not relevant here, thus it has been chosen.
The remaining part of the client node's block diagram \ref{f:client_node} not yet mentioned is switching. Either a mechanical relay or a semiconductor device, such as a thyristor or a \gls{ssr} isolated by an opto-coupler\cite{trzynadlowski2015introduction} will do. Mechanical relays tend to be larger and produce sound noise, have slow response time, but have inbuilt separate isolation and are capable of switching higher currents without additional thermal issues than their semiconductor counterparts\cite{blume2008electric}. The disadvantages of the mechanical relay are not relevant here, thus it has been chosen.
\subsection{Schematic and PCB} \label{ss:schematic_pcb}

BIN
figures/enclosure.pdf (Stored with Git LFS)

Binary file not shown.

@ -56,8 +56,8 @@
\newacronym{pcb}{PCB}{printed circuit board}
\newacronym{ddsn}{DDSN}{Dynamic Domain Name Service}
\newacronym{pwm}{PWM}{Pulse-width modulation}
\newacronym{ac}{AC}{Alternating Current}
\newacronym{dc}{DC}{Direct Current}
\newacronym{ac}{AC}{Alternating current}
\newacronym{dc}{DC}{Direct current}
\newacronym{rms}{RMS}{Root-mean square}
\newacronym{tcp}{TCP}{Transmission Control Protocol}
\newacronym{tcpip}{TCP/IP}{\acrlong{tcp}/\acrlong{ip}}

@ -13,4 +13,4 @@
The idea is to invent way of measuring the electrical power and some more related information, preferably in a non-invasive way. The non-invasive way means, that the appliance that is being measured does not require any modifications, for instance in a form of some probe or a man-in-the-middle plug, suggesting an embedded system. When the data are obtained, they are presented to the user, preferably plotted as a quantity over time, not just and actual measurement. Since the solution is going to be multi-purpose, it has to incorporate at least one additional function, than just the measurement. In this case it is going to be the remote power-on/power-off of the appliance. The name of the thesis also suggests, that the final solution has to be compatible with the electrical sockets used in the local region, in this case the European ones. Since the solution is going to be an \textit{embedded system} measuring a \textit{physical quantity}, these two topics are described in following chapters.
There are two fixed components/modules that are going to be included in the work, mostly because if the research purposes, but also because they fit the implementation greatly and are accessible. The components are GL.inet router board and ESP8266 Wi-Fi module. The fact that these two are already chosen beforehand will streamline the design and development and will narrow down the possible implementation paths a little. Topics revolving around these two are also complex on their own, thus they are deserving their own chapters.
There are two fixed components/modules that are going to be included in the work, mostly because of the research purposes, but also because they fit the implementation greatly and are accessible. The components are GL.inet router board and ESP8266 Wi-Fi module. The fact that these two are already chosen beforehand will streamline the design and development and will narrow down the possible implementation paths a little. Topics revolving around these two are also complex on their own, thus they are deserving their own chapters.

@ -1,17 +1,17 @@
\section{Realisation}
The manufactured client node has been inserted into the enclosure containing an European mains socket (female) on one side and an European mains plug (male) on the other side, forming a man-in-the-middle adaptor, that can be non-invasively put between wall socket and an appliance. The result can be observed in figure \ref{f:project_inside}.
The manufactured client node has been inserted into the enclosure\cite{online:enclosure}, portrayed in the figure \ref{f:enclosure}, containing an European mains socket (female) on one side and an European mains plug (male) on the other side, forming a man-in-the-middle adaptor, that can be non-invasively put between wall socket and an appliance. The result can be observed in figure \ref{f:project_inside}.
\begin{figure}[ht!]
\centering
\includegraphics[width=.7\textwidth,angle=0]{project_inside}
\caption{The view into the client node's enclosure, before the final assembly, exposing top side of the board containing linear transformer T1 (green), mains connectors J1 and J2 (blue), a fuse holder for F1 (yellow-ish), a relay K1 (white) and an ESP-12E module}\label{f:project_inside}
\includegraphics[width=.7\textwidth,angle=0]{enclosure}
\caption{The 3D visualisation of the enclosure, displaying both the plug and the socket}\label{f:enclosure}
\end{figure}
\begin{figure}[]
\centering
\includegraphics[width=.7\textwidth,angle=0]{project_inside}
\caption{The view onto a fully assembled client node}\label{f:project_outside}
\caption{The view into the client node's enclosure, before the final assembly, exposing top side of the board containing linear transformer T1 (green), mains connectors J1 and J2 (blue), a fuse holder for F1 (yellow-ish), a relay K1 (white) and an ESP-12E module}\label{f:project_inside}
\end{figure}
\subsection{Discovered problems} \label{ss:problems}
@ -24,7 +24,7 @@ After a few test runs performed on an assembled client node, the first problem b
\caption{The power line of the ESP-12E inspected during the boot-up by the oscilloscope - it looks the same either if the processors boots, or it doesn't, suggesting the possible occurence of the ESP8266 firmware problem}\label{f:oscilloscope}
\end{figure}
Ignoring the boot-up problem, the client node is sort of working as indented, apart from one huge issue with the MAX78615 \gls{ic}, that was not apparent during the design stage: the \gls{spi} protocol only allows for 6 bit long memory addressing, enabling only the first 64 words of the memory to be accessed, leaving the 104 words out of 186 completely inaccessible. The details can be observed in the table \ref{t:spi-read} and \ref{t:spi-write}. The byte number 1 contains the \texttt{ADDR[5:0]} value, thus the address can only by 6 bits long. The data are taked directly from MAX78615 data-sheet\cite{online:MAX78615}. As a result, from the required data, only a RMS Voltage and a RMS Current can be obtained. All the data depending on phase shift, namely real power, reactive power and power factor are not accessible.
Ignoring the boot-up problem, the client node is sort of working as indented, apart from one huge issue with the MAX78615 \gls{ic}, that was not apparent during the design stage: the \gls{spi} protocol only allows for 6 bit long memory addressing, enabling only the first 64 words of the memory to be accessed, leaving the 104 words out of 186 completely inaccessible. The details can be observed in the table \ref{t:spi-read} and \ref{t:spi-write}. The byte number 1 contains the \texttt{ADDR[5:0]} value, thus the address can only by 6 bits long. The data are taked directly from MAX78615 data-sheet\cite{online:MAX78615}. As a result, from the required data, only a RMS voltage and a RMS current can be obtained. All the data depending on phase shift, namely real power, reactive power and power factor are not accessible.
\setlength{\tabcolsep}{.3em}
\begin{table}[ht!]
@ -108,7 +108,7 @@ The web interface also contains a button for shutting the appliance on or off (b
\subsection{Measurement calibration}
Since the client's node is performing measurements of physical quantities, it is reasonable to perform the initial calibration, to make the device as accurate as possible. Since the actual measuring unit, the MAX78700\cite{online:MAX78700}, is an \gls{adc} converter, it cannot provide the results in an actual Volts and Amperes. To be able to interpret the 24-bit number obtained from the the conversion process, we have to multiply it by calibration constants. They depend on the resistors surrounding the converter.
Since the client's node is performing measurements of physical quantities, it is reasonable to perform the initial calibration, to make the device as accurate as possible. Since the actual measuring unit, the MAX78700\cite{online:MAX78700}, is an \gls{adc} converter, it cannot provide the results in an actual volts and amperes. To be able to interpret the 24-bit number obtained from the the conversion process, we have to multiply it by calibration constants. They depend on the resistors surrounding the converter.
This process is also outlined in the reference design\cite{online:SONOMA} provided by Maxim, displaying the calibration constants tailored for the configuration suggested by it, along with the formulas to do the calculations.
@ -118,7 +118,7 @@ The calibration performed in the laboratory resulted in similar, but not entirel
\subsection{Possible future improvements}
The most crucial thing to improve is to make the client node's start reliable. The ESP-12E module sometimes won't start. After this problem has been resolved, one can move on to some other issues, but not before.
It is possible to fulfil all the failed requirements due to inability of accessing all the data over \gls{spi} by switching to \gls{i2c}. The only downside of such a design is inability to obtain all the instantaneous measurements. This does not pose a significant problem at all, because a lot of them still lies in the region inaccessible by \gls{spi} (due to the bad \gls{ic} design by its manufacturer, there is simply no way of accessing instantaneous measurements stored in memory outside of the first 64 words). Also, \gls{i2c} requires one less pin than \gls{spi}, thus leaving more pins on the ESP8266 and MAX78615 for some additional future features. Such a transition would however definitely require another iteration of the \gls{pcb}, which is not instant and requires a bit of resources. If a project is to be maintained in the future, this is definitely a vital change.
It is possible to fulfil all the failed requirements due to inability of accessing all the data over \gls{spi} by switching to \gls{i2c}. The only downside of a such design is the inability to obtain all the instantaneous measurements. This does not pose a significant problem at all, because a lot of them still lies in the region inaccessible by \gls{spi} (due to the bad \gls{ic} design by its manufacturer, there is simply no way of accessing instantaneous measurements stored in memory outside of the first 64 words). Also, \gls{i2c} requires one less pin than \gls{spi}, thus leaving more pins on the ESP8266 and MAX78615 for some additional future features. Such a transition would however definitely require another iteration of the \gls{pcb}, which is not instant and requires a bit of resources. If a project is to be maintained in the future, this is definitely a vital change.
Speaking of a \gls{pcb} iteration, another opportunity to improve the \gls{pcb} design lies in utilising the MAX78615 in-built relay controlling mechanism, utilising one of its free multio-purpose \gls{io} pins. Fundamental part of responsibilities of the \gls{ic} is to track the phase shift, thus being informed about the zero-crossing\cite{chappell2013introduction}. Relay switching locked to the zero-crossing allows for a graceful start ofthe appliance. This is helpful in preventing damage to some sensitive appliaces when started at the point of mains line voltage peak, such as incandescent light bulbs\cite{dilouie2008lighting}. Relay is also not essential for actual measurements, so it could be removed from the system altogether to save some cost and space, in applications where the relay is not needed.

@ -10,22 +10,22 @@ Electrical Power, in a circuit is the amount of energy that is absorbed or produ
\subsection{Ohm's law}
Ohm's Law deals with the relationship between voltage and current in an ideal conductor. This relationship states that: The potential difference (voltage) across an ideal conductor is proportional to the current through it \cite{henry2008ohm}. The constant of proportionality is called the \textit{resistance}.
Ohm's Law deals with the relationship between the voltage and the current in an ideal conductor. This relationship states that: the potential difference (voltage) across an ideal conductor is proportional to the current through it \cite{henry2008ohm}. The constant of proportionality is called the \textit{resistance}.
$$I = \frac U R $$
where I is the current expressed in Amperes [A], U is the voltage, bearing the Volt units [V] and R is the electrical resistance in ohms [$\Omega$].
where I is the current expressed in amperes [A], U is the voltage, bearing the volt units [V] and R is the electrical resistance in ohms [$\Omega$].
The Ohms's law can be further expanded \cite{beaty1998electric}, to get these three quantities in relationship with \textbf{power}, such as
$$P = I \cdot U = I^2 \cdot R = \frac{U^2}R$$
\subsection{Direct current (DC) circuits}
Generally, Ohm's law is used on \gls{dc} circuits. A DC voltage or current has a fixed magnitude (amplitude) and a definite direction associated with it. Both DC currents and voltages are produced by power supplies, batteries, dynamos and solar cells to name a few.
Generally, Ohm's law is used on \gls{dc} circuits, containing a current of fixed magnitude (amplitude) and a definite direction associated with it. \acrlong{dc} is produced by power supplies, batteries, dynamos and solar cells to name a few.
We also know that DC power supplies do not change their value with regards to time\cite{herman2012direct}, they are a constant value flowing in a continuous steady state direction. In other words, DC maintains the same value for all times and a constant uni-directional DC supply never changes or becomes negative unless its connections are physically reversed.
We also know that \gls{dc} power supplies do not change their value with regards to time\cite{herman2012direct}, they are a constant value flowing in a continuous steady state direction. In other words, \gls{dc} maintains the same value for all times and a constant uni-directional DC supply never changes or becomes negative unless its connections are physically reversed.
\subsection{Waveforms and alternating current (AC) circuits}
An alternating function or \gls{ac} waveform on the other hand is defined as one that varies in both magnitude and direction in more or less an even manner with respect to time making it a “bi-directional” waveform \cite{whitaker2006ac}. An AC function can represent either a power source or a signal source with the shape of an AC waveform generally following that of a mathematical sinusoid as defined by
An alternating function or \gls{ac} waveform on the other hand is defined as one that varies in both magnitude and direction in more or less even manner with respect to time making it a “bi-directional” waveform \cite{whitaker2006ac}. An AC function can represent either a power source or a signal source with the shape of an AC waveform generally following that of a mathematical sinusoid as defined by
$$A(t) = A_{max} \cdot sin(2 \pi f t)$$
\begin{figure}[ht!]
@ -34,21 +34,21 @@ $$A(t) = A_{max} \cdot sin(2 \pi f t)$$
\caption{The common types of waveforms visualised as a function of amplitude}\label{f:waveforms}
\end{figure}
The term AC or to give it its full description of Alternating Current, generally refers to a time-varying waveform with the most common of all being called a \textbf{Sinusoid} better known as a \textbf{Sinusoidal Waveform}. Sinusoidal waveforms are more generally called by their short description as \textbf{Sine Waves}. Sine waves are by far one of the most important types of AC waveform used in electrical engineering.
The term AC or to give it its full description of Alternating Current, generally refers to a time-varying waveform with the most common of all being called a \textbf{Sinusoid} better known as a \textbf{Sinusoidal waveform}. Sinusoidal waveforms are more generally called by their short description as \textbf{Sine Waves}. Sine waves are by far one of the most important types of AC waveform used in electrical engineering.
This means then that the AC waveform is a “time-dependent signal” with the most common type of time-dependant signal being that of the Periodic Waveform. The periodic or AC waveform is the resulting product of a rotating electrical generator. Generally, the shape of any periodic waveform can be generated using a fundamental frequency and superimposing it with harmonic signals of varying frequencies and amplitudes but that is out of the waveform fundamentals theory.
This means then that the \gls{ac} waveform is a “time-dependent signal” with the most common type of time-dependant signal being that of the Periodic Waveform. The periodic or \gls{ac} waveform is the resulting product of a rotating electrical generator. Generally, the shape of any periodic waveform can be generated using a fundamental frequency and superimposing it with harmonic signals of varying frequencies and amplitudes but that is out of the waveform fundamentals theory.
Alternating voltages and currents can not be stored in batteries or cells like direct current (DC) can, it is much easier and cheaper to generate these quantities using alternators or waveform generators when they are needed. The type and shape of an AC waveform depends upon the generator or device producing them, but all AC waveforms consist of a zero voltage line that divides the waveform into two symmetrical halves. The main characteristics of an AC waveform \cite{nicolaides1996electrical} are defined as:
Alternating voltages and currents can not be stored in batteries or cells like \gls{dc} can, it is much easier and cheaper to generate these quantities using alternators or waveform generators when they are needed. The type and shape of an AC waveform depends upon the generator or device producing them, but all \gls{ac} waveforms consist of a zero voltage line that divides the waveform into two symmetrical halves. The main characteristics of an \gls{ac} waveform \cite{nicolaides1996electrical} are defined as:
\begin{itemize}
\item the \textbf{period (T)} is the length of time in seconds that the waveform takes to repeat itself from start to finish. This can also be called the Periodic Time of the waveform for sine waves, or the Pulse Width for square waves
\item the \textbf{frequency} is the number of times the waveform repeats itself within a one second time period. Frequency is the reciprocal of the time period, defined as $f = \frac 1 T$, with the unit of frequency being the Hertz [Hz]
\item the \textbf{amplitude} is the magnitude or intensity of the signal waveform
\item \textbf{Reriod (T)} is the length of time in seconds that the waveform takes to repeat itself from start to finish. This can also be called the Periodic Time of the waveform for sine waves, or the Pulse Width for square waves
\item \textbf{Frequency} is the number of times the waveform repeats itself within a one second time period. Frequency is the reciprocal of the time period, defined as $f = \frac 1 T$, with the unit of frequency being the Hertz [Hz]
\item \textbf{Amplitude} is the magnitude or intensity of the signal waveform
\end{itemize}
\subsection{Power in AC circuits} \label{ss:ac_power}
When a reactance (either inductive or capacitive) is present in an AC circuit, the Ohm's law formula does not apply and different approach must be taken to express and calculate power \cite{rawlins2000basic}.
When a reactance (either inductive or capacitive) is present in an \gls{ac} circuit, the Ohm's law formula does not apply and different approach must be taken to express and calculate power \cite{rawlins2000basic}.
\textbf{Real power} (or true power) is the power that is used to do the work on the load:
$$P = U_{RMS} \cdot I_{RMS} \cdot cos\,\varphi$$
@ -150,12 +150,12 @@ A special purpose \glspl{ic} are being developed for the exact purpose of measur
\caption{The simplified block diagram for a power measurement \gls{ic}}\label{f:meas_IC_diag}
\end{figure}
From the block diagram \ref{f:meas_IC_diag}, it can be seen that the power measuring \gls{ic} is just a specialised microcontroller. It takes the data from the sensing circuitry, which in case of voltage can be measured \textit{directly}, provided that the galvanic isolation is included, for the sake safety. The current however, must be measured \textit{indirectly}. There are three common ways \cite{srinivasan2015composite} of doing so:
From the block diagram \ref{f:meas_IC_diag}, it can be seen that the power measuring \gls{ic} is just a specialised microcontroller. It takes the data from the sensing circuitry, which in case of voltage can be measured \textit{directly}, provided that the galvanic isolation is included, for the sake of safety. The current however, must be measured \textit{indirectly}. There are three common ways \cite{srinivasan2015composite} of doing so:
\begin{enumerate}
\item \textbf{shunt resistor} - a resistor with a very small but precise value, that causes a voltage drop with a current passing through it due to the Ohm's law, regardless of frequency. The actual voltage drop is so small, that it can be assumed insignificant. However, the voltage drop is still present and may cause some issues, if not taken into account. The advantage is really low price. External galvanic isolation must be provided.
\item \textbf{current transformer} - a current passing wire inside a current sensing coil. Since it is a magnetic induction based transformer, the galvanic isolation is naturally present. The disadvantage is, that the transformer has a cut-off after which it's effect diminishes rapidly. External magnetic fields can cause problems too. Suitable for measuring current of a fixed (or non-decreasing) frequency.
\item \textbf{Hall-effect sensor} - a sensor measuring absolute electromagnetic field in a conductor. In contrast to the current transformer, this sensor is able to measure low frequency currents, down to \gls{dc}, which is a feat that the shunt resistor possesses too. Can be placed anywhere near the current path and doesn't require physical connection, thus providing galvanic isolation too. The price increases with operating currents range and precision. Prone to external magnetic fields too.
\item \textbf{shunt resistor} - a resistor with a very small but precise value, that causes a voltage drop with a current passing through it due to the Ohm's law, regardless of frequency. The actual voltage drop is so small, that it can be assumed insignificant, but measurable. However, the voltage drop is still present and may cause some issues, if not taken into account. The advantage is really low price. External galvanic isolation must be provided.
\item \textbf{current transformer} - a current passing wire inside a current sensing coil. Since it is a magnetic induction based transformer, the galvanic isolation is naturally present. The disadvantage is, that the transformer has a cut-off frequency, below which it's effect diminishes rapidly. External magnetic fields can cause problems too. Suitable for measuring current of a fixed (or non-decreasing) frequency.
\item \textbf{Hall-effect sensor} - a sensor measuring absolute electromagnetic field in a conductor. In contrast to the current transformer, this sensor is able to measure low frequency currents, down to \gls{dc}, which is a feat that the shunt resistor possesses too. Can be placed anywhere near the current path and doesn't require physical connection, thus providing galvanic isolation too. The price increases with operating currents range and precision. Prone to be disturbed by external magnetic fields, too.
\end{enumerate}
Using dedicated power measuring IC has another advantage apart from being more accurate. In fact, the part \gls{datasheet} can be consulted and if all application notes and advices are abided, the specified accuracy can be guaranteed.
@ -207,12 +207,6 @@ A \gls{rtos} is just a special purpose \gls{os}. The real time part of the name
\end{description}
\subsection{Embedded Linux}
\Gls{linux} itself is a \gls{kernel}, but \Gls{linux} in day to day terms rarely means so. Embedded \Gls{linux} generally refers to a complete \Gls{linux} distribution targeted at embedded devices. There is no \Gls{linux} \gls{kernel} specifically targeted at embedded devices, the same \Gls{linux} \gls{kernel} source code can be built for a wide range of devices, workstations, embedded \glspl{system}, and desktops though it allows the configuration of a variety of optional features in the \gls{kernel} itself. In the embedded development context, there can be an embedded \Gls{linux} \gls{system} which uses the \Gls{linux} \gls{kernel} and other software or an embedded \Gls{linux} distribution which is a prepackaged set of applications meant for embedded \glspl{system} and is accompanied by development tools to build the system\cite{hallinan2010embedded}.
With the availability of consumer embedded devices, communities of users and developers were formed around theses devices: Replacement or enhancements of the \Gls{linux} distribution shipped on the device has often been made possible thanks to availability of the source code and to the communities surrounding the devices. Due to the high number of devices, standardized build \glspl{system} have appeared, namely OpenWRT.
\subsection{Kernel}
The \gls{kernel} is the essential center of a \gls{computer} \gls{os}, the core that provides basic services for all other parts of the \gls{os} \cite{bovet2005understanding}. It has complete control over what happens in the \gls{system}. A \gls{kernel} can be contrasted with a \gls{shell}, the outermost part of an \gls{os} that interacts with user commands. \Gls{kernel} and \gls{shell} are terms used more frequently in Unix or Unix-like \glspl{os} than in IBM mainframe or Microsoft Windows \glspl{system}.
@ -225,6 +219,12 @@ The \gls{kernel} is the essential center of a \gls{computer} \gls{os}, the core
The simplified view on the \Gls{linux} \gls{system} structure can be seen on \ref{f:linuxbl}. It does not include device \gls{driver}, \glspl{compiler}, \glspl{daemon}, \glspl{utility}, \glspl{command}, \gls{library} files and such, but should be enough for a demonstration.
\subsection{Embedded Linux}
\Gls{linux} itself is a \gls{kernel}, but \Gls{linux} in day to day terms rarely means so. Embedded \Gls{linux} generally refers to a complete \Gls{linux} distribution targeted at embedded devices. There is no \Gls{linux} \gls{kernel} specifically targeted at embedded devices, the same \Gls{linux} \gls{kernel} source code can be built for a wide range of devices, workstations, embedded \glspl{system}, and desktops though it allows the configuration of a variety of optional features in the \gls{kernel} itself. In the embedded development context, there can be an embedded \Gls{linux} \gls{system} which uses the \Gls{linux} \gls{kernel} and other software or an embedded \Gls{linux} distribution which is a prepackaged set of applications meant for embedded \glspl{system} and is accompanied by development tools to build the system\cite{hallinan2010embedded}.
With the availability of consumer embedded devices, communities of users and developers were formed around theses devices: Replacement or enhancements of the \Gls{linux} distribution shipped on the device has often been made possible thanks to availability of the source code and to the communities surrounding the devices. Due to the high number of devices, standardized build \glspl{system} have appeared, namely OpenWRT.
\subsection{OpenWRT} \label{ss:openwrt}
OpenWrt is an \gls{os} (in particular, an embedded \gls{os}) based on the \Gls{linux} \gls{kernel}, primarily used on embedded devices to route \gls{network} traffic. It has been optimized for size, to be small enough for fitting into the limited storage and memory available in home \glspl{router}.
@ -232,7 +232,7 @@ OpenWrt is configured using a command-line \gls{interface} (ash \gls{shell}), or
\subsection{Components of the OpenWRT}
The main components are the \Gls{linux} \gls{kernel}, \texttt{util-linux-ng}, \texttt{uClibc} and \texttt{BusyBox}. The \Gls{linux} \gls{kernel} was already mentioned. \texttt{util-linux-ng} is self explanatory - it is a set of \gls{linux} utilities.
The main components are the \Gls{linux} \gls{kernel}, \texttt{util-linux-ng}, \texttt{uClibc} and \texttt{BusyBox}. The \Gls{linux} \gls{kernel} was already mentioned. \texttt{util-linux-ng} is self explanatory - it is a set of \gls{linux} utilities used inside the OpenWWT distribution.
\texttt{BusyBox} is a software that provides several stripped-down \Gls{unix} tools in a single executable file. It runs in a variety of \gls{posix} environments such as \Gls{linux}, \Gls{android}, \gls{bsd} family and others, such as proprietary \glspl{kernel}, although many of the tools it provides are designed to work with \glspl{interface} provided by the \Gls{linux} \gls{kernel}.
@ -243,7 +243,7 @@ The main components are the \Gls{linux} \gls{kernel}, \texttt{util-linux-ng}, \t
\newpage
\section{GL.inet board} \label{s:glinet}
GL.inet Smart \Gls{router} is a remake of a common TP-Link \gls{router} TL-WR703N. The board changes include, but are not limited to, increased \gls{ram} and \Gls{flash} memory, custom \gls{firmware} and what is the most important - 5 usable \gls{gpio} pins exposed to the 2cm pin header for utility. Whole thesis is revolving around taking advantage of this fact. The frequency of \gls{cpu} is 400 \gls{mhz} and it is suited for running \Gls{linux} distributions for embedded devices, preferably OpenWrt or DD-Wrt. The board provides \gls{lan} and \gls{wan} connection, as well as other \glspl{interface} defined in \gls{ieee}. The information about the board are summed up in the table \ref{t:charact}.
GL.inet Smart \Gls{router} is a remake of a common TP-Link \gls{router} TL-WR703N. The board changes include, but are not limited to, increased \gls{ram} and \Gls{flash} memory, custom \gls{firmware} and what is the most important - 5 usable \gls{gpio} pins exposed to the 2cm pin header for utility purposes. The frequency of \gls{cpu} is 400 \gls{mhz} and it is suited for running \Gls{linux} distributions for embedded devices, preferably OpenWrt or DD-Wrt. The board provides \gls{lan} and \gls{wan} connection, as well as other \glspl{interface} defined in \gls{ieee}. The information about the board are summed up in the table \ref{t:charact}.
\begin{table}[h]
\caption{The basic characteristics of the GL.inet board}\label{t:charact}

@ -428,3 +428,10 @@
pages={135}
}
@online{online:enclosure,
author = {COMBIPLAST},
title = {CP-Z-27/B - Kryt: pre napájací zdroj; X:70,9mm; Y:120,5mm; Z:45mm; polystyrén},
url = {http://www.tme.eu/sk/details/cp-z-27_b/skatulky-pre-napajacie-zdroje/combiplast/},
note = {(Accessed on 24/06/2016)}
}

BIN
tukethesis.pdf (Stored with Git LFS)

Binary file not shown.

@ -101,7 +101,7 @@ pdfsubject={Master's Thesis}
%% -----------------------------------------------------------------
%% Ak praca nema 'podnazov' zakomentujte riadky \subtitle a \podnazov,
%% alebo polozky nechajte prazdne
\author{Peter Babič}
\author{Bc. Peter Babič}
\title{Multi-purpose system for measuring electrical power supplied by electric sockets}
\subtitle{}
\abstrakte{This thesis shows the process of designing, building and programming of an inter-connected electronic system. It starts with explaining the fundamentals of the physics underlining the electronic power measurement process, transitioning into describing integrated components/modules used later in the proposed solution, such as ESP8266 Wi-Fi chip, GL.inet router board or OpenWRT - an unix-like operating system. The conceptual design of a final solution, utilising the aforementioned topics, follows. It includes diagrams describing the inner working of the hardware, and later software running on it. The manufactured device is capable of measuring the electric power provided by the electric socket to the appliance and send the measured values over Wi-Fi to the cloud, to be visualised on a custom web server employing a charting library to plot the measured quantities over time.

Loading…
Cancel
Save