Merge pull request #12 from VishnuEaswaran/vishnuDev

Updating repo structure and documentation

3 files changed, 316 insertions, 0 deletions

diff --git a/OpenPLC_version_1/Documentation/Creating-Ladders.rst b/OpenPLC_version_1/Documentation/Creating-Ladders.rst
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+Creating Ladders using Ld micro
+===============================
+
+LD Micro’s simple user interface is really easy to use and is self explanatory.To get started working with LD Micro, just double click the LD Micro executable present in your system. Once opened, you shall get such a GUI.
+
+.. image:: ../assets/ld1.png
+   :height: 540px
+   :width: 750px
+   :scale: 150
+
+Before starting to make the ladder, first make the necessary changes in
+the default settings, so as to generate the HEX code for your microcontroller.
+
+Under Settings tab, select the MCU Parameters Option
+
+.. image:: ../assets/Setup.png
+   :height: 340px
+   :width: 450px
+   :scale: 150
+
+Then after selecting, change the clock frequency to 16MHz and if using
+UART change the baud rate to 9600.
+
+.. image:: ../assets/cont.png
+   :height: 540px
+   :width: 650px
+   :scale: 150
+
+Now that the configurations are set, the next step can be followed to
+design the ladder with the appropriate logic.
+
+Start off with having a look at the Instruction tab. It has a lot of
+instructions that are in accordance with the Ladder logic followed for the PLCs and work in the same way and are similar to the ones described above under the ’Understanding the Instructions’ section.
+
+After selecting the appropriate instruction, just double click the instruction to edit the name of the variable and other parameters related to the particular instruction.
+
+.. image:: ../assets/change.png
+   :height: 540px
+   :width: 650px
+   :scale: 150
+
+After making the appropriate ladder for the application, the digital input and outputs should be given an appropriate pin number of the controller and the connections should be done accordingly. This can be done by double clicking the appropriate pin to be configured in the consolidated table just below the ladder made.
+
+.. image:: ../assets/PIN.png
+   :height: 540px
+   :width: 600px
+   :scale: 150
+
+Now that the logic is set, the ladder can be simulated to verify it’s working. This is done by clicking the Simulate tab and Simulation Mode option under it. This is then followed by a similar screen where Blue indicates LOW and Pink indicates HIGH. To start the simulation, under Simulate tab click Start Real-Time Simulation option. After this, to change the state, just double click the instruction. The appropriate changes and values pertaining to different variables can be seen in the consolidated instruction table under the State column. To come out of simulation mode, click the same Simulation Mode option.
+
+.. image:: ../assets/states.png
+   :height: 340px
+   :width: 450px
+   :scale: 150
+
+After the ladder along with assigning the appropriate pin numbers, the
+HEX code can be generated. This can be done by first saving the ladder
+under the File tab with the Save As option. Save the file in the appropriate destination folder with a suitable name. Remember the final destination of the same for future. Now, to generate the HEX file, select the Compile tab and then the option Compile As. Then save this text file in the desired destination folder. The location shall be noted as it’d be needed to burn the code onto the controller using the command line arguments later.
+
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+
diff --git a/OpenPLC_version_1/Documentation/Programming-OpenPLC.rst b/OpenPLC_version_1/Documentation/Programming-OpenPLC.rst
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+Programming the OpenPLC Board
+==========================
+
+There are several programmers available to program any controller IC. They are called as ISPs. USBASP is one of them. Before programming the IC, we need to set the fuses. 
+
+Setting up fuse bits
+--------------------
+
+Now that the programmer is installed on the system, we need to adjust the
+properties of the controller IC such that it meets the necessary requirements along with the peripherals installed on the board. Essentially, fuse bits are the ones that decide how the controller responds, like which clock frequency it responds to or its programming availabilities.
+
+Setting up the fuse is a crucial task as the controller may not respond later if the fuse bits that are set are not in accordance with the attached peripherals. Before setting the fuses, the factory settings on the controller make sure it works on the internal oscillator of clock speed 1MHz. It’s mostly dependent on 2 fuses - lfuse and hfuse. Both of these have hex 8 bit values. When working on communication with the device, like UART, these fuse bits play a key role, if not defined, the
+controller works on the internal clock that’s much slower than the external crystal. For the controller, 16MHz external crystal was selected. This meant the controller shall configure this external crystal and work on it.
+
+**WARNING:** Fuse bits control the way the controller responds. If
+any mistake is made in setting up the fuse bits, then the controller
+becomes isolated from the external circuit. This means that the
+controller doesn’t respond and renders useless. Hence, always triple
+check before entering the fuse bits. This is the best practice,
+or else you may end up wasting one IC.
+
+Type the following command into the Terminal:
+
+**sudo avrdude -p m16 -c usbasp -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -B10**
+
+Screen like below will pop up after giving the command line
+
+.. image:: ../assets/fuse1.png
+   :height: 540px
+   :width: 450px
+   :scale: 100
+
+You can read fuse bits after setting up, as shown below, 
+
+.. image:: ../assets/fuse2.png
+   :height: 540px
+   :width: 450px
+   :scale: 100
+
+Now the external crystal is working in sync with the controller. 
+
+USBASP as ISP
+-------------
+
+Step 1: We require a pre-compiled hex file to be burnt onto our microcontroller. In our case, we have generated it by doing simple ladder programming in LDMicro and then compiling it. Before that, ensure that the proper target controller from the drop-down menu is chosen. For input and output part, assign a certain pin no. of the controller to that of the desired application. Now, a certain name is given to the file(say, blink.hex) at the destination folder.
+
+Step 2: After being done with all the software part, one shall supply the power from 12V SMPS to the development board. Now check whether the
+controller is powered up properly with 5 Volt or not from the appropriate Vcc and GND pins of the controller.
+
+Step 3: Now, just connect the FRC cable from USBASP to the 10 pin
+shrouded header on the board.
+
+Step 4: Now, turn on Terminal and then change the directory to the one
+in which you have the saved HEX file to be dumped onto the processor.
+
+Step 5: Now, in the terminal, enter the following command.
+
+**sudo avrdude -c usbasp -p m16-U flash:w:Blink.hex**
+
+You shall see such a process going on in the terminal like the one shown
+below, which means that the process of erasing and writing the internal
+memory of the ATmega IC is in the process. On correct execution you shall
+get such a result. Whilst it’s burning the code, the red light on the USBASP will be lit showing that it is communicating with the controller appropriately.
+
+.. image:: ../assets/usb.png
+   :height: 540px
+   :width: 450px
+   :scale: 100
+
+Trouble shooting
+~~~~~~~~~~~~~~~~
+
+- Check if the board is powered from the SMPS, if not, power it and try
+  it once powered.
+- Check if all the essential flags in the command line are incorporated, 
+  if not make the appropriate changes.
+- Check if the FRC cable of the USBASP is not stranded in the midway,
+  if so, replace it.
+- If all these fail, check if the appropriate MOSI, MISO, SCK, RST and
+  GND pins of the header are appropriately shorted with the ones of the  
+  IC and also that the controller firmly sits on the base.
+
+These are the main errors you may get while programming the PLC.
+
+
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diff --git a/OpenPLC_version_1/Documentation/Software-Requirements.rst b/OpenPLC_version_1/Documentation/Software-Requirements.rst
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+Software Requirements
+=====================
+
+Many software support PLC simulation in various logic.
+The software that has been used in the subsequent sections is
+LDMicro, that incorporates Ladder Logic, supporting
+many microcontrollers, along with the AVR's ATmega16A. This
+software helps produce the HEX files according to the microcontroller
+and the pin selected which can be directly dumped onto the
+core.
+
+For windows based system
+------------------------
+
+The IC is a standalone one without the Bootloader. One of the ways of
+dumping the code, is using an In System Programmer or an ISP. So, for burning the same we use the software: AVRDUDE1 - AVR Downloader Uploader is a program for downloading and uploading the on-chip memories of Atmels AVR microcontrollers. It can program the Flash and EEPROM, and where supported by the serial programming protocol, it can program fuse and lock bits. It’s available as WINAVR for Windows and can be downloaded from 'here <https://sourceforge.net/projects/winavr/files/WinAVR/20100110>'_.
+
+Setting up WINAVR
+~~~~~~~~~~~~~~~~~
+
+Step 1: First, open up the start screen and then search : Command Prompt
+
+.. image:: ../assets/Figcmd.png
+   :height: 540px
+   :width: 550px
+   :scale: 150
+
+Step 2: Then, a screen like this shall pop up.
+
+.. image:: ../assets/Comm.png
+   :height: 540px
+   :width: 550px
+   :scale: 150
+
+Step 3: Enter into the command prompt for windows: avrdude
+
+You should get prompts and flags mentioned like this, which implies that you have downloaded the software properly.
+
+.. image:: ../assets/avrdude1.png
+   :height: 440px
+   :width: 650px
+   :scale: 100
+
+For Ubuntu system
+~~~~~~~~~~~~~~~~~~~~~~
+
+Instead if you have Ubuntu system, it’s already pre-installed under the
+name AVRDUDE. Just enter the below command line on your terminal
+
+**man avrdude**
+
+You would see a screen full of text, something like the one below. To
+exit press q. If you don’t get a screen like that, then open Ubuntu Software Center and on the search bar enter avrdude, then install it. Enter the same command into the terminal again and you shall see the manual.
+
+.. image:: ../assets/manavrdude.png
+   :height: 540px
+   :width: 450px
+   :scale: 100
+
+Setting up the Ld micro executable
+----------------------------------
+
+To download the software on your Windows system, go to [#] `<http://cq.cx/ladder.pl/>`_ The download is a direct executable, there’s no need to install it.
+
+.. image::../assets/Downloading-LD-Micro.png
+   :height: 540px
+   :width: 450px
+   :scale: 100
+
+
+Getting started with Ld micro
+-----------------------------
+
+A PLC is largely programmed using Ladder Logic, which is used in
+this software. It allows us to select the microcontroller that 
+we wish to program via its HEX codes generated, ATmega16A in this case. The naming convention is very intuitive and is easy to get accustomed to. Some of the naming conventions followed are: 
+
+[1] *Yvar* implies the component is connected to an input pin on the micro-controller, something like a push button that is user dependent. This generally works for the digital inputs, HIGH(+5V) or LOW(GND).
+
+[2] *Xvar* implies the component is connected to an output pin on the microcontroller. This can be something like an LED or a Buzzer that is used to show the outputs. It’s generally used to display digital outputs, HIGH(+5V) or LOW(GND).
+
+[3] *Tvar* implies, a timer. It can be a turn on, turn off or a retentive timer, just like the ones used in the actual PLCs.
+
+[4] *Cvar* implies a counter. The arguments in this are simple logical
+operands to decide the upper bound up to which the counter shall work.
+There are circular counter too, which count circularly, without any
+bound.
+
+[5] *Avar* implies the values read from the Analog pins of the controller.This can be used to take the intermediate readings say from components like Potentiometers, IR sensors etc.
+
+Things to remember are:
+
+- Variable names can incorporate alphabets, numbers and underscores.
+  It doesn’t support the special characters.
+- Do not start the name of the variable with a number.
+- The variable names are case sensitive, the variable names Relay1 and
+  relay1 signify two different variables.
+- The instructions such as the arithmetic ones can manipulate the vari-
+  ables associated with the timers, counters or input, output pins.
+- The variables are 16 bit signed decimals, so the variables can also
+  be containing values that are negative pertaining to that range.  
+- As counters, timers in physical sense are internal in the microcontroller, we can only assign the pins to the Xname, Yname and Aname objects and not others.
+
+Now that the basic ideas are clear, the use of certain instructions can be discussed.
+
+We shall understand normally open and normally closed connections. In
+normally open case, the contacts are open generally, which means, giving a high input closes the contact, hereby passing the signal over the rung.Whereas, a normally closed connection would imply a high signal to the connection would break the circuit hence giving low as the output.
+
+[1] **Contacts** are something like a prototype of a switch, which implies, if the signal going into the contact is true, only then it’ll be reflected as output, if false, then output is false for normally open case. These can be used as internal relays too.
+
+[2] **Coils** are basically corresponding to the output devices. They can set the output true, if the signal going into them is true for the normally open case, else it’s the other way. They can be used with internal relays too. There is an option of Set only (Reset-only) which are set(reset) when the input goes from Low to High, and retain their states. Hence they are used with Reset-Only(Set-Only) coils to change the states as and when wanted.
+
+[3] **Internal Relays** are the ones that are never assigned pin numbers.Basically, they are the ones that are used for counters or triggers, which are not given inputs or outputs, hence no pin on the controller.
+
+[4] **Turn on Delay** simply means delaying turning on of any coil. This mean the sensor, if gives a high at the input, it delays the turning on of the next part of the rung by those many units of time
+
+[5] **Turn off Delay** literally means turning off of any coil with some delay.This mean the sensor, if gives a false or a low at the input, it delays the turning off of the next part of the rung by those many units of time
+
+[6] **Retentive timer** is used to keep track of the how much time the
+module under consideration has been true, it cumulates the total time,
+if the input has been on for at-least that much time, the output of the
+timer is true. It will always remain true after this, hence it should be reset by using Reset instruction manually
+
+[7] **Counter** is used to count up to the given value threshold.The count is changed as the input to the counter is made high. This is used as an up counter, down counter or a circular counter. The variables can be manipulated and be suited for the application
+
+[8] **Mov** is used to move any value, be it character or numeric into the variable named under destination.
+
+[9] **Arithmetic operands** are used to manipulate the variables values to suit the logic, they can be used on any kind of variables like the counters variables.
+
+These are the basic ones that are used. A detailed help for the more
+instructions and general guidelines is provided on the Manual of the
+software under the Help menu.
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