Scilab/C2/Xcos-Introduction/English

Visual Cue	Narration
Introduction Slide	Welcome to the spoken tutorial on Xcos: Scilab Connected Object Simulator. Xcos is a Scilab package for modeling and simulation of dynamical systems. It includes both continuous and discrete systems.
Slide	In this tutorial you will learn What is XCOS. What is palette. Build block diagrams in Xcos Setup the parameters of blocks. Setup the simulation parameters. Simulate the constructed block diagram.
Slide	To practice this tutorial, Scilab should be installed on your system. I am using Ubuntu Linux 12.04 and Scilab version 5.3.3 for demonstration.
Open Scilab	Open the Scilab console window on your computer. Go to applications and select Xcos OR Type “xcos” in your Scilab console window and press Enter
Palette	By doing this, two windows will open. The two windows are Palette browser and Untitled-Xcos window In Palette browser, you will find different types of blocks Commonly Used Blocks Continuous time system blocks Discrete time systems blocks and many more. The other window, Untitled-Xcos is blank, with grids.
Collecting the blocks from different Pallete	We will now simulate a first order system with a step input. To begin, I will select a transfer function block from the Continuous time systems palette.
As per narration	Drag this block to the Untitled-Xcos window.
As per narration	Select the required source in the Sources palette. I will scroll down and use the STEP FUNCTION block.
As per narration	I will drag and place it before the transfer function block.
As per narration	Similarly, the output is displayed using the CSCOPE block, which is available in Sinks palette. The CSCOPE block is placed after the transfer function block.
Point to the red input port.	The red input port in CSCOPE denotes that this block is an “event driven” block.
As per narration	It needs an event input for execution. An event generator block is available in the Event handling palette. The name of this block is Clock underscore c.
As per narration	Drag and place this block above the CSCOPE block.
	We have collected all the required blocks to do the simulation.
Connect as per narration	Let us now connect the blocks together. Select the output port of step function block and connect it to the input port of the transfer function block.
Point to the green input port.	Notice that the selected input port gets highlighted in green colour.
As per narration	Similarly, connect the remaining blocks as shown.
Changing the parameter of step block	Now we will set the parameters of each block.
Double-click on step block	First, go to the step block and double-click on it.
Point the options in the Pop-up window	A pop up window appears, asking for the value of Step Time, Initial Value and Final Value.
Point to Step Time	Step Time is the time at which the step change will occur. We will keep it as 1, which is the default value.
	Initial Value is the initial output value of the step function. We will keep it as 0, which is the default value.
	Final Value is the output of the step function, after the Step Time is lapsed. We will change it to 2. Click on OK.
Changing the parameter of Transfer function block	Follow the similar procedure to configure any other block.
As per narration	For transfer function block, the following configuration is required. Numerator value in laplace domain has to be entered. We will keep it as 1, which is the default value.
As per narration	Denominator value in laplace domain has to entered. We will change it to 2 asteric s plus 1. Click on OK.
Changing the parameter of scope	Double click on CSCOPE block, to configure the following parameters.
Set Ymin to 0.	The value of Ymin and Ymax should be set, depending on the range of the value, of the variable to be plotted. Set the value of Ymin to 0.
Set Ymax to 3.	Since I have given step input as 2, to display the output on graph, I should change the Ymax to any higher value. We will change it to 3.
	Make a mental note of the default value of the refresh period. The default value is 30.
	We will keep the other parameters unchanged. Click on OK.
Changing the set up parameters	Now go to the Simulation in menu bar and click on Setup.
Pop up window.	A pop up window appears.
Point to Final integration time	We will change the value of Final integration time. Final integration time decides how long the simulation will run.
	Recall the value of refresh period of the CSCOPE block. I will keep the value of Final integration time equal to the value of refresh period of CSCOPE block So, I will change it to 30.
	Keep the other parameters unchanged. Click on OK.
saving the Xcos file	Now press Control S to save the file, with a suitable file name. I will save it as firstorder.xcos
simulation	To start the simulation, click on the Start button, available on the menu bar of Xcos window.
	A Graphic window will open, showing the step response of the first order transfer function.
Click on File >> Export to.	We can save this plot as an image file. To save the graph, go to the File menu and click on “Export to” option.
Name it firstorder.png	I will name it as firstorder.png and click on OK
	There are certain parameters which we chose to keep as the default value. These can be changed. For example In the Clock underscore c block, the period, which means the sampling period and initial time can be set.
	In the CSCOPE block, the output window number, position, size, buffer size , graph color etc can also be set.
Slide	Pause the video here and solve the exercise given with the video.
Slide	Simulate a second order transfer function with damping ratio of 0.5 and angular frequency equal to 1. Try changing the color of output graph. Using the first exercise, plot the Step input and the output in a single plot window.
Slide	Now let us summarize. In this tutorial we have learnt to: Create Xcos simulation diagrams using the palette browser Configure each block as per the simulation requirements Setup the simulation parameters Save the output plot.
Show slide	Watch the video available at the following link It summarizes the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it
Show slide	The Spoken Tutorial Project Team Conducts workshops using spoken tutorials Gives certificates for those who pass an online test For more details, please write to contact at spoken hyphen tutorial dot org
Show slide	Spoken Tutorial Project is a part of the Talk to a Teacher project It is supported by the National Mission on Education through ICT, MHRD, Government of India More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro
	Hope you found this tutorial useful. This is Rupak Rokade from IIT Bombay signing off. Thank You.

Contributors and Content Editors

Nancyvarkey, Pravin1389, Rupakrokade