View source for Scilab/C2/Xcos-Introduction/English-timed

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|'''Time'''
|'''Narration'''

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|00:01
|Welcome to the spoken tutorial on''' Xcos: Scilab Connected Object Simulator.''' 

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|00:07
|'''Xcos''' is a '''Scilab package''' for modeling and simulation of dynamical systems. It includes both '''continuous''' and '''discrete''' systems. 

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| 00:17
|In this tutorial you will learn What is '''XCOS'''.  What is '''palette''', Build block diagrams in '''Xcos'''

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|00:26
|Setup the parameters of blocks, Setup the simulation parameters, Simulate the constructed block diagram. 

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| 00:35
| To practice this tutorial, Scilab should be installed on your system. 

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|00:40
|I am using Ubuntu Linux 12.04 and Scilab version 5.3.3 for demonstration. 

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| 00:48
| Open the '''Scilab console''' window on your computer.

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|00:52
|Go to applications and select '''Xcos'''OR Type '''xcos''' in your '''Scilab console''' window and press '''Enter''' 

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| 01:02
|By doing this, two windows will open. The two windows are'''Palette browser''' and '''Untitled-Xcos''' window

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|01:14
|In '''Palette browser''', you will find different types of blocks '''Commonly Used Blocks''' 

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|01:20
| '''Continuous time system blocks''' , '''Discrete time systems blocks '''and many more.

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|01:26
|The other window, '''Untitled-Xcos''' is blank, with grids. 

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|01:31
|We will now simulate a '''first order system''' with a''' step input'''. 

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|01:36
|To begin, I will select a '''transfer function block''' from the '''Continuous time systems palette'''. 

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|01:43
|Drag this block to the '''Untitled-Xcos''' window. 

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|01:48
|Select the required source in the '''Sources palette'''. I will scroll down and use the '''STEP FUNCTION block'''. 

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|01:56
|I will drag and place it before the '''transfer function block.''' 

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|02:01
|Similarly, the output is displayed using the '''CSCOPE block''', which is available in '''Sinks palette.''' 

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|02:08
|The '''CSCOPE block''' is placed after the '''transfer function block.''' 

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|02:13
|The red input port in '''CSCOPE''' denotes that this block is an '''“event driven” block.''' 

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|02:19
|It needs an '''event''' input for execution. 

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|02:22
|An '''event generator block''' is available in the '''Event handling palette.''' 

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|02:29
|The name of this block is '''Clock underscore c'''.

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|02:34
|Drag and place this block above the CSCOPE block. 

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|02:39
|We have collected all the required blocks to do the simulation.  

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|02:44
|Let us now connect the blocks together.

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|02:47
|Select the '''output port''' of '''step function block''' and connect it to the '''input port''' of the '''transfer function block.''' 

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|02:55
|Notice that the selected '''input port''' gets highlighted in green colour.

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|03:00
|Similarly, connect the remaining blocks as shown.

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|03:05
|Now we will set the parameters of each block. 

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|03:10
|First, go to the '''step block''' and double-click on it. 

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|03:14
|A pop up window appears, asking for the value of '''Step Time, Initial Value''' and '''Final Value'''.

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|03:23
|'''Step Time''' is the time at which the '''step change''' will occur.We will keep it as 1, which is the default value.

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|03:32
|'''Initial Value''' is the initial output value of the '''step function'''. 

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|03:37
|We will keep it as 0, which is the default value. 

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|03:41
|'''Final Value''' is the output of the '''step function''', after the '''Step Time''' is lapsed.We will change it to 2. 

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|03:50
|Click on '''OK'''. 

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|03:52
|Follow the similar procedure to configure any other block. 

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|03:56
|For '''transfer function block,''' the following configuration is required. '''Numerator''' value in''' laplace domain''' has to be entered. 

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|04:05
|We will keep it as 1, which is the default value.

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|04:09
|'''Denominator''' value in '''laplace domain''' has to entered. We will change it to '''2 asterisk s plus 1'''.Click on '''OK'''. 

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|04:20
|Double click on '''CSCOPE block,''' to configure the following parameters. 

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|04:25
|The value of''' Ymin''' and '''Ymax''' should be set, depending on the range of the value, of the variable to be plotted.

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|04:34
|Set the value of '''Ymin''' to 0.

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|04:38
|Since I have given '''step input''' as 2, to display the output on graph, I should change the '''Ymax''' to any higher value.

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|04:46
|We will change it to 3.

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|04:50
|Make a mental note of the default value of the '''refresh period'''.The default value is 30.

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|04:57
|We will keep the other parameters unchanged.Click on '''OK'''. 

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|05:02
|Now go to the '''Simulation''' in menu bar and click on '''Setup'''. 

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|05:08
|A pop up window appears. 

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|05:11
|We will change the value of '''Final integration time'''.'''Final integration time''' decides how long the simulation will run.

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|05:20
|Recall the value of '''refresh period''' of the''' CSCOPE block.'''

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|05:24
|I will keep the value of '''Final integration time''' equal to the value of '''refresh period''' of '''CSCOPE block'''

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|05:30
|So, I will change it to 30. 

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|05:34
|Keep the other parameters unchanged. Click on '''OK'''. 

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|05:39
|Now press '''Control S''' to save the file, with a suitable file name.I will save it as '''firstorder.xcos''' 

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|05:50
|To start the simulation, click on the '''Start''' button, available on the menu bar of '''Xcos''' window.

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|05:58
|A Graphic window will open, showing the '''step response''' of the first order '''transfer function.''' 

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|06:04
|We can save this plot as an image file.

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|06:06
|To save the graph, go to the '''File''' menu and click on '''Export to''' option. 

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|06:12
|I will name it as firstorder.png and click on '''OK'''

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|06:20
|There are certain parameters which we chose to keep as the default value. These can be changed. 

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|06:26
|For example In the''' Clock underscore c block''', the '''period''', which means the '''sampling period''' and '''initial time''' can be set.

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|06:36
|In the '''CSCOPE block,''' the '''output window number

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|06:40
|position, size, buffer size , graph color''' etc can also be set.

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| 06:46
|Pause the video here and solve the exercise given with the video. 

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|06:52
|Simulate a '''second order transfer function''' with '''damping ratio''' of 0.5 and '''angular frequency''' equal to 1. 

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|07:01
|Try changing the color of output graph. 

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|07:04
|Using the first exercise, plot the '''Step input''' and the '''output''' in a single plot window.

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| 07:11
|Now let us summarize.In this tutorial we have learnt to: Create '''Xcos simulation''' diagrams using the '''palette browser'''

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|07:18
|Configure each block as per the simulation requirements

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|07:22
|Setup the simulation parameters. Save the output plot.

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| 07:26
|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 

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| 07:37
| The Spoken Tutorial Project Team Conducts workshops using spoken tutorials Gives certificates for those who pass an online test 

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|07:46
|For more details, please write to contact at spoken hyphen tutorial dot org 

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| 07:52
|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 

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|08:02
|More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro 

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| 08:12
|Hope you found this tutorial useful. This is Rupak Rokade from IIT Bombay signing off. Thank You.

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