Scilab/C2/Xcos-Introduction/English-timed
From Script | Spoken-Tutorial
| Time | Narration |
| 00:01 | Welcome to the spoken tutorial on Xcos: Scilab Connected Object Simulator. |
| 00:07 | Xcos is a Scilab package for modeling and simulation of dynamical systems. It includes both continuous and discrete systems. |
| 00:17 | In this tutorial you will learn What is XCOS. What is palette, Build block diagrams in Xcos |
| 00:26 | Setup the parameters of blocks, Setup the simulation parameters, Simulate the constructed block diagram. |
| 00:35 | To practice this tutorial, Scilab should be installed on your system. |
| 00:40 | I am using Ubuntu Linux 12.04 and Scilab version 5.3.3 for demonstration. |
| 00:48 | Open the Scilab console window on your computer. |
| 00:52 | Go to applications and select XcosOR Type xcos in your Scilab console window and press Enter |
| 01:02 | By doing this, two windows will open. The two windows arePalette browser and Untitled-Xcos window |
| 01:14 | In Palette browser, you will find different types of blocks Commonly Used Blocks |
| 01:20 | Continuous time system blocks , Discrete time systems blocks and many more. |
| 01:26 | The other window, Untitled-Xcos is blank, with grids. |
| 01:31 | We will now simulate a first order system with a step input. |
| 01:36 | To begin, I will select a transfer function block from the Continuous time systems palette. |
| 01:43 | Drag this block to the Untitled-Xcos window. |
| 01:48 | Select the required source in the Sources palette. I will scroll down and use the STEP FUNCTION block. |
| 01:56 | I will drag and place it before the transfer function block. |
| 02:01 | Similarly, the output is displayed using the CSCOPE block, which is available in Sinks palette. |
| 02:08 | The CSCOPE block is placed after the transfer function block. |
| 02:13 | The red input port in CSCOPE denotes that this block is an “event driven” block. |
| 02:19 | It needs an event input for execution. |
| 02:22 | An event generator block is available in the Event handling palette. |
| 02:29 | The name of this block is Clock underscore c. |
| 02:34 | Drag and place this block above the CSCOPE block. |
| 02:39 | We have collected all the required blocks to do the simulation. |
| 02:44 | Let us now connect the blocks together. |
| 02:47 | Select the output port of step function block and connect it to the input port of the transfer function block. |
| 02:55 | Notice that the selected input port gets highlighted in green colour. |
| 03:00 | Similarly, connect the remaining blocks as shown. |
| 03:05 | Now we will set the parameters of each block. |
| 03:10 | First, go to the step block and double-click on it. |
| 03:14 | A pop up window appears, asking for the value of Step Time, Initial Value and Final Value. |
| 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. |
| 03:32 | Initial Value is the initial output value of the step function. |
| 03:37 | We will keep it as 0, which is the default value. |
| 03:41 | Final Value is the output of the step function, after the Step Time is lapsed.We will change it to 2. |
| 03:50 | Click on OK. |
| 03:52 | Follow the similar procedure to configure any other block. |
| 03:56 | For transfer function block, the following configuration is required. Numerator value in laplace domain has to be entered. |
| 04:05 | We will keep it as 1, which is the default value. |
| 04:09 | Denominator value in laplace domain has to entered. We will change it to 2 asterisk s plus 1.Click on OK. |
| 04:20 | Double click on CSCOPE block, to configure the following parameters. |
| 04:25 | The value of Ymin and Ymax should be set, depending on the range of the value, of the variable to be plotted. |
| 04:34 | Set the value of Ymin to 0. |
| 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. |
| 04:46 | We will change it to 3. |
| 04:50 | Make a mental note of the default value of the refresh period.The default value is 30. |
| 04:57 | We will keep the other parameters unchanged.Click on OK. |
| 05:02 | Now go to the Simulation in menu bar and click on Setup. |
| 05:08 | A pop up window appears. |
| 05:11 | We will change the value of Final integration time.Final integration time decides how long the simulation will run. |
| 05:20 | Recall the value of refresh period of the CSCOPE block. |
| 05:24 | I will keep the value of Final integration time equal to the value of refresh period of CSCOPE block |
| 05:30 | So, I will change it to 30. |
| 05:34 | Keep the other parameters unchanged. Click on OK. |
| 05:39 | Now press Control S to save the file, with a suitable file name.I will save it as firstorder.xcos |
| 05:50 | To start the simulation, click on the Start button, available on the menu bar of Xcos window. |
| 05:58 | A Graphic window will open, showing the step response of the first order transfer function. |
| 06:04 | We can save this plot as an image file. |
| 06:06 | To save the graph, go to the File menu and click on Export to option. |
| 06:12 | I will name it as firstorder.png and click on OK |
| 06:20 | There are certain parameters which we chose to keep as the default value. These can be changed. |
| 06:26 | For example In the Clock underscore c block, the period, which means the sampling period and initial time can be set. |
| 06:36 | In the CSCOPE block, the output window number, |
| 06:40 | position, size, buffer size, graph color etc. can also be set. |
| 06:46 | Pause the video here and solve the exercise given with the video. |
| 06:52 | Simulate a second order transfer function with damping ratio of 0.5 and angular frequency equal to 1. |
| 07:01 | Try changing the color of output graph. |
| 07:04 | Using the first exercise, plot the Step input and the output in a single plot window. |
| 07:11 | Now let us summarize.In this tutorial we have learnt to: Create Xcos simulation diagrams using the palette browser |
| 07:18 | Configure each block as per the simulation requirements |
| 07:22 | Setup the simulation parameters. Save the output plot. |
| 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 |
| 07:37 | The Spoken Tutorial Project Team Conducts workshops using spoken tutorials Gives certificates for those who pass an online test |
| 07:46 | For more details, please write to contact at spoken hyphen tutorial dot org |
| 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 |
| 08:02 | More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro |
| 08:12 | Hope you found this tutorial useful. This is Rupak Rokade from IIT Bombay signing off. Thank You. |
