Scilab/C4/Simulating-a-PID-controller-using-XCOS/English

Title of script: Simulating a PID controller using Xcos

Author: Rupak Rokade

Keywords: Xcos, PID, Simulation, Closed loop

	Narration
Show Slide	Welcome to the spoken tutorial on Simulating a PID controller using Xcos.
Show Slide	In this tutorial we will learn how to implement a PID controller in Xcos.
Show Slide	Ensure that Scilab is installed on your computer. I am recording this tutorial on Ubuntu 16.04 64-bit Operating System and using Scilab 6.0.0
Show Slide	As a pre-requisite, watch the tutorial Xcos Introduction. This tutorial will make you comfortable with the Xcos environment. Also, we will use the firstorder.xcos file created in that tutorial. Hence, it is important that you practice the tutorial before continuing so that you have the file with you. Some basic knowledge of PID controller is necessary. Assuming that you have satisfied the pre-requisites, let us begin with the tutorial.
Launch Scilab	First of all, we will launch Scilab.
Applications >> Xcos	Then go to Applications and select Xcos.
	Or in your Scilab console window, type Xcos and press Enter.
Point to Palette Browser and An Untitled-Xcos window	By doing this, two windows will open. Palette Browser and An Untitled-Xcos window
Untitled-Xcos window>> click on File >> Open	On the Untitled-Xcos window, click on File and then click on Open.
Go to the saved folder>> click on the file >> OK	Browse to the directory where the file firstorder.xcos is saved. Choose that file and click on Ok.
Double-click transfer function block.	Double-click on the transfer function block.
Highlight the transfer function parameters	Check that you are using the same transfer function as I am using.
	For me, the numerator is 1 and denominator is 2 asteric s plus 1 Which is 2 multiplied by s plus one. Click on Ok.
Highlight the step input parameters	Double-click on the Step block. Check that you are using the same step input parameters as I am using.
	For me the Step time is 1, the Initial value is 0 and the Final value is 2. Click on OK
Simulation tab >> choose Start	Click on Simulation on the menu bar and choose Start to simulate the file.
	Expect a similar plot which ensures that the file has no mistakes.
Switch to the Palette Browser.	Switch to the Palette Browser.
Click on Continuous time systems >> drag-drop PID block inside Xcos	Click on Continuous time systems category. Drag and drop the PID block, which is here, inside the Xcos window
Click on Signal Routing >> drag-drop Mux block inside Xcos	Click on the Signal Routing category. Drag and drop the Mux block, which is here, inside the Xcos window.
Click on Mathematical Operations >> drag-drop Summation block inside Xcos	Click on Mathematical Operations category. Drag and drop the Summation block, which is here, inside the Xcos window.
	Note that this block, by default, subtracts the second input from the first input. We will use this default configuration of the summation block.
Click on the line joining the step input block + transfer function block >> press Delete	Click on the line joining the step input block and transfer function block. Then press the Delete button to delete it.
Drag away	Drag the step input block away from the transfer function block.
Click on the line joining the transfer function block and the cscope block >> press Delete	Click on the line joining the transfer function block and the cscope block. Then press the Delete button to delete it.
Drag away	Drag the cscope and clock input block away from the transfer function block
Do as narrated	Place the PID block before the transfer function block.
Do as narrated	Place the summation block before the PID block.
Do as narrated	Place the Mux block between the transfer function block and cscope block.
Do as narrated	Adjust the blocks, if required, so that they all come in a line.
Do as narrated	Connect the step input block to the first input port of the summation block. Note that this is the positive input port of the summation block.
Do as narrated	Connect the output port of summation block to the input port of PID block.
Do as narrated	Connect the output port of PID block to the input port of transfer function block.
Do as narrated	Connect the output port of transfer function block to the lower input port of Mux block.
Do as narrated	Connect the output port of Mux block to the input port of the cscope block.
Do as narrated	Locate the line connecting the step input block and the summation block. Connect the input port of Mux to that line.
	Use the left mouse click to create line bends while making the connection.
Do as narrated	Locate the line joining the transfer function block and the Mux block. Connect the second input port of the summation block to that line. Use line bends wherever necessary.
Do as narrated	Double-click on the PID block to open its parameter setting dialog box.
Point to the respective gains.	Here you can set the Proportional, Integral and Derivative gains. Please note that the Integral gain should be considered as 1 by tau I, where tau I is the integral time.
Click on Cancel	We will use the default settings. Click on Cancel to use the default settings.
	We are now ready to run the simulation.
Highlight step input block	Notice that we are using the step input block as a setpoint variable.
Highlight PID controller	The PID controller will generate an input to the Transfer Function block. It will be such that the output of the transfer function block matches the setpoint.
Click on Start simulation button	Click on the Start simulation button available on the menu bar.
Plot window Highlight setpoint Highlight transfer function	Expect a graphic window to open. It will have two variables plotted in a single plot. The step plot is the setpoint which has a final value of 2. The curved plot which is green in color, is the output of the transfer function which tries to meet the setpoint value of 2.
	You can now change the PID settings and learn how they affect the output. Pause the video here and solve the given exercises.
Exercise slide	Implement a Proportional Controller only That is, only P and not PID Change the proportional gain such that the setpoint matches the output but without overshoots.
Exercise slide	Include the output of the summation block in the plot. You may use CMSCOPE to keep it separate. Compare it visually with the output of the PID block
	This brings us to the end of this tutorial. Let us summarize.
Summary slide	In this tutorial we learnt To modify the firstorder.xcos file to implement a PID controller Configure each block as per the simulation requirements Setup the simulation parameters
Show Slide (About Spoken Tutorial Project)	The video at the following link, summarizes the Spoken Tutorial project. Please download and watch it.
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Show Slide 1 FORUMS	Do you have questions in THIS Spoken Tutorial? Please visit http://forums.spoken-tutorial.org Choose the minute and second where you have the question Explain your question briefly Someone from our team will answer them
Show Slide 2 FORUMS	The Spoken Tutorial forum is for specific questions on this tutorial Please do not post unrelated and general questions on them This will help reduce the clutter With less clutter, we can use these discussions as instructional material
Show slide	Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.. More information on this mission is available at the link shown.
	This is Rupak Rokade signing off. Thanks for joining.

Contributors and Content Editors

Nancyvarkey, Rupakrokade