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Today in Post-08 of Module-II, we will learn to create simulation model for open loop control. Along with that we also learn how to merge two waveform on single display. First of all open simulink library browser and create new simulink file. Drag some block i.e. sine wave, gain, mux and scope from simulink browser into new simulink file and connect this block as shown in figure-1.

Figure.1 - MATLAB Simulink model for open loop control

In this simulation sine wave is the input given to the system of gain. To analyze system input and system output on a single axis, we have used mux, which merge two signal in single axis. Mux output is fed to scope for analysis. The parameters of all the block has been set through their selection panel, which is being discuss below:

1) Sine Wave: Through selection panel of sine wave block, you can generate a sine wave of your choice. I have selected a sine wave of amplitude 10, frequency 5 Hz and Phase angle 0 degree.

Figure.2 - Selection Panel for Sine wave block.

The sampling time of the simulation is taken as 10 micro second.

2) Mux: : Through selection panel of mux block, you can merge number of signal into single axis. In this simulation I have merge two signal, hence number of inputs is 2.
Figure.3 - Selection Panel for Mux Block.

Through display option tab you can change the shape of mux block.

3) Gain: Through selection panel of gain block, you can create a system of your choice. I have selected a system with a gain 1.5
Figure.4 - Selection Panel of Gain block.

The sampling time of the simulation is taken as 10 micro second.

4) Scope: Through selection panel of Scope block, you can analyze the output of the system. You can also perform several function to analyze output through sub selection panel of scope.
Figure.5 - Selection Panel and sub selection panel of Scope Block.

Don't Forget to un-check limit data point to last, It limit your display data. Now your complete data will be display on the scope.

Now to analyze the open loop control system, Run the simulation by clicking on Start Simulation button. The output generated by simulation of open loop control is shown in figure-6.
Figure.6 - MATLAB Simulink output for Open Loop Control System.

The waveform shown with yellow color is input to the open loop control system while waveform shown with purple color is output of the open loop control system. It is clear from the figure 6 that the Output is 1.5 times of the input. Thus we can vary output of the system by varying its gain.

Video Tutorial :

Open Loop Control Using MATLAB Simulink.