Manual matlab simulink

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Quick Start
Running a Demo Model . Description of the Demo . . Some Things to Try . . . . What This Demo Illustrates Other Useful Demos . . .

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Building a Simple Model . . . . . . . . . . .. . . . 2-6 Setting Simulink Preferences . . . . . . . . . . . . . 2-16 Simulink Preferences . . . . . . . . . . . . . . . . . 2-16

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Quick Start

Running a Demo Model
An interesting demo program provided with Simulink models the thermodynamics of a house. To run this demo, follow these steps:
1 Start MATLAB. See your MATLAB documentation if you’re not sure how to

do this.
2 Runthe demo model by typing thermo in the MATLAB command window.

This command starts up Simulink and creates a model window that contains this model.

3 Double-click the Scope block labeled Thermo Plots.

The Scope block displays two plots labeled Indoor vs. Outdoor Temp and Heat Cost ($), respectively.
4 To start the simulation, pull down the Simulation menu and choose the

Start command(or, on Microsoft Windows, press the Start button on the Simulink toolbar). As the simulation runs, the indoor and outdoor

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Running a Demo Model

temperatures appear in the Indoor vs. Outdoor Temp plot and the cumulative heating cost appears in the Heat Cost ($) plot.
5 To stop the simulation, choose the Stop command from the Simulation

menu (or press the Pause button on the toolbar).If you want to explore other parts of the model, look over the suggestions in “Some Things to Try” on page 2-4.
6 When you’re finished running the simulation, close the model by choosing

Close from the File menu.

Description of the Demo
The demo models the thermodynamics of a house using a simple model. The thermostat is set to 70 degrees Fahrenheit and is affected by the outsidetemperature, which varies by applying a sine wave with amplitude of 15 degrees to a base temperature of 50 degrees. This simulates daily temperature fluctuations. The model uses subsystems to simplify the model diagram and create reusable systems. A subsystem is a group of blocks that is represented by a Subsystem block. This model contains five subsystems: one named Thermostat, one named House, and threeTemp Convert subsystems (two convert Fahrenheit to Celsius, one converts Celsius to Fahrenheit). The internal and external temperatures are fed into the House subsystem, which updates the internal temperature. Double-click on the House block to see the underlying blocks in that subsystem.

House subsystem

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Quick Start

The Thermostat subsystem models the operation of athermostat, determining when the heating system is turned on and off. Double-click on the block to see the underlying blocks in that subsystem.
Thermostat subsystem

Both the outside and inside temperatures are converted from Fahrenheit to Celsius by identical subsystems.

Fahrenheit to Celsius conversion (F2C)

When the heat is on, the heating costs are computed and displayed on the Heat Cost ($)plot on the Thermo Plots Scope. The internal temperature is displayed on the Indoor Temp Scope.

Some Things to Try
Here are several things to try to see how the model responds to different parameters: • Each Scope block contains one or more signal display areas and controls that enable you to select the range of the signal displayed, zoom in on a portion of the signal, and perform other usefultasks. The horizontal axis represents time and the vertical axis represents the signal value. • The Constant block labeled Set Point (at the top left of the model) sets the desired internal temperature. Open this block and reset the value to 80 degrees. See how the indoor temperature and heating costs change. Also, adjust the outside temperature (the Avg Outdoor Temp block) and see how it...