3.1. Understanding and Adding Blocks

Blocks are the fundamental elements of any Simulink model. Each block represents a specific component, mathematical operation, or signal source that contributes to the overall system’s behavior. Mastering the selection and placement of blocks is the first essential skill in model creation.

There are two primary methods for adding blocks from the Library Browser to your model canvas:

1. Using the Simulink Library Browser:
   • This method involves navigating through the library structure to find the block you need. For example, to find the ‘Add’ block, you would open the Math Operations library.
   • Once located, you can use the “drag-and-drop” technique: click and hold the block, drag your cursor over to the model canvas, and release the mouse button to place it.
   • Alternatively, you can right-click the desired block in the library and select the option Add block to model ‘[model name]’ from the context menu. If you have not yet saved your model, the name will appear as ‘untitled’.
2. Searching Directly within the Model Canvas:
   • This is often a more efficient method, especially when you know the name of the block you need.
   • Simply click anywhere on the blank model canvas and begin typing the name of the block (e.g., “Sine”).
   • As you type, Simulink will display a searchable list of relevant blocks from across all libraries, allowing you to select and place the desired block without opening the full Library Browser.

Using the Library Browser Search Bar

For situations where you know the function of a block but are unsure which library contains it, the search bar at the top of the Library Browser is an invaluable tool. Typing a keyword like “Sine” will instantly display all blocks related to that term, allowing for quick discovery and placement.

Once the necessary blocks are placed on the canvas, the next step is to define the flow of information between them using lines.

3.2. Connecting Blocks with Lines

In Simulink, lines are the connectors that establish the path of data flow between blocks. They visually represent the signals that pass from the output port of one block to the input port of another. Drawing these lines is how you define the relationships and operations within your model.

We will now demonstrate this with a simple, practical example: adding two constant numbers and displaying the result.

1. Goal: Our objective is to construct a model that calculates the sum of 10 and 20 and shows the result.
2. Add Blocks: First, add the necessary blocks to the model canvas:
   • Two ‘Constant’ blocks (from Commonly Used Blocks).
   • One ‘Add’ block (from Math Operations).
   • One ‘Display’ block (from Sinks).
3. Observe Block Ports: Examine the blocks. Each ‘Constant’ block has one output port. The ‘Add’ block has two input ports and one output port. The ‘Display’ block has one input port.
4. Draw the Lines: To connect the blocks, hover your cursor over an output port until it turns into a crosshair. Click and drag a line from that port to the desired input port on the next block.
   • Draw a line from the output of the first ‘Constant’ block to the top input of the ‘Add’ block.
   • Draw a line from the output of the second ‘Constant’ block to the bottom input of the ‘Add’ block.
   • Finally, draw a line from the output of the ‘Add’ block to the input of the ‘Display’ block.
5. Configure and Run: By default, the ‘Constant’ blocks have a value of 1. Double-click each one to change their values to 10 and 20, respectively. When you run the simulation, the model executes this data flow: the values 10 and 20 are passed to the ‘Add’ block, which outputs their sum (30) to the ‘Display’ block. The ‘Display’ block will then show the final result, 30.

Mastery of blocks and lines is analogous to learning the grammar and syntax of a language. With these fundamentals, we are no longer merely observing the environment; we are prepared to articulate our first complete, dynamic statement: a simulation model.