Sink blocks (Scope, Display, To Workspace) in Simulink - Mini Project: Build & Apply

Using Sink Blocks in Simulink: Scope, Display, and To Workspace

📖 Scenario: You are working on a simple Simulink model to observe and save the output of a signal generated by a sine wave block. You want to see the signal graphically, view its numeric values, and save the data for later analysis.

🎯 Goal: Build a Simulink model that uses three sink blocks: Scope to visualize the signal, Display to show numeric values, and To Workspace to save the signal data to the MATLAB workspace.

📋 What You'll Learn

Create a sine wave source block with frequency 1 Hz and amplitude 1

Add a Scope block connected to the sine wave output

Add a Display block connected to the sine wave output

Add a To Workspace block connected to the sine wave output with variable name 'sineData'

Run the simulation for 2 seconds

💡 Why This Matters

🌍 Real World

Engineers and data scientists use sink blocks in Simulink to monitor signals during simulations and save data for analysis, which helps in designing and testing control systems.

💼 Career

Understanding sink blocks is essential for roles involving system modeling, simulation, and data analysis in industries like automotive, aerospace, and robotics.

1

Create the sine wave source block

Add a Sine Wave block to your Simulink model. Set its Frequency parameter to 1 and Amplitude parameter to 1. This block will generate the signal you will observe.

Simulink

% Add a Sine Wave block with Frequency=1 and Amplitude=1
% Your code here

Hint

Use add_block to add the Sine Wave block and set_param to set its parameters.

2

Add sink blocks: Scope, Display, and To Workspace

Add three sink blocks to your model: a Scope block, a Display block, and a To Workspace block. Connect each block's input to the output of the Sine Wave block. Set the To Workspace block's variable name to 'sineData'.

Simulink

% Add Scope, Display, and To Workspace blocks connected to the Sine Wave output
% Set To Workspace variable name to 'sineData'
% Your code here

Hint

Use add_block to add each sink block and add_line to connect them to the Sine Wave output.

3

Configure simulation time

Set the simulation stop time to 2 seconds. This controls how long the model runs to generate data.

Simulink

% Set simulation stop time to 2 seconds
% Your code here

Hint

Use set_param on the model to set the StopTime parameter.

4

Run the simulation and display results

Run the simulation using sim('model'). After the simulation finishes, print the first five rows of the variable sineData saved in the workspace.

Simulink

% Run the simulation and print the first five rows of sineData
% Your code here

Hint

Use sim('model') to run the simulation and disp to print the data.

Practice

1. Which Simulink sink block is best for showing a live numeric value during simulation?

easy

A. Display block

B. Scope block

C. To Workspace block

D. Gain block

Solution

1. Step 1: Understand the purpose of Display block

   The Display block shows numeric values updating live during simulation.

2. Step 2: Compare with other sink blocks

   Scope shows graphs, To Workspace saves data, Gain modifies signals, so they don't show live numbers directly.

3. Final Answer:

   Display block -> Option A

4. Quick Check:

   Live numeric value = Display block [OK]

Hint: Display shows live numbers; Scope shows graphs [OK]

Common Mistakes:

• Confusing Scope with Display
• Thinking To Workspace shows live values
• Selecting Gain which is not a sink block

2. Which of the following is the correct way to configure a To Workspace block to save data as a structure?

easy

A. Set 'Save format' to 'Array'

B. Set 'Save format' to 'Timeseries'

C. Set 'Save format' to 'Structure with time'

D. Set 'Save format' to 'Matrix'

Solution

1. Step 1: Identify the save format options in To Workspace block

   To Workspace block allows saving data as Array, Structure with time, Timeseries, or Matrix.

2. Step 2: Choose the option that saves data as a structure

   'Structure with time' saves data as a structure containing time and signals.

3. Final Answer:

   Set 'Save format' to 'Structure with time' -> Option C

4. Quick Check:

   Structure save format = 'Structure with time' [OK]

Hint: Structure format is named 'Structure with time' in To Workspace [OK]

Common Mistakes:

• Choosing 'Array' which saves plain arrays
• Confusing 'Timeseries' with structure
• Selecting 'Matrix' which is not a valid option

3. Given this Simulink model snippet:

Signal -> To Workspace block (Save format: Array)

After simulation, what is the format of the saved data in MATLAB workspace?

medium

A. A numeric array containing signal values only

B. A structure with time and signals fields

C. A timeseries object with time and data

D. A cell array with signal data

Solution

1. Step 1: Understand 'Array' save format in To Workspace block

   When 'Array' is selected, only the signal values are saved as a numeric array without time info.

2. Step 2: Compare with other formats

   Structure and Timeseries formats include time; cell arrays are not used here.

3. Final Answer:

   A numeric array containing signal values only -> Option A

4. Quick Check:

   Save format 'Array' = numeric array [OK]

Hint: Array format saves only values, no time info [OK]

Common Mistakes:

• Assuming time is saved with Array format
• Confusing Array with Timeseries
• Expecting a structure instead of array

4. You added a Scope block but see no graph during simulation. What is the most likely cause?

medium

A. The simulation time is zero

B. The Display block is missing

C. The To Workspace block is set to 'Array' format

D. The Scope block is not connected to any signal

Solution

1. Step 1: Check Scope block connection

   Scope requires a connected signal to display data; no connection means no graph.

2. Step 2: Evaluate other options

   Display block absence doesn't affect Scope; To Workspace format doesn't affect Scope display; simulation time zero means no data but usually simulation runs longer.

3. Final Answer:

   The Scope block is not connected to any signal -> Option D

4. Quick Check:

   Scope needs signal connection [OK]

Hint: Scope shows graphs only if connected to signals [OK]

Common Mistakes:

• Thinking Display block affects Scope
• Confusing To Workspace settings with Scope display
• Ignoring signal connections

5. You want to analyze simulation data after running a model. Which sink block should you use to save the data for MATLAB post-processing, and how should you configure it to include time information?

hard

A. Use Scope block; enable data logging

B. Use To Workspace block; set 'Save format' to 'Structure with time'

C. Use Display block; no configuration needed

D. Use To Workspace block; set 'Save format' to 'Array'

Solution

1. Step 1: Identify the sink block for saving data

   To Workspace block is designed to save simulation data to MATLAB workspace for post-processing.

2. Step 2: Choose the save format to include time

   Setting 'Save format' to 'Structure with time' saves both signal data and time stamps.

3. Final Answer:

   Use To Workspace block; set 'Save format' to 'Structure with time' -> Option B

4. Quick Check:

   Save data with time = To Workspace + 'Structure with time' [OK]

Hint: To save with time, use To Workspace + 'Structure with time' [OK]

Common Mistakes:

• Using Display or Scope blocks to save data
• Choosing 'Array' format which lacks time info
• Not configuring save format properly