Block parameters configuration in Simulink

Introduction

Block parameters let you control how each block in Simulink works. Changing these settings helps you customize your model to fit your needs.

You want to set the input or output size of a block.

You need to change the behavior of a block, like gain value or sample time.

You want to configure solver options for simulation accuracy.

You need to specify initial conditions for a block.

You want to optimize block performance by adjusting parameters.

Syntax

Simulink

set_param('model_name/block_name', 'ParameterName', 'ParameterValue')

Use single quotes around model and block names.

ParameterValue is usually a string, even for numbers.

Examples

Sets the Gain block's gain value to 5.

Simulink

set_param('myModel/Gain', 'Gain', '5')

Sets the initial condition of the Integrator block to 10.

Simulink

set_param('myModel/Integrator', 'InitialCondition', '10')

Configures the Scope block to have 2 input ports.

Simulink

set_param('myModel/Scope', 'NumInputPorts', '2')

Sample Program

This code creates a new Simulink model named 'simpleModel', adds a Gain block, sets its gain parameter to 3, then reads and prints the gain value. Finally, it closes the model without saving.

Simulink

model = 'simpleModel';
open_system(new_system(model));
add_block('simulink/Commonly Used Blocks/Gain', [model '/Gain']);
set_param([model '/Gain'], 'Gain', '3');
gainValue = get_param([model '/Gain'], 'Gain');
disp(['Gain block parameter set to: ' gainValue]);
close_system(model, 0);

Important Notes

You can view and change block parameters interactively by double-clicking the block in Simulink.

Always use correct block path names when using set_param and get_param.

Parameter names are case-sensitive and must match exactly.

Summary

Block parameters control how each block behaves in Simulink.

Use set_param to programmatically change block settings.

Always check parameter names and values carefully.

Practice

1. What is the main purpose of configuring block parameters in Simulink?

easy

A. To export the block to another model

B. To control how each block behaves during simulation

C. To rename the block automatically

D. To change the color of the block icon

Solution

1. Step 1: Understand block parameters

   Block parameters define the behavior and settings of a block in Simulink.

2. Step 2: Identify the purpose

   Changing parameters affects simulation results, not appearance or export.

3. Final Answer:

   To control how each block behaves during simulation -> Option B

4. Quick Check:

   Block parameters = behavior control [OK]

Hint: Block parameters set behavior, not appearance [OK]

Common Mistakes:

• Confusing parameters with block appearance
• Thinking parameters rename blocks automatically
• Assuming parameters export blocks

2. Which of the following is the correct syntax to set a block parameter named Gain to 5 using set_param?

easy

A. set_param(model/block, 'Gain', 5)

B. set_param('model/block', 'gain', '5')

C. set_param('model/block', Gain, '5')

D. set_param('model/block', 'Gain', '5')

Solution

1. Step 1: Check parameter name and value type

   Parameter names are strings; values must be strings for set_param.

2. Step 2: Validate syntax

   Correct syntax uses quotes around parameter name and value: 'Gain', '5'.

3. Final Answer:

   set_param('model/block', 'Gain', '5') -> Option D

4. Quick Check:

   Parameter and value as strings = correct [OK]

Hint: Always quote parameter names and values in set_param [OK]

Common Mistakes:

• Passing numeric value without quotes
• Using wrong case in parameter name
• Omitting quotes around parameter name

3. Given the code snippet:

set_param('myModel/GainBlock', 'Gain', '10');
value = get_param('myModel/GainBlock', 'Gain');

What will be the value of value after execution?

medium

A. 10

B. Gain

C. '10'

D. Error

Solution

1. Step 1: Understand set_param effect

   set_param sets the 'Gain' parameter to string '10'.

2. Step 2: Understand get_param return type

   get_param returns parameter values as strings, so value is "10" (string without quotes in output).

3. Final Answer:

   "10" -> Option A

4. Quick Check:

   get_param returns string value [OK]

Hint: get_param returns parameter values as strings [OK]

Common Mistakes:

• Assuming get_param returns numeric value
• Confusing parameter name with value
• Expecting error from correct syntax

4. Consider this code:

set_param('model/Integrator', 'InitialCondition', 0);

What is the error in this code?

medium

A. Value 0 should be a string '0'

B. Parameter name 'InitialCondition' is incorrect

C. No error

D. Block path 'model/Integrator' is invalid

Solution

1. Step 1: Check parameter value type

   set_param accepts numeric values for InitialCondition; 0 is converted to '0'.

2. Step 2: Confirm parameter name and block path

   'InitialCondition' is valid; block path assumed correct.

3. Final Answer:

   No error -> Option C

4. Quick Check:

   set_param handles numeric values [OK]

Hint: set_param accepts numeric values directly [OK]

Common Mistakes:

• Assuming value must be quoted string
• Thinking parameter name is wrong
• Believing block path is invalid

5. You want to programmatically change the 'Gain' parameter of multiple Gain blocks in a model named controlModel. Which approach correctly updates all Gain blocks to value 3.5?

hard

A. Use find_system to get all Gain blocks, then loop with set_param setting 'Gain' to '3.5'

B. Manually open each block and set 'Gain' to 3.5 in the GUI

C. Use set_param('controlModel', 'Gain', '3.5') to set all blocks at once

D. Rename all Gain blocks to '3.5' using set_param

Solution

1. Step 1: Identify all Gain blocks

   Use find_system('controlModel', 'BlockType', 'Gain') to get all Gain blocks.

2. Step 2: Loop through blocks and set parameter

   For each block, use set_param(block, 'Gain', '3.5') to update the parameter.

3. Final Answer:

   Use find_system and loop with set_param to update all Gain blocks -> Option A

4. Quick Check:

   find_system + loop + set_param = bulk update [OK]

Hint: Use find_system to select blocks, then set_param in loop [OK]

Common Mistakes:

• Trying to set parameter on model instead of blocks
• Not quoting numeric values in set_param
• Renaming blocks instead of changing parameters