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Step

Generate step function

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  • Step block

Libraries:
Simulink / Sources

Description

The Step block provides a step between two definable levels at a specified time. If the simulation time is less than the Step time parameter value, the block's output is the Initial value parameter value. For simulation time greater than or equal to the Step time, the output is the Final value parameter value.

The numeric block parameters must be of the same dimensions after scalar expansion. If the Interpret vector parameters as 1-D option is off, the block outputs a signal of the same dimensions and dimensionality as the parameters. If the Interpret vector parameters as 1-D option is on and the numeric parameters are row or column vectors (that is, single-row or column 2-D arrays), the block outputs a vector (1-D array) signal. Otherwise, the block outputs a signal of the same dimensionality and dimensions as the parameters.

Examples

Double Bouncing Ball: Use of Adaptive Zero-Crossing Location

Double Bouncing Ball: Use of Adaptive Zero-Crossing Location

Choose the correct zero-crossing location algorithm, based on the system dynamics. For Zeno dynamic systems, or systems with strong chattering, you can select the adaptive zero-crossing detection algorithm through the Configure pane:

Engine Timing Model with Closed Loop Control

Engine Timing Model with Closed Loop Control

Develop and implement a closed loop control algorithm for the open loop engine model described in Model Engine Timing Using Triggered Subsystems. In this example, the model sldemo_enginewc contains a controller that regulates engine speed using a fast throttle actuator such that changes in load torque have minimal effect. The controller is implemented using a discrete PI controller.

Ports

Output

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Output step function signal defined by the parameters Step time, Initial value, and Final value.

Data Types: double | single

Parameters

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Specify the time, in seconds, when the output jumps from the Initial value parameter to the Final value parameter.

Programmatic Use

Block Parameter: Time
Type: character vector
Values: '1' | real- or complex-valued scalar, vector, or matrix
Default: '1'

Specify the block output until the simulation time reaches the Step time parameter.

Programmatic Use

Block Parameter: Before
Type: character vector
Values: '1' | real- or complex-valued scalar, vector, or matrix
Default: '0'

Specify the block output when the simulation time reaches and exceeds the Step time parameter.

Programmatic Use

Block Parameter: After
Type: character vector
Values: '1' | real- or complex-valued scalar, vector, or matrix
Default: '1'

Specify the sample rate of step. See Specify Sample Time for more information.

Programmatic Use

Block Parameter: SampleTime
Type: character vector
Values: scalar
Default: '0'

Select this check box to output a vector of length N if the Constant value parameter evaluates to an N-element row or column vector.

  • When you select this check box, the block outputs a vector of length N if the Constant value parameter evaluates to an N-element row or column vector. For example, the block outputs a matrix of dimension 1-by-N or N-by-1.

  • When you clear this check box, the block does not output a vector of length N if the Constant value parameter evaluates to an N-element row or column vector.

Programmatic Use

Block Parameter: VectorParams1D
Type: character vector
Values: 'on' | 'off'
Default: 'on'

Select to enable zero-crossing detection. For more information, see Zero-Crossing Detection.

Programmatic Use

Block Parameter: ZeroCross
Type: character vector | string
Values: 'off' | 'on'
Default: 'on'

Output data type. The type can be inherited, specified directly, or expressed as a data type object such as Simulink.NumericType.

When you select Inherit: Inherit via back propagation, the block uses the data type of the driving block.

Click the Show data type assistant button to display the Data Type Assistant, which helps you set the data type attributes. See Specify Data Types Using Data Type Assistant for more information.

Programmatic Use

Block Parameter: OutDataTypeStr
Type: character vector
Values: 'Inherit: Inherit via internal rule' | 'double' | 'single' | <data type expression>
Default: 'double'

Category of data type, specified as Inherit, Built in, or Expression. For more information on using this parameter, see Specify Data Types Using Data Type Assistant.

Dependency

Clicking the Show data type assistant button enables this parameter.

Select the data type override mode for this signal.

  • When you select Inherit, Simulink® inherits the data type override setting from its context, that is, from the block, Simulink.Signal object or Stateflow® chart in Simulink that is using the signal.

  • When you select Off, Simulink ignores the data type override setting of its context.

For more information, see Specify Data Types Using Data Type Assistant in the Simulink documentation.

Dependencies

To enable this parameter, click the Show data type assistant button, and set the Mode to Built in.

Tips

The ability to turn off data type override for an individual data type provides greater control over the data types in your model when you apply data type override. For example, you can use this option to ensure that data types meet the requirements of downstream blocks regardless of the data type override setting.

Block Characteristics

Data Types

double

Direct Feedthrough

no

Multidimensional Signals

no

Variable-Size Signals

no

Zero-Crossing Detection

yes

Extended Capabilities

Version History

Introduced before R2006a

See Also

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