Signal Properties

View and edit signal properties

Description

Use the Signal Properties dialog box to view and edit properties for signals in your model. Using the Signal Properties dialog box, you can mark a signal for logging, specify a signal name, and configure logging options, including which data points to log and the logging sample time.

When your model is configured for concurrent execution, the Signal Properties dialog box also includes a Data Transfer tab. For more information, see Configure Data Transfer Settings Between Concurrent Tasks and Configure Your Model for Concurrent Execution.

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Open the Signal Properties

• Right-click a signal line in the model and select Properties.

• When you select a signal line in your model, the Signal Properties are available in the Property Inspector.

Parameters

Signal Name Properties

Signal name — Signal name

string | character vector

Specify a name for the signal as a character vector or string.

When you select Signal name must resolve to Simulink signal object, the name must match the name of a Simulink.Signal object in the base workspace, the model workspace, or a data dictionary. The signal name can implicitly resolve to a Simulink.Signal object when you do not select Signal name must resolve to Simulink signal object. For more information, see Explicit and Implicit Symbol Resolution.

By default, the name for logged signal data matches the signal name specified in the model. To use a different name for the logged signal data, specify the name for the logged data using the Logging Name property.

Programmatic Use

To specify a signal name programmatically, use the set_param function to set the Name property for the line handle that corresponds to the signal or the port handle that corresponds to the block output port that produces the signal. For an example, see Name a Signal Programmatically.

Parameter: Name

Type: string | character vector

Signal name must resolve to Simulink signal object — Explicit signal name resolution

'off' (default) | 'on'

When enabled, the signal name specified in the Signal Properties dialog box must match the name of a Simulink.Signal object in the base workspace, the model workspace, or a data dictionary. When disabled, the signal name can implicitly resolve to a Simulink.Signal object. For more information, see Explicit and Implicit Symbol Resolution.

By default, signals that require resolution to a Simulink.Signal object are marked with the signal resolution icon to the left of the signal label. For more information, see Signal to Object Resolution Indicator.

Programmatic Use

To configure this option for a signal programmatically, use the set_param function to set the MustResolveToSignalObject property for the port handle that corresponds to the block output port that produces the signal. For an example, see Use Signal Objects.

Parameter: MustResolveToSignalObject

Value: 'on' | 'off'

Default: 'off'

Show propagated signals — Option to display propagated signal name

'off' (default) | 'on'

When a downstream signal originates from a block that supports signal label propagation, you can enable this option on the downstream signal line to display the propagated signal name as a label on the signal line.

For example, the output signal from the Subsystem block is configured for signal label propagation. The propagated signal label <const> comes from the name of the upstream Constant block output signal const.

For more information see, Signal Label Propagation.

Tips

To display propagated signal labels for all signals, in the Simulink^® Editor, on the Debug tab, select Information Overlays, then select Propagated Signal Labels.

Dependencies

The Show propagated signals property is only available for signals produced by blocks that support signal label propagation.

Programmatic Use

To configure a signal to display its propagated name programmatically, use the set_param function to specify the value of the ShowPropagatedSignals property for the port handle that corresponds to the block output port that produces the signal. For an example, see Display Propagated Signal Labels.

Parameter: ShowPropagatedSignals

Value: 'on' | 'off'

Default: 'off'

Logging and Accessibility

Log signal data — Signal logging

'off' (default) | 'on'

Select this option to mark a signal for logging. When the Signal logging option in the model configuration parameters is enabled, data for signals marked for logging is sent to the workspace and the Simulation Data Inspector during simulation. For more information, see Save Signal Data Using Signal Logging.

Programmatic Use

You can control whether to log a signal programmatically using the Simulink.sdi.markSignalForStreaming function or by using the set_param function to configure the DataLogging property of the port handle that corresponds to the block output port that produces the signal.

Parameter: DataLogging

Value: 'on' | 'off'

Default: 'off'

Test point — Test point designation

'off' (default) | 'on'

When enabled, the signal is designated as a test point. For more information, see Configure Signals as Test Points.

Programmatic Use

To designate a signal as a test point programmatically, use the set_param function to specify the value of the TestPoint property for the port handle that corresponds to port that produces the signal.

Parameter: TestPoint

Value: 'on' | 'off'

Default: 'off'

Logging Name — Name for logged signal data

'SignalName' (default) | 'Custom'

Specify a name for the logged signal data. By default, logged signal data uses the name of the signal specified in the model.

To specify a logging name for a signal that is different from the name of the signal in the model, select Custom and specify the logging name in the text box.

Dependencies

To enable the Logging Name property, select Log signal data.

Programmatic Use

To specify the logging name programmatically, use the set_param function to configure the DataLoggingNameMode and DataLoggingName parameters for the port handle that corresponds to the block output port that produces the signal.

Parameter: DataLoggingNameMode

Value: 'SignalName' | 'Custom'

Default: 'SignalName'

Parameter: DataLoggingName

Type: string | character vector

Limit data points to last — Option to log only last n data points

'off' (default) | 'on'

When you only want to save or analyze the data from the end of a simulation, you can configure logging to capture only the last n signal values. Select Limit data points to last and specify the number of data points you want to log.

When you only log the last simulation values, dashboard blocks and the Simulation Data Inspector do not display data during simulation. Consider data requirements for each signal before you reduce the number of data points logged in simulation.

For more information, see Specify Signal Values to Log and Limit the Size of Logged Data.

Dependencies

To enable the Limit data points to last property, select Log signal data.

Programmatic Use

To configure this option programmatically, use the set_param function to configure the DataLoggingLimitDataPoints and DataLoggingMaxPoints parameters for the port handle that corresponds to the block output port that produces the signal.

Parameter: DataLoggingLimitDataPoints

Value: 'on' | 'off'

Default: 'off'

Parameter: DataLoggingMaxPoints

Value: numeric scalar

Type: string | character vector

Default: '5000'

Decimation — Option to log every nth data point

'off' (default) | 'on'

When you want to reduce the effective sample rate for logged data, select Decimation and specify the desired decimation factor in the text box. For example, if you specify a decimation factor of 2, every other signal value is logged.

Consider data requirements for each signal before reducing the number of data points logged in simulation. Decimation can cause aliasing if the effective sample rate is too low.

For more information, see Specify Signal Values to Log and Limit the Size of Logged Data.

Dependencies

To enable the Decimation property, select Log signal data.

Programmatic Use

To configure this option programmatically, use the set_param function to configure the DataLoggingDecimateData and DataLoggingDecimation parameters for the port handle that corresponds to the block output port that produces the signal.

Parameter: DataLoggingDecimateData

Value: 'on' | 'off'

Default: 'off'

Parameter: DataLoggingDecimation

Value: numeric scalar

Type: string | character vector

Default: '2'

Sample time — Logging sample time

-1 (default) | scalar

Specify the sample time to use for logging the data for the selected signal. By default, the logging sample time is inherited (-1) from the block that produces the signal. For continuous logging sample time, specify the value as 0. To use a discrete sample time for logging data, specify the sampling interval as a scalar.

Setting the sample time for a logged signal in the Signal Properties dialog box:

• Separates design and testing because you do not need to insert a Rate Transition block to have a consistent sample time for logged signals

• Reduces the amount of logged data for a continuous time signal, for which setting decimation is not relevant

• Eliminates the need to post-process logged signal data for signals with different sample times

When you mark a signal for logging, the software inserts a hidden To Workspace block. When you specify a sample time for a logged signal, the software inserts a hidden Rate Transition block and a hidden To Workspace block.

Specifying a logging sample time may add a new sample time to the model. When you specify a logging sample time, the model calculates a value for the exact time hits. When you use a fixed-step solver, the logging sample time you specify must be a multiple of the base rate for the model.

Specifying a sample time for signal logging does not affect the simulation result. However, it is possible that the signal logging output for a logged signal varies depending on whether you specify a sample rate. For example, the interpolation method can differ depending on whether you specify a sample time for signal logging.

If you simulate in software-in-the-loop (SIL) mode, signal logging ignores the sample time you specify for logged signals.

Do not specify a sample time for:

• Frame-based signals

• Signals inside conditional subsystems or conditional referenced models

The Sample time property is the same as the Logging sample time property you configure using the Instrumentation Properties dialog box.

Dependencies

To enable the Sample time property, select Log signal data.

Programmatic Use

To configure this option programmatically, use the set_param function to configure theDataLoggingSampleTime parameter for the port handle that corresponds to the block output port that produces the signal.

Parameter: DataLoggingSampleTime

Value: numeric scalar

Type: string | character vector

Default: '-1'

Documentation

Description — Signal description

string | character vector

You can provide a description of the signal that shows in the Info tab of the Property Inspector when the signal is selected.

The description specified in the Signal Properties dialog box does not appear in generated code. To provide a signal description that becomes a comment in generated code, use a Simulink.Signal object.

Programmatic Use

To configure this option programmatically, use the set_param function to configure theDescription parameter for the port handle that corresponds to the block output port that produces the signal.

Parameter: Description

Type: string | character vector

Document link — Link to documentation about signal

MATLAB^® expression

Specify a MATLAB expression that opens documentation for the signal. For example, you can call the web function to open an HTML file. When you specify a value for the Document link property, you can click the Document link field label to open the document.

Programmatic Use

To programmatically specify a document link, use the set_param property to specify the DocumentLink property of the port handle that corresponds to the block output port that produces the signal.

Parameter: DocumentLink

Type: string | character vector

Version History

Introduced before R2006a