Simulink Reference

From Workspace

Read data from the workspace

Library

Sources

Description

The From Workspace block reads data from the MATLAB workspace. The block's Data parameter specifies the workspace data via a MATLAB expression that evaluates to a matrix (2-D array) or a structure containing an array of signal values and time steps. The format of the matrix or structure is the same as that used to load inport data from the workspace (see Loading Input from the Base Workspace"). The From Workspace icon displays the expression in the Data parameter.

Note    You must use the structure-with-time format to load matrix (2-D) data from the workspace. You can use either the array or the structure format to load scalar or vector (1-D) data.

The From Workspace block's Interpolate data parameter determines the block's output in the time interval for which workspace data is supplied. If the Interpolate data option is selected, the block interpolates between data values for time steps that occur between the times for which data is supplied from the workspace. Otherwise, the block uses the most recent data value supplied from the workspace.

The block's Form output after final data value by parameter determines the block's output after the last time step for which data is available from the workspace. The following table summarizes the output block based on the options that the parameter provides.

Form Output Option	Interpolate Option	Block Output After Final Data
Extrapolate	On	Extrapolated from final data value
Extrapolate	Off	Error
SettingToZero	On	Zero
SettingToZero	Off	Zero
HoldingFinalValue	On	Final value from workspace
HoldingFinalValue	Off	Final value from workspace
CyclicRepetition	On	Error
CyclicRepetition	Off	Repeated from workspace. This option is valid only for workspace data in structure-without-time format.

If the input array contains more than one entry for the same time step, Simulink uses the signals specified by the last entry. For example, suppose the input array has this data:

• time:     0 1 2 2
  signal:   2 3 4 5
  

At time 2, the output is 5, the signal value for the last entry for time 2.

Note    A From Workspace block can directly read the output of a To Workspace block (see To Workspace) if the output is in structure-with-time format (see Loading Input from the Base Workspace for a description of these formats).

Data Type Support

A From Workspace block accepts real or complex signals of any type except int64 and uint64 from the workspace. Real signals of type double can be in either structure or matrix format. Complex signals and real signals of any type other than double must be in structure format.

Parameters and Dialog Box

Data

An expression that evaluates to an array or a structure containing an array of simulation times and corresponding signal values. For example, suppose that the workspace contains a column vector of times named T and a vector of corresponding signal values named U. Entering the expression [T,U] for this parameter yields the required input array. If the required signal-versus-time array or structure already exists in the workspace, enter the name of the structure or matrix in this field.

Sample time

Sample rate of data from the workspace. See Specifying Sample Time in the online documentation for more information.

Interpolate data

This option causes the block to linearly interpolate at time steps for which no corresponding workspace data exists. Otherwise, the current output equals the output at the most recent time for which data exists.

Form output after final data value by

Select method for generating output after the last time point for which data is available from the workspace.

Characteristics

Sample Time	Inherited from driven block
Scalar Expansion	No
Dimensionalized	Yes
Zero Crossing	No

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