To Workspace (Using Simulink)

Write data to the workspace.

Library

Sinks

Description

The To Workspace block writes its input to the workspace. The block writes its output to a matrix or structure that has the name specified by the block's Variable name parameter. The Save format parameter determines the output format:

Matrix

The matrix has this form:

The amount of data written and the time steps at which the data is written are determined by block parameters:

The Maximum number of rows parameter indicates how many data rows to save. If the simulation generates more rows than the specified maximum, the simulation saves only the most recently generated rows. To capture all the data, set this value to inf.
The Decimation parameter allows you to write data at every nth sample, where n is the decimation factor. The default decimation, 1, writes data at every time step.
The Sample time parameter allows you to specify a sampling interval at which to collect points. This parameter is useful when using a variable-step solver where the interval between time steps may not be the same. The default value of -1 causes the block to inherit the sample time from the driving block when determining which points to write.

During the simulation, the block writes data to an internal buffer. When the simulation is completed or paused, that data is written to the workspace. The block icon shows the name of the matrix to which the data is written.

Structure

This format consists of a structure with three fields: time, signals, and blockName. The time field is empty. The blockName field contains the name of the To Workspace block. The signals field contains a structure with two fields: values and label. The values field contains the matrix of signal values.

Structure with Time

This format is the same as Structure except that the time field contains a vector of simulation time steps.

Using Saved Data with a From File Block

If the data written using a To Workspace block is to be saved and read later by a From File block, the time must be added to the data and the matrix must be transposed. For more information, see From File.

Using Saved Data with a From Workspace Block

If the data written using a To Workspace block is intended to be "played back" in another simulation using a From Workspace block, the data must contain the simulation time values. The way you include times depends on the save format.

If the save format is a structure, you can include the simulation time by choosing Structure with Time as the value of Save format. The block stores the simulation times as a vector in the time member of the output structure.

If the save format is a matrix, you must add a column of simulation times to the matrix. You can add a column with time values in two ways:

By multiplexing the output of a Clock block as the first element of the vector input line of the To Workspace block.
By specifying time as a return value on the Simulation Parameters dialog box or from the command line, described in Chapter 4. When the simulation is completed, you can concatenate the time vector (t) to the matrix using a command like this:

Examples

In a simulation where the start time is 0, the Maximum number of rows is 100, the Decimation is 1, and the Sample time is 0.5. The To Workspace block collects a maximum of 100 points, at time values of 0, 0.5, 1.0, 1.5, & seconds. Specifying a Decimation of 1 directs the block to write data at each step.

In a similar example, the Maximum number of rows is 100 and the Sample time is 0.5, but the Decimation is 5. In this example, the block collects up to 100 points, at time values of 0, 2.5, 5.0, 7.5, & seconds. Specifying a Decimation of 5 directs the block to write data at every fifth sample. The sample time ensures that data is written at these points.

In another example, all parameters are as defined in the first example except that the Maximum number of rows is 3. In this case, only the last three rows collected are written to the workspace. If the simulation stop time is 100, data corresponds to times 99.0, 99.5, and 100.0 seconds (three points).

Data Type Support

A To Workspace block can save input of any real or complex data type to the MATLAB workspace.

Parameters and Dialog Box

Variable name

The name of the matrix that holds the data.

Maximum number of rows

The maximum number of rows (one row per time step) to be saved. The default is 1000 rows.

Decimation

A decimation factor. The default is 1.

Sample time

The sample time at which to collect points.

Save format

Format in which to save simulation output to the workspace. The default is as a structure.

Characteristics


Sample Time	Inherited
Vectorized	Yes

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