Outport (Simulink Reference)

Simulink Reference

Outport

Create an output port for a subsystem or an external output

Library

Ports & Subsystems, Sinks

Description

Outport blocks are the links from a system to a destination outside the system.

Simulink assigns Outport block port numbers according to these rules:

It automatically numbers the Outport blocks within a top-level system or subsystem sequentially, starting with 1.
If you add an Outport block, it is assigned the next available number.
If you delete an Outport block, other port numbers are automatically renumbered to ensure that the Outport blocks are in sequence and that no numbers are omitted.
If you copy an Outport block into a system, its port number is not renumbered unless its current number conflicts with an Outport block already in the system. If the copied Outport block port number is not in sequence, you must renumber the block or you will get an error message when you run the simulation or update the block diagram.

Outport Blocks in a Subsystem

Outport blocks in a subsystem represent outputs from the subsystem. A signal arriving at an Outport block in a subsystem flows out of the associated output port on that Subsystem block. The Outport block associated with an output port on a Subsystem block is the block whose Port number parameter matches the relative position of the output port on the Subsystem block. For example, the Outport block whose Port number parameter is 1 sends its signal to the block connected to the topmost output port on the Subsystem block.

If you renumber the Port number of an Outport block, the block becomes connected to a different output port, although the block continues to send the signal to the same block outside the subsystem.

When you create a subsystem by selecting existing blocks, if more than one Outport block is included in the grouped blocks, Simulink automatically renumbers the ports on the blocks.

The Outport block name appears in the Subsystem icon as a port label. To suppress display of the label, select the Outport block and choose Hide Name from the Format menu.

Outport Blocks in a Conditionally Executed Subsystem

When an Outport block is in an enabled subsystem, you can specify what happens to its output when the subsystem is disabled: it can be reset to an initial value or held at its most recent value. The Output when disabled pop-up menu provides these options. The Initial output parameter is the value of the output before the subsystem executes and, if the reset option is chosen, while the subsystem is disabled.

Outport Blocks in a Top-Level System

Outport blocks in a top-level system have two uses: to supply external outputs to the workspace, which you can do by using either the Configuration Parameters dialog box or the sim command, and to provide a means for analysis functions to obtain output from the system.

To supply external outputs to the workspace, use the Configuration Parameters dialog box (see Exporting Output Data to the MATLAB Workspace) or the sim command (see sim). For example, if a system has more than one Outport block and the save format is array, the following command

```
[t,x,y] = sim(...);
```

writes y as a matrix, with each column containing data for a different Outport block. The column order matches the order of the port numbers for the Outport blocks.

If you specify more than one variable name after the second (state) argument, data from each Outport block is written to a different variable. For example, if the system has two Outport blocks, to save data from Outport block 1 to speed and the data from Outport block 2 to dist, you could specify this command:
- ```
[t,x,speed,dist] = sim(...);
```

To provide a means for the linmod and trim analysis functions to obtain output from the system (see Running a Simulation)

Data Type Support

The Outport block accepts complex or real signals of any data type supported by Simulink. An Outport block can also accept fixed-point data types if it is not a root-level outport. The complexity and data type of the block's output are the same as those of its input. For a discussion on the data types supported by Simulink, refer to Data Types Supported by Simulink in the Using Simulink documentation.

The elements of a signal array connected to an Outport block can be of differing complexity and data types except in the following circumstance: If the outport is in a conditionally executed subsystem and the initial output is specified, all elements of an input array must be of the same complexity and data types.

Typical Simulink data type conversion rules apply to an outport's Initial output parameter. If the initial output value is in the range of the block's output data type, Simulink converts the initial output to the output data type. If the specified initial output is out of the range of the output data type, Simulink halts the simulation and signals an error.

Parameters and Dialog Box

The Main pane of the Outport block dialog appears as follows:

Port number

Specify the port number of the Outport block.

Icon Display

Specify the information to be displayed on the icon of this Outport block. The options are:


`Port number`	Displays port number of this Outport block.
`Signal name`	Displays the name of the signal connected to this Outport block (or signals if a bus is connected to this block).
`Port name and signal name`	Displays both the port number and the name or names of the signals connected to this Outport block.

Output when disabled

This option is enabled only if the Outport resides in an Enabled Subsystem. It specifies what happens to the block output when the system is disabled.

Initial output

For conditionally executed subsystems, specify the block output before the subsystem executes and while it is disabled. You can specify [] if your model does not depend on the initial output of the conditionally executed subsystem. Simulink does not allow the initial output of this block to be inf or NaN.

The Signal specification pane of the Output block dialog appears as follows:

Specify properties via bus object

Select this option to use a bus object (see Working with Data Objects and Simulink.Bus class in the online documentation) to define the properties of a bus connected to this Outport block.

Bus object for validating input bus

Specifies the name of the bus object that defines the structure of that a bus must have to be connected to this Outport block. At the beginning of a simulation or when you update the model's diagram, Simulink checks whether the bus connected to this block has the specified structure. If not, Simulink displays an error message.

Output as structure in parent model

Select this option if you want code generated from this model to use a C structure to define the structure of the bus signal output by this block.

Port dimensions (-1 for inherited)

Specifies the dimensions that a signal must have in order to be connected to this Outport block. Valid values are:


`-1`	A signal of any dimensions can be connected to this port.
`N`	The signal connected to this port must be a vector of size `N`.
`[R C]`	The signal connected to this port must be a matrix having `R` rows and `C` columns.

Sample time (-1 for inherited)

Specify the sample time of this Outport block. See Specifying Sample Time in the online documentation for information on specifying sample times. The output of this block changes at the specified rate to reflect the value of its input.

Data type

Specify the data type of the signal output by this block. To output any data type, set this parameter to auto.

Output data type

Specify any data type, including fixed-point data types. This parameter is only visible if you select Specify via dialog for the Data type parameter.

Output scaling value

Set the output scaling using binary point-only or [Slope Bias] scaling. This parameter is only visible if you select Specify via dialog for the Data type parameter.

Signal type

Specifies the numeric type of the signal output by this block.The options are:


`real`	This Outport block outputs a real-valued signal. The signal connected to this block must be real. If it is not, Simulink displays an error if you try to update the diagram or simulate the model that contains this block.
`complex`	This Outport block outputs a complex signal. The signal connected to this block must be complex. If it is not, Simulink displays an error if you try to update the diagram or simulate the model that contains this block.
`auto`	This block outputs the numeric type of the signal that is connected to its input.

Sampling mode

Specify the sampling mode (Sample based or Frame based) that the input signal must match. To accept any sampling mode, set this parameter to auto. This parameter is intended to support signal processing applications based on Simulink. See the documentation for the buffer function provided by the Signal Processing Toolbox or "Frame-Based Operations" in the documentation for the Signal Processing Blockset for information about frame-based signals.

Characteristics

Sample Time
Inherited from driving block

Dimensionalized
Yes

Sample Time	Inherited from driving block
Dimensionalized	Yes

Mux Polynomial