fxptdlg (Simulink Reference)

Invokes the Fixed-Point Settings interface

Syntax

```
fxptdlg('model')
```

Description

fxptdlg('model') brings up the Fixed-Point Settings interface for the MDL-file model. You can also invoke this interface by

Selecting Fixed-Point Settings in the Tools menu in the model window
Right-clicking in any subsystem and selecting Fixed-Point Settings from the menu that pops up

With the Simulink Fixed Point product, the Fixed-Point Settings interface provides convenient access to global data type overrides and logging settings, the logged data, the automatic scaling script, and the Plot System interface. You can invoke the Fixed-Point Settings interface for any system or subsystem, and it controls the model specified by the Select current system parameter.

If Simulink Fixed Point is installed, the Fixed-Point Settings interface displays the name, minimum simulation value, maximum simulation value, data type, and scaling of each block in the model that logs data. Additionally, if a signal saturates or overflows, a message is displayed for the associated block indicating how many times saturation or overflow occurred. You can display a block's dialog box by double-clicking on the appropriate block entry in this pane.

Most of the functionality in the Fixed-Point Settings interface is for use with the Simulink Fixed Point product. However, even if you do not have Simulink Fixed Point, you can use the Fixed-Point Settings interface to perform a data type override that allows you to work with a fixed-point model.

If you do not have Simulink Fixed Point, you can work with a model containing Simulink blocks with fixed-point settings by doing the following:

Access the Fixed-Point Settings interface from the model by selecting Tools -> Fixed-Point Settings.
Set the Logging mode parameter to Force off model wide.
Set the Data type override parameter to True doubles or True singles model wide.

This procedure allows you to share fixed-point Simulink models among people in your company who may or may not have Simulink Fixed Point.

Parameters and Dialog Box

Select current system: Displays the names of all systems and subsystems in currently opened models in a hierarchical format. The menu can be expanded and collapsed using the + and - signs. The information displayed in the rest of the Fixed-Point Settings interface applies to the subsystem designated by this parameter.
Logging mode: Controls which blocks log data. The value of this parameter for parent systems controls logging for all child subsystems, unless Use local settings is selected:

Use local settings -- Data is logged according to the value of this parameter set for each subsystem. Otherwise, settings for parent systems always override those of child systems.
Min, max and overflow -- Minimum value, maximum value, and overflow data is logged for all blocks in the current system or subsystem.
Overflow -- Only overflow data is logged for all blocks in the current system or subsystem.
Force off -- No data is logged for any block in the current system or subsystem. Use this selection to work with models containing fixed-point enabled blocks if you do not have a Simulink Fixed Point license.

Data type override: Controls data type override of blocks that allow you to specify data types in their block masks. The value of this parameter for parent systems controls data type override for all child subsystems, unless Use local settings is selected:

Use local settings -- Data types are overridden according to the value of this parameter set for each subsystem. Otherwise, settings for parent systems override those of child systems.
Scaled doubles -- The output data type of all blocks in the current system or subsystem is overridden with doubles; however, the scaling and bias specified in the mask of each block is maintained.
True doubles -- The output data type of all blocks in the current system or subsystem is overridden with true doubles. The overridden values have no scaling or bias.
True singles -- The output data type of all blocks in the current system or subsystem is overridden with true singles. The overridden values have no scaling or bias.
Force off -- No data type override is performed on any block in the current system or subsystem.
Set this parameter to True doubles or True singles to work with models containing fixed-point enabled blocks if you do not have a Simulink Fixed Point license.

Note The following Simulink blocks allow you to set data types in their block masks, but ignore the Data Type Override setting: Probe, Trigger, Width.

Block Name: Displays blocks that log data in the selected system or subsystem. The block path is described in terms of the blockset model name. The minimum value, maximum value, data type, and scaling are shown opposite each block name when the simulation is run.
Logging type: Controls the logging type:

Overwrite log -- Information in the Simulation data logged for current system pane is completely cleared before new logging data is entered.
Merge log -- New logging data is merged with any information previously appearing in the Simulation data logged for current system pane.

Safety margin: The Safety margin parameter is used as part of the automatic scaling procedure. Before automatic scaling is performed, you must run the simulation to collect min/max data. To learn how to do this, refer to Tutorial: Feedback Controller Simulation.; Simulation values are multiplied by the factor designated by this parameter, allowing you to specify a range different from that defined by the maximum and minimum values logged to the workspace. For example, a value of 55 specifies that a range at least 55 percent larger is desired. A value of -15 specifies that a range up to 15 percent smaller is acceptable.

The Fixed-Point Settings interface contains eight buttons:

Run runs the model and updates the display with the latest simulation information.
Pause pauses the simulation.
Stop stops the simulation from running.
Show plot dialog invokes the Plot systems interface, which displays any To Workspace, Outport, or Scope blocks found in the model.
Open System invokes the Fixed-Point Settings interface for the system or subsystem displayed in the Select current system parameter.
Autoscale Blocks invokes the automatic scaling script autofixexp.
Close closes the interface.
Help displays the HTML-based help for the fxptdlg function.

The Plot systems interface is shown below. In this example, the interface is displaying variable names that correspond to Scope block outputs from the fxpdemo_feedback demo.

To plot the simulation results, select one or more variable names, and then select the appropriate plot button:

Plot Signals plots the raw signal data for the selected variable(s).
Plot Doubles plots doubles data for the selected variable(s). Doubles are generated when the Data type override parameter is set to True doubles.
Plot Both plots both raw signal data and doubles data for the selected signal(s). Note that the doubles override does not overwrite the raw data.
Cancel allows you to exit the interface without plotting.

Examples

To learn how to use the Fixed-Point Settings interface, refer to Tutorial: Feedback Controller Simulation in the Simulink Fixed Point documentation.

See Also

showfixptsimerrors, showfixptsimranges

float num2fixpt