|
|
|
| R2012a Documentation → Simulink | |
Learn more about Simulink |
|
| Contents | Index |
Ports & Subsystems
Adding an Enable block to a subsystem or at the root level of a model makes it an enabled system. A subsystem can contain no more than one Enable block. An enabled system executes while the input received at the Enable port is greater than zero.
At the start of a simulation, Simulink software initializes the states of blocks inside an enabled system to their initial conditions.
If you use an enable port for a root-level model:
For multi-rate enabled models, set the solver to single-tasking.
If the enabled model has a fixed-step size, at least one block in that model must run at that fixed-step size rate.
The Enable block supports signal label propagation.
The Enable block accepts signals of supported Simulink numeric data types, including fixed-point data types. For more information, see Data Types Supported by Simulink in the Simulink documentation.
The Main pane of the Enable block dialog box appears as follows:
Placing the Enable block at the root of a model enables the Signal Attributes pane:
At the instant when an enabled system is being disabled, specify what happens to the states of blocks in the enabled system.
Default: held
Holds the states at their previous values.
Resets the states to their initial conditions (zero if not defined).
| Parameter: StatesWhenEnabling |
| Type: string |
| Value: 'held' | 'reset' |
| Default: 'held' |
Specify when to propagate a variable-size signal.
Default: Only when enabling
Propagates variable-size signals only when reenabling the system containing the Enable Port block. When you select this option, sample time must be periodic.
Propagates variable-size signals at each time step.
| Parameter: PropagateVarSize |
| Type: string |
| Value: 'Only when enabling' | 'During execution' |
| Default: 'Only when enabling' |
Select this check box to output the enabling signal.
Default: On
On Shows the Enable block output port and outputs the enabling signal. Selecting this option allows the system to process the enabling signal.
OffRemoves the output port from the Enable block.
| Parameter: ShowOutputPort |
| Type: string |
| Value: 'on' | 'off' |
| Default: 'on' |
Select this check box to enable zero-crossing detection.
Default: On
| Parameter: ZeroCross |
| Type: string |
| Value: 'on' | 'off' |
| Default: 'on' |
Specify the dimensions of the input signal to the block.
Default: 1
Valid values are:
n | Vector signal of width n accepted |
[m n] | Matrix signal having m rows and n columns accepted |
See Block-Specific Parameters for the command-line information.
Specify the time interval between samples.
Default: -1
See How to Specify the Sample Time in the online documentation for more information.
See Block-Specific Parameters for the command-line information.
Specify the minimum value that the block should output.
Default: [] (unspecified)
This number must be a finite real double scalar value.
Note If you specify a bus object as the data type for this block, do not set the minimum value for bus data on the block. Simulink ignores this setting. Instead, set the minimum values for bus elements of the bus object specified as the data type. For information on the Minimum property of a bus element, see Simulink.BusElement. |
Simulink software uses this value to perform:
Simulation range checking (see Signal Ranges)
Automatic scaling of fixed-point data types
See Block-Specific Parameters for the command-line information.
Specify the maximum value that the block should output.
Default: [] (unspecified)
This number must be a finite real double scalar value.
Note If you specify a bus object as the data type for this block, do not set the maximum value for bus data on the block. Simulink ignores this setting. Instead, set the maximum values for bus elements of the bus object specified as the data type. For information on the Maximum property of a bus element, see Simulink.BusElement. |
Simulink software uses this value to perform:
Simulation range checking (see Signal Ranges)
Automatic scaling of fixed-point data types
See Block-Specific Parameters for the command-line information.
Specify the output data type of the external input.
Default: double
Data type is double.
Data type is single.
Data type is int8.
Data type is uint8.
Data type is int16.
Data type is uint16.
Data type is int32.
Data type is uint32.
Data type is boolean.
Data type is fixed point fixdt(1,16,0).
Data type is fixed point fixdt(1,16,2^0,0).
The name of a data type object, for example Simulink.NumericType
Do not specify a bus object as the expression.
See Block-Specific Parameters for the command-line information.
Display the Data Type Assistant.
The Data Type Assistant helps you set the Output data type parameter.
See Specifying Block Output Data Types for more information.
See Block-Specific Parameters for the command-line information.
Select the category of data to specify.
Default: double
Built-in data types. Selecting Built in enables a second menu/text box to the right. Select one of the following choices:
double (default)
single
int8
uint8
int16
uint16
int32
uint32
boolean
Fixed-point data types.
Expressions that evaluate to data types. Selecting Expression enables a second menu/text box to the right, where you can enter the expression.
Do not specify a bus object as the expression.
Clicking the Show data type assistant button enables this parameter.
See Block-Specific Parameters for the command-line information.
See Using the Data Type Assistant in the Simulink User's Guide.
Cause the block to interpolate or extrapolate output at time steps for which no corresponding workspace data exists when loading data from the workspace.
Default: On
On Cause the block to interpolate or extrapolate output at time steps for which no corresponding workspace data exists when loading data from the workspace.
OffDo not cause the block to interpolate or extrapolate output at time steps for which no corresponding workspace data exists when loading data from the workspace.
See Block-Specific Parameters for the command-line information.
Sample Time | Determined by the signal at the enable port |
Dimensionalized | Yes |
Virtual | Yes, if not connected directly to an Outport block For more information, see Virtual Blocks in the Simulink documentation. |
Zero-Crossing Detection | Yes, if enabled |
Learn more about Simulink through this collection of videos, articles, technical literature and the Getting Started with Simulink Guide.
| © 1984-2012- The MathWorks, Inc. - Site Help - Patents - Trademarks - Privacy Policy - Preventing Piracy - RSS |
