Simulink Reference

Enable

Add an enabling port to a subsystem

Library

Ports & Subsystems

Description

Adding an Enable block to a subsystem makes it an enabled subsystem. An enabled subsystem executes while the input received at the Enable port is greater than zero.

At the start of simulation, Simulink initializes the states of blocks inside an enabled subsystem to their initial conditions. When an enabled subsystem restarts (executes after having been disabled), the States when enabling parameter determines what happens to the states of blocks contained in the enabled subsystem:

• reset resets the states to their initial conditions (zero if not defined).
• held holds the states at their previous values.

You can output the enabling signal by selecting the Show output port check box. Selecting this option allows the system to process the enabling signal.

A subsystem can contain no more than one Enable block.

Data Type Support

The data type of the input of the Enable port can be any data type except int64 and uint64. See Creating Conditionally Executed Subsystems in the online Simulink help for more information about enabled subsystems.

Parameters and Dialog Box

States when enabling

Specifies how to handle internal states when the subsystem becomes reenabled.

Show output port

If selected, Simulink draws the Enable block output port and outputs the enabling signal.

Enable zero crossing detection

Select to enable zero crossing detection. For more information, see Zero Crossing Detection in the Using Simulink documentation.

Characteristics

Sample Time	Determined by the signal at the enable port
Dimensionalized	Yes

Dot Product

Enabled and Triggered Subsystem