About Conditional Subsystems
A subsystem is a set of blocks that have been replaced by a
single block called a Subsystem block. This chapter describes a special kind of
subsystem whose execution can be externally controlled. For information
that applies to all subsystems, see Creating Subsystems.
A conditional subsystem, also known
as a conditionally executed subsystem, is a subsystem
whose execution depends on the value of an input signal. The signal that controls
whether a subsystem executes is called the control signal. The signal enters the
Subsystem block at the control input.
Conditional subsystems can be very useful when you are building
complex models that contain components whose execution depends on
other components. The following types of conditional subsystems are supported:
An enabled subsystem executes
while the control signal is positive. It starts execution at the time
step where the control signal crosses zero (from the negative to the
positive direction) and continues execution while the control signal
remains positive. Enabled subsystems are described in more detail
in Enabled Subsystems.
A triggered subsystem executes
once each time a trigger event occurs. A trigger event can occur on
the rising or falling edge of a trigger signal, which can be continuous
or discrete. Triggered subsystems are described in more detail in Triggered Subsystems.
A triggered and enabled subsystem executes
once on the time step when a trigger event occurs if the enable control
signal has a positive value at that step. See Triggered and Enabled Subsystems for
more information.
A control flow subsystem executes
one or more times at the current time step when enabled by a control
flow block that implements control logic similar to that expressed
by programming language control flow statements (e.g., if-then, while, do,
and for. See Modeling Control Flow Logic
for more information.
For examples of conditional subsystems, see:
 | Creating Conditional Subsystems | | Enabled Subsystems |  |
Learn more about Simulink through this collection of videos, articles, technical literature and the Getting Started with Simulink Guide.
Get this Simulink Kit
Store 
