IC

Set initial value of signal

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Libraries:
Simulink / Signal Attributes

Description

The IC block sets the initial condition of the signal at its input port, for example, the value of the signal at the simulation start time (tstart). To do so, the block outputs the specified initial condition when you start the simulation, regardless of the actual value of the input signal. Thereafter, the block outputs the actual value of the input signal.

The IC block is useful for providing an initial guess for the algebraic state variables in a loop. For more information, see Algebraic Loop Concepts.

Behavior for Nonzero Sample Time Offset

If an IC block has a nonzero sample time offset (toffset), the IC block outputs its initial value at time t,

t = n * tperiod + toffset

where n is the smallest integer such that t ≥ tstart.

That is, the IC block outputs its initial value the first-time blocks with sample time [tperiod, toffset] execute, which can be after tstart.

Examples

Simulation of Bouncing Ball

Uses two models of a bouncing ball to show different approaches to modeling hybrid dynamic systems with Zeno behavior. Zeno behavior is informally characterized by an infinite number of events occurring in a finite time interval for certain hybrid systems. As the ball loses energy, the ball collides with the ground in successively smaller intervals of time.

• Open Model

Model Stick-Slip Friction and Hard Stops in Mass-Spring-Damper System

One way you can incorporate hard stops and friction changes from stick-slip motion into a mass-spring-damper model.

• Open Live Script

Ports

Input

Port_1 — Input signal

scalar | vector | matrix | N-D array

Input signal, specified as a scalar, vector, matrix, or N-D array. The block sets the initial condition of this signal to the Initial value you specify.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point | enumerated | bus

Output

Port_1 — Output signal

scalar | vector | matrix | N-D array

Output signal provided as the Initial value you specify, followed by the actual values of the input signal. See Behavior for Nonzero Sample Time Offset for more information.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point | enumerated | bus

Parameters

Initial value — Initial value

1 (default) | real, finite scalar, vector, matrix, or N-D array

Specify the initial value of the input signal as a finite, real-valued scalar, vector, matrix, or N-D array. The value must be a scalar, or have the same dimensions as the input signal.

Programmatic Use

Block Parameter: Value

Type: character vector

Values: scalar | vector | matrix | N-D array

Default: '1'

Sample time (-1 for inherited) — Interval between samples

-1 (default) | scalar | vector

Specify the time interval between samples. To inherit the sample time, set this parameter to -1. For more information, see Specify Sample Time.

Dependencies

This parameter is visible only if you set it to a value other than -1. To learn more, see Blocks for Which Sample Time Is Not Recommended.

Programmatic Use

To set the block parameter value programmatically, use the set_param function.

Parameter:	SampleTime
Values:	"-1" (default) | scalar or vector in quotes

Block Characteristics

Data Types	Boolean | bus | double | enumerated | fixed point | integer | single
Direct Feedthrough	yes
Multidimensional Signals	yes
Variable-Size Signals	no
Zero-Crossing Detection	no

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using Simulink® Coder™.

Not recommended for production code. Relates to resource limits and restrictions on speed and memory often found in embedded systems. Generated code can contain dynamic allocation and freeing of memory, recursion, additional memory overhead, and widely varying execution times. While the code is functionally valid and generally acceptable in resource-rich environments, smaller embedded targets often cannot support such code. Usually, blocks evolve toward being suitable for production code. Thus, blocks suitable for production code remain suitable.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a

R2023b: IC Block Row-Major Support Update

The IC block now supports code generation for row-major array layout.