Simulink®

IC - Set initial value of signal

Library

Signal Attributes

Description

The IC block sets the initial condition of the signal at its input port, e.g., the value of the signal at the simulation start time (t_start). The block does this by outputting 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.

Note   If an IC block inherits or specifies 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.

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

Data Type Support

The IC block accepts and outputs signals of any Simulink^® built-in and fixed-point data type. The Initial value parameter accepts any built-in data type supported by Simulink software.

Parameters and Dialog Box

Initial value

Specify the initial value for the input signal.

Sample time (-1 for inherited)

Specify the time interval between samples. To inherit the sample time, set this parameter to -1. See Specifying Sample Time in the online documentation for more information.

Examples

The following diagram illustrates how the IC block initializes a signal labeled "test signal."

At t = 0, the signal value is 3. Afterward, the signal value is 6.

Characteristics

Hit Crossing

If