PS Variable Delay

Delay input physical signal by variable time


Physical Signals/Delays


The PS Variable Delay block generates the output physical signal, y, by delaying the input physical signal, u:

y = u ( tτ )

where τ is the delay time, which can vary throughout the simulation. You supply the delay time as a signal through the input port T.

For the initial time interval, when t <= StartTime + τ, the block outputs the value of the signal supplied through the input port H.


    • When simulating a model that contains blocks with delays, memory allocation for storing the data history is controlled by the Delay memory budget [kB] parameter in the Solver Configuration block. If this budget is exceeded, simulation errors out. You can adjust this parameter value based on your available memory resources.

    • For recommendation on how to linearize a model that contains blocks with delays, see Linearizing with Simulink Linearization Blocks.

Dialog Box and Parameters

Maximum delay time

The upper limit for the delay time. Exceeding the maximum delay time during simulation results in a runtime error. The parameter value must be positive. The default value is 10 s.


The block has the following ports:


Physical signal input port for the original signal.


Physical signal input port that supplies the delay time.


Physical signal input port that supplies the output signal for the initial time interval, when time since the start of simulation is less than or equal to the delay time.


Physical signal output port for the delayed signal.


The Variable Transport Delay example shows how you can model a variable transport delay using Simscape™ language. The Transport Delay subsystem models signal propagation through media moving between the Input and the Output terminals. The media velocity may vary, thus it is specified through the block port. The distance between the terminals is constant and it is specified as a block parameter. To see the implementation details, look under mask of the Transport Delay subsystem, then right-click the Variable Transport Delay block and select Simscape > View source code.

Introduced in R2012a

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