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Simulation Pace

Set simulation rate for animation viewing

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  • Simulation Pace block

Libraries:
Aerospace Blockset / Animation / Animation Support Utilities

Description

The Simulation Pace block lets you run model simulation at a slower pace so that you can comfortably view connected animations and understand and observe the system behavior. Visualizing simulations at a slower rate makes it easier to understand underlying system design, identify design issues and demonstrate near real-time behavior. You can view the results and inspect your system while the simulation is in progress.

Use this block in scenarios where one simulation-second is completed in a few wall clock time milliseconds.

When configuring this block, also consider the block sample time, which affects the simulation pace. The default is 1/30th of a second, which corresponds to a 30 frames-per-second visualization rate (typical for desktop computers). For more information, see Sample time.

To use this block:

  • Set the model solver to Fixed-step.

  • Use a discrete sample time.

Tip

The Simulation Pace block:

  • Does not produce deployable code.

  • Is not supported in referenced models for simulation in accelerator or rapid accelerator mode. To slow down the simulation in these modes, in the Simulation tab of the Simulink® Editor toolstrip, select Run > Simulation Pacing.

Ports

Output

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Pace error, specified as a scalar.

The block optionally outputs the pace error value (simulationTime minus ClockTime), in seconds. The pace error is positive if the simulation is running faster than the specified pace and negative if slower than the specified pace.

Outputting the pace error from the block lets you record the overall pace achieved during the simulation or routing the signal to other blocks to determine if the simulation is too slow to keep up with the specified pace.

Dependencies

To enable this port, select the Output pace error (sec) check box.

Data Types: double

Parameters

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Ratio of simulation time to clock time, specified as a scalar, in seconds of simulation time per second of clock time.

Programmatic Use

Block Parameter: OutputPaceError
Type: character vector
Values:'1' | scalar
Default: '1'

Control simulation pace of model using one of these methods. MATLAB Thread, Busy-Wait, and Auto slow down the simulation pace at simulation-second 0.1 to wait for the wall clock to get to time 1. Use this parameter when one simulation-second is completed in a few wall clock time milliseconds.

  • Auto — Use the model configuration parameter setting Enable pacing to slow down simulation to control the simulation pace. If the model configuration parameter setting Enable pacing to slow down simulation is not selected, the block behaves as though the MATLAB Thread option is selected.

  • MATLAB Thread — Use the operating system sleep function during simulation to wait for the wall clock to get to time 1.

  • Off — Disable the pace functionality and let the simulation run as fast as possible.

  • Busy-Wait — Use a while loop in conjunction with the Simstruct to wait for the simulation to wait for the wall clock to get to time 1.

Programmatic Use

Block Parameter: SleepMode
Type: character vector
Values:'MATLAB Thread' | 'Off' | 'Busy-Wait' | 'Auto'
Default: 'Auto'

Select this check box to output the pace error value (simulationTime minus ClockTime), in seconds. The pace error is positive if the simulation is running faster than the specified pace and negative if slower than the specified pace. To disable the display, clear this check box .

Programmatic Use

Block Parameter: OutputPaceError
Type: character vector
Values:'off' | 'on'
Default: 'off'

Specify the sample time as a scalar. The default 1/30th of a second corresponds to a 30 frames-per-second visualization rate (typical for desktop computers). To set how often the Simulink interface synchronizes with the wall clock, use this parameter.

The block sample time must be:

  • Discrete

  • Greater than 0.0 or an inherited sample time (-1)

The block sample time and its optional offset time ([Ts, To]) must be finite and discrete.

Caution

Choose as slow a sample time as needed for smooth animation, since oversampling has little benefit and undersampling can cause animation jumpiness. Undersampling can also potentially block the MATLAB® main thread on your computer.

Programmatic Use

Block Parameter: SampleTime
Type: character vector
Values: scalar | vector
Default: '1/30'

Algorithms

The simulation pace is implemented by putting the entire MATLAB thread to sleep until it must run again to keep up the pace. The Simulink software is single threaded and runs on the one MATLAB thread, so only one Simulation Pace block can be active at a time.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced before R2006a

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See Also

Blocks

Tools

Topics