Real-Time Pacer for Simulink

Simulink block for forcing a simulation to run in real (wall clock) time

Description

The RealTime Pacer block slows down ("paces") simulation time so that it synchronizes with real elapsed time. The degree of slowdown is controllable via a Speedup parameter.

1) The block is implemented using an M S-function, so it works on any supported Simulink platform. It does not support code generation.

2) The block uses the MATLAB PAUSE function to slow down the simulation. The PAUSE command gives up the processor during the pause, so system performance does not degrade.

3) The M-S function illustrates how to use nested functions to simplify the code.

The matching between simulation time and elapsed real time is approximate, with expected differences on the order of 10 to 30 milliseconds. This limitation is due to difficulties of precise timing with a multitasking operating system.

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RELATED FX ENTRIES

The following FX entries also implement "real time" functionality for Simulink. They are based on C S-functions and therefore support code generation.

* Simulink Real Time Execution (Real-Time Slower) (Filex# 21908)
* Real-Time Blockset 7.1 for Simulink (Filex# 3175)
* RTsync Blockset (Filex# 24975)

• Required Products: Simulink
• MATLAB release: MATLAB 7.7 (R2008b)

[Gustavo]

Very nice work!

[Walter]

This pacer for Labview works very well for slowing a SIMULINK developed control system to match the timing of a real time device. We are using it to provide control logic to a LabView DAQ system which then controls a hydraulic pump and motor system. To overcome the problem of Microsoft Operating System interrupts, we have added memory to the control system to account for the time losses.