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simulation time in Simulink

I'm a recent user of Simulink. I would like to know whether the simulation stop time 24 is correct to simulate 24 hours (and so the signal in input has to be referred to a day of measurations with time = 24) or I have to indicate 3600s*24 = 86'400 as a simulation stop time (and so the input daily signal has to be created upon 86400s). Thank you for your precious help.


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1 Answer

Answer by Kaustubha Govind on 12 Mar 2012
 Accepted Answer

The simulation time is specified in seconds, so you would need to use 86400 to set a day's duration. (Note however that this doesn't mean the simulation will run for 24hrs in real-time, just that the data you provide is used as if provided for a 24hr period)


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Valentina on 12 Mar 2012
So, if I have 24 temperature's values, one for each hour in a day, and I would like to use the simulation time equal to 86400s, i have to create a signal of temperature with 3600 values identical in each hour, isn't it?
Doug Eastman on 12 Mar 2012
No, when you specify input to Simulink you need to use a time vector and a data vector. So the vector only needs points where you want. For example, if you are using seconds as the time unit you might use the following as the data in a From Workspace block:
[0 T1;60*60 T2; 60*60*2 T3; 60*60*3 T4; 60*60*4 T5; ...]
The first column (0, 60*60, ..) corresponds to the times and the second column (T1, T2, ...) corresponds to the temperatures at those times.
You can choose whether you want to interpolate between the temperature values or hold them until the next reading.
Valentina on 16 Mar 2012
Thank you very much Doug.

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