How to give time in hours in simulink?

Hello Everyone

As we know that Simulink runs simulation in seconds but I have a model which I need to run for many days. I wanted to give parameters values on hourly basis in my model as is given in my data but I know that Simulink runs simulation in seconds so any suggestions that How can I give these values in simulink input. I am attaching the image that shows nature of data. I hope you guys will get sense of my question from this data. Time here is in hours so every value

[Walter Roberson]

As long as you do not use a clock block, I think you could say that the times in the time signals are in "units".

If you do use the clock block as "information", perhaps you could scale the clock block value when you use it?

[Muhammad Saqlain Haider]

Like I am not using clock block so it means that when I am running simulation for 24 units, I can say that its 24 hours..rigt? Thats what are you trying to say?

[Walter Roberson]

I think so.

Of course the meaning of sin waves or square waves or the like are going to be affected: if you want N simulated samples/second for a generated wave you would have to make it 60*60 times larger to get the appropriate number of samples per hour.

And labels in plots and scopes might say Hz when your intended meaning is samples/unit instead. Cosmetics.

[Muhammad Saqlain Haider]

Probably you are right but I have doubt on it

Answer 1

[Jonas]

Can you set the sampling time of your model to 3600, such that it calculates once every hour?

[Muhammad Saqlain Haider]

I am not sure about that because I do not know how I will give values of temperature then?. 3600 means value of temperature or other parameters should also be 3600 times, then it will pick one value against every second..Thats why I am not sure and I need suggestions from experts

[Walter Roberson]

Setting the sampling time to 3600 would not help with the fact that the input times are 0 to 23: instead all of the data would be consumed in one or two time steps.

[Jonas]

Yes indeed, correct. But you could also just multiply the input data by 3600?

[Muhammad Saqlain Haider]

Exactly, Walter is right. Otherwise we have to repeate one value 3600 times then other value for next 3600 times and so on

[Jonas]

No you don't. If you multiply the first column with 3600 it will only take those samples.

However, just using sample rate 1 and seeing each sample as 1 hour instead of 1 second is easier to understand. Then you can quickly see on the horizontal scale that 5 is actually in hours and not in seconds.

[Walter Roberson]

A From Spreadsheet block is being used. The first column is not available as data: it is being converted into the times that the remaining columns are associated with.

There is no way that I know of to From Spreadsheet, consume all of the entries quickly, multiply them by 3600 on the fly, and use the results as time signals to make the remaining data columns available at.

Or rather, the only way I know how to do that in Simulink would be by way of initialization function callbacks that used a MATLAB Function Block to read the spreadsheet as data, do the multiplication, and write it out to a temporary file, and then connect the temporary file as the input of From Worksheet

[Muhammad Saqlain Haider]

Can you eleborate your last answer a little bit. I am sorrry I could not understand that. it will be much appreciated.

[Walter Roberson]

The idea is that during initialization you could replace the spreadsheet with a different one that had the time multiplied.