I constructed a simple system model which might address your concern.

The model has a DiscreteClock and a LineWriter. You can find the Clock in Actors/Sources/TimedSources. The clock fires (produces an output) every 86400 seconds. At every tick, it causes the LineWriter to write its output to a file (ClockOutput.txt) which must be on your file system.

Although the system model runs from 0 to 172800s with a period of 900 seconds, you can see that ClockOutput.txt has only three entries. Is that what you would like to achieve?

Notes:

• The model is at C:\fakepath\model.png.
• Please rename the model from model.png to model.xml so you can run it.
• Do not forget to specify the path to the output file (ClockOutput.txt) so the model can find it.