Have one query on the 'Evaluate frequency option'

Hi All,

Would like to have clarity on the 'Evaluate frequency option' that is available while configuring the alert.

For ex: if I have my polling settings as default and for disk place alert I select that it should evaluate every 30 minutes.

Then:

If the disk space is observed high on 10th minute and back to normal on 16th minute and again high on 20th minute, the trigger action gets initiated only once?

I am just trying to understand the relation of this option with polling settings.