I’ve updated the article with more detailed instructions on the time_period usage. For others having the same question here:
The period of time to which the limit applies. The default time period is one day. In any 24 hour period, if the user reaches the limit they will no longer be able to make new submissions.
If you want to limit by less than a day, you can provide the time period in seconds. A time period of 60 would be one minute (60 seconds). A time period of 60 * 60 (or 3600) would be one hour.
Also supported are three different calendar periods: per_day, per_month, per_year. Calendar time periods are more rigid time periods that “reset” when the calendar time period expires (i.e. one month ends and another begins).
If you do not want to limit by a time period at all, set the time period to false.