Question

So I was curious as to if this was possible. Would it be possible to have a PHP script go to a url at a set interval, say 30 minutes?

Answer 1

Cron jobs

Yes, just use cron jobs for calling PHP script in 30-minute intervals.

Also see my answer to another question: How to execute PHP code periodically in an automatic way

Delayed Unix call

There is also another option that should work on Unix and involves calling external script with delay without blocking the current script. It may look like this:

exec('( sleep 1800; my_php_script.php) &> /dev/null &');

although the availability of this solution depends on the system and safe_mode settings. For details about exec() function see the documentation.