CRON every X seconds

Hello,

I need a CRON trigger eg every 20 seconds.

Through crontab, I would solve this as follows:
* * * * * root echo 'date' >> /tmp/cron-date.log
* * * * * root sleep 20 ; echo 'date' >> /tmp/cron-date.log
* * * * * root sleep 40 ; echo 'date' >> /tmp/cron-date.log

Am I able to enter the three tasks via CRON in ISPConfig?

Thanks for the information.