The five cron fields
From left to right, the fields represent minute, hour, day of month, month, and day of week. An asterisk means every allowed value; ranges, lists, and step values narrow the schedule.
Example
The expression */15 9-17 * * 1-5 runs every fifteen minutes during hours 9 through 17 on weekdays.
Implementation differences
This tool interprets a traditional five-field expression. Some schedulers use a sixth seconds field or special characters; verify the syntax supported by your actual scheduler.