Several features in Ignition allow you to specify a recurring schedule using crontab syntax. Crontab is a well documented syntax across the web. However, this page will provide a short reference to crontab as it's implemented in Ignition.
Crontab formatting is made up of five fields, each of which represent a different unit of time. Normally crontab is represented horizontally, with the left most field representing minutes.
* * * * *
| | | | |
| | | | ----day of the week
| | | ----month
| | ----day of the month
Each field has a range of expected values, in addition to the special characters listed elsewhere on this page.
minute expects a value from 0-59
hour expects a value from 0-23
day of the month expects a value from 1-31
month expects a value from 1-12
day of the week expects a value from 0-6, with 0 representing Sunday and 6 representing Saturday.
Additional characters can be provided to a field in cases where multiple values or distinct intervals are required.
Example (using the Minutes field)
All ( * )
Denotes any possible value for the given unit.
The following executes every minute, starting at 2:00 AM, with the last execution being at 2:59 AM.
* 2 * * *
Comma ( , )
Allows multiple values to be specified for the unit of time.
The following would run at the start of every hour, and at the 25th minute of every hour.
0,25 * * * *
Dash ( - )
Used to specify a range of values. Useful if you want to have the action occur at consecutive intervals, but not at every interval.
The following would run every minute, starting at 2:00 AM, with the last execution at 2:06 AM.
0-6 2 * * *
Last ( L )
The last possible unit. Only available on the Days field. Useful in cases where something needs to run on the last day of the month.
The following would execute at 11:59 PM on the last day of the month.
59 23 L * *
Every Other ( /# )
Allows for a range of internals to be defined, where "#" is a number to step by. For example, setting the day field to */2 would execute the schedule every other day (assuming the other fields are set to * ).