Alert Status & Frequency
The Alert Status is checked every time the query is executed - Alerts only work with scheduled queries.
Alerts have 3 Status Types:
Get an Alert Upon Status Change
If you leave the REARM value empty alerts will only be sent when the status changes (from OK to Triggered or vice versa).
Get an Alert Everytime the Query Runs
To get an alert every time the query runs, set the REARM value - the value is for seconds that pass since the system detects a change until it sends the alert, a 1-minute "delay" would require entering '60' in the REARM field.