DataHub Email/SMS and Data Logging Trigger - Fire Only Once

Is it possible to define a trigger condition in DataHub for Email/SMS notification or Data Logging where the desired notification or logging only occurs a single time once the condition is true, i.e. a single email for a value over 9000 until that value has dropped back below the defined threshold of 9000?
With just the value and condition defined, multiple trigger events occur each time the value changes, if it is still over/under the threshold value defined in the condition.

Having only a single trigger event occur once over/under the defined threshold is a matter of defining a second condition. The example below uses Email/SMS notification but the same principles can be used with Data Logging functionality in DataHub as well.

Example: An Email/SMS Notification when the value of a tag is greater than 9000 such that only a single notification is sent once the value is greater than 9000 until the value returns below 9000 again, thereby resetting the condition.

1. In the Conditions section, you will enable the first two condition fields (there are 4 possible).
2. The first condition:
   • First Field:  should be the desired tag, selected from the Data Domain browser to the right of the conditions.
   • Condition Field:  Greater than (>)
   • Second Field:  should be the value 9000 (for this example)
3. The second condition:
   • First Field:  should be the word "previous" in all lower case letters (excluding the quote marks).
   • Condition Fields:  Less than (<)
   • Second Field:  should be the value 9000 (for this example)

The "previous" operator here defines that field as the previous value for the defined tag, rather than the current value, which is used when just the tag is specified as in the first condition.  This prevents this event from triggering for value changes greater than the threshold value if the value was already above the threshold to begin with, eliminating multiple Email/SMS notifications or logging events.