Previous values (Delta)

This example shows a Condition formula that checks for the amount of change in recorded readings; if sufficient, it then triggers its child Action(s).

In this case, the Condition’s formula references a Task with the Tag "SUCTPRESS" (for suction pressure). If the change is greater than or equal to 250, the calculation evaluates TRUE, and the child Action (a Message) fires.

The simplest implementation of this example is as follows:

The Condition is configured with the following formula:

@ABS(@GETVALUE(SUCTPRESS,&NULL)-@GETLASTVALUE(SUCTPRESS,&NULL))>=250

• The Absolute Value function (@ABS) is used to simplify the formula since the mathematical operation could result in a negative value.

• The @GETVALUE function references the "Suction Pressure" Task (parent to the highlighted Condition) by its Tag value.

• The @GETLASTVALUE function references the last value from the "Suction Pressure" task.

  Note: The availability of data points to functions that work with historical values (like "@GETLASTVALUE") is governed by the "Mobile History" setting (see Configure sync server settings for more details).

Once validated (see Formula validation), the Condition interprets its formula in a more user-readable form, as shown below.