Formula validation

Before a user can click "OK" in the Expression Editor to accept a Formula, it must be Validated.

Note: Validation is automatically performed on expressions created by a Wizard (see Expression Wizards).

In this example, the Formula calculates change between current and last readings of a suction pressure (with the Tag "SPress1"- see Task Attributes - Advanced tab) and checks to see whether the change has been more than 125. The formula used is:

@ABS((@GETVALUE(SPress1,&NULL))-(@GETLASTVALUE(SPress1,&NULL)))>125

The formula is correctly formatted, but while unvalidated, the OK button, as well as the "Validated" text field, are shaded.

To Validate a Formula, first click the "Validate" button. One of two things will happen.