Equation fields

• Event Tag

  For event-based calculations, the event tag appears in the read-only Event tag field.

• Equation

  Enter an equation using PI Performance Equation syntax:

  Enter point names in single quotes. For example, to simply add the current value of the sinusoid point to the current value of the ba:level.1 point:

  

  Enter timestamps in single quotes. To calculate the total time during the past hour where the sinusoid point had a value between 30 and 70:

  

  To calculate the time-weighted average value of the sinusoid point for the last hour:

  

  Calculation expressions longer than 300 characters are difficult to work with. If longer expressions are required, consider breaking down an equation into parts handled by individual PE points, and then use those points in equations for other points.

  Note: It is important that you use scan class offsets to schedule point calculations in the correct order.

• Evaluate

  Click Evaluate to test an equation. If evaluation is disabled, be sure a Data Archive server is selected on the General tab.

• Snapshot

  Click Evaluate to test an equation. If evaluation is disabled, be sure a Data Archive server is selected on the General tab.

See also:

• Event-based scheduling

• Schedule a PE calculation

• Scan class offsets for performance equations