Add child-event attributes as columns in the Compare Events task pane

Use the Add Attributes window to add child-event attributes to the Columns to display list in the Compare Events task pane. (Then you can include those columns in the function array inserted into the worksheet.) After you specify criteria for events in the task pane, this window lists the matched events and their child events. You can use this window to add any event attribute from these events. Most commonly, you use this window to add child-event attributes that will help you compare the matched events.

1. Open the Compare Events task pane and specify events to retrieve into the worksheet.

2. Next to the Columns to display list in the task pane, select to open the Add Attributes window.

   The window lists the events that match the criteria currently specified in the task pane.

3. Expand an event to see the event attributes stored for that event along with any child events.

   If two or more child events have the same name, PI DataLink automatically adds an index to the child-event name. To create the index, PI DataLink sorts those events by ascending start time, then ascending end time, and then ascending identifier.

   Event with two child events named Phase1

   

   You can include any event attribute as a column in the function array. When included in the function array, that column will show values stored for the event attribute.

4. Select the check box next to any attribute that you want to add to the Columns to display list in the task pane.

   The Compare Events function identifies attributes by name and path relative to the matched event. For example, suppose you select the Start time attribute under both a matched event and its child event.

   Select start-time attribute of matched and child event

   

   This adds two columns:

   • .|Start time

     In the worksheet, this column contains the start time of the matched event listed in each row.

   • .\Phase1|Start time

     In the worksheet, this column contains the start time of the Phase1 child event of the matched event listed in each row.

     Worksheet with child-attribute column

     

     You can add attributes from anywhere in the hierarchy. The window does not synchronize selections: if the path and attribute name are the same, you can add the same attribute more than once.

     When events have inconsistent event hierarchies, use care when selecting attributes of child events. If any event contains multiple child events with the same name, then select attributes under a duplicated child event (that is, an indexed child event) to ensure that you can view data for all events. For example, suppose you select the Start time attribute under a duplicated child event (the Phase1[1] child event of the TurbineStartUp.1.2 event) and a nonduplicated child event (the Phase1 child event of the TurbineStartUp.3.2 event).

     Select start-time attribute of duplicated child event and nonduplicated child event

     

     This adds two columns that return different results:

   • .\Phase1[1]|Start time

     In the worksheet, this column contains the start time of the first Phase1 child event of the matched event listed in each row. If the matched event has only one child event with this name, then the column lists the start time of that event in this column.

   • .\Phase1|Start time

     In the worksheet, this column contains the start time of the only Phase1 child event of the matched event listed in each row. If the matched event has more than one child event with this name, the column reports Duplicate event exists: specify index for Phase1.

     Worksheet with indexed and nonindexed child attribute

     

     The indexed attribute ensures that you return the desired data.

5. Select OK to insert the attribute into the Columns to display list and select that column.