Add attribute extensions to template-based elements

The Allow Extensions check box on the General tab for the element template upon which the attribute is based must be checked.

In some situations, you might want to add another attribute to an existing element. If the element is based on a template that allows extensions, you can define additional attributes in the element itself independently of the template.

1. In the Elements browser, select the element to which an attribute will be added.

2. Choose from the following actions.

   • In the toolbar, click New Attribute.

   • Right-click the element in the browser and click New > New Attribute.

   • Select the Attributes tab in the viewer, right-click and click New Attribute from the context menu.

3. In the Name and Description fields, enter a unique name and a description for the attribute template.

   Note: When you need to search for an attribute, you can search on up to 440 characters of a description.

4. Configure the type of value that the attribute holds:

   • For attributes with constant values, set the attribute Value Type. This setting determines what you can enter in the Value field.

     Constant attribute values can be numbers, strings, files, date-times, Boolean, URLs, arrays, and more.

     Note: While allowed, the Anything value type is not recommended. When the value type is unspecified, many client applications may have difficulty working with that attribute. For example, PI OLEDB Enterprise and AVEVA PI Vision would all have reduced capability with such attributes, such as the inability to trend a value numerically. Furthermore, standard PI AF features such as automatic UOM conversion, formulas, and analytics cannot function with attributes that have no value type.

     Optional. Enter or modify the default value for the attribute in the Value field.

   • For formulas, PI point values, PI point arrays, and table data (including data from relational databases) click Settings to configure a data reference.

     See Understand configuration of data references for information about configuring different types of data reference.

5. Set other configuration fields, as needed.

   Field	Description
   Properties	Select one or more of the following properties, as needed. Configuration Item Excluded Hidden Indexed Manual Data Entry For more information, see Set up attribute properties.
   Categories	Click and select one or more previously defined categories from the Categories window. You can also create a new category. For more information, see Object categorization.
   Default UOM	Select a UOM from the drop-down list. For more information, see Learn about units of measure in PI AF. Note: You can change the UOM that is displayed for the attribute in PI System Explorer; however, the UOM defined in the template is not changed.

6. To save your work, press CTRL-S or click Check In.