When you have added a search key field, you can define whether the search key can also be used as an OPC tag. If you enable the tag feature, it means that a new tag will be created for the search key field. This tag can be used as a reference instead of Group names and will be available for any item that has a Form containing the search key field.
NOTE: The Tag feature is designed for use with systems that need to obtain data via OPC, where one database is unable to use the <group>.<item property> reference format.
Example:
A search key field named SiteLocation is added to the CDBPoint table. This means that points will have a SiteLocation search key field added to their Forms. The SiteLocation search key field has its Tag check box selected (tag feature enabled), so a search key tag is created for the field. The search key tag is named SiteLocation (same name as search key field).
The system contains 200 points. Every one of these points has a SiteLocation field as the points are in the CDBPoint table. This means that the search key tag provides access to 200 entries for the SiteLocation field, with each individual entry sharing its name with the entry made in the SiteLocation field on the Point Forms.
A point named CurrentInput has ‘West 646’ as its SiteLocation entry. In the Database Bar, the CurrentInput point is located in a Group named ‘West Area’ which is within a parent Group named ‘Main Group’.
If the tag feature was disabled for the search key field, the only way to reference the CurrentInput point in an animation would be to use the complete database reference:
"Main Group.West Area.CurrentInput"
However, as the tag feature is enabled, the CurrentInput point can be referenced by its search key tag:
".West 646.CurrentState"
To enable or disable the tag feature, you need to use the Tag setting on the Edit Field window. For information on accessing the Edit Field window, see Add a New Extra Field. You can also use the Edit Field window to modify the Target Type of an existing custom field (see Modify an Existing Extra Field).
When you have displayed the Edit Field window, use the Tag setting to enable or disable the tag feature:
- Tag—Use the Tag check box to define whether the search key can also be used as an OPC tag. Select the check box to enable the tag feature for the selected search key field; clear it to disable the tag feature for that field.
- If you clear the check box, the search key cannot be used as an OPC tag. Item references use the group names and item names.
- If you select the check box, the search key can be used as an OPC tag. It shares its name with the Field Name entry for the search key field.
When you have defined the Tag setting, you can continue to define the other field settings as required.