The Rule
In Aveva Edge (InduSoft Web Studio), you must remove all references to a tag from screens, scripts, and graphics before deleting the tag from the tag database. There is no automatic cleanup — orphaned references will cause runtime errors.
Where Tags Hide
Tags can be referenced in more places than you might expect:
- Screen objects — text displays, bar graphs, buttons, animations linked to the tag.
- Scripts — screen scripts, application scripts, global scripts, scheduler scripts.
- Alarm definitions — alarm setpoints tied to the tag.
- Trend objects — historical trends configured to log the tag.
- Recipe definitions — tags used in recipe groups.
- Communication drivers — driver sheets that map the tag to a PLC address.
The Hunt-and-Find Process
Unfortunately, Aveva Edge does not provide a comprehensive cross-reference tool for tags across all object types. You need to manually search:
- Use Find/Replace in the screen editor to search for the tag name across all screens.
- Search script files — open each script file and search for the tag name. Script files are text-based and can also be searched externally with a text editor.
- Check the alarm worksheet for any rows referencing the tag.
- Check trend configurations for the tag name.
- Check driver sheets — the communication driver configuration maps tags to device addresses.
After Deletion
After removing all references and deleting the tag, do a full build and run the application in development mode. Watch for any runtime errors that indicate a missed reference. Fix any orphaned references before deploying to production.