What is a "licensed tag" in the Canary Historian?

A licensed tag is a single data source for which the Canary Historian collects and stores TVQs (Time stamp/Value/Quality). Some industries may refer to tags as points or channels.

The license count in the Canary Historian is determined by the total number of tags in the last file of each dataset. Even if a tag is not be actively logged, if it resides in the last file it is counted as a licensed tag. To remove a tag from the historian a new file must be created without the tag in it.

UA logger

The UA logger (located under the OPC collector tile) removes tags and updates tag counts as the tags are removed. 

DA logger

The DA logger will do the same as long as the check box for creating a new file is checked. To do this simply:

• Open up your logger  
• Check the box "Create new file when logging starts"
• Stop and start logging session

Every time you restart a logging session and select “New File”, the current HDB file is closed and a new HDB file is started. When this occurs, the new tag names are referenced and licensing is updated.

When a tag has been released from the license count, all historical data records remain in the Canary Historian but are no longer accessible for client tools like Axiom, the Excel Add-in, and Web API.

Tags within the {Diagnostics} DataSet do not consume a tag license and are automatically installed with every Canary Historian.