What command must be issued from the System Management Console before implementing a tag import if Historian has already been started?

The command that must be issued from the System Management Console before implementing a tag import when the Historian has already been started is "Commit Pending Changes." This command is essential because it ensures that any changes or updates that have been made to the system are saved and finalized before importing new tags.

When the Historian is running, it may have pending changes that need to be applied to maintain system integrity and consistency. By committing those changes first, you prevent any potential conflicts or issues that could arise during the tag import process. This step is crucial in maintaining a stable environment for the data that will be processed and stored in the Historian.

Importing new tags without committing pending changes could lead to discrepancies in the data structure or even errors during the import, as the Historian might not recognize the new tags properly if there are uncommitted changes in the system. Thus, issuing the "Commit Pending Changes" command is an important preparatory step to ensure the successful implementation of the tag import.