Which of the following does not represent a Historian extension table?

The extension tables in AVEVA Historian are used to enhance the capabilities of the core data structure by providing additional information or organization of the historized data. Among the options mentioned, TagHistory specifically represents the main storage mechanism for time-series data associated with each tag, encompassing both the values and timestamps. This is integral to the operation of the historian and functions as the primary data repository.

In contrast, TagDetails serves to store metadata about each tag, such as its description and data type, while DataSummary provides summarized data, such as averages or totals, of the raw time-series data for efficient analysis. EventLogs are typically utilized to log specific events and system messages rather than time-series data.

Thus, since TagHistory is the foundational table housing the main time-series data in the historian, it clearly does not fit into the category of extension tables like the other options do.