Compact HMI :- History data storage support
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Try to check documents on teh next link:
Open "Product Guide" document (in the same section name) and you can find info on pages 78/79.
The Basic History service is "limited"* to 90 days of storage in System 800 HMI (CHMI's "Big brother").
*) Limited: its possible to create logs sampling every second and stretching for over a decade, but Basic History has not been fully tested and marketed with such high capacity in favor for other historians.