I'm on 8.1.22
Not sure if I missed something, I try to set history on a tag with a sample rate of 1 minutes. I use Power chart to display the history and export data to csv file, in my file i see that tag value is insert every 2sec.
I Also tried by used tag group and got same issue


The observed rate from a query will not be the same as the actual sample rate unless you're using 'Natural' aggregation mode in your history query. What does your history query/binding/etc look like?
I use PowerChart, it don't requier any binding to access data
Try setting the aggregate mode to LastValue
? And/or try changing the point count property to -1.