Historical Trend is a periodic data logging feature that can be configured with specific logging parameters for each point. Users can not change the content of the Historical Trend database.
Snapshot logging is designed to store a set of data with a current timestamp or a timestamp in the past. For example, you can build logic to create previous day average and total values for a set of points at 10:00 AM , but store this information in the database for 8:00 AM timestamp.
You can use Automation to collect and convert data to create the final dataset. You can then use the Automation Snapshot Write function block to store this information for 8:00 AM.
You can repeat writing the same dataset multiple times. Snapshot database stores all instances of the values you sent to it and use the latest entry as the value to show unless you want to see the previous values from the Snapshot Audit Trail page.