Migrating Data from Another Historian to Ignition

I’m trying migrate from another historian to Ignition. I need to copy the last 2 years of data from the other system to the Ignition historian. The other system provides an export utility that I can use to get tagnames, timestamps, and values in Excel. I was planning to write a script in Ignition to parse the Excel file and use the system.tag.storeTagHistory() function to store each value in Ignition. That approach should be fine except for the data affected by the ending of daylight saving time when an hour of timestamps from 1:00 AM to 1:59:59 AM is repeated. I’m thinking a better approach will be to take the data from the overlap hours and convert the Excel timestamps to the format used in the tag historian database (milliseconds since “epoch”) and insert those records using SQL statements. Does that seem like a reasonable plan? Anybody care to offer a better approach?

Thank you.

Use the epoch timestamps at all times. Use system.date.fromMillis() to generate tz-aware timestamps to pass to storeTagHistory().