OPC UA Historical Access


Was wondering if historical access to OPC tags would be supported in v8. Would be huge if we didn’t have to backfill data into our OSISoft/PI corporate historian – and just leverage the functionality that is planned for OPC UA directly.

Thanks in advance!


It won’t be part of Ignition 8.0 and I doubt this will be implemented any time soon.

There’s very little demand (although I’m counting your request) and it’s a significant amount of effort to implement.

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Thanks Kevin for the (amazingly) quick reply. Yes – please count this as a request :slight_smile: I imagine there will be much more demand for this as UA becomes more widely adopted. Would be great to see…


Is this the kind of thing that should be posted on the Ignition Features and Ideas page?

Never hurts to post it there.

yep – I posted there too a while back :slight_smile: – was just curious what was in the works with the beta


Paul. How are you currently backfilling the data into Osisoft PI?

Hi Mark,

It can be done manually by inspecting a combination of the sql tables managed by the historian module – I would suggest taking a quick look at the SDK reference for these tables to better understand how they function: https://docs.inductiveautomation.com/display/SE/Tag+History+Tables+Reference

Generally – you will need to inspect the following (names/etc may not be exact – going from memory here…)

  • sqlth_te (find the id of the tag based on it’s TagPath within the historian db)
  • sqlth_partitions (find the data table(s) for the time-range you’re after)
  • sqlt_data_x_x_x (this is the table returned for your time-range in question…use the “WHERE” clause to filter entries pertaining to your specific tag id)

Hope this helps!


PS – I think there is a more elegant way of doing this via the PI RDBMS interface – but I’m assuming you’re trying to fill the missing data that may have been captured via OPC-UA connector?)