Does the history follow tag changes?

Ignition
1

Hey all,

quick question: When I make changes to the history properties on a tag, does Ignition pull all the previously recorded history associated with that tag path?

My current thought is yes, as I just changed a tag historical group today and it looks like the previous history (over the last week) is being displayed as well. I'm using an XY Chart to graph this tag to try and confirm whether or not this actually works. Side note: I'm not 100% on using charts for tag history yet, so there's that.

Here is the chart:

image
image761×301 18.8 KB

(remember I changed the tag history group today)

Here is a sample of data from April 12th.

image
image249×437 6.27 KB

It looks pretty close.

2

Yes, no history is deleted when history settings are changed, unlike some other unscrupulous SCADA platforms...

However, when you move a tag, the history will become disassociated with the new path, however you can manually relink it.. this will be fixed in v8.3

3 Likes
3

See Ignition Database Table Reference | Ignition User Manual for details on the Historian database structure.

4

I knew that the tagid changes, but wasn't sure if the history would still be available for that tag. Didn't see anything in the docs that specifically said the history follows the tag when changes, other than moving, are made.

Thanks guys.