We are facing something strange in our historical data. We are storing our tag according to these settings:
Max time between samples is 1 hour, so when the values doe not change, it's normal to see a record in the database every hour.
When looking at the data as stored, we see something odd. As you can see in the following screenshots, there is exactly 1 hour between the two storing moments, but the value is changed.
It's highly unlikely that our operators changed the setpoint right at the exact timestamp that there is an auto-storing of the tag, so in my eyes this looks like a bug.
In this test we use a history splitter, splitting to both Postgres and to Influx, and we see the data in both databases at the same timestamps.
Are we overlooking something? Or should we take this up with support?
Thanks for looking along.
Is the data in your screenshot taken directly from the sqlth tables, or did you use some kind of history binding to display it ?
If the latter, it might not be the actual data as it is stored.
This is, I suspect, a problem with analog compression in the historian.
The tag history Auto section says,
The setting will automatically pick either Analog or Discrete, based on the data type of the tag.
- If the data type of the tag is set to a float or double, then Auto will use the Analog Style.
- If the data type of the tag is any other type, then the Discrete style will be used.
Your screenshot doesn't show what datatype your tag is, but try setting Deadband Style to Discreet.
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It's in Ignition, but I have also checked it directly in the database, it's the same.
It's a Float. Thanks, I've changed it to Discreet. I will see what that changes.
