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AVEVA HISTORIAN 2023 : Unable to log data cyclically

Iftekhar Shaikh

Hello,

I’m Iftekhar, and I would like to ask about data logging behavior in AVEVA Historian 2023.
I’ve configured data logging through IOServer with a 1-second cyclic frequency, but I’ve observed that the Historian is logging data in Delta mode — that is, only when the tag value changes.

Could you please advise how to configure the system so that data is logged cyclically every 1 second, regardless of value change?

Thank you for your assistance.

Please see attached images.

Best Regards,

Iftekhar

  • 0

    Hi, could you try to add this to your query after the WHERE clause? AND wwRetrievalMode = 'Full'

    If you don't specify the retrieval mode it will default to Delta.

  • 0

    There are a lot of details to consider here:

    1. As Kristian indicated, independent of the storage rate, you can sample the stored value in query output with "cyclic" storage, but this is not the default mode. 
    2. In the old "classic" storage system (retired in Historian 2014 R2?), there were separate mechanisms for "cyclic" and "delta" storage. These were folded into a common mechanism with the "Storage Engine" technology. The result is that "cyclic storage" now works as more of a "preprocessing layer" that filters what gets stored, but internally stores "delta" values.
    3. I/O servers (your example source) communicate using SuiteLink, which will not send duplicate values + quality: if the value and quality haven't changed, the IDAS layer won't receive a new value, so the storage layer won't store another value

    The system is quite flexible, though, so if this information hasn't addressed your need, please explain the application need (vs. the system settings). For example, two common cases for periodic storage are:

    • At Least: A minimum frequency, such as "I need to store it every hour, even if it hasn't changed"
    • At Most: A maximum frequency, such as "Don't store it any faster than 1000 milliseconds, even if new values are reported every 50 milliseconds"
  • 0 in reply to Kristian Dahle

    Hi Kristian,

    Thanks for your suggestion, unfortunately, it’s still not working.