How can one measure PI Data quality?
Hi Tubo Soye,
We have some data quality flags that you may use depending on the interface you are using. See below article:
2966OSI8 - Data Quality Flag attribute
For example, for OPC Interface:
If you want only to indicate whether quality of data is either bad or good, you could use the questionable flag: https://techsupport.osisoft.com/Troubleshooting/KB/3030OSI8
Also, OPC interface can set the questionable flag if the quality on OPC server is not good https://livelibrary.osisoft.com/LiveLibrary/content/en/int-opc-v2/GUID-12A28818-4E45-4BE8-B07C-C736DA98C7E6
Thanks Luis for this answer.
You can manually flag a value as questionable using something like the PI System Management Tools > Data > Archive Editor, and checking the box for Questionable.
Some of our interfaces can get the quality flag from the data source itself. The most notable case of that is the OPC interface. If you're sending data progamatically via the AFSDK, PI API, PI WebAPI, PI SDK, Powershell tools, then you can flag the value as questionable using the KB that Luis linked.
As for bad data, anything without a value but with something like "I/O Timeout" or "Shutdown", etc, is considered "bad".
In regards to finding the questionable or bad data, you can follow this KB for questionable data, and for bad data you can use the "percent good" attribute on any query tool, such as DataLink's Time Filtered Data:
I created a summary for the topic: Overview about Data Quality Handling options in PI System
Please feel free to add your comments, questions, implementations, challenges, etc. in the discussion.
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