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07/19/2015
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Hi,
In “OPC UA Part 11 – Historical Access 1.03 Specification.pdf”, there is a description about Range in section 6.8.2.2:
“If the Time does not fall within range that can be stored then the related operationResults entry shall indicate Bad_OutOfRange.”
What’s the definition of this “range” ?
04/01/2014
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The term “range” in this clause and in other clauses in 6.8.x refer to the earliest or latest the historical data can be stored. More specifically the earliest or latest timestamps associated with data the request from the UA Client is trying to store in the HA enabled UA Server.
A simple example is if a user wants to store data that is 24 hours into the future. The UA Server may, for technical reasons, only be able to store entries 10 minutes into the future. The result of requesting to store data 24 hours into the future would be a returned status code of Bad_OutOfRange.
Similarly if there is a technical limit to the earliest times that can be stored and a request comes in to store data before that time the same Bad_OutOfRange status would be returned. This could be for many reasons and the reason is vendor specific and not returned to the UA Client. The status just says that the range is outside what can be stored.
There is no call in HA that will tell a client what is the earliest or latest timestamp that will be accepted. This is information the vendor of the HA UA Server must supply.
Regards,
Rod
Rod Stein Manager of Technology Matrikon OPC http://www.matrikonopc.com
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