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02/24/2022
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Hello,
Apologies in advance for my limited knowledge of OPC UA.
I am a little bit confused about the difference of quality codes and status codes.
If I am not mistakes both can be set to a node/tag.
So e.g. a node/tag can have a status of Bad_WaitingForInitialData or a quality of Bad.
What is the difference? Why are there quality codes if the list of status codes looks is more comprehensive?
Quality Codes
https://honeywellprocess-commu…..lity-Codes
Status Codes
https://honeywellprocess-commu…..tatus-Code
Thank you,
Simon.
05/30/2017
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Quality Code are a concept from OPC Classic (COM DA).
They are an set of bits that is returned in addition to an HRESULT.
In OPC the HRESULT and Quality Code were combined in to the StatusCode.
You can convert from Quality Code/HRESULT to a StatusCode and back again.
02/24/2022
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Ah, I see!
I think I have found the document that talks about this:
https://reference.opcfoundatio…..rt8/A.4.3/
This seems a bit abstract to me. Are there any practical examples available that you know of?
Or a way to call this “COM UA Proxy” that is mentioned?
05/30/2017
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That reference explains how to map between QualityCode and StatusCode.
GetQualityCode implements that mapping:
https://github.com/OPCFoundati…..omUtils.cs
02/24/2022
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If I look at the list of status codes in GetQualityCode() compared to the full (?) list that can be found here, it looks rather limited.
Is this because of this particular implementation or is there another reason?
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