Is there a development guideline? & Major issues in History Management

Unified Architecture topics related to OPC UA Specification, compliant behavior and any technical issues of OPC UA, like Security, Information Model, Companion Specs DI, PLCopen, ADI, ...

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Esma
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Is there a development guideline? & Major issues in History Management

Post by Esma »

Hi,
I am a beginner in OPC area and I want to implement an OPC UA server by using the sdk. Thanks to the explanations/examples on this website, I am able to run the sample server codes (ie Lesson1-7) and I am trying to learn more about OPC UA by reading ebooks, presentations, and so on. However, I couldn’t find a detailed tutorial/guideline (for the implementation) that describes which methods of the sdk “must be” implemented and which “should be”... Maybe, I should finish reading “UaSdkCppBundleEvaldoc” first, but I wonder whether there is “a quick development guideline” or sth like that, since I am confused when I read theoretical data and then look to the implementation examples, which are just a few..
For example, due to the implementation examples, I learnt that I have to implement “readValues” and “writeValues” methods and also indicate set my variable handles as “UaVariable_Value_Cache” so that when a client sends a read/write request, my methods are called. But I am still in confusion about History Management. In the tutorials where OPC classic is compared with OPC UA, I see that ReadRaw, ReadProcessed, .. methods are mapped onto ReadHistory method. However, in the UnifiedAutomation’s example, ReadRaw method has been implemented... I also couldn’t understand whether creating an internal session is a must or just an example for history management. Could it somehow possible to record/save the values of the variables while they are read, for example?

Best regards,
Esma

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Re:Is there a development guideline? & Major issues in History Management

Post by Support Team »

Hi Esma,

It is hard to answer such a generic question.

If you are looking for features you must implement and a grouping of features, you should start from the OPC UA profiles.

Please read this FAQ article about OPC UA profiles. It provides also a link to the list of profiles on the OPC Foundation website.

http://www.unified-automation.com/forum ... ofiles.htm

For a server you must start from one of the FullFeatured profiles like the "Standard UA Server Profile". This profile defines the minimum requirements. All other Profiles like Mehods and Events can be added on top.

How you deal with Variables in the SDK and the different ways of implementing an IOManager depends on the type of data source you have to integrate with. The server tutorial lesson 3 tries to describe the different options.

Creating an internal session is just used to act as client internally to subscribe for data changes stored for history. If your history is filled from another source, this is not necessary.

Best Regards,
Unified Automation Support Team
Best regards
Unified Automation Support Team

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