Is there a development guideline? & Major issues in History Management
Posted: 08 Apr 2012, 11:34
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
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