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Random Disconnect from OPC server

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31 Jan 2013 09:14 #1216 by algorithmica
The exception is not thrown. See the code below for exception catching. I see no entries in my log file. try { vResults = new CComVariant((*dac)->ReadMultipleItems(machine.c_str(), server.c_str(), CComVariant(LPSAFEARRAY(*ItemInArray)), vMissing)); } catch(_com_error& e) { _bstr_t bstrSource(e.Source()); _bstr_t bstrDescription(e.Description()); *log << "Exception " << e.Error() << ": " << e.ErrorMessage() << ". Source: " << (LPCTSTR) bstrSource << ". Description: " << (LPCTSTR) bstrDescription << "." << endl; }

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31 Jan 2013 08:43 #1214 by admin
Yes, but does the exception still throw (is caught), and if so, what are its details? Or, do you stop receiving values, without an exception being thrown?

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31 Jan 2013 08:39 #1213 by algorithmica
Hello,At the moment I am running your newest version and I am catching the exceptions. The application does not crash anymore. However, at some point the application stops retriving values from the OPC Server and does not recover on its own -- the application must be manually terminated and re-started. This is the original problem.The problem is not at the server end because, after the client is re-started, the whole process works again. The problem appears to be in automatically re-establishing contact with the server.

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31 Jan 2013 08:33 #1212 by admin
Hello,
I do not quite understand what you mean by that the problem has re-appeared. Can you please re-state the current symptoms.
We have discussed how _com_error should be caught, is your code already doing it?
Thank you

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30 Jan 2013 06:02 #1192 by support
Dear Sir,
I apologize for not replying sooner - it appears that we had a technical problem, and some notifications about forum activity have been lost. I will now answer the posts one by one, hopefully during today and tomorrow.

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22 Jan 2013 06:50 #1184 by algorithmica
For a while it seemed to work, partially because the OPC server crashed twice. However, the problem has re-appeared twice in the last three days. Thus, the update to your newest version did not cure the problem, at least not fully. What can I do? Shall we try via a debug build of this new version?I and paticularly my client are getting a bit desparate for a running system ... time is starting to be important.

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06 Jan 2013 10:09 #1143 by algorithmica
Thank you! Because of the holidays, I only now got to download it but I will try it now and let you know how it goes.

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21 Dec 2012 14:46 #1140 by support
Hello. If you are interested, please download and use the latest build (now on our Web site), 5.20.524. It contains a fix for the issue discovered by our stress test application. The question is whether the same is also a fix for your problem.
Best regards

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23 Nov 2012 08:54 #1114 by support
Yes, I think this will prevent the crash on your side. Assuming that EasyOPC runs out-of-process, which is the default.

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22 Nov 2012 17:45 #1111 by algorithmica
Hi, I'm happy that you can reproduce the error. Good luck hunting the memory error.In the meantime, I have modified my code so that the reading is done like so:try{ vResults = new CComVariant((*dac)->ReadMultipleItems(machine.c_str(), server.c_str(), CComVariant(LPSAFEARRAY(*ItemInArray)), vMissing));}catch(_com_error& e){ _bstr_t bstrSource(e.Source()); _bstr_t bstrDescription(e.Description()); _tprintf(_T("Exception %08lx: %s. Source: %s. Description: %s.\n"), e.Error(), e.ErrorMessage(), (LPCTSTR) bstrSource, (LPCTSTR) bstrDescription);}My question is: Will this prevent a crash eventhough you have a memory corruption? Thanks. I will keep you posted on developments. Thank you very much for your prompt and good help !!Best, Patrick

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