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  9. EasyDAClient first call of WriteItemValue fails

EasyDAClient first call of WriteItemValue fails

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24 Jul 2013 15:52 #1362 by support
Replied by support on topic EasyDAClient first call of WriteItemValue fails
[Received your data via email]

Dear Sir,

it is clear from the OPC Analyzer trace that the OPC "Write" call is made properly, and also that the OPC server indicates it has succeeded. If reading the value back does not give the value written (which I can see on the DataSpy screenshot, but cannot verify in the analyzer log provided), you should contact the OPC Server vendor, give him the same OPC Analyzer log, and ask for a fix.

Regarding the trace messages in the .LOG file you asked about, they are not coming from our software either. The number in brackets [] is I think the process ID, so that should give you the information about who is generating the message. I agree that the quality value appears suspicious, but since we are not creators of the message, we cannot interpret it reliably.

Best regards,

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23 Jul 2013 08:43 #1359 by SILI
Replied by SILI on topic EasyDAClient first call of WriteItemValue fails
Hi,
now I used the OPC Analyzer together with my application and I saved the OPC Analyzer file.
The data is confident so I can`t upload it to the forum.
As it`s described in FAQ, the technical support should contact me now, is it right?
Thanks for your help!
Best regards

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29 May 2013 14:22 #1324 by support
Replied by support on topic EasyDAClient first call of WriteItemValue fails
Hello.
Please download the OPC Analyzer from: www.opclabs.com/files/transient/20130529/OPCAnalyzer%201.03.1014.msi .

The OPC Analyzer is available to purposes of OPC Foundation Members only (such as OPC Labs). You can therefore use it for troubleshooting this case, but nothing else.

The analyzer acts both as OPC Server and Client, and it stands between your app and the target OPC server. You need to temporarily change the app so that it connects to the OPC Analyzer instead of the real server. After you run your test, do a File -> Save Trace, and deliver the file to us (zipped, most likely). We can then run our own instance of the Analyzer and view the communication trace.

Best regards

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29 May 2013 11:22 #1323 by SILI
Replied by SILI on topic EasyDAClient first call of WriteItemValue fails
Hi,
thanks for you reply.
I can install the special tool and create logs from communication in two weeks.
Wherefrom do I get OPC Analyzer?

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28 May 2013 17:32 #1321 by support
Replied by support on topic EasyDAClient first call of WriteItemValue fails
Hello.

The delay on first call is due to connection being made to the server etc.

We are not aware of any bug that would cause the Write call to appear succeeded while it isn't. It looks like a server problem, but it's impossible to say without further analysis. Would you be willing to install a special tool (OPC Analyzer) that logs the communication between the server and the client?
The following user(s) said Thank You: SILI

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23 May 2013 07:25 #1316 by SILI
EasyDAClient first call of WriteItemValue fails was created by SILI
Hi,
I use QuickOPC.NET 5.12.
When writing a value (WriteItemValue) for first time in my application via my single instance of EasyDAClient, the method WriteItemValue returns after a bit of time (about 1-2s) but the value on OPC server is not written. I get no Exception. Second time I write the value, it works.
I tested it also with the OPC Lab`s Demo application:
writing first time doesn`t work, also reading the value first time shows "Bad quality". Reading or writing the value second time works fine.
By the way I noticed that calling WriteItemValue first time endures a bit (about 1-2s), while calling it afterwards it returns fast. I suppose that first time the EasyDAClient initializes something. But if the method WriteItemValue returns without success (no OPC values are written) and no exception is returned, my application is not executed further more.
I`m grateful for your help!

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