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Cannot connect Data Access client (timeout) while writing values to tag/item

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04 Sep 2015 09:18 - 04 Sep 2015 09:21 #3542 by saravana48
Thanks for the response.

1) Subsequent write request succeeds.
2) Keeps the default value(False) for Isolated property.
3) Write operation performs randomly(approximately 15 times per hour. In that 7 or 8 request fails)
4) The application has subscription from the remote server. But i have used a seperate EasyDAClient object to write to the tag/item in local server.

Public m_opcSubscriptionClient As New EasyDAClient
Public m_opcWriteClient As New EasyDAClient

m_opcSubscriptionClient.SubscribeMultipleItems(RemoteMachine, ServerClass, ItemID, UpdateRate)
m_opcWriteClient.WriteItemValue(localmachine, ServerClass, ItemID, Value)



Note: The tag which I am writing is subscribed in another application which is running on the same server.
Last edit: 04 Sep 2015 09:21 by saravana48.

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04 Sep 2015 08:35 #3541 by support
The error means that the connection process to the server (which consists of multiple steps) has taken longer than the timeout period. It could be because something (either in the client or in the server) has taken too long - either is blocked (waiting for something), or busy (e.g. high CPU load).

Can you please give some details:

1) Does the error go away, in the sense that some subsequent Write to the same server succeeds, or do you have to restart the client process for the error to go away?

2) Are you setting the Isolated property on the EasyDAClient to 'true', or do you keep it at the default ('false')?

3) How often do you read or write? Is it somehow periodic, or "random" (e.g. based on user's actions)?

4) Do you also use subscriptions in the same client program?

Thank you
Best regards

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03 Sep 2015 13:30 - 03 Sep 2015 13:35 #3540 by saravana48
I have developed OPC client application using VB.NET and OPC Labs QuickOPC Classic 5.31 to read/write the tags/items in the OPC server(SoftwareToolBox's Top server V5).

Both the client application and the Top server located in same machine. I am writing values to the tags/items using WriteItemValue function with the default Timeout value(60 seconds).

The following error throws occasionally while writing to tag.

Error: Cannot connect Data Access client (timeout).
ErrorCode : -1073430527

I have checked the event log in the Top server and didn't find any errors.
What is the cause for this error? and how to fix it?
Last edit: 03 Sep 2015 13:35 by saravana48.

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