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  1. Forum
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  5. QuickOPC-Classic in .NET
  7. Reading, Writing, Subscriptions, Property Access
  9. Read sync or async

Read sync or async

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05 Jun 2014 06:56 #2031 by support
Replied by support on topic Read sync or async
Both these errors can either be

- A proper behavior of the QuickOPC component. In this case, the error messages describe pretty well what has happened, and the troubleshooting would be to analyze what has happened to the server, i.e. why is it not giving the responses it should.

- Or, as with any software, it can be some kind of a problem inside the component, that just manifests itself with these errors.

The way to tell which is the case would be to place OPC Analyzer in between the client and the server. If you, however, suspect that the problem might be related to the settings you/we have mentioned (sync/async, and automatic subscriptions), I'd rather suggest to modify the settings first, and see if it helps.

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04 Jun 2014 21:31 #2030 by chromatin
Replied by chromatin on topic Read sync or async
Hello,

We are using version 5.23.494.1

Any ideas regarding the errors below?
OpcLabs.EasyOpc.OpcException: An OPC operation failure with error code -1073430513 (0xC004C00F) occurred, originating from 'OpcLabs.EasyOpcRaw.DataAccess.RawEasyDAClient'. The inner exception contains details about the problem. ---> System.Runtime.InteropServices.COMException: Topic not updated with quality that is not bad (timeout). 
   --- End of inner exception stack trace ---
   at OpcLabs.EasyOpc.DataAccess.EasyDAClient.CheckSuccess(OperationResult operationResult)
   at OpcLabs.EasyOpc.DataAccess.EasyDAClient.ReadItemValue(ServerDescriptor serverDescriptor, DAItemDescriptor itemDescriptor, DAReadParameters readParameters)
   at OpcLabs.EasyOpc.DataAccess.EasyDAClient.ReadItemValue(ServerDescriptor serverDescriptor, DAItemDescriptor itemDescriptor)
   at OpcLabs.EasyOpc.DataAccess.EasyDAClient.ReadItemValue(String machineName, String serverClass, String itemId, VarType dataType)
   at OpcLabs.EasyOpc.DataAccess.EasyDAClient.ReadItemValue(String machineName, String serverClass, String itemId)

other error

OpcLabs.EasyOpc.OpcException: An OPC operation failure with error code -1073430509 (0xC004C013) occurred, originating from 'OpcLabs.EasyOpcRaw.DataAccess.RawEasyDAClient'. The inner exception contains details about the problem. ---> System.Runtime.InteropServices.COMException: Read not completed. This error indicates that it could not be verified that the requested read operation was completed during the timeout period. It is possible that the read operation will actually succeed or fail, but later. Increase the timeout period if you want to obtain positive or negative indication of the operation outcome. Other reason for this error may be that under  heavy loads, topic request or response queue is overflowing. Check the event log for queue overflow errors (if event logging is supported by the product and enabled).

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04 Jun 2014 12:28 #2029 by support
Replied by support on topic Read sync or async
Hello,

can you please provide 1) the product version&build number with which you are seeing the problem, and 2) what precisely are the symptoms of "it crashes".

To your questions:

- Even if you do not explicitly subscribe, the component may subscribe internally, in order to optimize further reads. This can be disabled: www.opclabs.com/forum/reading-writing-subscriptions-property...scriptions-made-with-opc-reads .

- By default, both sync and async reads are allowed, and the async is preferred. This means that by default, whenever the target OPC server support async reads AND the component succeeds in establishing the callback interface with the server, async is used. You can switch to sync-only by setting (on EasyDAClient object) the InstanceParameters.Mode.AllowAsynchronousMethod property to 'false'.

Location of some of the parameters mentioned above depends on the product version.

Best regards,

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04 Jun 2014 08:02 - 04 Jun 2014 08:03 #2026 by chromatin
Read sync or async was created by chromatin
Hi All,

We have some problems with using opclabs .net with readitemvalue every x minutes. After some days it crashes.

As the items are not subscribed, we need to know if it is a sync or async read, and what other parameters are used in opclabs dll.

Can you provide us some info regarding this issue.

Tks in advance!
Last edit: 04 Jun 2014 08:03 by chromatin.

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  1. Forum
  3. Discussions
  5. QuickOPC-Classic in .NET
  7. Reading, Writing, Subscriptions, Property Access
  9. Read sync or async
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