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- QuickOPC-Classic in .NET
- Reading, Writing, Subscriptions, Property Access
- Very slow periodic WriteItemValue() calls
Very slow periodic WriteItemValue() calls
easyDAclient = new EasyDAClient();
easyDAclient.InstanceParameters.HoldPeriods.TopicRead = 300000;
easyDAclient.InstanceParameters.HoldPeriods.TopicWrite = 300000;
Best regards
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Can you please give me a link to download OPC Analyzer?. We already have a license for QuickOPC
Thank for your support
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- pcollins01
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I was hoping to be able to use OPC Analyzer to prove that the issue is NOT with QuickOPC.NET.
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- pcollins01
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Yes, OPC Writes are not done in one step. Internally, a call to OPC method AddItems must be made for any particular item first, only then the actual Write can be made. We handle this internally for you, therefore the first Write involves more than subsequent ones. The effect of AddItems is reverted by a call to RemoveItems, and we call that when the item is no longer "in use" for some time, which is configurable (a "hold period"). This could be the reason. I must say, however, that if AddItems (for 1 item) inside the OPC server is largely responsible for this delay, it would be an unusually slow implementation. Either way, doing the OPC Analyzer trace would be beneficial.
Best regards
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FYI, I have added another periodic write once per second and on the first write it takes 600ms. On subsequent writes its 5ms-15ms. My original issue may be occurring if I haven't written to that tag in quite a while. Is there some additional setup that may be happening on infrequent writes, say 1-2 minutes?
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- Forum
- Discussions
- QuickOPC-Classic in .NET
- Reading, Writing, Subscriptions, Property Access
- Very slow periodic WriteItemValue() calls