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  5. QuickOPC-Classic in COM
  7. Speed up reading OPC values

Speed up reading OPC values

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15 Nov 2020 22:12 #9146 by Sacha
Replied by Sacha on topic Speed up reading OPC values
Hello,
The ReadMultipleItem function is very fast - I need only 1,2 seconds to read 1700 items. :)

Now I have another question: every function call increase the occupied memory up to 10MB.

Code:
Dim EasyDAClient As New OleObject ("OPCLabs.EasyOpc.DataAccess.EasyDAClient")
Dim RequestList() As OleObject
Dim ReturnedList() As Variant
Dim TempOleObject As OleObject
 
For Looper = 0 To ItemCount-1
     'Loading array with elements to read
    RequestList.AddRow(New OleObject("OpcLabs.EasyOpc.DataAccess.OperationModel.DAReadItemArguments"))
    RequestList(RequestList.LastRowIndex).ServerDescriptor.ServerClass = Utility.ItemGetServerID(Looper)
    RequestList(RequestList.LastRowIndex).ItemDescriptor.ItemID = Utility.ItemGetItemID(Looper)
  Catch
  End Try
Next
 
'This Statement give memory issue
ReturnedList = EasyDAClient.ReadMultipleItems(RequestList)
 
.....

Why ?

Best Regards

Sacha

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10 Nov 2020 20:15 #9122 by support
Replied by support on topic Speed up reading OPC values
Hello,
the answers are here:

- opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...%20instead%20of%20looping.html

- opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...20Read%20multiple%20items.html

Best regards

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10 Nov 2020 20:09 #9121 by Sacha
Speed up reading OPC values was created by Sacha
Hi,
My software build with Xojo reads 1000 - 1500 values in 18 - 20 seconds.
  • This process runs on a separate thread
  • The CPU usage is 2 - 3 %

Code:
Dim EasyDAClient  As New OleObject ("OPCLabs.EasyOpc.DataAccess.EasyDAClient")
Dim QTVData As oleObject
.....
QTVData = EasyDAClient.ReadItem(Utility.ItemGetMachineName(Looper), Utility.ItemGetServerID(Looper),Utility.ItemGetItemID(Looper))
.....
How can I speed it up ?

Best Regards

Sacha

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  7. Speed up reading OPC values
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