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Getting started with VB6

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22 Aug 2013 13:39 #1408 by support
Replied by support on topic Getting started with VB6
If it works in other OPC clients, but you get "Access Denied" when using the EasyOPC component, please do the following:

From the Start menu, run the EasyOPC Options Utility. On the "OPC-DA Globals" tab, under "Client Parameters", push the button "COM arameters for OPC servers. Then, try different settings for "Use custom security", "Turn off call security", "Turn off activation security".

After each change, re-start our application, and make sure the component's process (EASYOPCL) has unloaded itself as well; only then the new settings will take effect.

I hope this helps.

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22 Aug 2013 11:00 #1406 by michaeltoward
Thanks for your response. I am using Matrikon OPC Explorer to test the server and noticed the item syntax in there. I received an Access is Denied error with the follow connection attempt:

Note: I replaced the IP address with XXXs since this is a public forum.

Me.Text1 = EasyDAClient.ReadItemValue("xxx.xxx.xxx.xxx", "B&R.PViOPC.2", "Public.M01.Various.Values.PowerActive")

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22 Aug 2013 10:30 #1405 by support
Replied by support on topic Getting started with VB6
Take this code (from the example that ships with the product):
Private Sub Form_Load()
    ' Create EasyOPC-DA component
    Dim EasyDAClient As New EasyDAClient
 
    ' Read item value and display it
    Me.Text1 = EasyDAClient.ReadItemValue("", "OPCLabs.KitServer.2", "Demo.Single")
End Sub

You can change it to your usage with this knowledge:
  1. The first argument to ReadItemValue is the machine name. Empty string for your local computer. For remote computers, it can be something like "MYTESTPC", or "192.168.1.88".
  2. The second argument is the ProgID of the server. I suppose you can see it in your other OPC clients so it should not be a problem to place it here. Note that we also have browsing functions to enumerate the servers that exist on the remote machine - but that would be too much for the first experiment I think,
  3. The third argument is the OPC "ItemID" of the item you want to read. It MIGHT be e.g. "Public\Various\Value\PowerActive" with your server, but I cannot tell for sure without knowing which server it is/having it here. The syntax for ItemIDs is different with each server. Again, you should see the ItemIDs in other OPC clients, or we have functions to browse for them.

If you try this and get an error, then from the error we should be able to determine which argument is wrong, and go from there.

Best regards

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22 Aug 2013 09:58 #1404 by michaeltoward
I'm not not even sure how to begin trying to connect to a server on the network with the sample code provided in the simple vb6 read one item project. Can you provide the syntax for the connection string?

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22 Aug 2013 07:34 #1403 by support
Replied by support on topic Getting started with VB6
Hello,

can you please describe the error you are getting, or the other symptoms if there is no particular error message?

Thank you

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21 Aug 2013 20:47 #1402 by michaeltoward
I downloaded the QuickOPC-com to test it in a small VB app before purchasing and I'm having trouble connecting to the OPC sever. I can't find documentation how to connect to an OPC server over the LAN. We have dcom configured and are able to see OPC item values with other test cliets. I know the IP address of the computer the OPC server is on and the OPC server name. I also know the item name I want to connect to although it is in a subfolder so I need to know how to path to that also. The sooner I get this test going the sooner we will purchase the software.
Thanks.

the item would be in Public\Various\Value\PowerActive

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