Can't configure OPC Client I/O Server

[bjla]

I am trying to configure an OPC Client I/O server to connect to an OPC Server that runs on a PLC. However, when I specify the Machine address and Prog ID, I get an error message saying:

"Unable to browse OPC Server from the selected machine.

Error -2147467262 occurred at GetOPCServerList.vi"

I cannot browse to system in the Network because the PLC will not show up in the WORKGROUP. 

I can sucessfully connect to the OPC server using the NI Quick Client and also an OPC Client from Softing. But I have to specify the full path to the server i.e "opcda://192.168.1.2/BR.OPC.Server_AR/" (Softing address format). But, typing this in when adding I/O Server will not work.

Anyone, any ideas?

Thanks,

Bjorn 

[Davidek]

Hi Bjorn

Have a look at this KB, it has a possible solution.

Best Regards

David

NISW

[bjla]

Thanks for your answer, but this KB refers to connecting to an OPC using a datasocket.

I am using the DSC module and trying to setup an I/O server.

I did however register opcproxy.dll, but I do not think that is the problem since other OPC servers seems to work fine.

I will try to read an OPC tag using datasockets to see if this works. But, this is not the preffered solution for me because I want to tie OPC tags to a shared variable.

Best regards,

Bjorn 

[Pcorcs]

Hello,

Have you looked at this document. 

Does your server enumerate in the UI's provided by the DSC module? Are the tags listed as available? 

Cheers, 

[bjla]

Hi,

Looking at the document link provided. I can easily connect to the NI OPC server that runs on the local machine (all local OPC servers enumurate fine).

But, when I set the "Machine" to my PLC IP address (192.168.1.2), I get the error message I described above (and no OPC servers enumerate in the UI).

Also, when I push Browse only the local machine shows in the list. (I think it is because the PLC will not identify itself on the Windows Network, since it is not running Windows?)

Best regards,

Bjorn

[Pcorcs]

I noticed the opcda tag in the URL, what version of OPC DA Server is running on the PLC? 

[bjla]

OPC DA 2.0

[bjla]

Here is a screenshoot showing the problem:

One clue could be that the NI OPC Client get BAD Quality on the data and the Softing reads GOOD. Could this be a DCOM user access problem?   

[Pcorcs]

Yes, that was the next set of questions. The attached should provide a detailed walkthrough for DCOM configuration techniques.

Cheers, 

[bjla]

Hi,

I have read the document and looked at my settings for DCOM. I've changed the default computer settings to be wide open. That is Everyone has full access. I have also added SYSTEM user to have full access in case it is not part of Everyone?

After doing this I restarted the computer.

Now I can succesfully read the OPC tags in the NI Quick OPC Client.

But, I still get the same error message when trying to add an I/O server. I seem like it will not even try to connect to the OPC if the PLC won't show up as a computer on the Microsoft Windows Network.

Best regards,

Bjorn