LabWindows and remote OPC client

[Bob_P]

I have created an OPC server using Network Variables.  I can successfully use a third party OPC client to connect to the server and see the variable values on the same computer.  When I launch the OPC client on a remote computer I see the OPC server, but I can't see the variables.

Do I need to have the Variable Engine service running on the remote client?  If so, I thought I would get the Variable Engine service by installing the LabWindows/CVI RTE, but it was not installed.

These are both Windows XP SP2 systems and I have gone through the DCOM configuration and Firewall settings and all should be set properly.

Thank you,

Bob

[A_Patel]

Hi Bob,

 What are you using toview the OPC server on a remote client?

Flash

[Bob_P]

Hi,

Prosys OPC Test Client version 1.9.3.0.  This client works fine when on the same machine as the server.

Thanks,

Bob

[A_Patel]

Hi Bob,

Are you sure all your firewalls are open?

Flash

[Bob_P]

Hi,

The firewalls on both machines are off. 

Do I need the Variable Engine service running on the remote client computer?  Should I be installing anything specific to National Instruments on the remote client computer?

Thank you,

Bob

[Mohan]

You should have the NI Variable Engine running on the machine hosting the variables. If the variable address is \\machine1\..., then you should have the NI Variable Engine running on machine1. The NI Variable Engine is NOT part of the CVI runtime engine. You can get this installed by creating a distribution in CVI that includes this part and then running the distribution's installer.

[Mohan]

The Variable Engine can act as an OPC server and publish network/shared variables to OPC clients, but by default, it cannot communicate with arbitrary OPC servers and reflect the data to network/shared variable clients. The latter can be achieved by creating an IOServer item in Variable Manger or Distributed System Manager to subscribe to the OPC server - this is only possible if you have purchased the LabVIEW DSC Module/DSC runtime.

An alternative is to use the DataSocket library to subscribe to the OPC items. With the DataSocket library, you can connect to the OPC server without going through Network/Shared Variable Engine and without needing the DSC runtime.

[Bob_P]

Thank you very much for your replies.

I have resolved my issue of getting an OPC Classic Client on a remote Windows XP SP2 computer to work with an OPC Classic Server also running Windows XP SP2. It turns out I had corrupt registry entries for one or both the Dlls netshell.dll and ole32.dll. Re-registering those got everything working.

Bob