How do you connect an OPC Client to an NI OPC Server?

[Aly]

I'm trying to connect an OPC Client (on a Win2K machine) to the NI OPC Server (on a Win98 machine). My client reports that the server is not registered. As far as I can tell from the NI documentation it should be called National Instruments.OPCLabVIEW. But I need to know the CLSID to add that entry into my registry. Or is there a simple exe I can run that will do that for me? Another SCADA package we have comes with just such a program. Any help would be greatly appreciated.

Thanks!

[Roli]

Hi Aly,

you could run a "shiping" (quite hidden) VI to register the LabVIEW DSC OPC Server. Normally this should be executed by the first start of LabVIEW after the DSC installation.

This VI is located under \vi.lib\lvdsc\Srvrlibs\OPC and is called 'Register OPC Server.vi'. If you run this VI it would set the correct CLSID.

Hope this helps
Roland

PS: The only reason I can think of using this VI in regular circumstances would be, if you have serveral versions of LabVIEW DSC or LabVIEW DSC Run-Time Systems installed on the same computer. There could be just one version running and registerd as OPC server. To change the registration you could run the mentioned VI.
A second possibility to re-register and check all the Servers (VI-based, proxi
es and OPC) could be done by launching the dsc_DYN_CheckAllSrvrs.vi from vi.lib\lvdsc\_dsc.llb\

[Roli]

PPS: If you delete the init.ini file in vi.lib\lvdsc and you launch LabVIEW (DSC) it would have the same effect as LabVIEW DSC would be started the first time after installation. It would invoke to check as well all the servers and its registration - as dsc_DYN_CheckAllSrvrs.vi...

[Aly]

The server IS registered on the computer that has LabVIEW DSC running on it. What I need is to somehow register the server on the computer that is running my OPC client (doesn't have any NI software on it). Can I just copy the registry entry from the NI computer to the other? Or do I need to install a runtime version of LabVIEW and then run the register VI on my client. (I was hoping not to have to load even the runtime NI software on my OPC Client computer.)

Thanks
Aly

[Roli]

Aly,

ah, that's another story. Remote OPC Server is not that easy to get to work! Especially when you connect different versions of Windows.
The thing is that Remote OPC is based on Microsoft's DCOM and the whole networked security and remote registry configuration needs to be set up correctly.
There might be different knowladgebase articles which discusses how to set up DCOM for OPC.
National Instruments has as well some documents on the web. I hope those would help you. Here is a link with some other links:
http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/4466f7754e94da79862569ee00781eb1?OpenDocument

Btw. - What OPC client are you using? The OPC client should support remote connection to OPC servers - And why do
you not consider to run the OPC server part on a more stable OS (Win2k) and the client maybe on Win98?

Hope this helps
Roland