Invalid value for registry error while browsing for external database in ciect SCADA

I never had to browse for an external database using OFS.

All you have to do is create an I/O device and use protocol OFSOPC (not OPC). For address use the name of the PLC you configured in OFS Configuration Tool. In OFS config make sure to use data dictionary.

After this you can create Variable Tags in SCADA using the PLC variable name as address.

It appears that some registry settings of OPC on your machines are missing. The problem likely occurs when OFS server and SCADA browsing client running on different machines via DCOM. Could you please refer to the following article and carry out a troubleshooting?

https://www.opcti.com/Dictionary.aspx?type=2&term=206

Hope it helps

 sarath kumar 
As Patrick pointed out, you should move your OFSOPC server to the same machine as I/O servers that host OFSOPC I/O devices. This architecture is recommended and avoids DCOM implications.

I believe Jacky is on the right track. I had not drawn the conclusion that the OPC server was remote.
The Plant SCADA OFSOPC driver is restricted to a local connection to OFS by design. DCOM will not work. OFS must be installed on the I/O server(s).