OPC DA Client Connection to OPC Server
I am currently testing Kepware Server 7 to connect to an OPC Server via OPC DA.The OPC Server, in production, is currently has working OPC DA Client. I have configured the DCOM configuration for the Kepware Server.
Set the Launch and Access Permission default and limits with the user that is also in the OPC Server as well as Access Permission. I can browse the tags but when OPC Quick Client (OQC) is connected to the Kepware, data is Bad and not updating. Here are what I observe during the testing:
- Data is updating: Kepware Runtime “Use DCOM configuration” = disabled
- Data is not updating: Kepware Runtime “Use DCOM configuration” = enabled
- Data is updating: “My Computer” authentication level = None and “Use DCOM remote security” is enabled (connected directly to OPC Server)
- Data is not updating: “My Computer” authentication level = Default/Connect and “Use DCOM remote security” is enabled. (connected directly to OPC Server)
However, I tried to set the authentication levels to None with OpcEnum and Kepware Server in dcomcnfg just to replicate the “My Computer” None authentication level, Kepware still don’t give updates with the browsed tags.
I have tried the interactive user and system service for the runtime and still cannot get asynchronous callbacks updates. Synchronous Poll is working but is not the ideal solution. The server is in production so we are strictly not allowed to just change the DCOM configuration of it but as mentioned, there is already existing OPC DA client of it.

