Driver not available for user when OPC server was started by OPC client

FAQ #100238

 

This problem is caused by the fact that the Merz SBC S-Bus OPC Server (SaSBus.exe) was launched under the "Interactive User". As result the SaSBus as well as the SCommDrv and SCommDll will not appear in the system tray of the user (logged in). Nevertheless an instance of the SCommDll is running (under the "Interactive User") and it can't be started again by the logged in user.

 

The error messages will be something like "The driver is not available" or "Another instance of the driver is already running".

As workaround the logged in user has to launch the SaSBus before the OPC client will request data from the OPC server. Once the SBC S-Bus OPC server is started by the logged in user, it won't be started a second time by the Interactive User and therefore it will be possible to communicate over the same SCommDrv (logged in user and OPC Server).