Hi many thanks to all for the help and comments.
Yes, - i do make Music 
despite all the technical issues.
Please note that I DO know how to control the cue Levels (the cue send-Levels from the Audio tracks to the control room) but there does not seem to be a way to control the cue-studioleves in the control room mixer! (or?)
Concerning Eucon 3.0 and the “disconnection” - maybe this depends on Network Card or on the question whether the eucon Controller ist connected to a Switch? My Setup brings the two Artist Controllers to the Network via a Switch that is connected to a router (on the LAN-Side of course). the Computer cubase is running on is also connected to that router.
Cheers, Ernst
PS.: Any idea what the “dyn” knobset does?