There are IP strings that both awake the unit and put it to sleep - it’s what Mosaic ACTUS sends to your Varèse (which I don’t own, so unfortunately I can’t tell you what it is).
The following thread will show you what they are for the Vivaldi;
Maybe ask your dealer for assistance on this. Alternatively, if you know anyone competent with WireShark, they’ll be able to get at the exact IP command.