I have set-up DietPi Pi3 with WiFi, and put home automation project.
It works and autostarts fine.
However, in the morning the DietPi has disappeared from network. It is not anymore accessible even though ssh.
Looks like it while idle w/o internal or external action is goes in kind of sleep, and after that is not anymore reachable.
What it is and how to switch off any kind of power saving?