On either PC or Mac, the computer can go to sleep or ("app nap" in Mac terminology) with ETCnomad Eos is running. Alternatively, it may never go to sleep while the software is running.
Description/Explanation of Issue
ETCnomad Eos software will not allow your computer to go to sleep so long as it is in Primary or Backup mode (able to output sACN/Artnet/DMX data). However, if it is started in Offline or Offline w/Viz mode, it will allow the computer to go to sleep. Depending on the operating system, you should be able to change how long your computer remains idle before going to sleep.