A terminal left alone logs itself out after a short while, so the next person cannot ring on your name. The countdown shows in the header for the last five seconds:
Logging out in 5…
Any tap or key resets it. It never fires mid-payment or while the till is sending, and a kitchen or bar screen never logs out at all.
Your shift stays open and your tabs stay yours; it is the same Log out as the button. Sign back in with your PIN. A manager sets the delay under ⚙ → This terminal: 30, 45 or 60 seconds, or off.
Related: Log out is not Clock out · Enter your PIN