It was indeed not clear that the minutesAgo attribute is only written during setting the persistent data.
I've updated the script with the proposal of boum, and now it working.
Thanks.

Hi, I cannot find the problem with this dzVentz scene. The value of minutesAgo is always 0. local Time = require('Time') return { on = { scenes = { 'Huiskamer*', }, -- timer riggers timer = { -- timer triggers.. if one matches with the current time then the script is executed '15 minutes after ...