@tomas_hora, I have one 1-wire temp -meter and 2 external I2C relay-cards (emorelay-boven and emorelay-beneden). These relay-cards and the unipi card are supplied by separate adapters, so the grounds are not coupled. Can this have influence on the speed? if in the program 2 relays are switched at the same time (each relay on a separate relay card), i can see that they are switched one after the other. at least 0.5 sec after each other. I would be nice if all relays could be switched in 100ms. I use the older mervis runtime (version 2.5) on a Rasberry Pi B+, is the last runtime faster or is there no difference is speeds. Kind regards, Frans.