I need to drive about twenty realys using ULN2803A. The MCU and the relays can't be locate on merely one PCB. So I separate the relays to another board, and the two boards are connected with wires. The wires may be longer than 30cm, and the relays are rated 24V. Then what about the drivers (ULN2803A), at MCU side or the relay side? Which one is better?
Any suggestions are appreciated.