What is the minimum distance between 2 devices on PROFIBUS DP?
When the transmission speed is 1,5 Mbps or higher, it is highly recommended to have at least 1 m of cable between 2 devices. De input capacitance of both devices will be compensated by the cable in order to preserve the common impedance. When the devices would be very close together, there is a big chance the input capacitance causes reflections in the data communication (small short circuits). The effect is much less at transmission speeds lower than 1,5 Mbps.
