OpenSprinkler Forums Hardware Questions OpenSprinkler Pi (OSPi) OSPi 1.3 schematic available? Re: Re: OSPi 1.3 schematic available?



That’s a good question. Indeed 24V AC (COM) is not carried over the extension cable. That’s why on the expansion board the TVS is tied to ground, which is carried over the extension cable. This should still work because there is a TVS between COM and ground, so this is equivalent to have two TVS connected in series between a station wire and COM wire.