OpenSprinkler › Forums › Hardware Questions › OpenSprinkler Pi (OSPi) › OSPi 1.3 schematic available? › Re: Re: OSPi 1.3 schematic available?
April 22, 2014 at 5:09 pm
#26415
Ray
Keymaster
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.