This is a question for SmashTV I suppose…
The new DOUT R3 has provisions for loading ULN2803s for driving relays
and such. Is there any provision for a separate input voltage (say 12v)
for the ULN2803s? In many applications, higher voltages ( >5v) are
required for solenoids, i.e. pipe organ valves.
Yes.
When loaded for relay drive the 2803’s Vcc pin is brought out from each chip separately to it’s respective output header.
I figured the relay supply voltage would be near the devices to be driven rather than always near the DOUT itself.
It’s the one pin left unnamed on the J3-J6 connection silkscreen.
Smash
Wow badass. I really like the new boards man, very professional! Probably terribly difficult designs if we had to make them ourselves, but… we don’t! 
Thanks again Smash!
Johnh,
No problem with the higher voltage. I am using the R3 design with a separate 12vdc for pipe magnets along with the 5vdc from the pic. The ground from core and douts is connected to the negative side of the 12 vdc supply. My system uses jOrgan as the master control system since it will output to my pipe drivers.
Good luck,
Johnc