Hi,
I have two circuits on one PCB, isolated magnetically and optically from each other, with two grounds, an analog and a digital, right now they are completely separate, is it ok to leave them separate or should I connect them with a 1Mohm resistor or even tie the two ground planes together at one point to keep them both at a similar voltage? I don't see any reason to tie them together except that the two grounds could be at a voltage larger than that allowed by the optoisolators.
cheers, Jamie