Hi Mark,
how about this idea, about as simple as I can make it. Two opamps (LM358 dual), one as unit gain voltage follower the other as unit gain
inverter, selected by contacts of a double throw relay. The relay when de-energised connects 0-10V to the output terminal and when REV is
active the relay connects -10V-0 to the output, easy. Haven't bothered with too much logic, surely you can cause Mach not to have conflicting
FWD REV signals. I have shown a 5V to -15V-0-+15V DC to DC converter for power supply. I have become quite a fan of these little units, dual
rail supplies from 5V, galvanaically isolated for $10-$15, whats not to like?
Craig