I kind of see what your talking about now, it was two things that threw me, 0..20v, was thinking you had the second . in the wrong place but now see you are meaning 0-20v and the other thing was I am wanting 0-10v so your 4:1 divider giving 0-5v was also throwing me.
Still not grasping exactly how it would work though, would have to think about it a bit more as the way I am seeing it at the moment the range would be much smaller as the -10 would be 0 and 0 would be 5.
Now the weather, i wish it was snowing, I like the cold, this 26 deg C is killing me.
Hood