200e

Thanks for all the previous info!  I am curious if the 256e can do 
simple inverting?

I should clarify. The 256e will invert scaling, but I guess that's not 
really the same thing as if you turn the input knob counterclockwise 
on a 255 or an oscillator CV input. If you set the little dots on the 
256e so the first one is all the way up and the last is all the way 
down, an input voltage of 0V (or nothing) will yield 10V on the 
output, and the higher the voltage you put in, the lower the output 
voltage will go.