[Julesomega]

Returning to this thread now I've had time to read and think about it, I can see this is a useful and well thought out project. The statistical theory of improving accuracy by multiplication is counter-intuitive and would not have occurred to me. The range switching and output protection are impressive augmentations.

Following the "Statistical DVM Reference" webpage shows the latter sophistications progressively being added while the statistical basis is being dropped, and we end up with one reference device being used for the 2.5V o-p, 2 for 5V, and it is not til you select 12.5V that you benefit from the full 0.48% accuracy from the 1% devices, Would it perhaps be more comprehensive to derive all outputs from the 12.5V by using resistive dividers made of series or parallel combinations of equal values?