Data words transported over the ARINC 429 bus is defined and built-in units, ranges, refresh rates, number of significant bits, and resolution. 

For resolution, I am having trouble understanding why it is necessary to include resolution? Does resolution really have any significant impact on the signal? I think resolution is mere a step size for the signal, so why use incremental resolutions, like 0.0000000002.  Does this small incremental really make a difference in the data word?