Audio Bit Depth "mapping" from DAW to Audio card: is this correct?
If your sound card has input range 2Vp-p (2 volts peak to peak = -1V to +1v) and has 24 bits of resolution (ENOB doesn't play any role in this, you still get 24 bits for each sample for each channel, but the higher ENOB the smaller noise you get), here is what voltage represents the output code of ADC:

00000000 00000000 00000000 (lowest possible result from ADC) =&gt; -1V
10000000 00000000 00000000 (midpoint) =&gt; 0V
11111111 11111111 11111111 (highest possible value) =&gt; +1V


Or with 3 bit ADC:

000 (0 dec) =&gt; -1V
001 (1 dec)
010 (2 dec)
011 (3 dec)
100 (4 dec) =&gt; (midpoint approximately) 0V
101 (5 dec)
110 (6 dec)
111 (7 dec) =&gt; +1V


So the voltage is proportionally distributed in the full ADC range, to calculate the voltage correspondig to specific code, you can use following formula:

U = (code/(2^bits-1)) * (Umax - Umin) + Umin


where Umin = -1V, Umax = 1V, bits = 24
For conversion between binary and decimal numbers refer to this document