I am working with AD7609 and after taking the 18 bits result from GPIO's hex-code, it should be converted to voltage using the equation below.
I have used +/-10V range.
+/-10V code = (V+ +/- (V-)) * 13107.2, [131072/10=13107.2][REF/2.5 = 2.5/2.5 = 1]
(V+ +/- (V-)) = (+/-10V code)/13170.2,
o/p(in voltage) = hex code/13107.2,
for 10V(V+ +/- (V-)) i/p,
o/p(in voltage) = 4.9V,(4.9*2 = 9.8)
for 8V(V+ +/- (V-)) i/p,
o/p(in voltage) = 3.9V,(3.9*2 = 7.8)
The o/p is around less by a factor 2.
Is the equation wrong or my calculation is wrong? Please clarify.