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AD7609 equation for code conversion solving..

Question asked by rndlab on Feb 13, 2014
Latest reply on May 5, 2014 by davepage

Hi all,

 

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.

            

 

Thanq,

Lakshmi

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