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I need help for programming a AD8555

Question asked by Yoontts on Mar 13, 2015
Latest reply on Mar 17, 2015 by JGunao

Hi, I'm a college student in Seoul, Korea.  Thanks for reading my post. I speak english, I hope you understand what I mean and want to know..please......


Nowadays I study about Amplifier AD8555 for Wheatstone bridge with strain gauge. AD8555 is very nice for amplification and DAC.


but, when I program the signal for the operation of AD8555, It's weird that the operation of GAIN between Offset.


In the datasheet of AD8555, THEORY OF OPERATION, equation 1 and 2 show us how to calculate the code for operation we need.


It means that code of GAIN and Offset is independent. But when I change the code of first and second GAIN, the Output of AD8555 is


also changed. I think if we do not change the code of Offset, Voltage offset of output does not change either. But, it's wrong.


So, I wonder that CODES OF GAIN and OFFSET are operating independently?? Did I have a wrong code?


I attach my code for AD8555. I use dsPIC for MCU.


I hope you understand what I mean, and want to get I need.


Sincerely yours. Appreciate for reading my words.