Thank you Bob. I updated and posted my block diagram to hopefully show the addition of the common mode filters that you suggested as well as the reference filter that you recommended. That makes perfect sense what you said regarding the Vref staying constant due to the 50uA constant current source through the 24.9Kohm resistor. I wasn't thinking about that correctly in my previous post. I see the benefit you mention regarding the usage of the constant current source as well along with the ratiometric measurement and using the voltage across the 24.9 Kohm as Vref for the A2D. As you said the current cancels out in the ratio leaving: Rs/24.9K = Code Measured / +Full Scale Code For my application I think I should also plan on using the 50/60 Hz filters within the ADS1220 . -Sean M
↧