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NAU-7802 24-bit adc output stabilization

chaitrali

Jul 8, 2016
6
Joined
Jul 8, 2016
Messages
6
Hello i am using NAU-7802 24-bit adc.I want to stabilize the digital ouptput.I have already done filterng ,averaging,Not getting constant output.
I want to measure the exact grams (not kilograms)from the load cell.Because of fluctuating ADC output i cannot measure the exact weight.
Please send the circuit diagram if anybody has already used NAU-7802 24bit ADC. and calculation for mapping.
 

hevans1944

Hop - AC8NS
Jun 21, 2012
4,889
Joined
Jun 21, 2012
Messages
4,889
You may have stepped off into the deep end of the pool. Please post a schematic diagram of your complete load-cell weighing circuit, including load-cell excitation method, load cell full-scale range, load-cell sensitivity, load-cell calibration method, load-cell model number (if available), connections to the NAU7802, and clear, focused, photographs of how you have implemented the circuitry.

What signal shielding have you implemented? The NAU7802 does not claim 24-bit accuracy, only 24-bit resolution. Since it accepts bipolar signal inputs, one of those 24 bits is a sign bit and (for weighing applications) is not significant. In fact, the NAU7802 claims as little at 16.5 bits, increasing to only 20.09 noise-free bits, depending on PGA gain and reference voltage settings. So, in reality, you may only have a 16-bit ADC, or at best, a 20-bit ADC. If you are expecting 24-bit accuracy and resolution, this particular ADC doesn't meet that specification. See this datasheet for more information.
 
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