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i have the load cell of 100kg i have a ADC NAU7802. i have to calculate weight through this ADC. can anyone have idea how to convert ADC value to weight.
Give a fixed input voltage to Analog input of ADC and check if you get fluctuations in the readings. Monitor the fluctuation in the power supply at the ADC supply pins (between Vref & gnd), if fluctuations still persist. Also, there will always be some minimal fluctuations (5-10 counts) Hence perform averaging of more than 5 (average of 5 is good, but you may reduce or increase depending upon the speed of conversion - dont exceed 16 and perform average of 3 readings atleast).
Load cell=2mv/v ... Supply Voltage= 5v Which simply tells me that at full load, the output of the load cell will be 10mV ( = 10000uV). i.e. 65535 count for 10000uV. By using simple mathematical calculations, calculate the counts vs voltage. Now, the load cell will generate 5000mV for max load. So calculate mV vs weight and then integrate everything.
"dont exceed 16 "
Why put a limit at 16?
Averaging is basically a form of low-pass filter, and depending on needed time constant and sampling speed, a good solution can be to use way more than 16 samples.
Note that rolling averages means that the CPU load doesn't increase with the number of samples. It's just a trade-off on amount of RAM for the sample buffer.
gain =128 excitation=4.5 v 24 bit adc so 2^24 -1=16777215;
//convert adc value into volt volt=(((float)present_adcdata*excitation)/((float)16777215*gain)); volt=present_adcdata*.000002095; // i get in mili volt 128 gain
load cell capacity is 100kg load cell sensitivity=2mv/v excitation=4.5 v
100kg -> 9mv
1:100,00 = x *9 mv
x= 9/100,000
x=0.00009 1 gram want 0.00009 mv
not convert adc volt into gram
gram=volt/0.00009;
is my calculation is right or wrong