Hi,
I am wondering what the accuracy in grams of the 500g load cell (TAL221)
In the datasheet, it seemed that the rated output has an accuracy range, but I am not sure how the mv/V translates to the actual accuracy/precision of the device. Is the device able to get to 0.001g accuracy or 0.1g accuracy?
The mV/V is the sensitivity, which is not related to the accuracy, as the ADC precision, scaling and calibration comes in between. Take a look at the actual error specifications lower down in the data sheet.
For example, “combined error” is given as 0.05% of the full scale value, which for 500g full scale would be 0.25g.
Mechanical compromises in the mechanical support structure (the parts of the scale platform that aren’t the load cell) will almost certainly cause more headaches than the load cell’s specs.
5000 divisions is likely a realistic expectation for an inexpensive load cell like OP’s. 10k divisions (0.05 grams) is starting to push it but might not perform too badly under the right circumstances. A milligram or 0.001 gram readability is 500k divisions and represents fantasyland for a strain gauge load cell of any kind, even if the instrumentation could adequately resolve the tiny signals.