Commissioning goes faster when you can predict the numbers instead of watching the display. The arithmetic is simple and worth doing before the first weight goes on the platform.
Worked example
Take a 2 mV/V cell, 10 V excitation, 500 kg capacity. Rated output is 20 mV. An amplifier with gain 200 gives 4 V at full scale, feeding a 16-bit ADC with a 10 V range, so full scale is about 26200 counts, or roughly 52 counts per kilogram. If the indicator needs 3000 divisions for trade use, that is 0.167 kg per division, comfortably inside the count resolution.
Where the resolution goes
Real systems lose counts to noise, to the stability of the excitation supply and to mechanical vibration. A cell that predicts 52 counts per kilogram may deliver a stable display of only 5 counts, because the noise floor is set by the installation, not the electronics.
Using the number
If the predicted counts per division are below about 5, either increase excitation within the cell rating, increase gain, or accept a coarser division. Doing this arithmetic first avoids the situation where a perfectly good cell is blamed for an indicator that was configured for the wrong range.
Kevin Huang