A load cell produces a few millivolts. Turning that into a stable digital weight involves four stages, and the weakest one sets the performance of the whole system, which is rarely the load cell itself.
The chain
Excitation sets the bridge voltage. The bridge divides it by its sensitivity, giving rated output in mV/V. The amplifier applies gain, typically 100-500, and the ADC digitises. A 24-bit converter with a 20 mV full-scale input resolves about 2 nV per count, far beyond any load cell noise floor, so resolution is almost never the limiting factor.
Where performance is actually lost
Noise pickup before the amplifier, ground loops between the cell frame and the instrument, and mechanical vibration. A cell with 0.02% repeatability mounted on a vibrating frame will show 0.1% swings no matter how good the electronics are. Filtering helps the display but does not recover the measurement.
Filter settings
Use the fastest filter that gives a stable reading at the required update rate. Over-filtering hides real changes and makes the scale feel sluggish; under-filtering makes the last digit unreadable. For filling applications, a two-stage filter with a fast response during the coarse fill and a slow one near the target is standard practice.
Kevin Huang