Urgent help need from u

The less of the load cell range you use, the larger noise and nonlinearities become, in proportion to your signal.

It gets to be a little like picking your nose with a back hoe. The back hoe doesn't have any difficulty but its jitter and stiction tends to leave you noseless... or faceless.

Good load cells are astonishing. They typically have resolution, linearity, and stability in the parts-per-million range. A decent 100 kg load cell with good electronics will be accurate to a couple grams. Of course, the smaller the full-scale range, the better the low-end resolution.

Note that load cells must be zeroed ("tared") and calibrated (using a standard weight) regularly. Their as-purchased accuracy can be as bad as several per cent off.

This is interesting: buy, say, 25 small bags of potato chips and note the advertised net weight. Now weigh them. You'll usually find that none are underweight, and rarely are they more than a percent or so over, even though a single chip may weigh several per cent of the total. They way they accomplish this is clever and complex.

John

Hello John,

That can be a problem. We bought a fancy bathroom scale a couple years ago. It was ok for a few weeks and then showed me gaining several weight, big time. Then losing, then gaining again. It had four load sensors in the pods and the rest was glass plus an LCD with a uC underneath. Nice design but I returned it. If calibrated regularly they are great but for some applications they are more a 'technology looking for a home'.

Regards, Joerg