4 ms·

Easy solution though, just limit the scale's display to a magnitude that it can accurately measure reproducible.

by q87b 3y ago

riskable 3y ago
This is how the market for scales works: You buy a scale for the weight class you're planning on measuring. For example, you can't buy a scale made for weighing humans and expect it to be useful for weighing herbs or jewelry. It's because of how load cells (and scales) are manufactured. They're made for weight classes like 100g, 1kg, 2kg, 3kg, 5kg, 10kg, etc. So to make a scale for a particular weight you pick the load cells you'll need for the range you want. Higher quality scales don't select higher quality load cells; they're all the same (reasonable quality) for the most part! Instead they just use more load cells and just take an average of all their values, multiplied by the number of cells, to measure weight. So if you want a damned accurate industrial scale for measuring weights around 1kg you'd use like twelve 100g load cells rather than a single 2kg load cell or two 1kg load cells. Of course, then the hard part becomes, "how do I distribute this weight perfectly evenly across all of them?" so you have to take tolerances into account to make sure that at no point can weighing part of your scale rub against the side of its container or accidentally get something wedged between the scale part and the case. There's loads of other things to consider as well but for the most part the accuracy of the scale is a factor of how many load cells its using, not the quality/manufacturing tolerances of the load cells themselves. Because even with the most precise manufacturing methods load cells will still drift and be impacted by temperature. All you can do is calibrate regularly, test them, and hope for the best (or use a completely different technology).
aulin 3y ago
Easy solution if your customer understands accuracy. They don't. They want the highest resolution so they can see their 10 gram progress when dieting. But they want the measurement to be stable enough to not cause them too much anxiety.
- pnt12 3y ago
  >They want the highest resolution so they can see their 10 gram progress when dieting. Do they? 100g is already quite granular, and you can lose that in a day. I have two scales which are giving me different measures - I've been weighting myself and assume I'm in the middle of both. It's a bit annoying, but works for my goals.

Easy solution though, just limit the scale's display to a magnitude that it can accurately measure reproducible.

by q87b 3y ago

Easy solution though, just limit the scale's display to a magnitude that it can accurately measure reproducible.

This is how the market for scales works: You buy a scale for the weight class you're planning on measuring. For example, you can't buy a scale made for weighing humans and expect it to be useful for weighing herbs or jewelry. It's because of how load cells (and scales) are manufactured. They're made for weight classes like 100g, 1kg, 2kg, 3kg, 5kg, 10kg, etc. So to make a scale for a particular weight you pick the load cells you'll need for the range you want. Higher quality scales don't select higher quality load cells; they're all the same (reasonable quality) for the most part! Instead they just use more load cells and just take an average of all their values, multiplied by the number of cells, to measure weight. So if you want a damned accurate industrial scale for measuring weights around 1kg you'd use like twelve 100g load cells rather than a single 2kg load cell or two 1kg load cells. Of course, then the hard part becomes, "how do I distribute this weight perfectly evenly across all of them?" so you have to take tolerances into account to make sure that at no point can weighing part of your scale rub against the side of its container or accidentally get something wedged between the scale part and the case. There's loads of other things to consider as well but for the most part the accuracy of the scale is a factor of how many load cells its using, not the quality/manufacturing tolerances of the load cells themselves. Because even with the most precise manufacturing methods load cells will still drift and be impacted by temperature. All you can do is calibrate regularly, test them, and hope for the best (or use a completely different technology).

aulin 3y ago

Easy solution if your customer understands accuracy. They don't. They want the highest resolution so they can see their 10 gram progress when dieting. But they want the measurement to be stable enough to not cause them too much anxiety.

pnt12 3y ago
>They want the highest resolution so they can see their 10 gram progress when dieting. Do they? 100g is already quite granular, and you can lose that in a day. I have two scales which are giving me different measures - I've been weighting myself and assume I'm in the middle of both. It's a bit annoying, but works for my goals.