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Re: [IP] Food scale information

> Here is some additional information re: digital scales. It may be useful to
> you and others ...
Here is a description of the problem with digital scales.

The accuracy of the readout of most digital scales is directly 
related to the total weight placed on the platform. If you just want 
to weigh a slice of bread and it has a weight of 30 grams, the 
accuracy will be very good ..... say 1% of 30 grams or 0.3 grams.

However, if you want to weigh the bread placed on a 1 pound plate, 
this is where the problem lies. First you put the plate on the scale 
and ask the scale to zero the reading. The plate weighs 454 grams 
(remember this). The scale now reads zero. Place the bread (30 grams) 
on the plate and read the weight. The answer may be inaccurate if the 
scale can only resolve 1% of the weight on the scale. The total 
weight is now 484 grams the error may be 4.8 grams (say 5 grams) 
which is 1/6 th or 17% of the measurement. It may be high or low.

The acid test is to pick up the empty plate  and place it back on the 
scale, noting the new supposedly zero weight amount.

A high cost scale, capable of greater resolution, will usually not 
exhibit this problem. The cheap $100-200 variety almost all suffer 
this problem (at least all the ones I've checked - about a half 
dozen). The mechanical Pelouze scale, can be manually adjusted to 
remove this type of error almost completely. 

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