Digital scale/balance with "bug"??? Help me.

[All Darc]

Funny how every service I get, every technic fix, every buy of something, always have a problem with me.

I got a precision scale/balance (0,1g to 500g) to measure weights lower than 1g if needed, to help in the vegan burger project, since some yeast extract flavors it's used at 0,3%, and I will make many different tests of it with low amounts of soy protein, like 100g or less of hydrated soy textured protein.

This model :


I got the same model of a seller who had it for 25 reals (coin on Brazil), while other seller had ir by 35 reals. It looked to work, as we tested it with a paper card or so.
But in home I found it could not measure things bellon 0,4 or 0,5g if put direct, since it would display just 0,0g.
But if I put a paper card (visit card) and it weighted 1.2g on display, and then add a very weighless thing, as a small piece of very thin plastic film, and the weight would go to 1,3g. I did similar tests with other pieces of paper and always worked. I imagined the sensor of the balance/scale needed some weight above 0,4 or 0,5g to start work properly, and I could measure the weight of things of 0,1 or 0,2g, using this approach of paper card.
Or I could try to demand other scale/balance from the seller, claiming this one was not working well.

But I did other test today, using the button TARE to subtract the weight of the paper visit card. The visitcard weights 1,2g, so the after put it over the sensor and set TARE function and remove the card, the display showed -1,2g. So I added the thin film piece plastic and the weight changed to -1,1g (-1,2+0,1=-1,1).
The same worked to weight pop corn grains (single grain) of 0,2g. For me this is a digital bug. The next test would prove it :

This time I placed the visit card paper (1,2g) set TARE to subtract the weight, remove it and it showed -1,2g on display. Ok... But instead to add the piece of plastic to it show -1,1 ( the thin plastic weights about 0,1g), I added the visit card again, and the displaye showed 0,0g, and then I added the thin plastic film, and the sensor did not showed 0,1g.
I did this test many times. I also did using visit card and single popcorn grain.

Result, the balance/scale only fails to show values of less than 0,4g or 0,5g when the display was 0,0g at begining. It would weigh a 0,1g thing, if added over a 1,2g of the visit card over the sensor (1,2+0,1=1,3). Or it could weight even 0,1g alone over the sensor but only after use the TARE function and then place the thin plastic aloner on the sensor.
And it would not measure the extra weight (0,1g) of the thin plastic film if I added it over the visit card weigh, if the display was in 0,0g for the visit card alone over the sensor (result of TARE function activated to subtract the visit card weight).

So it's looking like a bug rather than a sensor problem, since it measures 0,1g things, as long the display do not start at 0,0g.

Suggestions?
Do you agree thatit's logic to presume it's a bug?
Made on China...

[Xist]

Replace the built-in display with a CRT. Problem solved!

[redpoint5]

Yes! The LCD is clipping the results. Digital scales are the worst! Get a beam balance scale before the LCD destroys your life. :P

[All Darc]

I never had problem with LCD for watches, number display, and indeed they are good (better) to show things even under sun light in this case (LCD without backlight).


I got mad when they start to push such things to generate moving images, TVs, PC monitors etc.

Originally Posted by Xist

Replace the built-in display with a CRT. Problem solved!

Come on, you are intellignet. Tell me if you agree with me that's it's problably a bug.

Originally Posted by redpoint5

Yes! The LCD is clipping the results. Digital scales are the worst! Get a beam balance scale before the LCD destroys your life. :P

[redpoint5]

I used to rage against cell phones that had color LCD screens. The color didn't provide any useful benefit, but was impossible to see in sunlight because it had to be backlit. Black/white LCD didn't require a backlight and can be seen better in sunlight. The whole color LCD thing was a gimmick back then.

[All Darc]

I visit the seller's store today, and test another scale/balance, a identical model, and it behave the same way. Indeed the attendent found the behavior of the balance weird.
It's probably a design problem, since all models behave like that.
But I still can use. I just need to use a piece of paper of 1g over the sensor, to add things that weight things bellow 0,5g, and subtract 1g of the final total weight. Not that bad, considering it was cheap.