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Topic: HX711 and 50kg load cells - unstable values (Read 335 times) previous topic - next topic

Gormd

Hi there

I have a problem with unstable values from 4 (50 kg)- load cells. The load cells are connected like shown here - with a HX711 ADC: https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide/all

Load cells : https://www.sparkfun.com/products/10245

I have used the code shown in the link - where I have to find the "calibration_factor" first. There is no problem in finding this - it was about -3050, which means, that when I add 61,9 kg on the load cells - the value show 61,9 kg.

There are 2 problems:
1) When I take of the load of 61,9kg and add it again - I do get another value - not the same - ex 58 kg.
2) The value of 61,9kg decreases over time - ex it starts with 61,9kg and decreases to 60 in 15 minutes, and goes on for a long time.

I have tried a lot, and cant find a solution for this problem. I really hope there is some help out there.

Thanks
Gorm 




 

pylon

The combinator board has a connector for a temperature sensor. Do you have the temperature changes in your calculation? How stable is your power supply?

MarkT

How are the load cells arranged mechanically?
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Gormd

Hi there

First - thanks for reply. I found the solution. Until now I connected the load cells black wire to white wire - like on sparkfuns instruction page https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide/all

But the solution is to connect them like on this page - black to black and white to white... https://electronics.stackexchange.com/questions/196057/arduino-with-weighing-scale/196064#196064



Gorm

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