HX711 Data Variations

Sensors Force & Weight
1

I’m trying to figure out what is going wrong with the data collection from a strain gauge set up on a metal rod for a customer. The strain gauge is connected to the Sparkfun Hx711 Load Cell Amplifier which is connected to a Raspberry Pi 3B+. All of this was set up as specified in documents for the products. The test consists of the same weight being put on the rod for 30 seconds and the output is recorded. The problem with the data is that each time the test is performed the output is higher than the last time. For example the average output would be: 43893, 44677, 50510, and 56392.

I have been attempting to locate the source of this problem and my current idea is that voltage they are supplying is around 7 volts instead of the max operating range of the Hx711 which is 5 volts. Could this higher voltage be the cause of the issue or somewhere else?

Strain_Test.jpg
Strain_Test.jpg1600×1200 368 KB

2

Hi TPBUILD.

Running the board at 7 volts could definitely be causing issues. It could potentially even damage the IC.

Other things to check would be that there is no leftover flux residue on the load cell connections on the board and that all of your connections between the load cell and board are tight and secure. Any stray resistance in those connections will show up in your readings.