Diy logitech brake pedal

[hozes]

hi there, i have modded my logitech pedals to use loadcell, in the first attemt i try it with a 20kg loadcell, but cause its to light to use i changed the design to use 100kg loadcell.
i use derek speare 12bit controllers without any issue with the 20kg one.

after i changed to 100kg loadcell, i got bizarre stutter in brake without any force applied, its jumping between 50-200steps, and when fully pressed it rwaches a maximum of 1500s, dereks board is 4096 step.
the loadcell i use is the link below

https://www.galoce.com/Uploads/Download/loadcell/GPBseries/GPB100.pdf

i measure the ohms input and output and its fine totally the same as spec.
i set the derek variable gain different levels, try min max 200 400 etc ", although the adjustable steps changes, its never smooth
what will be the problem, the exitation voltage of loadcell, or the direction of loadcell or sth else?
thanks.