Electronics > Projects, Designs, and Technical Stuff

Load cell zero offset - how much is too much?

<< < (4/4)

wraper:
1.4 mV/V is an oddball value, normally they are either 1 mV/V or 2 mV/V. Zero offset super way too high for a good load cell. You can expect a few % of full scale offset from a cheap load cell but not something like this.
EDIT: This is of course if it's single load cell with a bridge, not 4 separate load cells connected together where expected offset is much higher, especially if load cells are not well matched.

r6502:
Hello all,

I just looked at the loadcells, I have in stock, it is a Telda model 1004 with a max load of 300g, and measured the offset voltage in 2 conditions:

It has an offset in the range of 20µV to 30µV, 3 different load cells tested. This works only, if the point of load is free, and the point of attachement is fixed. In my test setup there was a groove of about 0.5mm milled away that the load cell could free move, when a load was applied. refer to "loadcell_1.jpg"

When you put the loadcell just on the desk, like shown in the photo "loadcell_2.jpg" ther is a large offset of  about -500µV.

This loadcell, model 1004 is very sensitive with a max load of 300g and a short term resolution of  30000d, so for loacells, that are specified for 3000d only this may not be that critical. But try to fix the loadcell at the fixing point, make sure that the the point where the load is applied, could free move and then observe the offset and it's drift. Observe also the drift when you apply a constant load to the cell.

Guido

Navigation

[0] Message Index

[*] Previous page