The millivolt output of a non amplified load cell is linearly proportional to the excitation voltage.
Load cell calibration mv v.
The difference voltage proportional to the load then appears on the signal outputs.
Most quality load cells will come with a factory load cell calibration sheet which specifies the actual sensitivity rating for that individual load cell.
Span sensitivity mv v this is the full span output per supply volt characteristic for the load cell wheatstone bridge.
Supply voltage v this is the excitation voltage in volts applied to the load cell wheatstone bridge strain gauge circuit.
In this example the actual non linearity is about 0 031 using mv v values and 0 032 when using calculated values which is well below the specification.
This equates to 50 mv per volt or has a 50 1 ratio.
Figure 3 above is an example of a morehouse calibration shear web load cell with a non linearity specification of better than 0 05 of full scale.
If the load cell s sensitivity is 3 mv v and the excitation voltage provided by the converter is 10 volts then the divider will be 30 millivolts or 0 03 volts.
If a load cell has a 5 volt dc vdc excitation voltage and a 0 250 mv output the resultant ratio is 250mv 5vdc.
So a 2 96 mv v load cell will provide 29 6 millivolt signal at full load when excited with 10 volts.
Divide the product from step 2 2 7 volt pounds by sensitivity in millivolts volt times the excitation voltage.
This load cell sensitivity rating is specified on a load cell data sheet often in the 1 mv v 3 mv v range.