What excitation sense pins are used for in loadcells?

[seyyah]

What are excitation sense pins are used for in loadcells? Are they some kind of feedback to ensure loadcell is properly excited, and in case of faulty excitation, to correct the fault? Should we use it even if our supply is a good one or how should we use it? Thanks. By the way i ask the question by means of designing a loadcell converter or weigh scale, not using a loadcell with a standart converter or scale.

 

[FvM]

Loadcell sense pins

As the load cell measurement is basically ratiometric, using sense as measurement reference eleminates the cable voltage drop as error term. That's the purpose of sense terminals, depending on your application, the difference may be neglectible.

 

[seyyah]

Re: Loadcell sense pins

Since i won't use ratiometric design, it won't be used then, right?

 

[FvM]

Loadcell sense pins

If non-ratiometric design means using different references for bridge supply and ADC, it would effectively double all reference error terms.

Sense terminals can be used also as a feedback for bridge supply. I think the properties of the different circuits are rather obvious and can be easily calculated.

 

[seyyah]

Re: Loadcell sense pins

Actually the reason that i want to use different references is to obey the manufacturers' guidelines. E.g. supplying the bridge with 10V while the reference voltage of the ADC is 2.5V (or 5V). Also i read that, ratiometric design does not work very well for high frequency components in the supply. First i thought that i can use a single 10V reference for bridge and with a resistor divider and may be feeding it into a buffer, i may obtain 2.5V for reference. But i assumed that it would be more precise if i use separate and precision voltage references for the bridge and ADC reference. So i'm going on the second idea for now for a prototype. Does this assumption correct?

Actually it would be great if we could supply the bridge with 10V and the ADC reference with 2.5V with a precision reference, while keeping the stability and precision of the reference unaffected and also using ratiometric design. But i couldn't find a way that i comfort.