How this circuit works?

[ex4]

I'm using this circuits to interfacing load cell with 3mV/V specifications
But i'm not quite understand how this circuit works?
But it works very great
So anybody can explain how?

 

[paulux]

Before answering your question, may I know more about the content of block (jumper) or any voltage excitation/flipping?

 

[Davood Amerion]

I dont think this cicuit is good one for your application.
for loadcell usualy instromentation amplifier is used.
In your circuits opamp configured as differencial amplifier and connect to loadcell [resistor] bridge output.
if VCC is 10V (for example) then 3mV/V produce 30mV FSD voltage between pin2,3 .
PIN 2 of JP1 [loadcell] is positive and pin3 of JP1 are negative to differential amplifier of U1.
opamp gain depend on loadcell resistor value.

 

[pillar_chen]

Please give the more detail information on the circuits!