Load Cell Output

Hi,

Output of any load cell, given in mV/V means the mV output per V excitation at full scale loading. In your case, you will have 2/200 = 0.01 mV/kg signal per V excitation, if your excitation is, for example, 5 V then you will have 0.05 mV/kg signal.

The resolution of the system normally is not limited by the load cell, but the electronic bridge conditioning/measuring device.

Which are the specifications of the bridge conditioning device?

Kind regards

The output voltage will be 2.00 mV at the rated load, 200 kg, for every volt of supplied to the load cell.

For instance if the power supply to the load cell is +5 Volt, then a 200 kg load on the load cell will give an output of 10 mV (5 V * 2 mV/V). So the scale factor from kg of load to voltage output of the load cell would be 10 mV/200 kg or 0.05 mV/kg.

If you are using the load cells to measure 550 kg + 0.2 kg up to 20 kg, then your total load varies between 550.2 kg and 570 kg. Without knowing the geometric distribution of the load it's difficult to say how much load will be on each load cell. Regardless the load cell should be able to measure loads down to zero kg. And if the load is poorly placed (meaning more than 200 kg of the load is over one load cell), then you may saturate the load cell output.

How are you reading the output? With an analog volt meter? Or do you have some sort of digital read out? If it's digital, then there's a good chance the limitation is in the electronics or the software providing the display.

My experience is to use a box of addition, it supplies 10V exactly and adjustable to each cell and also adds the mV of each cell, obtaining a single signal in mV in all cells.
Moreover you must know the recommendation to use, if possible, only three cells. A weight is supported on a plane, a plane is defined by three points. With four, maybe a cell instead of weight-bearing, whether it is subject to the charge, is being stretched, so it shows 0 mV, but the other three show more weight than real.

Wrong! If cells have SAME sensitivity ALWAYS the sum of outputs will be the load which ever is the load position.

This is obtained by a calibration in situ of the load cells+conditioners by placing e load in different KNOWN positions. Depending on obtained (displayed) results corrections are made for each load cell acquisition line till result INDEPENDENT of load position.

I made weighings up to 3.000 T with such calibrated load cell groups (4) and results were able to show that weight is an invariant!