FAQS

Common questions

1.- How to connect the load cells?
  • •    4 wires connection

  • RED -> IN+


    BLACK -> IN–


    WHITE -> OUT–


    GREEN -> OUT+



  • •    6 wires connection

RED -> IN+


YELLOW -> SENSE+


BLACK -> IN–


BLUE -> SENSE-


WHITE -> OUT–


GREEN -> OUT+

2.- How can I find the faulty load cell?

In several installations is quiet difficult to know which load cell is not working properly.



In the following points we detail a simple tests that could help to know if a load cell is broken.



Check the input resistance (red and black) and output resistance (green and white). Check the specifications of your load cell and verify that the values are inside the specified margins.



Supply the load cell with a tension not bigger than 15V (red and black) and measure with a multimeter in mV the output value (green and white). In this example we consider a power supply of 10V. First verify the signal without load on the load cell, the measure should be less than 1mV, after that put the maximum load on it and measure, the measure should be around 20mV, if you don’t have the full load please apply proportionality to the values specified.

3.- What does the specifications inform us ?

Number of divisions


Number of fractions where the manufacturer certifies the linearity of the load cell



Combined Error


The sum of linearity, repeteability and hysteresis.



Creep


The variation in load cell output with time after loading from zero to a constant load.



Eccentric Load


Load applied to a load cell displaced from the normal axis.



Excitation


The voltage used to excite the load cell.



Hysteresis


The difference in load cell output at the same load value, between increasing and decreasing load.



Insulation Resistance


Insulation Resistance is the resistance between each cable core (including screen) and the body of the load cell.



Linearity


The output deviation at intermediate loads from a straight line drawn between zero load and full load outputs.



Overload Limit


Load cells are specified to resists loads beyond rated capacity without permanent zero shift typically up to 150% of rated capacity.



Senses, Six Wire Circuit


An additional pair of wires which are use to mantain a constant supply to the load cells, to remove the errors from long cable lenghts or varying cable temperatures.



Repeatibility


The difference in load cell output with successive load cycling to the same load.



Sensitivity mV/V


The output of load cell in milivolts (mV) per volt (V) of excitation at the rated load.



Span Drift


Variation in weight measurement with temperature or time at maximum live load.



Zero Drift


Variation in weight measurement with temperature or time, at zero live load.