How to conduct testing after receiving the weighing sensor?

Want to determine aLoad CellIf it is damaged, it can be tested in two stages: measuring resistance and measuring voltage. The next two steps are specifically explained.

1. Measuring resistance

If it is a genuine weighing sensor, the merchant will provide a manual and use a multimeter for testing to measure the input and output resistances of the weighing sensor. Then, compare the input and output impedances on the manual to see if they are within the standard range. If they are not within the range, it indicates that the sensor is damaged.

If the instruction manual is not provided at the time of purchase, measure the input resistance, that is, the resistance between EXC+and EXC -; Output resistance, i.e. the resistance between SIG+and SIG -; Bridge resistance refers to the resistance between EXC+to SIG+, EXC+to SIG -, EXC - to SIG+, EXC - to SIG -. The input resistance, output resistance, and bridge resistance should meet two conditions: ① input resistance>output resistance>bridge resistance; ② The bridge resistances are equal or equal in pairs. If the bridge resistance is slightly different and the linearity is poor, there is a possibility that it cannot be used if it is severely different.

2. Measure voltage

Firstly, use a multimeter to measure the voltage between the instrument terminals EXC+and EXC - in the DC voltage range. This is the excitation voltage of the sensor, which can be either DC5V or DC10V. Here, we take DC5V as an example.

The output sensitivity of the sensors we come into contact with is generally 2 mv/V, which is a linear relationship between the sensor output signal and the output 2mv for every 1V excitation voltage.

When unloaded, use a multimeter to measure the mv value between the SIG+and SIG - wires. If it is around 1-2mv, it indicates that it is correct; If the mv number is particularly large, it indicates that the sensor is damaged.

When loading, measure the mv number between the SIG+and SIG - wires using the mv range of a multimeter, which will increase proportionally to the weight of the load, with a maximum of 5V (excitation voltage) * 2 mv/V (sensitivity)=about 10mv. If not, it indicates that the sensor is damaged.

After calibration in the above table, check if the linearity is normal. In addition, check if the zero output of the instrument is around 0MV. If the zero output is too high, it will be damaged.