What are the characteristics of the tension load cell

What are the characteristics of the tension load cell

1. Linearity (Nonlinearity)

It is defined as the ratio of the maximum deviation value and output value of full scale, between the actual characteristic curve and the best straight fitting line.

2. Hysteresis

It is defined as a difference of input- output between loading and unloading by every test cycle. In other words, loading from 0 to 10kg and unloading from 20kg to 10 kg, the input is the same, but there will be a slight different output which is called hysteresis.

3. Repeatability

It is defined as the degree of inconsistency of each measurement when the sensor detected by the same physical condition, which is also called stability. Generally, under same input condition, through multiple continuous measurements, then take the maximum random error as repeatability. The degree of repeatability is related to many random factors and is similar to the cause of hysteresis. It can be measured by experimental method.

4. Creep

It is defined as the deformation degree increases with time when the material is under full scale loading (external load remains unchanged). It is shown in the sensor as the percentage change of its output.

5. Sensitivity:

For a linear sensor, its sensitivity is its static characteristic, is the slope of the line.

6. Resolution

Resolution is the ability of the sensor to perceive the smallest change to be measured. It is the minimum measured value of the value to cause a change in the value indicated. It should be separated from the sensitivity coefficient (sensitivity coefficient -- refers to the ratio of output to input). In theory, the sensor's resolution is infinite, but there is a limit to how many bits we can accurately see in the display instrument or acquire equipment

Such as:

Loading is from 0.01233N to 0.01235 N is a small changes (or even smaller), so we have output change from sensor, but for display equipment we will only show to four digits, if it is the change of output voltage from 0.0000x V to 0.0000 y V (or even smaller), the reading or display machine probably can’t read such a change. So resolution and precision are two concepts that should not be confused.

7. Drift

It is defined as external interference, output value changed by the input which is unwanted or unnecessary. Drift includes zero - point drift and sensitivity drift. Zero drift or sensitivity drift can be divided into time drift and temperature drift. Time drift is defined under specified conditions. The zero or sensitivity changes slowly with time. Temperature drift is a zero drift or sensitivity drift caused by changes in ambient temperature.

For temperature drift, we can compensate it by manufacturing process, such as using thermal insulation material as sensor housing, or selecting a strain gauge with self-temperature compensation, or using a material with lower temperature coefficient as sensor measurement element.