Reasons for temperature characteristics of weighing sensors

Load CellThe main reasons for the generation of zero temperature coefficient and sensitivity temperature coefficient are different. Now let's give explanations separately.

1. The main reasons for the zero temperature coefficient are:

We know that when making sensors, we need to paste one piece of strain gauge onto an elastic body. The strain gauge generally consists of two parts: the base and the wire grid. When pasting, we need to use patch adhesive. We also know that most substances in the world have the characteristics of thermal expansion and contraction, that is, they expand when heated and contract when cooled. The strain gauge wire grid, strain gauge substrate, patch adhesive layer, and elastomer mentioned earlier all have this characteristic, and their expansion and contraction sizes are also different; On the other hand, the strain gauge wire grid is made of a resistive material, and its material resistivity also changes with temperature. When they are combined together, in the temperature field, the final manifestation is a change in the resistance value of the strain gauge; Due to the large amount of manual labor involved in the production of strain gauges and sensors, each strain gauge on the same sensor exhibits different resistance changes. After being collected into a zero point output (Z.0) by the detection circuit, it is easy to imagine that the zero point output at this time becomes a function of temperature, which constantly changes with temperature.

2. The main reasons for the sensitivity temperature coefficient are:

As we mentioned earlier, makingLoad CellWhen, we need to attach the strain gauge to the elastomer. The strain gauge has an important parameter, which is the sensitivity coefficient K of the strain gauge. It describes the relative rate of change of its resistance value when strain occurs in the length direction of the wire grid. Research has shown that the sensitivity coefficient of a strain gauge changes with changes in environmental temperature, meaning that although a strain gauge experiences the same strain at different temperatures, the magnitude of the resistance change it produces is different.

In addition, we know that the elastic body of sensors is generally made of metal materials, and metal materials have an important parameter, which is their elastic modulus E (also known as Young's modulus), which describes the magnitude of deformation caused by metal materials under stress. Research has shown that the elastic modulus changes under the influence of temperature, generally decreasing with increasing temperature. This causes the sensor to undergo greater deformation with the increase of ambient temperature without changing the external force. Combined with the change in the sensitivity coefficient of the strain gauge, the output of the sensor will increase. This increase means that the sensitivity of the sensor increases with the increase of ambient temperature. This is the so-called sensitivity temperature coefficient of the weighing sensor.