Working principle of weighing sensor

Working principle of weighing sensor

A weighing sensor is actually a device that converts a mass signal into a measurable electrical signal output. When using sensors, the actual working environment in which the sensor is located should be considered first, which is crucial for the correct selection of weighing sensors. It is related to whether the sensor can work normally, its safety and service life, and even the reliability and safety of the entire weighing apparatus. There are qualitative differences between the new and old national standards in the basic concepts and evaluation methods of the main technical indicators of weighing sensors. There are several styles available, including S-shaped, cantilever, spoke, plate ring, film box, bridge, and cylindrical.

Sensors generally use voltage excited resistance bridge structure sensors, which are related to constant voltage (current) output voltage and linearity.
The weighing sensor is mainly composed of elastic beams, strain gauges, adhesives, etc. When an external force acts on the sensor, the elastic beam of the sensor will deform, causing the strain gauges attached to the elastic beam adhesive to act. In the measurement circuit composed of the strain gauges, a certain amount of electricity will be output under the corresponding excitation voltage. A typical electronic scale weighing sensor bridge typically uses a 300fl resistor. The basic lead terminals of the four terminal sensor are VIN+, VOUT+or S+, VIN or E -, VOUT - or S -. The basic lead terminals of the six terminal sensor are+FORCE,+SENSE,+VO, - VO, - SENSE, - FORCE

The excitation power terminal of the sensor is generally connected in series with a temperature compensation resistor and a zero point compensation resistor.

The elastic body of the sensor is made of metal material and pasted on the surface of the strain sensitive area

Four strain gauges, R1, R2, R3, and R4, form a Wheatstone bridge. When subjected to an external force F,

Elastic deformation causes strain gauges R1 and R3 to be stretched, resulting in an increase in resistance value; R2 and R4 are compressed, electrically

The decrease in resistance causes the bridge to lose balance and output a voltage signal proportional to the external force F.

The measuring bridge has high sensitivity, wide measurement range, simple circuit structure, and high accuracy

Easy to achieve temperature compensation and other advantages, therefore it can well meet the requirements of strain measurement.