How to Choose a Weighing Sensor?

The weighing sensor is known as the heart of electronic scales, and its performance largely determines the accuracy and stability of electronic scales. When designing electronic scales, one often encounters the question of how to choose sensors.

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 must be considered first, which is crucial for the correct selection of 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.

The selection of sensor range can be determined based on a comprehensive evaluation of factors such as the maximum weighing value of the scale, the number of sensors selected, the weight of the scale body, the maximum possible signal load, and the dynamic load that may be generated. Generally speaking, the closer the range of a sensor is to the load assigned to each sensor, the higher the accuracy of its weighing. However, in practical use, due to the presence of loads on the sensor, in addition to the object being weighed, there are also loads such as the weight of the scale body, tare weight, off-center load, and vibration impact. Therefore, when selecting the sensor range, various factors should be considered to ensure the safety and lifespan of the sensor.

Based on experience, sensors should generally operate within the range of 30% to 70% of their rated capacity. However, for some instruments that have significant impact forces during use, such as dynamic railway scales, dynamic vehicle scales, steel scales, etc., when selecting sensors, their range should generally be expanded to operate within 20% to 30% of their range, increasing the overload capacity of the sensor to ensure its safety and lifespan.

The selection of sensor types mainly depends on the type of weighing and installation space, ensuring appropriate installation and safe and reliable weighing. On the other hand, we need to consider the manufacturer's suggestions. Manufacturers generally define the scope of application of sensors based on their stress conditions, performance indicators, installation form, structural type, elastic material, and other characteristics. For example:

• Aluminum cantilever beam sensors are suitable for pricing scales, platform scales, bench scales, etc.
• Steel cantilever beam sensors are suitable for hopper scales, electronic belt scales, sorting scales, etc.
• Steel bridge sensors are suitable for railway scales, truck scales, overhead crane scales, etc.
• Column sensors are suitable for truck scales, dynamic railway scales, large-tonnage hopper scales, etc.

Therefore, the sensors used should meet the requirements of instrument input sensitivity and can be matched with the selected instrument. They should meet the accuracy requirements of the entire electronic scale. An electronic scale is mainly composed of three parts: the scale body, sensors, and instruments. When selecting the accuracy of the sensors, the accuracy of the sensors should be slightly higher than the theoretical calculation value, because theory is often limited by objective conditions, such as the strength difference of the scale body, the poor performance of the instruments, and the harsh working environment of the scale, which directly affect the accuracy requirements of the scale. Therefore, it is necessary to improve the requirements from all aspects and consider economic benefits to ensure the achievement of the goal.