The closer the weighing value of the weighing system is to the rated capacity of the sensor, the higher the weighing accuracy is. However, in actual use, due to the weight, tare and vibration, impact, and eccentric load of the scale body, it is different. The principle that the measurement system uses the sensor's limit is very different. As a general rule, there are: * Single sensor static weighing system: fixed load (weighing platform, container, etc.) + variable load (load to be weighed) ≤ rated load of selected sensor X 70% * multi-sensor static weighing System: fixed load (weighing platform, container, etc.) + variable load (load to be weighed) ≤ selected sensor rated load X number of sensors X 70%, 70% of which is considering vibration, shock, eccentric load And other factors add.
It should be noted that: First, the rated capacity of the sensor should be selected to meet the value of the manufacturer's standard product series. Otherwise, non-standard products are selected, which are not only expensive but also difficult to replace after damage. Secondly, in the same weighing system, sensors with different rated capacities are not allowed. Otherwise, the system cannot work normally. Furthermore, the so-called variable load (the load to be weighed) refers to the actual load applied to the sensor. If the force value is transmitted from the weighing platform to the sensor, there is a mechanism for multiplying and attenuating (such as a lever system). Then the impact should be considered.
The accuracy level of the load cell should be selected to meet the accuracy level of the weighing system, as long as it meets this requirement. That is, if the 2500-division sensor can meet the requirements, do not use 3000-division. If several identical forms are used in a weighing system and the sensors of the same rated capacity are operated in parallel, the combined error is Δ, then: Δ=Δ/ n1/2 (2-12)
Where: Δ: the combined error of a single sensor; n: the number of sensors. In addition, electronic weighing systems generally consist of three major components, they are weighing sensors, weighing displays and mechanical structural components. When the tolerance of the system is 1, the integrated error (Δ) of the load cell, which is one of the main components of the non-automatic weighing instrument, can only reach a proportional component of 0.7. According to this and the formula (2--12), it is not difficult to make a choice of the required sensor accuracy.