1、 Overview
1. Multi scale weighing apparatus
With respect to the same load carrier, the weighing instrument has two or more weighing scales, which have different maximum weighing capacity and different division values. Each weighing scale ranges from zero to its maximum weighing capacity.

2. Multiple index scale
With respect to the same load carrier, the weighing instrument has only one weighing scale, and this weighing scale is divided into several weighing scales with different division values. The weighing scales of several parts here are actively recognized according to the increasing or decreasing load. The maximum weighing scale of the smallest section from zero load to its corresponding top section; The minimum scale of the second section is the maximum scale of the first section; And so on.
In the early 1990s, when the "postal scale" was just produced in China, many manufacturers chose the principle of multi dividing scale and planned three different dividing values for one weighing scale. For example, a multi graduation postal scale with a maximum weighing capacity of 15kg can be divided into three weighing scales of 2kg/5kg/15kg, and the corresponding graduation value is 1g/2g/10g. The characteristics of the weighbridge, however, in the subsequent application, the price of the weighbridge encountered the problem that the 2kg weighing section verification was difficult to reach the measurement request, especially the zero accuracy of the back check weighing function. Therefore, some companies have made numerous changes to their plans. Later, they changed the weighing scales of barcode scales and postal scales to two, making the relative error of the minimum weighing section larger, which is convenient for commodity verification.

3. Multi carrier weighing apparatus
A weighing indicator is equipped with multiple weighing processing units. When multiple carriers are connected, the load values of different carriers can be displayed on the indicator.
Therefore, through multiple weighing processing units, the weighed load values of multiple loaders can be displayed individually or in combination, so they are used in some special areas. However, if it is used in the field of transaction settlement, it is necessary to prevent cheating, so as to prevent being confused with the measured value of the object.
2、 Multi scale weighing apparatus
1. Application of multi-scale weighing instrument
This kind of scale used to be the main commodity in the balance category, and has also been used in some table scales and platform scales in recent years. Because the same carrier can be used for several weighing scales, the switching of different weighing scales can be easily completed and the corresponding graduation value can be used for some items with different wholesale prices and different weights.

2. Inspection of multi-scale weighing instrument
(1) Weighing function inspection process
It can be clearly seen from the following table that when the multi-scale weighing instrument is loaded for inspection, the weighbridge recommendation is based on the request of two weighing scales. If there is no active switching function after 60t, the weighing of this scale will be ended; If there is active switching function, it will actively switch to the weighing scale of the second section with the maximum weighing capacity of 150t. In the unloading inspection, if it is manually changed, according to the maximum weighing scale of 60t in the top section, the zero point tolerance error of weighbridge detail loading and unloading should be "± 10kg"; According to the maximum weighing scale of 150t in the second section, the zero allowable error of loading and unloading should be "± 25kg". If there is an active switching function, the unloading is always an error in fulfilling the 150t function request (see Table 2). When unloading, the user is given a relaxed request, so that the zero tolerance error is fulfilled "± 25kg". The weighing function during unloading will not affect the accuracy of the weighing instrument in actual use, because it is only a parameter during inspection.

(2) Bias load test
According to the detailed method and load in A.4.7 of R76, if a composite load cell is installed in the commodity, the 1/3Maxi of each scale should be tested separately; If only a single load cell is installed, only 1/N-1 Max2 should be tested.
(3) Weighing function inspection
In principle, each weighing scale should be tested as a separate weighing instrument. Weighing instruments for active transformation of weighing scale can be merged for testing. However, if 60t weight is used to check the 60t weighing point, and the apparent value exceeds 60t, the 20kg dividing value should also be checked; If the appearance value exceeds 60t when weighing with articles, the weighing results shall be read according to 50kg graduation value. Of course, the verification fee should be charged according to multiple weighing instruments.

3、 Comparison of three weighing instruments
1. Advantages and disadvantages of multi-scale weighing instrument
(1) The same scale has two or more maximum weights and different division values of different sizes.
For example, when a truck scale with a maximum weighing capacity of 150t is used as a weighing instrument with a maximum weighing capacity of 150t, the calibration graduation value is 50kg; When used as a weighing instrument with a maximum weighing capacity of 60t, the calibration graduation value is 20kg.
⑵ The calibration graduation value can be switched actively.
For example, for a truck scale with a maximum weighing capacity of 150t, when the weighing capacity is within 60t, the calibration graduation value is 20kg. Once it exceeds 60t, its calibration graduation value will be automatically switched to 50kg.
(3) Once entering the large scale, under the active transformation condition, only the load on the carrier is required. Even if the load is unloaded to the empty scale, the allowable error of the scale is also to comply with the specifications of the large scale. This is the advantage of multi-scale weighing apparatus over multi index weighing apparatus.
2. Advantages and disadvantages of multi index weighing instrument
(1) The multi dividing scale can be composed of multiple partial scales in one scale, and each partial scale is of the same accuracy level; Because there are multiple graduation values in all scales, it can be used not only as a small scale scale, but also as a larger scale scale. One scale scale can be used as multiple scales.
⑵ The accuracy request of small weighing section is improved.
(3) Whether it is loading inspection or unloading inspection of the multi indexing scale, the same weighing points are subject to the same allowable error value, so the difficulty of small weighing points passing the verification during unloading is increased.
⑷ Because the graduation value in the small scale section is small, the absolute value of the maximum scale of the scale will become larger, and the request for the selected load cell and load indicator of the scale is relatively high.
3. Advantages and disadvantages of multi carrier weighing instrument
(1) Because each carrier is processed by an independent weighing processing unit, and the information input by each carrier can be accumulated in different combinations through the data processor as required. Therefore, it is widely used in such occasions as "weight weighing of locomotive and vehicle parts", "weight weighing of aircraft gravity center orientation", etc.
(2) Anti cheating requirements for multi carrier weighing instrument used for transaction settlement: compensate for different no-load values of different carriers and (or) load transfer equipment; The various arbitrary combinations of different load measuring equipment and different bearers shall be set to zero accurately without error; The selected equipment shall not be weighed during switching; The combination of the carrier and load measuring equipment shall be clearly identified.