JP3706078B2 - Combination weighing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a combination in which objects to be weighed are supplied to a plurality of weighing units, a combination of objects to be weighed within a target range is selected based on the weighing result of each weighing unit, and the selected objects to be weighed are discharged together. The present invention relates to a technique for making it possible to easily grasp a change in a single quality amount of an object to be weighed in a weighing device.
[0002]
[Prior art]
Conventionally, a combination weighing device has been used to collect articles whose masses vary individually within a preset target range of mass and number.
[0003]
The combination weighing device has a plurality of sets of weighing hoppers capable of receiving and discharging the objects to be weighed, and weighing machines that support the weighing hoppers and output signals corresponding to the loads of the objects to be weighed accommodated in the weighing hoppers. Each weighing hopper is supplied with an appropriate amount of objects to be weighed from the supply device, the mass of the objects to be weighed contained in each weighing hopper is obtained from the output signal of each weighing instrument, and the number is converted from that mass. The number of objects to be weighed is determined, and the combination mass is set in advance within the preset target mass range or the number of combinations is preset from the combinations of objects to be weighed stored in each weighing hopper. A combination that falls within the target number range or both ranges is selected, and the objects to be weighed are discharged from the weighing hopper selected for the combination to the collecting device, and are grouped together.
[0004]
As described above, when combining not only the mass of the object to be weighed but also the number, it is necessary to previously investigate and set parameters necessary for converting the detected mass into the number.
[0005]
When converting from the mass to the number, the average value and standard deviation of the mass (single quality quantity) of each object to be weighed are required.
[0006]
That is, as shown in FIG. 6, assuming that the mass of each object to be weighed follows a normal distribution, if the average value of the single quality quantity obtained by measurement is A and its standard deviation is σ, The mass distribution falls within the range of A ± 3σ with a probability of approximately 99.7 percent.
The mass distribution of m objects to be weighed is within the range of mA ± 3σm ^1/2 with a probability of approximately 99.7%. Note that 4σ may be used instead of 3σ, and in this case, the probability is further increased.
[0007]
Therefore, the mass range for each number in advance,
A ± 3σ when m = 1
When m = 2, 2A ± 3σ2 ^1/2
When m = 3, 3A ± 3σ3 ^1/2
......
, The number can be detected by examining which of the above ranges the mass obtained from the output signal of the measuring instrument is.
[0008]
Moreover, as shown in FIG. 7, the upper limit of the distribution of m objects to be weighed and the lower limit of the distribution of m + 1 objects to be weighed intersect each other.
mA + 3σm ^1/2 = (m + 1) A-3σ (m + 1) ^1/2
That is,
A = 3σ {m ^1/2 + (m + 1) ^1/2 }
Is true.
[0009]
Therefore, the number m of objects to be weighed can be distinguished from the number m + 1.
A> 3σ {m ^1/2 + (m + 1) ^1/2 }
The number can be correctly converted from the mass up to the maximum value L of the number m in which 3σ {m ^1/2 + (m + 1) ^1/2 } is smaller than the average value A of the single quality quantity. .
[0010]
As described above, when the number is converted from the mass obtained by weighing the objects to be weighed, an average value and a standard deviation of single quality quantities are required.
[0011]
For this reason, conventionally, a single quality quantity is obtained by placing the objects to be weighed on a stationary balance one by one, and the average value and standard deviation are obtained by calculation, and the mass range for each piece is calculated from the average value and standard deviation. Is set in the number conversion unit of the combination weighing device.
[0012]
[Problems to be solved by the invention]
However, as described above, before performing combination weighing, the mass of each object to be weighed is measured with a static balance, the average value and standard deviation are calculated, and the mass range for each piece is further calculated. Even if the operation is started with setting to, even if the average of the single quality quantity of the object to be weighed or the size of the variation has changed due to the change of the lot of the object to be weighed, this cannot be grasped, There was a problem that defective products would occur due to incorrect number conversion.
[0013]
An object of the present invention is to solve this problem, and to provide a combination weighing device that can easily grasp an average of single quality quantities and variations of a weighing object and can quickly cope with the variations.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a combination weighing device according to claim 1 of the present invention comprises:
A plurality of weighing units (23 ₁ to 23 _P , 24 _{1 to} 24 _P , 26) for measuring the supplied objects to be measured and detecting the mass of the objects to be weighed, and the objects detected by the plurality of weighing units A number conversion means (27) for converting each mass of the weighing object into a number, a combination of objects to be weighed is selected based on at least one of the mass or the number, and the object to be weighed selected by the combination In a combination weighing device that discharges from the weighing unit,
A statistic that calculates, as a statistic, an average value and a standard deviation of a single quality quantity of an object to be weighed for each predetermined period based on the mass detected by the plurality of weighing units and the number converted by the number conversion means A calculation means (40);
At least transition graph showing changes in the temporal change of the statistical quantity computing means of the mean and separately mass contour is determined by the standard deviation subjected to statistical single item weight calculated by the distribution diagram or the mean and standard deviation Statistical chart data generating means (41) for generating one display data;
Output means (44, 45) for receiving display data generated by the statistical chart data generating means and displaying and outputting at least one of the distribution chart or the transition graph ;
The statistical chart data generating means generates a reference distribution chart whose outer shape is determined by a preset reference average value and standard deviation when generating display data of the distribution chart of the single quality quantity calculated by the statistical quantity calculating means. Display data is generated, and the distribution map of the single quality quantity calculated by the statistic calculation means and the reference distribution chart are displayed in a comparable manner .
[0015]
A combination weighing device according to claim 2 of the present invention is the combination weighing device according to claim 1,
A comparison means (42) for comparing the average value and standard deviation of the single quality quantity calculated by the statistic calculation means with the average value and standard deviation of the reference, respectively;
It has a comparison result notification means (43) for notifying the comparison result of the comparison means .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of a mechanism unit of a combination weighing device 20 to which the present invention is applied, and FIG. 2 shows a configuration of a control unit.
[0018]
In FIG. 1, a plurality of P (P is, for example, 10) feeders 21 _{1 to} 21 _P convey objects to be weighed received at one end side from a supply line (not shown) to the other end side substantially horizontally and are arranged below. An appropriate amount is supplied to each of the supplied hoppers 22 _{1 to} 22 _P.
[0019]
The supply hoppers 22 _{1 to} 22 _P are formed so that their bottoms can be freely opened and closed so that the objects to be weighed can be accommodated and discharged. The supply hoppers 22 _{1 to} 22 _P receive the objects to be weighed supplied from the feeders 21 _{1 to} 21 _P. To the measured weighing hoppers 23 ₁ to 23 _P.
[0020]
As with the supply hoppers 22 _{1 to} 22 _P , the weighing hoppers 23 ₁ to 23 _P are formed to be openable and closable so that the objects to be weighed can be accommodated and discharged, and are supported by the weighing devices 24 _{1 to} 24 _P , respectively. Each of the weighing devices 24 _{1 to} 24 _P calculates a weight value signal s _{1 to} s _P corresponding to the load of the corresponding weighing hopper and the object to be weighed accommodated in the weighing hopper, as will be described later. It outputs to the means 26. The weighing hoppers 23 ₁ to 23 _P and the weighing devices 24 _{1 to} 24 _P together with the mass calculation means 26 constitute a weighing unit of this embodiment.
[0021]
The collective discharge device 25 collectively discharges the objects to be weighed discharged from the weighing hopper.
[0022]
As shown in FIG. 2, the mass calculation unit 26 receives the weight value signals s ₁ ~s _P from the meter 24 ₁ to 24 _P, it has become the mass (empty weighing hopper itself from the measuring value subtracting metric signal) each time, to calculate the mass _g 1 to g _P of the objects to be weighed stored in each weighing hopper ₂₃ 1 ~ 23 _P.
[0023]
Here, although the calculation means 26 for calculating the respective masses from the measurement value signals of a plurality of measuring instruments is used, this mass calculating function may be provided for each measuring instrument, and the measuring instrument itself has this mass calculating function. A calculation function may be provided.
[0024]
The number conversion means 27 is based on the conversion information preset by the conversion information setting means 37 to be described later, that is, based on the information indicating the relationship between the mass range and the number, each mass g ₁ to mass calculated by the mass calculation means 26. g _P respectively converted to the number _m 1 ~m _P.
[0025]
The combination selecting means 30, the mass calculation unit 26 and the mass _g 1 to g _P of the objects to be weighed in each weighing hopper ₂₃ 1 ~ 23 _P calculated by the respective weighing hoppers ₂₃ 1 obtained by the number conversion means 27-23 based on the number _m 1 ~m _P of the objects to be weighed of _P, a preset target weight range Ga～Gb, selects a combination of weighing hoppers to enter the target number range Ma～Mb.
[0026]
The weighing hopper control means 31 opens and closes the weighing hoppers selected by the combination selecting means 30 among the weighing hoppers 23 ₁ to 23 _P , and the objects to be weighed stored in the weighing hoppers are sent to the collective discharge device 25. Let it drain.
[0027]
The supply hopper control means 32 opens and closes the supply hopper corresponding to the measurement hopper opened and closed by the weighing hopper control means 31 among the supply hoppers 22 _{1 to} 22 _P , and supplies the weighing hopper to the measurement hopper. Let
[0028]
The feeder control means 33 drives a feeder corresponding to the empty supply hopper opened and closed by the supply hopper control means 32 among the feeders 21 _{1 to} 21 _P , and supplies a new object to the supply hopper. .
[0029]
The feeders 21 _{1 to} 21 _P , the supply hoppers 22 _{1 to} 22 _P, and the supply hopper control means 32 and the feeder control means 33 that control the opening and closing of the feeders 21 _{1 to} 21 _P are fed to the weighing hoppers 23 ₁ to 23 _P. It constitutes supply means for supplying.
[0030]
The target amount setting unit 36 sets the target mass range Ga to Gb and the target number range Ma to Mb input by the operation of the operation unit 39 in the combination selection unit 30.
[0031]
The conversion information setting means 37 obtains a limit number L that can be converted from the single-unit average mass _Ar and the standard deviation σ _r input by the operation of the operation unit 39, and obtains the limit number L for each number from 1 to L. The mass range H (1) to H (L) is set in the number conversion means 27 as conversion information.
[0032]
Based on the mass calculated by the mass calculator 26 and the number converted by the number converter 27, the statistic calculator 40 is a statistic of the single quality quantity of the object to be weighed for a predetermined period, that is, the single quality quantity. Calculate the mean and standard deviation.
[0033]
Here, the statistic calculation means 40 is
(A) When only the mass converted into a specific number (for example, one) by the number conversion means 27 is to be calculated,
(B) When only the mass converted into a predetermined number range (for example, 1 to 3) by the number conversion means 27 is to be calculated,
(C) Any of the cases where all masses converted in number by the number conversion means 27 are to be calculated.
[0034]
Further, in the case of (a) and (b) above, if the feeding force of the feeder is set so that the supply target number of objects to be weighed with respect to the weighing hopper is a specific number or a predetermined number range, the specific number or the predetermined number range The frequency that is converted into is increased, and necessary information can be obtained in a short time. However, since the efficiency of the weighing operation may decrease when the specific number or the predetermined number range is not within the optimum number range for the combination selection, a small number (for example, one or two) of the specific number of all the weighing hoppers For the weighing hopper only, the necessary information can be obtained in a short period of time without lowering the weighing efficiency by setting the feeder supply power so that the supply target number of objects to be weighed is within a specific or predetermined number range. .
[0035]
In addition, when the converted number is 1, the mass before conversion is the single quality quantity itself, but when the converted number is 2 or more, the individual mass of the object to be weighed cannot be obtained. In this case, the mass before conversion is divided by the converted number, and the division result (that is, the average value) is defined as a single quality quantity.
[0036]
As for the standard deviation, when calculating with only one converted number, the standard deviation of a single item can be obtained accurately, but when the converted number is 2 or more, the mass is converted as described above. If a single quality quantity divided by the number and averaged is used as a calculation target, variation is compressed by the averaging, and a correct standard deviation cannot be obtained.
[0037]
In this case, the standard deviation is obtained by assuming a plurality of objects to be weighed as one single item, and the standard deviation of the single item is calculated from the standard deviation.
[0038]
That is, as described above, when the single product of the average value A and the standard deviation σ is a set of m, the average value is m · A, and the standard deviation is equal to σ · m ^1/2 .
[0039]
Therefore, the standard deviation σ _m calculated as m single items is
σ _m = σ · m ^1/2
Therefore, the standard deviation σ of a single item is
σ = σ _m / m ^1/2
Can be calculated.
[0040]
Further, when there are a plurality of types of m as in the cases (b) and (c), the average value of the standard deviations of single items obtained for each m may be used as the final standard deviation.
[0041]
The statistical chart data generation means 41 receives the statistics of the single quality quantity calculated by the statistical quantity calculation means 40, generates display data of the distribution map or transition graph, and outputs this to the display device 44 and the printer 45. .
[0042]
This statistical chart data generation means 41 has a distribution chart generation mode and a transition graph generation mode, generates display data according to the mode instructed by the operation of the operation unit 39, and displays it on the display device 44. .
[0043]
That is, when the distribution chart generation mode is designated, the distribution chart of the single quality quantity determined by the average value A and the standard deviation σ of the single product, and the reference statistic (the average value _Ar and the standard deviation set by the conversion information setting means 37) Display data for displaying the reference distribution map of the single quality quantity determined by σ _r ) in a state where it can be compared is generated and displayed on the display device 44.
[0044]
In addition, when the transition graph generation mode is designated, the graph is plotted on the time axis so that the temporal change of the average value A and the standard deviation σ and the standard statistics (the average value A _r and the standard deviation σ _r ) can be grasped. Display data is generated and displayed on the display device 44.
[0045]
The comparison unit 42 compares the statistic of the single quality amount calculated by the statistic calculation unit 40 with the reference statistic.
[0046]
The comparison result notifying unit 43 outputs information (for example, character string information) corresponding to the comparison result of the comparison unit 42 to the display device 44 and the printer 45.
[0047]
The display device 44 constitutes a display output means together with the printer 45, receives the display data and comparison result information generated by the statistical chart data generation means 41, receives a distribution map or transition graph of a single quality quantity, and a comparison result Display information.
[0048]
The printer 45 prints out the content displayed on the display device 44 when receiving a print instruction by operating the operation unit 39 or the like.
[0049]
In the combination weighing device 20 configured as described above, when starting a weighing operation for a new type of object to be measured, a target mass and a target number are set in the combination selection unit 30 by the target amount setting unit 36 in advance and converted. set the conversion information H (1) ~H (L) to the number conversion means 27 by the information setting means 37, in accordance with the further set target amount and combination hoppers such as the number, the supply of feeder ₂₁ 1 through 21 _P Start operation after setting.
[0050]
When this operation is started, the objects to be weighed are supplied from the feeders 21 _{1 to} 21 _P to the supply hoppers 22 _{1 to} 22 _P , respectively, and from the supply hoppers 22 _{1 to} 22 _P to the weighing hoppers 23 ₁ to 23 _P , respectively. The weighing object is supplied, the mass of the supplied object to be weighed is calculated by the mass calculation means 26, the number is calculated from the mass by the number conversion means 27, and the combination selection means 30 calculates the target number within the target mass range. A combination that falls within the range is selected, and the weighing hopper containing the objects to be weighed selected by the combination is opened and closed by the weighing hopper control means 31, and the objects to be weighed stored in the weighing hopper are collected and discharged by the collective discharge device. 25 is discharged.
[0051]
On the other hand, a new weighing object is supplied to the empty weighing hopper by the supply hopper control means 32 from the supply hopper corresponding to the weighing hopper, and the empty supply hopper is fed by the feeder control means 33. A new object to be weighed is supplied from a feeder corresponding to the supply hopper.
[0052]
The weighing operation by the weighing hopper, the combination selection, and the discharge operation of the selected product and the operation of supplying the objects to be weighed to the empty weighing hopper are performed in parallel. In addition, the objects to be weighed within the target number range are collected together and discharged sequentially.
[0053]
During the weighing operation, the statistic calculation means 40 receives the mass calculated by the mass calculation means 26 and the number converted by the number conversion means 27, and sequentially stores a set of the number and mass to be calculated. Each time the stored number reaches a predetermined number, the average mass A and the standard deviation σ of the single item are calculated by the above-described method and output to the statistical chart data generating means 41 and the comparing means 42.
[0054]
When the distribution chart generation mode is designated, the statistical chart data generation means 41 calculates the calculated average mass of a single item on the same mass axis as shown in, for example, (a) to (d) of FIG. A figure of distribution B determined by A and standard deviation σ (actual distribution is a normal distribution of a curve, but here it is schematically represented as a peak at average mass and is in an isosceles triangle shape having a width proportional to the standard deviation) The figure of the single-quality quantity distribution Br determined by the standard statistic (average value _Ar and standard deviation σ _r ) is displayed in a state where it can be identified by color difference, line type difference, brightness difference, etc. Display data to be generated is generated and displayed on the display device 44.
[0055]
The comparison means 42 compares the calculated average mass A of the single item with the reference average value _Ar , compares the calculated standard deviation σ with the reference standard deviation σ _r, and the comparison result notification means 43 The character string information corresponding to the comparison result is displayed on the display device 44.
[0056]
Incidentally, (a) in FIG. 3 is substantially equal to the average value A _r of average mass A reference single item, a distribution diagram of the case that the calculated standard deviation sigma is the reference of the smaller standard deviation sigma _r, in this case A character string such as “Good” is displayed by the comparison result notification means 43.
[0057]
FIG. 3B is a distribution diagram in the case where the average mass A of the single _product is larger than the standard average value _Ar , and the calculated standard deviation σ and the standard standard deviation σ _r are substantially equal. The result notification means 43 displays a character string such as “average value is large”.
[0058]
Further, (c) in FIG. 3 is a distribution diagram of a case substantially equal, the calculated standard deviation sigma is the reference of the larger standard deviation sigma _r and the average value A _r of average mass A single item reference, the comparison result A character string such as “the variation is large” is displayed by the notification means 43, and (d) of FIG. 3 shows that the average mass A of the single item is larger than the standard average value _Ar , and the calculated standard deviation σ is This is a distribution diagram when the standard deviation σ _{r is} larger than the reference, and a character string such as “average value and variation is large” is displayed.
[0059]
Therefore, by confirming this display, anyone can grasp the average value and variation status of the single quality quantity of the currently supplied objects intuitively and accurately, and provide appropriate feedback to the production line. The
[0060]
In addition, when the transition graph generation mode is designated, the statistical chart data generation means 41 displays a transition graph that shows how the average mass A and the standard deviation σ of the single item vary, for example, as shown in FIG. Data is generated and displayed on the display device 44.
[0061]
From this display, the tendency of fluctuations in the average mass A and standard deviation σ of a single item can be easily grasped, and future predictions can be easily made from the tendency, and appropriate measures can be taken for the predictions.
[0062]
Further, when a print instruction is given by operating the operation unit 39 or the like, the content displayed on the display device 44 is printed out from the printer 45.
[0063]
Here, only one of the distribution chart and the transition graph is displayed here, but the statistical chart data generation means 41 displays the distribution chart and the transition graph on the same screen as shown in FIG. 5, for example. Display data may be generated and displayed on the display device 44.
[0064]
In the above description, the comparison result notifying unit 43 outputs the character string corresponding to the comparison result together with the distribution chart. However, this does not limit the present invention, and the comparison result is notified by an audio signal. Notification may be made by lighting or flashing the lamp.
[0065]
In the above description, the combination selection unit 30 selects a combination that falls within the target mass range and within the target number range. However, the present invention can be applied to the case where the objects to be weighed are combined using only the number regardless of the mass. Applicable.
[0066]
On the contrary, by combining the objects to be weighed only by mass, the number conversion result is obtained for another purpose, for example, the number of objects to be weighed discharged in a batch by selecting the combination, and this is obtained in the subsequent line (for example, Output to the packaging line) and indicate each product individually in the subsequent line, or sequentially determine the number of objects to be weighed that have been selected as a combination and discharged together, and store it as statistical data on the product before proceeding to the manufacturing process. It can be used as information to be fed back. When the number conversion result is used for such a purpose, out of the numbers for each hopper output from the number conversion means 27, the total number of objects to be weighed selected based on the mass by the combination selection means 30 is calculated. The data is obtained by an adder, and this is transmitted to the subsequent line and the data totaling unit using the communication means.
[0067]
In the combination weighing device 20 described above, the weighing unit is configured by the weighing hopper 23, the weighing device 24, and the mass calculating means 26. However, the object to be weighed by the weighing hopper 23 is placed below (directly below or obliquely). A weighing unit with a structure that discharges and holds each holding hopper placed in the holding hopper (below), and a combination of objects to be weighed stored in each holding hopper, or a weighing object housed in the holding hopper and weighing hopper The present invention can be similarly applied to a combination weighing device that selects and discharges a combination of objects.
[0068]
In addition, the combination weighing device 20 is provided with the feeder 21 and the supply hopper 22 in order to automatically supply the objects to be weighed to the weighing unit, but manually feeds the objects to be weighed into a plurality of weighing units. The present invention can also be applied to a semi-automatic combination weighing device.
[0069]
【The invention's effect】
As described above, the combination weighing device of the present invention receives the mass detected by the weighing unit and the number from the number conversion means during the weighing operation, and calculates the single quality quantity statistics of the currently supplied weighing object. The quantity is obtained and the distribution pattern of the single quality quantity or its transition graph is displayed and output.
[0070]
For this reason, it is possible to intuitively and accurately grasp the single quality amount, its variation, its variation, and its tendency during the metering operation, appropriately feedback to the production line, and prevent the generation of defective products.
[0071]
In addition, in the display that can be compared with the reference distribution chart, it is possible to easily grasp the difference between the statistic of the single quality quantity of the current measurement object with respect to the reference statistic, and appropriate processing can be performed for the difference. .
[0072]
In addition, when the calculated statistic is compared with the reference statistic and the comparison result is notified, the difference between the statistic of the single quality quantity of the current weighing object with respect to the reference statistic is further increased. It can be surely grasped, and appropriate processing can be performed for the difference.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a mechanism unit according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a control unit according to an embodiment of the present invention. FIG. 5 is a diagram showing a display example of the embodiment. FIG. 5 is a diagram showing a display example of the embodiment. FIG. 6 is a diagram showing a mass distribution of an object to be weighed. Description】
20 ...... combination weighing _device, 21 1 through 21 _P ...... _feeder, 22 1 through 22 _P ...... feed _hopper, 23 1 ~ 23 _P ...... weighing _hopper, 24 1 to 24 _P ...... meter, 25 ...... set Discharge device, 26... Mass calculation means, 27... Number conversion means, 30... Combination selection means, 31... Weighing hopper control means, 32. Target amount setting means, 37... Conversion information setting means, 39... Operation unit, 40... Statistic calculation means, 41 .... statistical diagram data generation means, 42 .. comparison means, 43. 44 …… Display device, 45 …… Printer

Claims (2)

A plurality of weighing units (23 ₁ to 23 _P , 24 _{1 to} 24 _P , 26) for measuring the supplied objects to be measured and detecting the mass of the objects to be weighed, and the objects detected by the plurality of weighing units A number conversion means (27) for converting each mass of the weighing object into a number, a combination of objects to be weighed is selected based on at least one of the mass or the number, and the object to be weighed selected by the combination In a combination weighing device that discharges from the weighing unit,
A statistic that calculates, as a statistic, an average value and a standard deviation of a single quality quantity of an object to be weighed for each predetermined period based on the mass detected by the plurality of weighing units and the number converted by the number conversion means A calculation means (40);
At least transition graph showing changes in the temporal change of the statistical quantity computing means of the mean and separately mass contour is determined by the standard deviation subjected to statistical single item weight calculated by the distribution diagram or the mean and standard deviation Statistical chart data generating means (41) for generating one display data;
Output means (44, 45) for receiving display data generated by the statistical chart data generating means and displaying and outputting at least one of the distribution chart or the transition graph ;
The statistical chart data generation means means a reference distribution whose outer shape is determined by a preset standard value and standard deviation when generating the display data of the distribution chart of the single quality quantity calculated by the statistical quantity calculation means. A combination weighing device that generates display data of a figure and displays the distribution map of the single quality quantity calculated by the statistic calculation means and the reference distribution chart so that they can be compared . A comparison means (42) for comparing the average value and standard deviation of the single quality quantity calculated by the statistic calculation means with the average value and standard deviation of the reference, respectively;
The combination weighing device according to claim 1 , further comprising comparison result notification means (43) for notifying the comparison result of the comparison means .

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