JP5890140B2 - Weighing device - Google Patents

Description

  The present invention relates to a weighing device, and more particularly, to a weighing device for weighing an article while conveying it.

  This type of weighing device, for example, a weight sorter, weighs articles while being conveyed by a weighing conveyor, and sorts and sorts articles on the downstream side of the weighing conveyor according to the weight of the weighed articles.

  In such a weight sorter, since the articles are measured within a short time while being conveyed by the weighing conveyor, a vibration component by a motor attached to the weighing conveyor is superimposed on the load signal, or the articles are loaded on the weighing conveyor. Because the transient response of the resulting load signal is weighed in a short time that does not sufficiently converge, a weighing error occurs, and the dynamic weighing value obtained by weighing while conveying the article is the true weight value of the article It will be different from the static weighing value (static weight value).

  For this reason, for example, in Patent Document 1, an article having a known static weighing value is weighed while being conveyed by the weighing conveyor a plurality of times, and based on the obtained dynamic weighing value, it is substantially equal to the static weighing value. Is provided with a setting mode for obtaining a correction value for correcting the dynamic weighing value. Then, in the normal weighing mode in which the correction value is obtained by this setting mode and the articles are selected, the dynamic weighing value is substantially equal to the static weighing value by the previously obtained correction value. Correction is performed, and the article is selected based on the corrected correction weight value.

  In the setting mode of Patent Document 1, the correction value is obtained as follows.

  That is, an article whose static weighing value Ws is known is set as a sample article, and the static weighing value Ws is set.

Next, this sample article is weighed for the first time while being conveyed by the weighing conveyor, and when the dynamic weighing value W _{1 of the first} sample article is obtained, (Ws−W ₁ ) / W ₁ is calculated, the correction value a ₁ is calculated by the following equation.

A ₁ = 1 + (Ws−W ₁ ) / W ₁ = Ws / W ₁
In order to display the correction state, during this first measurement, Ws−W _1, which is the difference between the static measurement value Ws and the first dynamic measurement value W ₁ , is calculated and displayed.

Next, the second sample is weighed while the sample article is conveyed by the weighing conveyor, and when the dynamic sample value W _{2 of the second} sample article is obtained, the dynamic measurement is performed using the _first correction value A _1. The corrected weight value W ₂ · A ₁ with the corrected value is calculated, and the second correction value A ₂ is calculated by the following equation.

A ₂ = {(Ws / W ₂ ) + A ₁ } / 2
In order to display the correction state, Ws−W ₂ · A ₁ , which is the difference between the static weighing value Ws and the corrected weight value W ₂ · A ₁ , is calculated and displayed during the second weighing.

When the dynamic weighing W _n of N-th sample article is obtained in the same manner, using a correction value A _n-1 of the N-1 th calculates a correction weight value Wn · A _n-1, N-th correction calculating a value a _n by the following equation.

A _n = {(Ws / W _n ) + A _n-1 } / 2
In order to display the correction status, during the n-th measurement, Ws−W ₂ · A _n−1 , which is the difference between the static weight value Ws and the corrected weight value Wn · A _n−1 , is calculated and displayed. Is done.

  When the display value indicating the correction state falls within a predetermined error range, the setting mode is terminated assuming that the correction weight value is substantially equal to the static weighing value Ws.

For example, when the setting mode is ended by N dynamic weighings, the finally stored correction value _An is
A _n = {(Ws / W _n ) + A _n-1 } / 2
It becomes.

In normal weighing mode for sorting articles, such that substantially equal to the static weight value using the correction value A _n of the dynamic weight value obtained by weighing while conveying the article was determined by setting Mode The corrected weight value is compared with the upper limit value and lower limit value of the weight regarded as a non-defective product, and the article is selected as a non-defective product and a defective product.

Japanese Patent Publication No. 6-95034

The dynamic weighing values W ₁ , W ₂ , W ₃ ,... W _n from 1 to N times in the setting mode have variations due to vibration components of the weighing conveyor. Whether or not to end the setting mode is determined by the display value (Ws−W _n · A _n−1 ) indicating the correction state. Since the dynamic weighing value Wn is included, the variation of the dynamic weighing value Wn appears every time.

  For this reason, although the correction value has not yet been obtained correctly and is not a sufficiently good correction value, the display value happens to fall within a predetermined error range due to variations in the dynamic measurement value, The setting mode for obtaining the correction value may end, and even if there is a better correction value, the setting mode ends with an insufficient correction value. Such an end of the setting mode often occurs when the display value and the magnitude of the variation of the dynamic metric value are close to each other.

  In addition, during measurement of the dynamic measurement value in the setting mode, mechanical noise such as floor vibrations and winds that occur by chance and electrical noise due to electromagnetic waves are mixed in, and the dynamic measurement value that should be excluded is taken in originally. In such a case, since the dynamic measurement value far from the correct dynamic measurement value is taken, an unnecessarily large number of measurement times are required before the display value falls within a predetermined error range. Will be necessary.

  The present invention has been made in view of the above-described points, and an object thereof is to accurately obtain a correction value for correcting a dynamic metric value.

  In order to achieve the above object, the present invention is configured as follows.

(1) A weighing apparatus according to the present invention includes a weighing mode for calculating a corrected weight value by correcting a dynamic weighing value obtained by performing dynamic weighing for weighing an article while conveying the article with a correction value;
In order to calculate the correction value, correction is performed by performing dynamic weighing that is performed while transporting a sample article having a known static weight value a plurality of times more than a preset number to obtain a plurality of dynamic weighing values. With mode,
Each of the plurality of dynamic metric values acquired in the correction mode includes a determination unit that determines whether each is suitable for calculating the correction value ,
The determination means determines whether each of the dynamic metric values is suitable for calculating the correction value depending on whether the dynamic measurement value is within an allowable range,
In the weighing mode, the dynamic weighing value is corrected by the correction value so that the correction weight value becomes equal to the stationary weight value,
The boundary value of the allowable range used for the determination by the determination unit is defined based on the allowable accuracy of the corrected weight value in the weighing mode and the set number.

  A sample article is a representative article that is a sample of an article that is actually weighed in the weighing mode, for example, an article having an average weight and an average property of an article that is actually weighed in the weighing mode. Is preferred.

According to the weighing device of the present invention, in the correction mode for calculating the correction value for correcting the dynamic weighing value, a plurality of dynamic weighing values acquired by performing dynamic weighing more than the set number are corrected. Because it is determined whether or not it is suitable for calculating the value, dynamic measurement values with large variations obtained during the execution of the correction mode, for example, mechanical noise such as floor vibration and wind, and electromagnetic waves caused by accident It is possible to exclude dynamic measurement values that are not suitable for calculating correction values, such as dynamic measurement values mixed with electrical noise due to noise, so that only dynamic measurement values suitable for calculation of correction values can be used. An accurate correction value can be calculated, and the corrected dynamic weighing value corrected by this correction value is also accurate.
In addition, dynamic weighing values that fall outside the permissible range are excluded as dynamic weighing values that are not suitable for calculating correction values, so accurate correction is made using only dynamic weighing values that are suitable for calculating correction values. A value can be calculated.
Furthermore, when the allowable accuracy of the corrected weight value obtained by correcting the dynamic weighing value with the correction value, that is, the allowable accuracy of the static weight value and the set number that is the minimum number of times of performing dynamic weighing in the correction mode, are set. The boundary value of the allowable range that is the determination criterion of the determination means is automatically defined.

  As another embodiment of the present invention, the boundary value may be defined so that a corrected weight value corrected by a correction value satisfies the allowable accuracy.

(2) weighing equipment of the present invention, the metering mode for calculating a correction weight value dynamic weighing values obtained by performing the dynamic weighing of weighing while conveying the articles, and corrected by the correction value,
In order to calculate the correction value, correction is performed by performing dynamic weighing that is performed while transporting a sample article having a known static weight value a plurality of times more than a preset number to obtain a plurality of dynamic weighing values. With mode,
Each of the plurality of dynamic metric values acquired in the correction mode includes a determination unit that determines whether each is suitable for calculating the correction value,
When the number of dynamic metric values determined to be suitable for calculating the correction value by the determination means is equal to or greater than the set number, it is determined to be suitable for calculating the correction value. And calculating means for calculating the correction value based on the measured dynamic weighing value and the static weight value.

  In the calculation means, the correction value is calculated using a plurality of dynamic weighing values equal to or greater than the set number.

According to the weighing device of the present invention, when the number of dynamic weighing values determined to be suitable for calculating the correction value exceeds the preset number, it is determined to be suitable. Since the correction value is calculated based on the dynamic weighing value and the static weight value, the correction value is calculated using a dynamic weighing value equal to or larger than the set number, and an accurate correction value can be obtained. it can.

  As another embodiment of the present invention, a correction value is calculated when the number of dynamic weighing values determined to be suitable for calculating the correction value reaches a preset number. At the same time, it may be notified that the number of dynamic weighings in the correction mode has reached the set number, or that the correction mode has ended. This eliminates the need for the user to unnecessarily perform dynamic weighing of the sample article.

(3) weighing equipment of the present invention, the metering mode for calculating the dynamic weight value obtained by performing a dynamic weighing of weighing while conveying the article, the correction weight value is corrected by the correction value,
In order to calculate the correction value, correction is performed by performing dynamic weighing that is performed while transporting a sample article having a known static weight value a plurality of times more than a preset number to obtain a plurality of dynamic weighing values. With mode,
Each of the plurality of dynamic metric values acquired in the correction mode includes a determination unit that determines whether each is suitable for calculating the correction value,
When the number of times that the sample article has been dynamically weighed in the correction mode reaches a number greater than or equal to the set number, the movement determined to be suitable for calculating the correction value by the determination unit. When the number of target weighing values does not reach the set number, a notification means is provided for notifying that the number of times of dynamic weighing of the sample article is insufficient in the correction mode.

  The notification means preferably reports the number of shortages, but may notify only the shortage without notifying the number of shortages. This notifying means is preferably notified by display output, but may be notified by voice output, print output, or a combination thereof.

According to the weighing device of the present invention, the dynamic weighing value determined to be suitable for calculating the correction value even when the dynamic weighing of the sample article is performed more than a preset number of times in the correction mode. When the number of samples does not reach the preset number, it is informed that the number of dynamic weighing for the sample article is insufficient. Can be added and dynamic weighing can be performed on the sample article.

  As another embodiment of the present invention, when the number of times that the sample article is dynamically weighed in the correction mode does not reach the set number, the number of times that the sample article is dynamically weighed is insufficient. It may be notified by the notification means as being.

( 4 ) In another embodiment of the weighing device according to the present invention, the weighing device includes a determination unit that determines the quality of the article based on the corrected weight value calculated in the measurement mode.

  According to this embodiment, since the quality of the article is determined based on the corrected weight value, it is suitable as a weight sorter that sorts the article into a non-defective product and a defective product.

  According to the present invention, it is determined whether each of a plurality of dynamic weighing values acquired by performing dynamic weighing more than a set number is suitable for calculating a correction value. It is possible to exclude dynamic weighing values that are not suitable for calculating correction values, such as dynamic weighing values or dynamic weighing values that include mechanical noise such as floor vibrations and winds that occur by chance or electrical noise due to electromagnetic waves. Thus, an accurate correction value can be calculated using only the dynamic weighing value suitable for calculating the correction value, and the corrected dynamic weighing value corrected by this correction value is also accurate. Become.

FIG. 1 is a diagram showing a schematic configuration, a measurement timing, and the like of a weight sorter as a weighing device according to an embodiment of the present invention. FIG. 2 is a block diagram of the weight sorter of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration and measurement timing of a weight sorter as a weighing device according to an embodiment of the present invention, and FIG. 2 is a block diagram of the weight sorter in FIG.

  As shown in FIG. 1A, the weight sorter 1 of this embodiment is a load composed of, for example, a load cell (LC) that supports the carry-in conveyor 2, the weighing conveyor 3, the carry-out conveyor 4, and the weighing conveyor 3. A sensor 5 and an article sensor 7 for detecting an article 6 immediately before being carried into the weighing conveyor 3 are provided.

  Each of the conveyors 2, 3, and 4 is a belt conveyor that conveys the article 6 by an endless belt wound around rollers disposed in the front and rear of the conveyance direction indicated by an arrow A, and is synchronized by a driving unit (not shown). Then, the roller is driven. Each of the conveyors 2, 3, and 4 is not limited to a belt conveyor but may be a chain conveyor, a roller conveyor, or the like.

  The carry-in conveyor 2 loads the articles 6 supplied from the upstream side in the conveying direction into the weighing conveyor 3, and the weighing conveyor 3 conveys the articles 6 sequentially loaded from the carry-in conveyor 2 and carries them out to the carry-out conveyor 4. The dynamic weighing value of the article 6 is acquired from the load signal of the load sensor 5 during the period in which the article 6 is being conveyed by the weighing conveyor 3 as will be described later. In addition, a sorting device (not shown) is provided on the downstream side of the carry-out conveyor 4, and according to the weighing result of the article 6, the sorting destination of the delivery destination of the normal weight of the non-defective product and the defective product whose weight is excessive or insufficient It is configured to be.

  As shown in FIG. 2, the weight sorter 1 includes an amplifier 8 that amplifies an analog load signal from the load sensor 5, an A / D converter 9 that converts the load signal from the amplifier 8 into a digital signal, and an input. A filter process for attenuating vibration noise and the like included in the output signal (I / O) circuit 10 and the load signal from the input / output circuit 10 is performed, a CPU 11 for controlling each part, and a control program are stored. , A memory 12 for storing data such as dynamic weighing values, an input unit 13 having operation keys operated for various settings and switching of operation modes, a liquid crystal display for displaying weighing values and messages, etc. The display part 14 which consists of. You may comprise the input part 13 and the display part 14 with the touchscreen which integrated them.

 In addition to the above filter processing, the CPU 11 calculates the dynamic measurement value of the article 6 by subtracting the zero point movement stored in the memory 12 by adjusting the weight and zero point adjustment of the weighing conveyor 3 serving as a tare from the load signal, Judgment to determine whether or not the dynamic measurement value is suitable for calculating the correction value, as well as a function as a calculation means for performing various calculation processes such as calculating a correction value for correcting the dynamic measurement value It has a function as a means.

  In this embodiment, in the operation operation mode in which the articles 6 are weighed and sorted, the articles 6 to be sorted are supplied to the carry-in conveyor 2, and the carry-in conveyor 2 conveys the articles 6 to the weighing conveyor 3. The article 6 from the carry-in conveyor 2 is detected by an article sensor 7 such as a photo sensor at a position immediately before the weighing conveyor 3, and this detection output is input to the CPU 11 via the input / output circuit 10. When the article 6 is carried onto the weighing conveyor 3, the load of the article 6 is applied to the load sensor 5 as shown by the load straight line L1 in FIG. 1B, and the load sensor 5 is shown in FIG. The load signal shown in the transient response curve L2 of c) is output. This load signal is filtered by the CPU 11 to become a filter response curve L3 shown in FIG. A dynamic measurement value is acquired from the load signal at a point p, for example, at a timing when the load signal becomes stable after a predetermined time has elapsed from the detection of the article 6 by the article sensor 7. The dynamic weighing value is corrected with a correction value obtained in advance in the dynamic correction test mode described later, and the corrected dynamic weighing value is compared with the upper limit value and the lower limit value to determine whether the product is within the normal weight range. Then, the articles 6 are sorted into defective products having excess and deficiency in weight.

  Even with the filtered load signal, a small vibration component still remains, so that the dynamic weighing value acquired from the load signal includes a variation error component and the article is present on the weighing conveyor 3. Since the load signal must be acquired in a short time, the load representing the true weight value of the article 6 as shown in FIG. A static deviation value (static weight value) Ws measured in anticipation of a sufficient convergence time of a transient response in a weighing instrument having a fixed deviation component e based on the response delay of the filter is included.

  Therefore, the dynamic weighing value measured while conveying the article 6 is a weight value measured when the weighing conveyor 3 is stopped and the article 6 is placed on the weighing conveyor 3 and a sufficiently long time is allowed. This is different from the static weighing value (static weight value) Ws.

  For this reason, in the weight sorter 1 of this embodiment, the above-described operation mode as a weighing mode for weighing and sorting articles that are normal products, the static weighing value is known, and the actual product Dynamic weighing is performed a plurality of times while sample articles having the same weight and properties are conveyed under the same operating conditions as in the operation mode, and based on a plurality of dynamic weighing values obtained by this dynamic weighing, There are two operation modes including a dynamic correction test mode as a correction mode for obtaining a correction value for correcting the dynamic weighing value so as to be substantially equal to the static weighing value. An operation mode can be selected.

  In the operation mode, the dynamic weighing value obtained by weighing a normal article is corrected so as to be approximately equal to the static weighing value by the correction value obtained in advance in the dynamic correction test mode. Based on the static weighing value, which is a value, the article is sorted into a non-defective product and a defective product.

  Here, the dynamic correction for correcting the dynamic weighing value to the static weighing value will be described.

  Since the weight sorter measures the weight of articles having the same type of external shape and properties with almost no weight difference, it is considered that the transient response characteristics of the weight sorters of all the articles are substantially equal, and the average weight among the articles. And an average outer shape are used as sample articles to obtain correction values. As the sample article, a representative article may be selected from the products, or a sample article having properties close to the article may be specially manufactured.

As a conventional general method, dynamic weighing is performed P times by conveying an article having a known static weighing value (static weight) Ws as a sample article, and when P dynamic weighing values are obtained, Wpa, which is an average value of P pieces of the measured values, is obtained, and the dynamic correction value as the correction value is wd.
wd = Wpa-Ws (1)
When the dynamic weighing value Wx of an arbitrary article is measured in the operation mode, the static weighing value (= corrected dynamic weighing value) Wsx of the arbitrary article is
Wsx = Wx−wd (2)
And correct.

Alternatively, if the dynamic correction coefficient as the correction value is K,
K = Wpa / Ws (3)
When the dynamic weighing value Wx of an arbitrary article is measured in the operation mode, the static weighing value (= corrected dynamic weighing value) Wsx of the arbitrary article is
Wsx = ( 1 / K ) · Wx (4)
And correct.

  In this embodiment, the same dynamic correction as this conventional one is performed, and the dynamic correction value wd may be used as the correction value, or the dynamic correction coefficient K may be used.

  Furthermore, in this embodiment, in the dynamic correction test mode, a plurality of dynamic weighing values obtained by dynamic weighing in the dynamic correction test mode are obtained in order to obtain a correction value for correcting the dynamic weighing value more accurately. Among them, it is determined whether or not the dynamic weighing value is suitable for calculating the correction value, and the correction value is calculated using only the dynamic weighing value suitable for calculating the correction value. .

  In this embodiment, whether or not the dynamic metric value is suitable for calculating the correction value is determined by whether or not the obtained dynamic metric value satisfies the allowable accuracy of the dynamic metric value.

  The allowable accuracy of the dynamic weighing value is defined based on the dynamic weighing value obtained by correcting the dynamic weighing value by the correction value, that is, the allowable variation width of the static weighing value. The allowable variation range of the static weighing value is set by the key operation of the input unit 13 as the allowable accuracy of the static weighing value in the dynamic correction test mode, as will be described later.

  Hereinafter, the allowable accuracy of the dynamic weighing value will be described.

  In order to correct the dynamic weighing value to the static weighing value as described above, a correction value calculated according to the above formula (1) or (3) is obtained based on the average value of the dynamic weighing value. As shown in the above formula (2) or (4), the correction value must be subjected to arithmetic processing such as addition, subtraction, multiplication and division with respect to the dynamic measurement value, which is a basis for calculating the correction value. Since the dynamic measurement value includes a variation due to a vibration component or the like, the correction value calculated using the dynamic measurement value also includes the variation of the dynamic measurement value.

  Therefore, in evaluating the allowable accuracy of static weighing values obtained by correcting dynamic weighing values with correction values, both the variation included in the dynamic weighing values and the variation included in the correction values are considered. There must be.

  In the dynamic correction test mode, ± a (g) is set as the allowable accuracy of the static weighing value, and the minimum number of times N (times) at which the dynamic weighing value is to be obtained is determined by the key operation of the input unit 13. Is set. The allowable accuracy ± a (g) of the static weighing value means the allowable variation width E = 2 · a (g) of the static weighing value. In this embodiment, the allowable variation width E of the static weighing value. Is used. The minimum number of tests N is the minimum number of times that the sample article should be dynamically weighed in the dynamic correction test mode, and the minimum number of tests N is determined by the manufacturer of the weight sorter by setting a recommended value in advance. The user sets in advance an arbitrary value based on the recommended value (at least a value equal to or greater than the recommended value).

Assuming that N is the minimum number of tests for obtaining the dynamic weighing value in the dynamic correction test mode and the standard deviation of the dynamic weighing value is Sd, the correction value is as shown in the above equation (1) or (3): Since the average value of N dynamic weighing values having variations of the standard deviation Sd is subtracted or divided by the static weighing value Ws, this correction value must have a variation of Sd / N ^1/2. become.

Therefore, the corrected dynamic weighing value obtained by correcting the dynamic weighing value with the correction value, that is, the standard deviation Ss of the static weighing value, averages the standard deviation Sd of the dynamic weighing value and the dynamic weighing value. The standard deviation Sd / N ^{1/2 of} the correction value obtained by
Ss = {Sd ² + (Sd / N ^1/2 ) ² } ^1/2
= {(N + 1) / N} ^1/2 · Sd (5)
It is expressed.

  That is, the equation (5) represents the standard deviation Ss of the variation of the static weighing value, which is the dynamic weighing value after correction, by the standard deviation Sd of the dynamic weighing value and the minimum test number N of the dynamic weighing value. ing.

If the variation width of the static measurement value, which is the corrected dynamic measurement value, is 6 · Ss,
6 · Ss = 6 · {(N + 1) / N} ^1/2 · Sd (6)
Here, the variation range 6 · Ss of the static measurement value, which is the dynamic measurement value after correction, needs to be equal to or less than the allowable variation range E of the static measurement value set as described above. That is,
6 ・ Ss ≦ E
Substituting the above equation (6) into this left side,
6 · {(N + 1) / N} ^1/2 · Sd ≦ E
It becomes.

Therefore, 3 times the standard deviation Sd of the dynamic weighing value is
3 · Sd ≦ E / [2 · {(N + 1) / N} ^1/2 ] (7)
It becomes.

  If the standard deviation Sd of the dynamic weighing value satisfies the above equation (7), the static weighing value, which is the corrected dynamic weighing value corrected using the dynamic weighing value, is set to the allowable value. It is within the variation width E.

Therefore, in this embodiment, the boundary value 3 · Sd for defining the allowable accuracy of the dynamic weighing value as an allowable range of ± 3 · Sd centering on the average value of the dynamic weighing value is the above (7). The upper limit of the expression,
3 · Sd = E / [2 · {(N + 1) / N} ^1/2 ]
age,
When an average value of dynamic weighing values obtained by a plurality of dynamic weighings is Wa, the dynamic weighing value is within an allowable range of Wa ± 3 · Sd centering on Wa, that is,
Wa ± E / [2 · {(N + 1) / N} ^1/2 ]
The determination criteria as to whether or not the dynamic measurement value is suitable for calculating the correction value. A dynamic weighing value that satisfies this criterion is an appropriate dynamic weighing value, and a correction value calculated using the dynamic weighing value is also an appropriate correction value. The measured value, that is, the static measured value satisfies the allowable variation width E that is the allowable accuracy of the static measured value.

  The boundary value of the allowable range of the dynamic measurement value is not limited to three times the standard deviation Sd, but may be two times the standard deviation Sd.

  Here, the minimum number of tests N is examined based on the above equation (5).

When the value of the integer N representing the minimum number of tests is small, the value of {(N + 1) / N} ^1/2 is larger than 1, so that the variation Ss of the static measurement value increases. Accordingly, if the set value of the minimum test number N for obtaining the dynamic measurement value is small, the variation Ss of the static measurement value due to the dynamic correction becomes larger than that when the minimum test number N is large, and such a correction value is set. In the static weighing value which is the dynamic weighing value corrected by using, it becomes more difficult to satisfy the allowable variation width E.

Assuming that a value of about N = 20 is set as the minimum evaluation test number N, and the correction value is obtained using the average value of 20 dynamic weighing values, Ss = {(N + 1) / N} ^1/2 · Sd = (21/20) ^1/2 · Sd
≒ 4.5826 / 4.47221 ・ Sd
= 1.025 · Sd
≒ 1 ・ Sd
If the number of dynamic weighing values is as large as about 20, the variation Ss of the static weighing value, which is the corrected dynamic weighing value, is substantially equal to the variation Sd of the dynamic weighing value. The value variation Sd does not affect the accuracy of the static weighing value which is the corrected dynamic weighing value. However, when the minimum number of tests N is small and the number N of obtained dynamic weighing values is small, it becomes larger than 1. Therefore, the variation Ss of the static weighing value that is the corrected dynamic weighing value is the dynamic weighing. Since the value is larger than the value variation Sd, the influence of the dynamic measurement value variation Sd is increased.

Assuming that N = 5 is set as the minimum test number N, for example,
Ss = {(N + 1) / N} ^1/2 · Sd = (6/5) ^1/2 · Sd
= 1.095 · Sd
Thus, the variation Ss of the static weighing value, which is the dynamic weighing value after correction, is about 1.1 times the variation Sd of the dynamic weighing value, which has an influence of about 10%.

  In order to reduce the minimum number N of dynamic weighing tests, the original fluctuation amount (standard deviation value) Sd of the dynamic weighing value before dynamic correction is small with a margin of 10% or more with respect to the allowable accuracy. Must be a value. By doing so, errors can be absorbed even if the minimum number N of dynamic correction tests is about five. Therefore, if the manufacturer of the weight sorter adjusts in advance so that the standard deviation Sd of the dynamic weighing value becomes small, the minimum number N of dynamic weighing tests in the dynamic correction test mode on the user side is set. Less can be set. As described above, the minimum number of tests N is determined by the manufacturer of the weight sorter, and the minimum number of tests N is determined according to the weighing accuracy or allowable accuracy of the weight sorter adjusted by the manufacturer. The recommended value will be specified.

  Next, a specific operation in the dynamic correction test mode of this embodiment will be described.

  First, the user operates the mode switching key of the input unit 13 to select the dynamic correction test mode. When the dynamic correction test mode is selected, the data in the dynamic correction test data storage area for storing the dynamic weighing value and the like in the memory 12 is reset.

  The user sets the permissible accuracy ± a (g) of the static weighing value and the minimum number of tests N (times) as a preset number by operating the operation keys of the input unit 13.

  The user further inputs the static weighing value Ws of the sample article necessary for calculating the correction value according to the above equation (1) or (3) by operating the operation key of the input unit 13. Note that the static weighing value Ws of the sample article is obtained by stopping the weighing conveyor 3, placing the sample article on the weighing conveyor 3, and measuring and storing the static weighing value instead of the input by the input unit 13. Also good.

  Next, the dynamic weighing in which the sample article is weighed while being conveyed on the weighing conveyor 3 is repeated at least N times which is the minimum number of tests. The dynamic metric values obtained by each dynamic metric are sequentially stored in the memory 12.

  After at least N dynamic weighings are completed, the user operates the dynamic correction value calculation key of the input unit 13.

  When the dynamic correction value calculation key is operated, the above-described CPU 11 as the determination unit determines whether or not the obtained at least N dynamic measurement values are dynamic measurement values suitable for calculating the correction value. And whether or not the number of dynamic weighing values suitable for calculating the correction value is equal to or greater than N, which is the minimum number of tests.

That is, as described above, an average value Wa of at least N obtained dynamic metric values is calculated, and the obtained dynamic metric value is Wa ± E / [2 · {(N + 1) / N} ^{1 / 2} ] is determined, and it is checked whether the number of dynamic weighing values within the allowable range is N or more. The allowable variation width E of the static weighing value is calculated as E = 2 · a (g) from the set allowable accuracy ± a (g) of the static weighing value.

  As a result of the determination, if the number of dynamic weighing values within the allowable range, that is, the number of dynamic weighing values suitable for calculating the correction value is less than N, an additional test of dynamic weighing is performed. The fact that it is necessary and the insufficient number of dynamic weighing values are displayed on the display unit 14 serving as notification means as the number of additional dynamic weighing tests. In this case, the correction value is not calculated, and the dynamic metric value determined to be unsuitable for calculating the correction value is deleted.

  As a result of the determination, when the number of dynamic weighing values suitable for calculating the correction value is N or more, the dynamic weighing values are used to correct according to the above formula (1) or (3). The value is calculated, the correction value is stored in the memory 12, and the fact that the dynamic correction test is completed is displayed on the display unit 14.

  When the display unit 14 indicates that an additional test is required and the number of additional tests, the user performs dynamic weighing in which the sample article is weighed while being transported on the weighing conveyor 3. By repeating the above, the obtained dynamic metric value is additionally stored in the memory 12.

When the dynamic weighing over the number of additional tests is completed and the user operates the dynamic correction value calculation key of the input unit 13 again, the dynamic weighing value within the range obtained by the first dynamic weighing is The average value Wa is calculated by adding the dynamic weighing value added by the additional test, and the dynamic weighing value obtained by the additional testing and the dynamic weighing value obtained by the first dynamic weighing are Wa ± E / [2 · {(N + 1) / N} ^1/2 ]
It is determined whether it is within the allowable range.

  Then, it is checked whether or not the number of dynamic metric values within the allowable range is N or more.

  When the number of dynamic weighing values is N or more, it is assumed that the number of dynamic weighing values suitable for calculating the correction value is N or more, and the above expression (1) or (3) The correction value is calculated according to the above, the correction value is stored in the memory 12, and the fact that the dynamic correction test is completed is displayed on the display unit 14.

  When the number of dynamic weighing values is not N or more, the fact that an additional test is required and the insufficient number are displayed on the display unit 14 as the number of additional tests, and the same operation as described above is performed.

  When the number of dynamic correction tests reaches the minimum number of tests N, the determination of the suitability of the dynamic measurement values obtained so far is automatically performed without pressing the dynamic measurement value storage key as described above. If there is no dynamic metric value to be excluded, using these dynamic metric values, a correction value is calculated and stored in the memory 12, and the fact that the dynamic correction test is completed is displayed on the display unit 14. If there is a dynamic weighing value to be excluded, it is displayed that an additional test is required at that time, and the number of insufficient dynamic weighing values may be displayed as the required number of additional tests. .

  When the display unit 14 displays that the dynamic correction test has been completed, the user shifts to an operation mode for selecting articles by operating the mode switching key of the input unit 13.

  In this operation mode, the articles 6 to be sorted are weighed while being conveyed by the weighing conveyor 3 to obtain a dynamic weighing value, and the CPU 11 as the calculation means obtains the dynamic weighing value in the dynamic correction test mode. The CPU 11 as a determination unit compares the calculated static weighing value with the upper limit value and the lower limit value, and calculates a normal weighing value that is a corrected dynamic weighing value. A non-defective product within the weight range and a defective product with excessive or insufficient weight are discriminated, and a sorting device (not shown) on the downstream side of the carry-out conveyor 4 sorts the articles 6 based on the discrimination result.

  The dynamic weighing value, the correction value, the static weighing value, and the standard deviation stored in the memory 12 can be displayed on the display unit 14 by the key operation of the input unit 13, and the weight sorter 1 Can be transmitted to a personal computer connected to the printer, or printed out by a printer.

  Here, an example of the dynamic correction test mode will be described with an example of specific numerical values.

  The static weighing value (static weight value) Ws of the sample article is 150 (g), the allowable accuracy of the static weighing value is ± 0.6 (g), and the minimum number of tests N is 10. These numerical values are set by operating the operation keys of the input unit 13 as described above.

  Since the allowable accuracy of the static weighing value is ± 0.6 (g), the variation width E of the static weighing value is E = 1.2 (g), and the minimum number of tests N = 10. .

Therefore, the boundary value E / [2 · {(N + 1) / N} ^1/2 ] of the above-described allowable range, which is a criterion for determining whether or not the dynamic metric value is suitable for calculating the correction value, is
E / [2 · {(N + 1) / N} ^1/2 ]
= 1.2 / 2 ・ (11/10) ^1/2
= 0.572
It becomes.

  Dynamic weighing in which sample articles are weighed while being conveyed by the weighing conveyor 3 is repeated 10 times. It is assumed that ten dynamic metric values from 1 to 10 are obtained.

  In Table 1, the above-mentioned Wa, which is the average value of the 10 dynamic weighing values obtained, and the standard deviation are shown together.

When ten dynamic weighings are completed and the user operates the dynamic correction value calculation key of the input unit 13, the CPU 11 calculates an average value Wa = 149.8 of the obtained ten dynamic weighing values. Whether or not each obtained dynamic metric value is within an allowable range of Wa ± E / [2 · {(N + 1) / N} ^1/2 ], that is, 149.8 ± 0.572. It is determined whether it is within the allowable range.

  In Table 1, No. 10 which is the tenth data. The dynamic metric value of 10 is 151.0, which is 149.8 + 1.2, which is not within the allowable range. Therefore, it is excluded, and the remaining number of dynamic metric values is 9, and the minimum number of tests N = 10 is insufficient, the display unit 14 displays that the additional test is required once.

  The user performs dynamic weighing of the sample article once in accordance with the display on the display unit 14, for example, as shown in Table 2 below, It is assumed that 10 dynamic metric values 149.7 are newly added.

  When the user operates the dynamic correction value calculation key of the input unit 13, the average value Wa = 149.6 of the 10 dynamic weighing values including one added is calculated, and each dynamic weighing value is It is determined whether it is within the allowable range of 149.6 ± 0.572.

  In this case, since all of the ten dynamic weighing values are appropriate dynamic weighing values within the allowable range, for example, the dynamic correction value wd is calculated as the correction value according to the above equation (1). To do.

wd = Wpa (= Wa) -Ws
= 149.6-150.0
= -0.4 (g)
The calculated dynamic correction value wd is stored in the memory 12, and the display unit 14 displays that the dynamic correction test has been completed.

  The user operates the mode switching key of the input unit 13 to shift from the motion correction test mode to an operation operation mode in which actual articles are weighed and selected. In this operation mode, when the dynamic weighing value Wx of the article to be sorted is obtained, the static weighing value (= corrected dynamic weighing value) Wsx of the article is stored in the memory 112 as the dynamic correction value wd. Is calculated according to the above equation (2).

Wsx = Wx-wd
= Wx-(-0.4)
The quality of the article is selected based on the calculated static weighing value Wsx that is the corrected dynamic weighing value.

  As described above, according to this embodiment, in the dynamic correction test mode, it is determined whether or not the dynamic weighing value is appropriate, and the inappropriate dynamic weighing value is excluded. Dynamic weighing values, or dynamic data acquired under improper conditions, such as when the weight sorter 1 accidentally receives large floor vibrations or winds, or when the sample article is not properly transported during testing. Weighing values can be eliminated. As a result, an accurate correction value can be calculated using only an appropriate dynamic weighing value. In addition, the dynamic weighing value corrected by the accurate correction value, that is, the static weighing value is also accurate.

  Therefore, unlike the conventional example of Patent Document 1 described above, although the accurate correction value is not obtained, the display value happens to fall within a predetermined error range due to the variation of the dynamic measurement value, and the setting mode. Until the display value falls within the specified error range, or the measured value obtained under improper conditions affected by floor vibration, wind, etc. There is no problem that the number of times of dynamic weighing is unnecessarily large.

  In this embodiment, when the number of dynamic weighing of the sample article is insufficient in the dynamic correction test mode, it is displayed, so that the user can grasp the progress state of the dynamic correction test mode. Knowing the number of shortages of dynamic weighing, the dynamic weighing can be performed as many times as necessary.

DESCRIPTION OF SYMBOLS 1 Weight sorter 2 Carry-in conveyor 3 Weighing conveyor 4 Carry-out conveyor 5 Load sensor 6 Goods 7 Goods sensor 11 CPU
13 Input unit 14 Display unit

Claims (4)

A weighing mode for calculating a corrected weight value by correcting a dynamic weighing value obtained by performing dynamic weighing for weighing an article while conveying the article, and a correction weight value;
In order to calculate the correction value, correction is performed by performing dynamic weighing that is performed while transporting a sample article having a known static weight value a plurality of times more than a preset number to obtain a plurality of dynamic weighing values. With mode,
Each of the plurality of dynamic metric values acquired in the correction mode includes a determination unit that determines whether each is suitable for calculating the correction value ,
The determination means determines whether each of the dynamic metric values is suitable for calculating the correction value depending on whether the dynamic measurement value is within an allowable range,
In the weighing mode, the dynamic weighing value is corrected by the correction value so that the correction weight value becomes equal to the stationary weight value,
A boundary value of the allowable range used for determination by the determination unit is defined based on an allowable accuracy of the correction weight value in the measurement mode and the set number.
A weighing device characterized by that. A weighing mode for calculating a corrected weight value by correcting a dynamic weighing value obtained by performing dynamic weighing for weighing an article while conveying the article, and a correction weight value;
In order to calculate the correction value, correction is performed by performing dynamic weighing that is performed while transporting a sample article having a known static weight value a plurality of times more than a preset number to obtain a plurality of dynamic weighing values. With mode,
Each of the plurality of dynamic metric values acquired in the correction mode includes a determination unit that determines whether each is suitable for calculating the correction value,
When the number of dynamic metric values determined to be suitable for calculating the correction value by the determination means is equal to or greater than the set number, it is determined to be suitable for calculating the correction value. A calculation means for calculating the correction value based on the dynamic weighing value and the static weight value,
A weighing device characterized by that . A weighing mode for calculating a corrected weight value by correcting a dynamic weighing value obtained by performing dynamic weighing for weighing an article while conveying the article, and a correction weight value;
In order to calculate the correction value, correction is performed by performing dynamic weighing that is performed while transporting a sample article having a known static weight value a plurality of times more than a preset number to obtain a plurality of dynamic weighing values. With mode,
Each of the plurality of dynamic metric values acquired in the correction mode includes a determination unit that determines whether each is suitable for calculating the correction value,
When the number of times that the sample article has been dynamically weighed in the correction mode reaches a number greater than or equal to the set number, the movement determined to be suitable for calculating the correction value by the determination unit. When the number of target weighing values does not reach the set number, a notification means for notifying that the number of times of dynamic weighing of the sample article in the correction mode is insufficient is provided.
A weighing device characterized by that . Based on the corrected weight value calculated in the weighing mode, comprising a determination means for determining the quality of the article,
The weighing device according to any one of claims 1 to 3.

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