JP2013101061A - Measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately perform evaluation of measuring accuracy of a measuring device which conveys and simultaneously measures an article under the consideration of allowable accuracy of a static measured value.SOLUTION: In an accuracy evaluation mode for evaluating measuring accuracy, dynamic measuring for conveying and simultaneously measuring a sample article is performed several times, and a CPU 11 evaluates quality of measuring accuracy in accordance with whether or not a plurality of dynamic measurements to be obtained from a load signal to be applied from a load sensor 5 via an amplifier 8, A/D converter 9 and input/output circuit 10 satisfy an evaluation standard successively for the set number of times or more. The evaluation standard is set under the consideration of allowable accuracy of a static measurement obtained by correcting the dynamic measurement by a correction value. Thus, it is possible to accurately perform evaluation of measuring accuracy under the consideration of the allowable accuracy of the static measurement.

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 an article is measured while being conveyed by a weighing conveyor, a vibration signal due to an eccentric load of a rotating body in a motor or roller attached to the weighing conveyor is superimposed on the load signal, or the article is transferred to the weighing conveyor. Since a vibration signal that is a transient response of the load signal generated by the loading of the load is measured within a short time that does not sufficiently converge, a measurement error occurs. Therefore, a filter for attenuating the amplitude of these vibration signals is provided. However, a response delay due to the filter occurs, the dynamic response value obtained by weighing while conveying the article, the response signal of the filter does not respond to the static weighing value within the time that the article stays on the weighing conveyor, This is different from the static weighing value (static weight value), which is the true weight value of the article.

  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.

  A manufacturer that manufactures such a weight sorter designs and manufactures a weight sorter according to the specifications required by the customer, and evaluates whether the weighing accuracy satisfies the allowable accuracy based on the specifications. It is carried out.

  As a technique for evaluating the weighing accuracy of a weight sorter, for example, in Patent Document 2, a test work having a known weight is conveyed a plurality of times, and a dynamic weighing value is calculated from an average value of the top portion of the obtained load signal. Based on the distribution diagram centered on the average value of the plurality of dynamic weighing values, a value of ± 3σ is taken as the weighing accuracy of the dynamic meter value, and the evaluation is compared with the allowable accuracy.

Japanese Patent Publication No. 6-95034 JP 2008-296201 A

  However, in the above-mentioned Patent Document 2, a dynamic metric value that is an average value at the top of the load signal, that is, a dynamic metric value that has been subjected to an averaging process, is used. Therefore, there is a deviation caused by a response delay component, and the variation component remains even though it is attenuated by the averaging process, so that the measurement accuracy cannot be accurately evaluated.

  Therefore, in order to accurately evaluate the weighing accuracy, the weight value obtained by correcting the deviation to bring the dynamic weight value close to the true weight value (static weight value), that is, the dynamic weight value is a correction value. It is necessary to evaluate with the accuracy of the static weighing value, which is the weight value corrected by.

  The present invention has been made in view of the above-described points, and makes it possible to accurately evaluate the weighing accuracy of a weighing device that performs weighing while conveying an article in consideration of a static weighing value. The main purpose.

  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 evaluate the weighing accuracy, it is equipped with an accuracy evaluation mode in which dynamic weighing is performed a plurality of times while the sample article is conveyed, and a plurality of dynamic weighing values are sequentially obtained.
Evaluation means is provided for evaluating the accuracy of measurement accuracy according to whether or not the dynamic measurement values sequentially acquired in the accuracy evaluation mode satisfy an evaluation criterion continuously for a preset number or more.

  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. The static weight value of the sample article need not be known.

  The evaluation standard is a standard for evaluation of weighing accuracy, for example, an evaluation standard for variation in dynamic weighing values, and this evaluation standard is a corrected weight value obtained by correcting a dynamic weighing value with a correction value. It is preferable that this is a criterion considering the allowable accuracy of the static measurement value.

  According to the weighing device of the present invention, in the accuracy evaluation mode, based on whether or not the dynamic weighing values sequentially acquired by the dynamic weighing that weighs the sample article while conveying the sample article satisfy the evaluation criteria continuously for a set number or more. Thus, the weighing accuracy is evaluated, and as this evaluation criterion, for example, an evaluation criterion considering the allowable accuracy of the static weighing value obtained by correcting the dynamic weighing value with the correction value can be used. The evaluation can be accurately performed in consideration of the allowable accuracy of the static weighing value.

  (2) In a preferred embodiment of the weighing apparatus according to the present invention, the evaluation means evaluates the measurement accuracy as poor when the dynamic measurement values sequentially acquired in the accuracy evaluation mode do not satisfy the evaluation criteria.

  According to this embodiment, regardless of the number of times of dynamic weighing of the sample article, when the dynamic weighing value does not satisfy the evaluation standard, it can be immediately evaluated that the weighing accuracy is poor.

  (3) In another embodiment of the weighing device according to the present invention, the evaluation standard of the evaluation means defines an allowable range of variation of the dynamic measurement value.

  Examples of the variation of the dynamic weighing value include a difference between the maximum value and the minimum value of the dynamic weighing value, or a standard deviation of the dynamic weighing value, and these can be used as evaluation criteria. .

  According to this embodiment, the evaluation criterion defines an allowable range of variation of the dynamic weighing value, and this allowable range is a corrected weight value obtained by correcting the dynamic weighing value by the correction value, that is, a static weighing. It can be defined so as to satisfy the allowable accuracy of the value, whereby the measurement accuracy can be evaluated accurately in consideration of the allowable accuracy of the static measurement value.

(4) In another embodiment of the weighing device of the present invention, in the weighing mode, the dynamic weighing value is corrected by the correction value so that the corrected weight value becomes equal to the stationary weight value of the article. ,
The evaluation criteria of the evaluation means are defined based on the allowable accuracy of the corrected weight value in the weighing mode and the set number.

  According to this embodiment, 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 (static weighing value) and the set number are set, Evaluation criteria will be defined automatically.

  (5) In another embodiment of the weighing device according to the present invention, it is provided with notifying means for notifying an evaluation result by the evaluating means.

  The notification means preferably notifies by display output, but may also notify by voice output, print output, or a combination thereof.

  According to this embodiment, since the evaluation result of the measurement accuracy, that is, whether the measurement accuracy is good or not, is notified, the worker who knows the evaluation result can end the accuracy evaluation mode if the measurement accuracy is good. If the weighing accuracy is poor, the weighing accuracy can be evaluated again in the accuracy evaluation mode after adjusting the accuracy of the weighing device.

  In addition, as described above, when the dynamic weighing value does not satisfy the evaluation standard, the evaluation unit immediately evaluates that the weighing accuracy is poor. Therefore, the number of times of dynamic weighing of the sample article is set in the accuracy evaluation mode. When it is determined that the measurement accuracy is poor at the time when the number does not reach, it can be immediately notified, and an operator who knows the measurement accuracy failure can start adjusting the accuracy of the weighing device. Thereby, it is possible to prevent the dynamic weighing of the sample article from being unnecessarily repeated, and to improve the working efficiency.

  (6) In another embodiment of the weighing device according to the present invention, when the weighing accuracy is evaluated as good by the evaluation unit, the dynamic weighing value equal to or more than the set number continuously satisfying the evaluation criterion and Computation means for calculating the correction value of the weighing mode based on the stationary weight value of the sample article is provided.

  According to this embodiment, when the weighing accuracy is evaluated as good by the evaluation means, the weighing mode is corrected based on the dynamic weighing value continuously exceeding the set number that satisfies the evaluation criteria and the static weight value of the sample article. Because the value is calculated, it is not suitable for calculating correction values such as dynamic measurement values with large variations, such as dynamic measurement values that include mechanical noise such as accidental floor vibration or wind, or electrical noise due to electromagnetic waves. It is possible to exclude dynamic weighing values, which makes it possible to calculate accurate correction values using only dynamic weighing values that are suitable for calculating correction values. In addition, the static weighing value, which is the dynamic weighing value after correction, is also accurate. In addition, since the correction value is calculated using the dynamic weighing value acquired in the accuracy evaluation mode, it is not necessary to perform dynamic weighing of the sample article again in order to obtain the correction value.

  (7) 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, in the accuracy evaluation mode, the weighing is performed based on whether or not the dynamic weighing value sequentially obtained by the dynamic weighing for weighing the sample article while conveying the sample article satisfies the evaluation criterion continuously over the set number. Since the accuracy is evaluated, for example, the evaluation standard can be an evaluation standard considering the allowable accuracy of the static measurement value obtained by correcting the dynamic measurement value with the correction value. It is possible to accurately evaluate the weighing accuracy of the weighing device in consideration of the allowable accuracy of the static weighing value.

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 a 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, It has a function as a calculation means for performing various calculation processes such as calculating a correction value for correcting the dynamic measurement value, and also has a function as an evaluation means for evaluating the measurement accuracy.

  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 accuracy evaluation 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 a normal product, and a sample article having the same weight and properties as an actual product are operated. Dynamic weighing is performed multiple times while transporting under the same operating conditions as in the mode, and the weighing accuracy is evaluated based on the dynamic weighing values obtained by this dynamic weighing, and the weighing accuracy is evaluated as good. Accuracy evaluation test as an accuracy evaluation mode to find a correction value for correcting the dynamic measurement value so that it is substantially equal to the static measurement value based on the obtained dynamic measurement value multiple times The operation mode can be selected by the key operation of the input unit 13. In this embodiment, in addition to the accuracy evaluation test mode, a dynamic correction mode for performing a dynamic correction test for obtaining a correction value may be selected so that the dynamic measurement value is substantially equal to the static measurement value. it can.

  In the operation mode, the dynamic weighing value obtained by weighing the product, which is a normal article, is corrected so that it is approximately equal to the static weighing value by the correction value obtained in the accuracy evaluation test mode. Based on the static weighing value, which is a static weighing value, the articles are sorted into non-defective products and defective products.

  The accuracy evaluation test mode is mainly performed by the manufacturer who designed and manufactured the weight sorter 1 according to the specifications required by the customer. After completing the adjustment operation of the weighing accuracy of the weight sorter 1, the customer request is made. It evaluates whether or not the acceptable accuracy according to the specification is satisfied. The customer can also evaluate the weighing accuracy by selecting the accuracy evaluation test mode.

  In this embodiment, in the accuracy evaluation test mode, when the weighing accuracy of the weight sorter 1 satisfies the allowable accuracy and is evaluated to be good, based on the dynamic weighing value obtained in the accuracy evaluation test mode. The correction value is calculated to correct the dynamic measurement value so as to be substantially equal to the static measurement value.

  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 the accuracy evaluation test mode of this embodiment, as described above, when it is evaluated that the weighing accuracy is good, the same dynamic correction as this conventional one is performed, and the dynamic correction value wd is set as a correction value. Alternatively, the dynamic correction coefficient K may be used.

  In this embodiment, in the accuracy evaluation test mode performed by the manufacturer of the weight sorter, the weighing accuracy of the weight sorter 1 can be accurately evaluated in consideration of the allowable accuracy of the static weighing value. .

  In the specification required by the customer, the allowable accuracy of the static weighing value (static weight value), which is the true weight value of the article to be weighed, is generally given in the form of ± a (g).

  In the accuracy evaluation test mode of this embodiment, the allowable accuracy ± a (g) of the static weighing value based on this required specification is set from the input unit 13, and the sample article necessary for accuracy evaluation is further dynamically weighed. A continuous evaluation test number N (times), which is the minimum number of times, is set from the input unit 13. In addition, the static weight value Ws of the sample article is also set for determination of accuracy evaluation, although it is not used directly.

  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, as the allowable accuracy of the static weighing value, The allowable variation width E = 2 · a (g) of the static weighing value is used.

  The number N of continuous evaluation tests is the number of continuous dynamic weighings (test times) necessary for evaluating that the weighing accuracy satisfies the allowable accuracy, and is generally the international legal metrology organization OIML (International Organization of Legal Metrology), or the number of times specified independently by the manufacturer. The number N of continuous evaluation tests is the number of dynamic weighing values acquired by dynamically weighing the sample article.

  Hereinafter, the allowable accuracy of the static 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 the evaluation of the allowable accuracy of the static weighing value obtained by correcting the dynamic weighing value with the correction value, the deviation between the dynamic weighing value and the static weighing value is corrected by the correction calculation using the correction value described above. This may be performed in consideration of both the variation included in the dynamic measurement value and the variation included in the correction value.

N is the number of continuous evaluation tests for obtaining the dynamic measurement value in the accuracy evaluation test mode as described above, that is, the number of dynamic measurement values acquired in the accuracy evaluation test mode, and the standard deviation of the dynamic measurement value is Sd. Then, the correction value for correcting the dynamic weighing value to the static weighing value is N times of the dynamic weighing value having the variation of the standard deviation Sd as shown in the above equation (1) or (3). Since this average value is subtracted or divided by the static weighing value Ws, this correction value has a variation of Sd / N ^1/2 .

Therefore, the corrected dynamic weighing value obtained by correcting the dynamic weighing value by the correction value, that is, the standard deviation Ss of the static weighing value is obtained by changing the standard deviation Sd of the dynamic weighing value and the N dynamic weighing values. By the standard deviation Sd / N ^{1/2 of} the correction value obtained by averaging,
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) expresses the standard deviation Ss of the variation of the static measurement value, which is the dynamic measurement value after correction, based on the standard deviation Sd of the dynamic measurement value and the number N of continuous evaluation tests of the dynamic measurement value. Represents.

If the variation range of the static measurement value, which is the dynamic measurement value after correction, is 6 · Ss, for example, from equation (5),
6 · Ss = 6 · {(N + 1) / N} ^1/2 · Sd (6)
Here, the variation width 6 · Ss of the static measurement value that is the dynamic measurement value after correction is less than the allowable variation width E = 2 · a (g) that is the allowable accuracy of the static measurement value described above. To do. That is,
6 ・ Ss <E
Substituting the above equation (6) into this left side,
6 · {(N + 1) / N} ^1/2 · Sd <E (7)
It becomes.

Here, when the maximum variation width R which is the difference between the maximum value and the minimum value of the dynamic weighing value is defined as, for example, 6 times the standard deviation Sd of the dynamic weighing value (R = 6 · Sd), the above ( 7)
R · {(N + 1) / N} ^1/2 <E
Therefore, the maximum variation width R of the dynamic weighing value is
R <E / {(N + 1) / N} ^1/2 (8)
It becomes.

  If the maximum variation width R of the dynamic weighing value satisfies the above equation (8), the static weighing value that is the corrected dynamic weighing value corrected using the dynamic weighing value is Variations are taken into account, and the static weighing value is within the set allowable variation width E (= 2 · a), that is, the allowable accuracy ± of the static weighing value based on the customer's required specifications ± a (g) is satisfied.

  Therefore, in the accuracy evaluation test mode performed by the manufacturer, representative products among the products used by the customer during actual operation are taken as sample articles by borrowing, for example, and the sample articles are weighed while being transported. The dynamic weighing test is continuously performed a plurality of times, and the dynamic weighing values are sequentially acquired.

  The value of the maximum variation width R of the dynamic weighing value, which is the difference between the maximum value and the minimum value of the dynamic weighing values acquired sequentially, is calculated each time the dynamic weighing value is acquired by the dynamic weighing, The value of the maximum variation width R that is sequentially calculated continues to satisfy the above formula (8), which is the evaluation standard for accuracy evaluation, and the number of dynamic weighings is the number N of continuous evaluation tests that is a preset number. That is, that is, when the value of the maximum variation width R of the dynamic measurement value satisfies the above-mentioned formula (8), which is the evaluation standard, N times in succession, the measurement accuracy is the allowable accuracy of the static measurement value. Satisfactory, the weighing accuracy is evaluated as good, and the accuracy evaluation test mode is terminated.

  When the weighing accuracy is evaluated to be good, the N dynamic weighing values acquired in the accuracy evaluation test mode are all appropriate dynamic weighing values that satisfy the allowable accuracy of the static weighing value. In this embodiment, based on these N dynamic weighing values and the set static weight value Ws of the sample article, a correction value is calculated according to the above-described equation (1) or (3) and stored in the memory 12. I remember it.

  On the other hand, if the maximum variation width R of the dynamic weighing value does not satisfy the above equation (8) before or when the number of continuous evaluation tests N is reached, the weighing accuracy is acceptable for the static weighing value. The accuracy is not satisfied and the weighing accuracy is evaluated as poor, and the fact is displayed on the display unit 14.

  In this way, the worker who knows that the weighing accuracy is poor will review the cause of the weighing accuracy failure at that time, adjust the filter, adjust the level of the conveyor, and make adjustments to further improve the weighing accuracy. The accuracy evaluation test mode is performed again in the same manner as described above. If the measurement accuracy is evaluated to be poor even in this second accuracy evaluation test mode, adjustment for increasing the measurement accuracy is further performed to perform the accuracy evaluation test mode. Thereafter, the measurement is repeated until the measurement accuracy is evaluated as good.

  In this embodiment, in the accuracy evaluation test mode, when the maximum variation width R of the dynamic weighing values sequentially acquired does not satisfy the above equation (8), N sample articles, which are the number of continuous evaluation tests, are used. Even if the dynamic weighing is not finished, it is evaluated that the weighing accuracy is poor, and the fact that it is bad is displayed on the display unit 14 and notified, so the operator immediately ends the accuracy evaluation test mode. Adjustment for increasing the weighing accuracy can be performed, and it is not necessary to continue the accuracy evaluation test mode and unnecessarily perform dynamic weighing of the sample article, thereby improving work efficiency.

  As another embodiment of the present invention, the quality of the weighing accuracy may be evaluated when the number of dynamic weighing of the sample article becomes N or more, which is the number of continuous evaluation tests.

  When the operator sets the allowable accuracy ± a in anticipation of the safety factor in the value of the above-described allowable variation width E (= 2 · a), the allowable variation width E is set to, for example, 90 of the set allowable accuracy. It may be converted to a value of% (E = 2 · a · 0.9).

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

When the value of the integer N representing the number of continuous evaluation tests is small, the value of {(N + 1) / N} ^{1/2 in} the equation (5) is larger than 1, so that the variation Ss of the static measurement value increases. . Therefore, if the set value of the continuous evaluation test number N for obtaining the dynamic measurement value is small, the variation Ss of the static measurement value due to the dynamic correction is larger than that when the continuous evaluation test number N is large, and such correction is performed. In the static weighing value which is the dynamic weighing value corrected using the value, it becomes more difficult to satisfy the allowable variation width E.

As the number N of continuous evaluation tests, for example, a value of about N = 20 is set, and the correction value is obtained using an 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, if the number N of continuous evaluation tests is small and the number N of the obtained dynamic weighing values is small, it becomes larger than 1. Therefore, the variation Ss of the static weighing values, which are dynamic weighing values after correction, is dynamic. Since it becomes larger than the variation Sd of the measured value, the influence of the variation Sd of the dynamic measured value is increased.

  Next, specific operations in the accuracy evaluation test mode of this embodiment will be described. Here, the case where the manufacturer who designed and manufactured the weight sorter 1 according to the specifications required by the customer evaluates the weighing accuracy will be described.

  First, the manufacturer's operator selects the accuracy evaluation test mode by operating the mode switching key of the input unit 13 after completing the adjustment of the weighing accuracy. When the accuracy evaluation test mode is selected, the data in the storage area for storing the dynamic weighing value and the like in the memory 12 is reset.

The operator sets the allowable accuracy ± a (g) of the static weighing value by operating the operation keys of the input unit 13 and sets the number of consecutive evaluation tests N (times) based on the customer's required specifications. . As a result, the allowable variation width E = 2 · a of the static measurement value is calculated, and further, the right side E / {(N + 1) / N} ^{1/2 serving as} the evaluation criterion of the above equation (8) is calculated.

  The operator 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, a dynamic weighing test in which the sample article is weighed while being conveyed on the weighing conveyor 3 is repeated until the number N of continuous evaluation tests is reached unless the weighing accuracy is evaluated as poor. The dynamic metric value obtained by each dynamic metric is sequentially stored in the maximum value register and the minimum value register of the memory 12. The first obtained dynamic weighing value is stored in both registers and registered as the maximum value and the minimum value, and the maximum variation width of the dynamic weighing value R = the maximum register value−the minimum value register value is calculated. First, the maximum variation width R = 0.

  Next, the obtained dynamic metric value is compared with the maximum value and the minimum value, respectively. If it is larger than the maximum value, the value of the maximum value register is updated to the dynamic metric value. The value of the value register is updated to the dynamic metric value, and the maximum variation width R is calculated.

  Each time the dynamic measurement value is acquired and the maximum variation width R is calculated, it is determined whether the maximum variation width R satisfies the above formula (8), which is the evaluation criterion, and the number of continuous evaluation tests When the maximum variation width R based on the dynamic weighing values acquired by all N dynamic weighings always satisfies the above equation (8), it is evaluated that the weighing accuracy is good and acquired. Based on the N dynamic weighing values and the static weighing value Ws of the sample article, a correction value is calculated and stored in the memory 12, and the fact that the accuracy evaluation test mode is completed is displayed on the display unit 14. To do.

  When the maximum variation width R calculated by acquiring the dynamic weighing value does not satisfy the above equation (8), even if the number of dynamic weighing tests has not reached the number N of continuous evaluation tests, at that time The display unit 14 displays that the weighing accuracy is evaluated as poor and readjustment is to be performed.

  As a result, an operator who knows that the weighing accuracy is poor can readjust the weighing accuracy again without performing N dynamic weighings, which is the scheduled number of continuous evaluation tests, and then return to the accuracy evaluation test mode. Reassess the weighing accuracy with.

  In this embodiment, as described above, when the measurement accuracy is evaluated to be good in the accuracy evaluation test mode, the above-described ((8) or more appropriate dynamic measurement values satisfying the above equation (8) are used. A correction value is calculated according to the formula (1) or (3), and the correction value is stored in the memory 12.

  N or more appropriate dynamic weighing values for calculating the correction value are all accurate dynamic weighing values satisfying the above equation (8), and the dynamic weighing values having large variations, for example, accidentally Dynamic measurement values that are not suitable for calculating correction values, such as dynamic measurement values that include mechanical noise such as floor vibration and wind that occur, and electrical noise due to electromagnetic waves are excluded, so accurate correction values are calculated. be able to.

  In this manner, the manufacturer ends the accuracy evaluation test mode, and the weight sorter 1 in which the correction value is stored is delivered to the customer. In the above-described operation operation mode in which the customer sorts the article, the article 6 to be sorted is weighed while being conveyed by the weighing conveyor 3 to obtain a dynamic weighing value, and the CPU 11 obtains the dynamic weighing value from the accuracy evaluation test. A static metric value, which is a corrected dynamic metric value, is calculated using the correction value obtained in the mode. Further, the CPU 11 as the determining means compares the calculated static weighing value with the upper limit value and the lower limit value to determine a non-defective product within the normal weight range and a defective product with excessive or insufficient weight, and the determination. Based on the result, a sorting device (not shown) on the downstream side of the carry-out conveyor 4 sorts the articles 6. Therefore, the customer does not need to obtain a correction value for correcting the dynamic weighing value to the static weighing value.

  In addition, in a conventional weight sorter, when trying to evaluate whether the weighing accuracy satisfies the allowable accuracy of static weighing values, first, a dynamic correction value is obtained by performing a dynamic correction test. It is necessary to perform an accuracy evaluation test that verifies the result of correcting the dynamic weighing value to the static weighing value using the dynamic correction value. According to this embodiment, it is necessary to perform the accuracy evaluation test again. There is no.

  The dynamic weighing value, the correction value, the static weight value of the sample article, etc. acquired in the accuracy evaluation test mode stored in the memory 12 can be displayed on the display unit 14 by operating the input unit 13. It can also be transmitted to a personal computer connected to the weight sorter 1 or printed out by a printer.

  In addition, the memory 12 stores the number of dynamic measurements necessary for calculation of the standard deviation of the dynamic measurement values, the square addition value, and the like instead of the individual dynamic measurement values. You may make it memorize | store a value.

  As a result, the standard deviation of the static weighing value obtained by correcting the dynamic weighing value with the correction value, the maximum value and the minimum value of the static weighing value can be calculated and displayed on the display unit 14 or printed by a printer. As the evaluation result of the measurement accuracy, it can be confirmed whether or not the static measurement value satisfies the allowable accuracy.

  Next, an example of the accuracy evaluation test mode will be described with an example of specific numerical values. Here, an example will be described in which the measurement accuracy is evaluated by operating the accuracy test evaluation key of the input unit 13 after continuously performing N dynamic weighings that are the number of continuous evaluation tests.

  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 number of consecutive evaluation tests N is 20. Yes, 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).

Therefore, the right side of the above equation (8), which serves as an evaluation criterion as to whether the measurement accuracy satisfies the allowable accuracy, is
E / {(N + 1) / N} ^1/2
= 1.2 / {(20 + 1) / 20} ^1/2
= 1.2 / (21/20) ^1/2
= 1.171
It becomes.

  Dynamic weighing in which sample articles are weighed while being conveyed by the weighing conveyor 3 is repeated 20 times. Assume that 20 dynamic weighing values from 1 to 20 are obtained.

  In Table 1, the average value and standard deviation of the 20 dynamic weighing values obtained are shown together.

  When the dynamic weighing is completed 20 times and the operator operates the accuracy test evaluation key of the input unit 13, the maximum variation width R is calculated based on the maximum value and the minimum value, and the measurement accuracy is evaluated.

  In the example of Table 1, since the maximum value = 151.0 and the minimum value = 149.4, the maximum variation width R = 1.6> 1.171, and the above equation (8) is not satisfied.

  Since the dynamic weighing values that do not satisfy the allowable accuracy are included in the 20 dynamic weighing values, the display unit 14 displays that the weighing accuracy is poor and that readjustment should be performed.

  The operator re-adjusts the weight sorter 1 and then repeats dynamic weighing 20 times while the sample article is conveyed again by the weighing conveyor 3, for example, No. 1 shown in Table 2 below. Assume that 20 dynamic weighing values from 1 to 20 are obtained.

  When the operator operates the accuracy evaluation test key of the input unit 13, the maximum variation width R is calculated based on the maximum value and the minimum value, and the weighing accuracy is evaluated.

  In the example of Table 2, the maximum value = 149.9, the minimum value = 149.4, and the variation width R = 0.5 <1.171, which satisfies the above expression (8).

Since all of the N dynamic measurement values acquired by 20 continuous dynamic measurements satisfy the evaluation criteria, the display unit 14 displays that the accuracy evaluation test mode has been completed. In this case, since all of the 20 dynamic weighing values are appropriate dynamic weighing values that satisfy the evaluation criteria and are within the allowable accuracy, the dynamic correction value wd is, for example, Calculation is performed according to the above equation (1). In this case, Wpa which is an average value of P dynamic dynamic values in the formula (1) is W _N a which is an average value of N (= 20).

wd = W _N a−Ws
= 149.6-150.0
= -0.4 (g)
The calculated dynamic correction value wd is stored in the memory 12.

  In this way, the weighing accuracy is evaluated as good by satisfying the allowable accuracy of the static weighing value based on the customer's required specifications, and the correction value is calculated and stored based on the correct dynamic weighing value. 1 is delivered to the customer.

  On the customer side, when actually selecting the product, the operation mode is selected, and when the dynamic weighing value Wx of the article to be sorted is obtained, the static weighing value (= corrected movement value) of the article is obtained. The target measurement value Wsx is calculated using the dynamic correction value wd stored in the memory 12 according to, for example, 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 accuracy evaluation test mode, the dynamic weighing value obtained by correcting the dynamic weighing value with the correction value, that is, the static weighing value is defined so as to satisfy the allowable accuracy (( 8) Since the measurement accuracy is evaluated using the evaluation criteria of the equation, it is possible to accurately evaluate the measurement accuracy in consideration of the allowable accuracy of the static measurement value, and at the same time, obtain a dynamic correction value that satisfies the allowable accuracy. be able to.

  In the conventional weight sorter, when trying to evaluate whether the weighing accuracy satisfies the allowable accuracy of the static weighing value, the operator first confirms that the dynamic weighing value satisfies the allowable accuracy. Later, a dynamic correction test is performed to obtain a correction value, and the dynamic weighing value is corrected to a static weighing value by the correction value obtained in the dynamic correction test. The static weighing value finally satisfies the allowable accuracy. You must evaluate whether or not to do so.

  Even if the dynamic weighing value satisfies the allowable accuracy, when the dynamic correction test for obtaining the correction value is performed, the number of dynamic weighing in the dynamic correction test is too small and the error included in the correction value is It can be large against the true deviation or accidentally mixed with mechanical noise such as floor vibration or wind, or electrical noise due to electromagnetic waves during work of the dynamic correction test. It is necessary to carry out a final accuracy evaluation check using static weighing values corrected for the values.

  Therefore, in the conventional accuracy evaluation, even if the accuracy is evaluated using the dynamic weighing value, the final accuracy evaluation work must be additionally performed with the corrected static weighing value as long as dynamic correction is necessary. .

  In addition, if the final accuracy evaluation work using such static weighing values does not satisfy the allowable accuracy, it will return to the previous work and carry out the dynamic correction test more times than the previous work, so that a large number of dynamic weighing tests will be performed. Calculate the fluctuation range of the correction value according to the value, and perform the final accuracy evaluation again with the static measurement value, or perform the dynamic correction test in an appropriate environment while checking the surrounding noise environment By doing so, it is necessary to obtain a correct correction value and then perform the final accuracy evaluation work using the static weighing value obtained by correcting the dynamic weighing value again by the accuracy evaluation test, which increases the work procedure.

  On the other hand, in the accuracy evaluation test mode of this embodiment, as described above, the dynamic weighing value obtained by correcting the dynamic weighing value with the correction value, that is, the static weighing value is defined so as to satisfy the allowable accuracy. Since the measurement accuracy is evaluated using the evaluation criteria of the above equation (8), when it is evaluated that the measurement accuracy is good, a dynamic correction test is performed again to obtain a correction value, or a dynamic value can be determined by the calculated correction value. It is not necessary to correct the weighing value to a static weighing value and perform a final accuracy evaluation again by using the static weighing value, and the weighing accuracy evaluation work can be simplified.

  Furthermore, in the accuracy evaluation test mode, when the weighing accuracy is evaluated as good, the correction value is calculated using the acquired appropriate dynamic weighing value. It is possible to eliminate dynamic measurement values with large variations obtained under inappropriate conditions, such as when 1 accidentally receives large floor vibrations or winds, or when the sample article is not properly transported during testing. This makes it possible to calculate an accurate correction value 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.

  As described above, when the measurement accuracy is evaluated to be good by the accuracy evaluation test mode, the correction value for converting the dynamic measurement value to the static measurement value is calculated. It is not necessary to perform a final accuracy evaluation test using a dynamic correction test and a static weighing value corrected with the obtained correction value, and work time can be shortened. In addition, since the correction values are calculated based on a sufficiently large number of dynamic weighing values obtained in the accuracy evaluation test mode, even if the dynamic weighing values vary, the true dynamic correction caused by the variation Since the deviation, which is an error from the value, is small, an accurate static measurement value can be obtained during operation.

  Further, in this embodiment, in the accuracy evaluation test mode, when it is evaluated that the measurement accuracy is poor, the display unit 14 even if the number of dynamic weighing of the sample article has not reached the number N of continuous evaluation tests. Therefore, the operator can immediately end the accuracy evaluation test mode and adjust the measurement accuracy, thereby improving work efficiency.

  In the above-described embodiment, when the measurement accuracy is evaluated as good in the accuracy evaluation test mode, the correction value is calculated based on the N dynamic measurement values and stored in the memory 12. As an embodiment of the present invention, after calculating the correction value, the N dynamic weighing values are converted into static weighing values by correcting with the correction values, and all the static weighing values are converted into the static weight value of the sample article. It may be determined whether or not the range of Ws ± a (g) is satisfied centering on Ws, and the final accuracy evaluation is performed. In this case, when all the static measurement values satisfy the range of Ws ± a (g), the final accuracy evaluation is good, the accuracy evaluation test mode is terminated, and the correction value at that time is stored in the memory 12. Remembered. If any of the static weighing values does not satisfy the range of Ws ± a (g), the final accuracy evaluation is poor, and the weighing accuracy is adjusted again.

  In the above-described embodiment, the maximum variation width R of the dynamic weighing value is used as the evaluation standard of the weighing accuracy. However, as another embodiment of the present invention, N dynamic weighing values are set in the accuracy evaluation test mode. At the time of acquisition, a sigma value that is a standard deviation value of N dynamic weighing values is calculated, and values such as 6 sigma, 7 sigma, and 8 sigma are used instead of the maximum variation width R in the above equation (8). The weighing accuracy may be evaluated.

  In the above-described embodiment, the case where the manufacturer evaluates the measurement accuracy has been described. However, the customer may evaluate the measurement accuracy in the same manner, or may perform a dynamic correction test for obtaining a correction value. Of course.

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 (7)

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 evaluate the weighing accuracy, it is equipped with an accuracy evaluation mode in which dynamic weighing is performed a plurality of times while the sample article is conveyed, and a plurality of dynamic weighing values are sequentially obtained.
The dynamic weighing value sequentially acquired in the accuracy evaluation mode includes an evaluation unit that evaluates the accuracy of the weighing accuracy according to whether or not the evaluation criteria are continuously satisfied for a preset number or more.
A weighing device characterized by that. The evaluation means evaluates the measurement accuracy as poor when the dynamic measurement values sequentially acquired in the accuracy evaluation mode do not satisfy the evaluation criteria;
The weighing device according to claim 1. The evaluation standard of the evaluation means defines an allowable range of variation of the dynamic metric value,
The weighing device according to claim 1 or 2. 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 of the article,
The evaluation criterion of the evaluation means is defined based on the allowable accuracy of the correction weight value in the weighing mode and the set number.
The weighing device according to any one of claims 1 to 3. Informing means for informing the evaluation result by the evaluating means,
The weighing device according to any one of claims 1 to 4. When the weighing accuracy is evaluated to be good by the evaluation means, the weighing mode is determined based on the dynamic weighing value that is equal to or more than the set number that satisfies the evaluation criteria and the static weight value of the sample article. A calculation means for calculating the correction value;
The weighing device according to claim 1. 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 6.

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