JP5329205B2 - Combination scale - Google Patents

Description

  The present invention relates to a combination weigher.

  In general, a combination weigher is provided with a plurality of measuring instruments, and various weights of articles weighed by these measuring instruments are combined, and the total weight of each combination is defined by an allowable lower limit weight, for example, a target weight and an allowable upper limit weight. Select a combination that is within the allowable range and is equal to or closest to the target weight. An example of such a combination weigher is disclosed in Patent Document 1.

  According to the technique of Patent Document 1, a feeder that supplies articles to the weighing instrument is provided, and when the target value Wt of the combination weight and the number of articles constituting the selected combination are M, The feeder is controlled so that the supply amount becomes Wt / M.

Japanese Patent Publication No. 2-6007

  The weight of the articles weighed by the combination weigher varies depending on the manufacturing process and product type, and is normally distributed. Therefore, the combination weight is also normally distributed. Assuming that the average combination weight is Wa, the target weight is Wt, and the allowable upper limit weight is Wu, the relationship between the cumulative distribution of combined weights, the allowable upper limit weight Wu, and the target weight Wt is the combination average weight Wa. According to the change, it changes as shown in FIGS. In FIG. 1, a hatched area between the allowable upper limit weight Wu and the target weight Wt is an allowable upper / lower limit range, for example, a selected weight range, and a combination weight distributed in this range is a selection target. .

  In the cumulative distribution for a very large number of combination weights as shown in FIG. 1, there are many combination weights in the selected weight range. In an actual combination weigher, there are only a few combination weights for articles weighed by a very few predetermined scales. Accordingly, the selected weight range exists in a region having a value smaller than the combined average weight Wa as shown in FIG. 1A, or the selected weight range has a value larger than the combined average weight Wa as shown in FIG. There is a possibility that the relationship between Wu, Wt and the cumulative distribution may change until a situation exists in the region, and there may be no combination weight included in the selected weight range. On the other hand, if the combination average weight Wa exists within the selected weight range as shown in FIGS. 5 (c) and (d), it is determined from a small number of combination weights composed of articles weighed by a very small number of measuring instruments. Even in the case of selection, there is a high possibility that many combination weights are included in the selection weight range to some extent.

  In this case, if the combination weight of M pieces is slightly larger in the vicinity of Wt, if the state shown in FIG. 6D is created, most of the M combination weights are larger than Wt and close to Wt. The combination weights that fall within the range increase, and among the combination weights that fall within the selected weight range, the deviation between the combination weight selected as being closest to Wt and Wt increases.

  On the other hand, if the weight of the article is too large or too small for Wt / M, most of the combined weights do not fall within the selected weight range, and even if they are within the selected weight range, they are selected far away from Wt. Therefore, even if it can be selected, the deviation from Wt becomes large and the yield deteriorates.

  In the technique of Patent Document 1, by controlling the feeder, the weight of the articles supplied to each measuring instrument is made close to Wt / M, so that the states shown in FIGS. 1C and 1D can be realized. The combination selection is surely established, the production capacity of the combination weigher can be increased, and the deviation from Wt is reduced to improve the yield.

  However, if the articles are one or a few solids, the weight of each article itself cannot be finely adjusted, and the combined weight also depends on the variation in the weight of the articles supplied to the scale. The For example, when the article is a primary product such as fish or fruit, the supply weight cannot be finely adjusted, and the supply weight changes stepwise.

  Even in such a case, it is necessary to realize an appropriate deviation and production capacity from the production start time. However, in the case of a manual combination weigher, the production capacity depends on how efficiently the selection of the combination is performed if the ability of the operator handling the article is the same.

  As described above, in a combination weigher of a type in which the supply weight of an article cannot be finely controlled due to the properties of the article, an appropriate deviation cannot be automatically obtained by applying the technique of Patent Document 1.

  Further, in the combination weigher, the combination weigher closest to Wt among the combination weighers belonging to the selected weight range is selected. Therefore, the portion close to Wt with respect to the area of the selected weight range in FIGS. The larger the area, the greater the number of combination weights close to Wt, and the combination weight is selected from these. Therefore, there is a high probability that the deviation will be small, that is, the average deviation will be small. For example, in the comparison between (e) and (b) in FIG. 1 and the comparison between (f) and (a), the average deviation is smaller in (e) and (f). Also in the comparison between (c) and (d), the average deviation is smaller in (d).

  For example, when the combined average weight Wa increases from the state shown in FIG. 1D and approaches the state shown in FIG. 1B, the area of the selected weight range decreases, so the selection probability decreases, and the area near Wt also decreases. Therefore, the ratio of the distribution range of the selected weight to the distribution range of all the combined weights, that is, the selection probability in the selected weight range of the combined weight is reduced, and the area near Wt is also reduced, so that the average deviation is increased. Further, when the combined average weight Wa decreases from the state shown in FIG. 1D and approaches the state of FIG. 1E, the area of the selected weight range decreases, so the selection probability decreases, but the area near Wt is Since it becomes larger, the average deviation becomes smaller.

  The two parameters of selection probability and average deviation are set in the initial state so that the combination average weight Wa exists in the selected weight range and the combination average weight Wa is close to Wt as shown in FIG. Even then, the above two parameters do not both become good due to the subsequent change in the combined average weight Wa, and it is difficult to make both parameters simultaneously good unless the weight of the article is adjusted. .

  The larger the selection probability, the more reliable the combination weight is selected in the combination operation, and the production capacity is improved.

  However, depending on the convenience of the product to be produced, depending on the combination weigher, even if the selection probability is lowered, if you want to maintain the product deviation to the desired value, or conversely increase the product deviation, maintain the production capacity. You may want to

  Further, there are cases where it is desired to realize the selection probability and the deviation in a well-balanced manner, and it is advantageous if both the deviation and the selection probability of the product in operation can be estimated by Wu and Wt set at the start of operation.

  In addition, even if the target selection probability and the estimated deviation of the product determined by setting Wu and Wt at the start of the work are different from the actual values generated during operation, the difference is calculated. In order to make correction easy by stopping in a small range, and to avoid frequent correction of Wu and Wt during operation, it is desirable to set an appropriate value at the work site at the start of operation.

  The present invention estimates the selectivity index value indicating the difficulty of the selectivity of a combination product belonging to the selection weight range, such as the selection probability, and the average weight or deviation of the selected combination product at the time of setting the selection weight range. It is an object of the present invention to provide a combination scale that can be used.

One aspect of the combination weigher according to the present invention selects a combination in which the weight is normally distributed, the weights of individual items composed of one or a small number of solids are variously combined, and the combined total weight is within an allowable upper and lower limit range. Is. The individual product has a relatively large shape, and the amount supplied to the weighing means of the combination weigher changes only in a step shape. It is desirable that the selected combination is close to the lower limit of the allowable upper and lower limit range. This combination weigher includes a combination weight simulation generating means for generating various simulated combination weights of the individual articles based on the weight distribution of the individual items collected in advance, and a preset allowable upper limit weight among the simulated combination weights. And a simulation selecting means for selecting those within the allowable upper and lower limit range defined by the allowable lower limit weight. Further, an average estimated value calculation means for calculating an average value of the selected simulated combination weights and / or a combination selectivity for calculating a selectivity index representing selection difficulty related to the total number of the selected simulated combination weights An index estimated value calculating means is provided. The deviation of the average value of the simulated combined weight from the allowable lower limit weight can also be calculated. As the selectivity index estimated value calculation means, it is assumed that _N C _M combination weights calculated from the number N of measuring instruments and the target combination number M are normally distributed. The number of certain combination weights can be used as a means for calculating the selection probability.

  In this way, the average deviation of the combined weight or the deviation of the average value of the simulated combined weight and the selectivity index are calculated from the set value of the selected weight range based on the statistical value of the individual product, and the selectivity index is calculated. Output, before running the combination weigher or before producing many combinations, the average weight or average deviation and / or selectivity index of the selection of combination weights actually occurring at the work site Can be set to be realized as a value close to the average deviation and the selectivity index. Even if there is a need to correct the selected weight range in order to match the average deviation that actually occurs during operation, the setting can be easily and quickly corrected because the difference is small.

  In addition, a first setting unit for manually or automatically setting a plurality of allowable upper and lower limit ranges is provided, and for each of the set allowable upper and lower limit ranges, the plurality of selected simulated combination weights are set. An average value or a deviation between the average value and the allowable lower limit weight and / or a selectivity index can be calculated. Further, an allowable upper / lower limit range to be set is determined from an average value of the calculated plurality of simulated combined weights or a deviation between the average value and the allowable lower limit weight and / or a selectivity index, and the second setting is determined. Depending on the part, it can also be set to a combination weigher.

  As described above, according to the present invention, an average value of combined weights or a deviation from a target weight value that is an allowable lower limit weight and / or a selectivity index can be estimated, and based on these, an allowable upper and lower limit can be estimated. It can be used to help set the range, or an allowable upper and lower limit range can be set.

  The combination weigher of one embodiment of the present invention is a manual combination weigher. The manual combination weigher manually performs an operation of placing an article on a weighing instrument and an operation of removing the article selected for combination from the weighing table. The article used in this embodiment is an individual article, for example, a regular article, specifically an agricultural product or a marine product, and the supply amount of the article to the measuring instrument does not change continuously but changes step by step. Is.

  As shown in FIG. 2, the combination weigher includes a plurality of, for example, N measuring devices 2-1 to 2 -N. Since these measuring instruments 2-1 to 2-N have the same configuration, only the configuration of the measuring instrument 2-1 will be described. The measuring device 2-1 has measuring means, for example, a load cell 4. The load cell 4 is connected to a weighing table (not shown), and the load cell 4 generates an analog weighing signal indicating the weight of an article placed on the weighing table. The analog weighing signal is amplified by the amplifier 6, converted into a digital weighing signal by the A / D converter 8, and supplied to the measuring instrument control means, for example, the CPU 12 via the input / output interface 10. The CPU 12 uses the memory 14 as a work area according to a program stored in a memory 14 such as a ROM, RAM, EEPROM or the like, and processes the digital weighing signal to calculate the weighing value of the article. The measured value is transmitted to the control device 18 via the serial data communication line 16.

  The control device 18 creates a plurality of combinations based on the respective measured values transmitted from the respective measuring devices 2-1 to 2 -N. From these combinations, the control device 18 selects the one whose total weight is between the predetermined target weight Wt and the allowable upper limit weight Wu set larger than this, and is equal to or closest to the target weight Wt. That is, the target weight Wt is used as the allowable lower limit weight value.

  The control device 18 notifies that the measuring instrument on which the articles constituting the selected combination are placed among the measuring instruments 2-1 to 2-N is selected via the communication line 16, This is indicated by the lighting of the display means provided in each of the measuring devices 2-1 to 2 -N, for example, the lamp 30.

  Among the measuring instruments 2-1 to 2 -N, the article is removed from the measuring instrument whose lamp 30 is lit, and a new article is placed on the empty measuring instrument, and the processing is performed again as described above. Is called.

  In order to perform such control, the control device 18 includes control means, for example, a CPU 20. The CPU 20 operates using the memory 22 as a work area in accordance with a program stored in a memory 22 composed of storage means, for example, ROM, RAM, EEPROM, or the like. The CPU 20 receives weighing values from the weighing devices 2-1 to 2-N via the input / output interface 24. Further, data such as the target weight Wt and the allowable upper limit weight Wu used for creating the above combination is set by the setting unit 26 and supplied from the setting unit 26 to the CPU 20 via the input / output interface 24. The set data is displayed on the display unit 28 via the input / output interface 24. Further, the number of combinations selected as a result of processing by the CPU 20 is also displayed on the display unit 28.

  In this combination weigher, before its operation, the CPU 20 determines the average deviation Ea and the selectivity index, for example, the index value P of the selection probability, from the set target weight Wt and allowable upper limit weight Wu and the distribution probability of the combination weight. And calculate. The CPU 20 functions as an average deviation estimated value calculating means and a selection probability estimated value calculating means. The average deviation Ea and the index value P of the selection probability are displayed on the display unit 28. From the displayed average deviation Ea and the index value P of the selection probability, the previously set allowable upper limit weight Wu and allowable lower limit weight are set. Can be reviewed by workers. Further, since the average deviation Ea and the index value P of the selection probability are derived based on the statistical data of the article as will be described later, the estimated value is close to the value actually generated during the operation operation. If the estimated value is different from the target value, it is expected to be close to the target value, and the allowable upper limit weight Wu and the target lower limit weight Wt can be easily set so that the estimated value is close to the target value. Can be corrected promptly.

  In order to calculate the average deviation Ea and the index value P of the selection probability, the weights of the articles on the measuring instruments 2-1 to 2-N are investigated and recognized before the combination weigher is operated, and the average weight wa and the standard deviation σ ′ (= ws), the number N of measuring instruments constituting the combination weigher, and the number M of articles constituting the combination are set and input to the CPU 20. The CPU 20 can automatically input the weight of each article, collect the average weight wa, and the standard deviation σ ′ by the CPU 20. It is assumed that the weight of each article is normally distributed. Note that the weights of the respective articles are approximately equal, and the total weight of the M articles is approximately the target weight Wt.

Based on the average weight wa and the standard deviation σ ′, the CPU 20 calculates an average value Wa = M * wa, standard deviation σ = M ^1/2 * ws = Ws, and the number _N C _M of the combination weights.

If it is necessary to take into account the variation in the measurement value of the measuring instrument applied to the combination weigher, the standard deviation of the measurement value variation in the measurement value of the combination weighing instrument is set to σw, If the standard deviation of the weight variation of the article itself is σ ″, the standard deviation σ ′ of the weight value of the article is set by setting σw and σ ″,
σ ′ = (σw ² + σ ′ ² ) ^1/2 = ws
And calculate the standard deviation of the article weight and the standard deviation of the combined weight.

  Next, the operator operates the setting unit 26 to set the target weight Wt. Since the target weight Wt is not appropriate if it is far from the remainder Wa, it is set in the range of Wa> Wt> Wa-3σ = Wa-3 * Ws. Since the allowable upper limit weight Wu cannot be a weight far from Wa, Wa + 3σ = Wa + 3 * Ws> Wu> Wa is set. Wa + 3σ = Wa + 3 * Ws> Wu> Wt ≧ Wa may be set.

  In the combined weight distribution shown in FIGS. 1A to 1F, the range surrounded by Wu and Wt is the allowable upper and lower limit range, that is, the selected weight range. Of each combination weight, those within the selected weight range are selected. However, when a plurality of combination weights exist within the selected weight range, the one closest to Wt is selected.

  The narrower the width of the selected weight range (interval between Wu and Wt), the better the average value of the deviation of the combined total weight from the target weight Wt (the one closer to Wt is selected). However, the probability that the combined total weight falls within the selected weight range, that is, the selection probability is reduced. In order to allow many combination weights to be included in the selected weight range while the interval between Wt and Wu is narrow, the combination average weight Wa is set to the allowable upper limit weight Wu as shown in FIGS. It is necessary to set the allowable upper limit weight Wu and the target weight Wt such that the target weight Wt is sandwiched between the upper limit weight Wu and the target weight Wt.

  The maximum deviation value of the combination product during the operation operation can be determined by Wu−Wt. However, the average deviation of the combination product cannot be immediately estimated from Wu and Wt. In addition, it is not possible to immediately estimate the index value of the selection probability, which is a value indicating the degree to which the combination product is selected, such as the ratio of the combination weight within the selected weight range to the total combination weight. Hereinafter, a method for setting the index values of the average deviation and the selection probability by setting Wu and Wt in the combination weigher will be described.

  In this combination weigher, as described above, the average deviation Ea and the index value P of the selection probability are calculated, and this calculation mode is referred to as a statistical data calculation mode. By the operation of the setting unit 26, with the combination weigher set to the statistical data calculation mode, the individual articles to be used for creating the combination product are placed on the weighing devices 2-1 to 2-N and weighed. This is repeated a plurality of times, the weight values of many individual items are acquired, and the average weight wa and standard deviation ws of the individual items are calculated and stored in the memory 14.

  Since the standard deviation ws of the individual articles obtained in this way includes the variations of the measuring instruments 2-1 to 2 -N, the calculation for including the measuring instrument variations described above is performed in this embodiment. Not performed.

  If the statistical data of the individual article is known in advance, the average weight wa and the standard deviation ws of the individual article can be set by the setting unit 26 without being calculated.

  Of the measuring instruments 2-1 to 2 -N, the number of measuring instruments used for the combination is set by the setting unit 26. When all the measuring instruments are used, they may be stored in the memory 14 in advance or manually set by the setting unit 26. Here, it is assumed that the number N of all measuring instruments is set.

  The setting unit 26 sets a target value M for the number of combinations. If there is a possibility that combination selection may be realized even with a different number of combinations from the relationship between the variation in the weight of the individual articles and the target weight, the number with the highest probability of selection is set as M.

When the number N of scales and the target combination number M are set, the number of combination products calculated by each combination calculation is
_N C _M = N! / M!・ (NM)!
Is calculated by Further, the combined average weight Wa = M · wa and the standard deviation Ws = M ^1/2 · ws are calculated and estimated. The estimated combination average weight Wa and standard deviation Ws are displayed on the display unit 28.

  As the selected weight range, the target weight Wt and the allowable upper limit weight Wu that have the meaning as the allowable lower limit weight are set by the setting unit 26, and the combination selection work count Q is set by the setting unit 26.

  The control unit 18 includes simulation calculation means, and the simulation calculation is performed as follows by operating the estimation calculation execution key in the setting unit 26 after the data as described above is set. .

  The simulation calculation means includes a combination weight simulation generation means, for example, a combination weight random number generation means. This combination weight random number generation means calculates a combination weight obtained by selecting and combining M pieces out of N measuring instruments. Various occurrences occur in a state of normal distribution under the conditions of the combination average weight Wa and the standard deviation Ws.

By selecting and combining M pieces out of N measuring instruments, _N C _M combination weights can be created. Therefore, _N C _M weights generated by the combination weight random number generating means can be combined once. The various combined weights obtained as a result of

  Each of these combination weights is compared with the selected weight range, and it is determined whether or not it belongs to the selected weight range by the simulated selection means. Based on the combination selection principle, it is within the selected weight range and is equal to or closest to Wt. This is a combination selection item in one combination operation. The combination weight of this combination selection product is Wm. Wm is accumulated each time the combination work is performed, except that no combination belongs to the selected weight range in one combination work. Further, the number of combination operations C3 is also counted. Of the number of times of combination work, the number of times that at least one combination product is selected (the number of times the combination weight belongs to the selected weight range) C4 is also counted.

Further, during one combination operation, the number of combinations C1 belonging to the selected weight range is counted, and the ratio P1 (= C1 / _N C _M ) of the count value C1 to the number _N C _M of all combinations is combined. Ask for each work. This ratio P1 is an index value of the selection probability of the combination product. If the index value of the selection probability is too small, the number of combinations belonging to the selected weight range is small, making it difficult to select a combination weight having a small deviation from the target weight Wt, and reducing the probability that a combination product is selected. As a result, combinations often fail to be established and production efficiency decreases. Each time the simulated combination work is performed, the ratio P1 obtained by the simulated combination work is accumulated.

  When the predetermined number Q of combination operations is completed, the added combination selection product weight is divided by the accumulated value C4 of the selected number of combination products, and the target weight Wt is subtracted from this division value, thereby performing simulation calculation. The average deviation Ea of the combination product at is calculated. Further, the accumulated value of the ratio P1 is also divided by the combination product selection work count C3 to obtain an average value P of the selection probability index.

  A value obtained by dividing the number of times C4 at which the combination product is selected by the number of times of combination work Q can also be used as an index of selection probability.

  3 and 4 show a flowchart of the above-described simulation calculation. In FIG. 3, first, the combination weight register Wm of the combination selection product, the combination weight accumulation register ΣWm of this combination selection product, the counter C1 of the number of combinations belonging to the selection weight range, and generated during one combination operation. The selected combination weight counter C2, combination product selection counter C3, combination product selection counter C4, and combination product selection probability index accumulation register ΣP1 are set to 0 (step S2). ).

Next, the allowable upper limit weight Wu is stored in the combination weight register Wm of the combination selection product (step S4). This is a preparation for obtaining a combination weight closest to the target weight Wt in the combination calculation. Next, a combined weight Wx that is normally distributed under the condition that the average weight is wa and the standard deviation is ws is randomly generated (step S6). It is determined whether the combined weight Wx is not less than the target weight Wt and not more than the allowable upper limit weight Wu, that is, it belongs to the selected weight range (step S8). If the answer to this determination is yes, the value of the counter C1 is incremented by 1 (step S10). Next, it is determined whether the combination weight Wx is smaller than the allowable upper limit weight Wu (step S12). If the answer to this determination is yes, the value of the register Wm is changed to Wx (step S14). Following this, or if the answer to the determination in step S8 or S12 is no, the value of the counter C2 is incremented by 1 (step S16). Next, it is determined whether the value of the counter C2 is equal to or greater than the number of all combinations _N C _M (step S18). If the answer to the determination is no, the process is executed again from step S6. Therefore, when the answer to the determination in step S16 is yes, the counter C1 counts the number of combination weights belonging to the selected weight range, and the register Wm stores the target weight among the combination weights belonging to the selected weight range. A value equal to or closest to the weight Wt is stored.

Next, as shown in FIG. 4, the ratio P1 is calculated by dividing the value of the counter C1 by the number _N C _M of all combinations (step S20). Then, the value of the counter C3 that counts the number of times of combination work is incremented by 1 (step S22). Next, it is determined whether the value of the counter C1 is not zero (step S24). That is, it is determined whether at least one combination weight belonging to the selected weight range exists during one combination operation. If the answer to this determination is yes, the value of the register Wm storing the weight equal to or closest to the target weight Wt among the combination weights generated in the current combination work is accumulated in the accumulation register ΣWm, and the combination product The selection probability index P1 of the combination product calculated this time is accumulated in the selection probability index accumulation register ΣP1, and the number of combination operations in which the combination weight exists within the selected weight range is counted among the number of combination operations. The value of the counter C4 is incremented by 1 (step S26). Subsequent to step S26 or if the answer to the determination in step S24 is no, it is determined whether the value of the counter C3 counting the number of combined operations is equal to or greater than Q (step S28). If the answer to this determination is no, the counters C1 and C2 are reset (step S30) and executed again from step S4.

  Accordingly, when the answer to the determination in step S28 is yes, the accumulation register ΣP1 stores the accumulated value of the selection probability index of the combination product in the Q combination operations, and the accumulation register ΣWm stores the Q value. When the combination weight belongs to the selected weight range in the combination operation of the first time, an accumulated value of the combination weight that is equal to or closest to the target weight Wt is stored, and the counter C4 is within the selected weight range in the combination operation of Q times. The number of times the combination weight belongs is stored.

  If the answer to the determination in step S28 is yes, the accumulated value of the accumulation register ΣP1 is divided by the value of the counter C3 that stores the number of times of combination work, thereby calculating the index value P of the selection probability ( Step S32). Next, the accumulated value of the accumulation register ΣWm is divided by the count value of the counter C4 to calculate a divided value A (step S34). The target weight Wt is subtracted from the division value to calculate the average deviation Ea (step S36), and this process is terminated.

  The average deviation Ea and the selection probability P are displayed on the display unit 28, but can be transmitted to an external device such as a personal computer connected to the combination weigher.

  As the allowable upper limit weight Wu is set closer to the target weight Wt, the weight of the combination product closer to the target weight Wt is selected, so the average deviation Ea becomes smaller, but the selected weight range becomes narrower and narrower. As a result, the index value P of the selection probability becomes smaller, and it becomes difficult to select.

  The operator sets the target weight Wt and the allowable upper limit weight Wu before starting the combination work, and displays the average deviation Ea and the selection probability P on the display unit 28 by executing the above-described simulation calculation. Compared with the average deviation Ea and the selection probability index value P, as a result, an appropriate selection weight range that takes into account the degree of yield and production efficiency of the combined product is set before actually performing the combination work. can do.

  In the above embodiment, the target weight Wt and the allowable upper limit weight Wu are set one by one, and the average deviation Ea and the selection probability index value P corresponding to these are displayed. The average deviation Ea and the selection probability index value P can be calculated and displayed each time the allowable upper limit weight Wu is set. In this case, the previously set target weight Wt and allowable upper limit weight Wu, the average deviation Ea based on them, and the selection probability index value P are simultaneously displayed in, for example, a list display format. When the most appropriate allowable upper limit weight Wu is determined with reference to the average deviation Ea and the selection probability index value P displayed in the list and set by the setting unit 26, the most appropriate allowable upper limit weight Wu is set in the CPU 20. In the operation of the combination weigher, the determined allowable upper limit weight Wu is used. The average deviation is obtained by changing the allowable upper limit weight by fixing the target weight Wt, or by changing the target weight Wt by fixing the allowable upper limit weight, or by changing the allowable upper limit weight and the target weight, respectively. Ea and the selection probability index value P may be calculated and displayed, or the most appropriate allowable upper limit weight Wu and target weight Wt may be set by the setting unit 26 based on this display. .

  A plurality of allowable upper limit weights and / or target weights are set at a time, and the average deviation Ea and the selection probability index value P corresponding to these are all calculated at once and displayed on the display unit 28 in, for example, a list format. You may make it do. In this case as well, the most appropriate allowable upper limit weight Wu and target weight Wt may be set by the setting unit 26 based on this display.

  The above simulation calculation can be performed even while the combination work is continued. For example, a temporary target weight Wt and an allowable upper limit weight Wu are set, a combination operation is performed, a simulation operation is performed while the operation is continued, and an average deviation Ea and a selection probability index value P obtained as a result of the simulation operation And the allowable upper limit weight Wu and the target weight Wt may be corrected.

  The average deviation Ea and the selection probability index value P are estimated values, but are calculated based on the statistical value of the article weight. Therefore, the average deviation obtained by actual work and the combination selection probability index value are the average deviation. The value is close to Ea and the selection probability index P. Even if the actual average deviation and the selection probability index are different from the estimated average deviation Ea and the selection probability index value P, since the difference is small, the actual average deviation and the selection probability index value are estimated. Correction to make the average deviation Ea, which is a value, and the selection probability index value P close to each other can be easily performed.

  In the above embodiment, only one allowable upper limit weight Wu is set, but a means for automatically setting a plurality of allowable upper limit weights may be provided. In this case, when the operator sets one allowable upper limit weight by the setting unit 26 based on his / her prediction, a plurality of, for example, six allowable upper limit weights including the allowable upper limit weight are automatically set. Is done. Therefore, in this embodiment, registers Wu <1> to Wu <6> for storing six allowable upper limit weights are provided, respectively, and a combination weight is stored corresponding to these allowable upper limit weights. Registers Wm <1> to Wm <6> are provided, and a counter for counting the number of combinations belonging to the selected weight range is also defined by C1 <1> to C1 <6>, each allowable upper limit weight and target weight Wt. Counters C4 <1> to C4 <6> for counting the number of times at least one combination is selected in each of the six selected weight ranges, and a cumulative register ΣP1 for accumulating selection probability index values in each allowable upper / lower limit weight range <1> to ΣP1 <6> are provided. Also, counters C2 and C3 are provided as in the above embodiment.

  Then, processing as shown in FIGS. 5 and 6 is performed. Hereinafter, the values stored in the registers Wu <1> to Wu <6> are also expressed as Wu <1> to Wu <6>, and the values of the registers Wm <1> to Wm <6> are also Wm <1> to Wm. <6>, the values of the counters C1 <1> to C1 <6> are also expressed as C1 <1> to C1 <6>, and the values of the accumulation registers ΣP1 <1> to ΣP1 <6> are also ΣP1 <1> to It represents as ΣP1 <6>.

  As shown in FIG. 5, first, each register and counter are initialized (step S2a). Next, the counter q is set to 1 (step S36). Next, the value Wu <q> calculated by Wu + (q−4) wd is stored in the allowable upper limit weight register Wu <q> designated by the counter q (step S38). wd is, for example, a weight value corresponding to the weight accuracy of the combination product or the display resolution of the combination weight. Next, the calculated allowable upper limit weight Wu <q> is stored in the combination weight register Wm <q> of the combination selection product designated by the counter q (step S40). Then, the value of the counter q is incremented by 1 (step S42), it is determined whether it is 7 or more, which is 1 larger than the automatically set allowable upper limit weight number 6 (step S43), and if the answer is no, Execute again from step S38. As a result, when the answer to the determination in step S43 is yes, Wu <1> to Wu <6> are set as the automatically set allowable upper limit weights, and the corresponding combination weights Wm <1> to Wm Corresponding allowable upper limit weights Wu <1> to Wu <6> are stored as <6>.

If the answer to the determination in step S43 is yes, similarly to step S6, a combined weight Wx that is normally distributed under the condition that the average weight is wa and the standard deviation is ws is randomly generated (step S44). Next, the counter q is set to 1 (step S46), and it is determined whether the combined weight Wx is not less than the target weight Wt and not more than the allowable upper limit weight Wu <q> (step S48). If the answer to this determination is yes, the value of the counter C1 <q> is incremented by 1 (step S50). Next, it is determined whether the combined weight Wx is smaller than the allowable upper limit weight Wu <q> (step S52). If the answer to this determination is yes, the value of the register Wm <q> is changed to Wx (step S54). Following this, or when the answer to the determination in step S48 or S52 is no, the value of the counter q is incremented by 1 (step S56), and it is determined whether the value is 7 or more (step S58). If the answer to the determination is no, the process is executed again from step S48. Accordingly, when the answer to step S58 is YES, the number of combined weights that fall within the selected weight range defined by the target weight Wt and each allowable upper limit weight Wu <q> is counted as C1 <q>, and the register Wm < In q>, the weights that are equal to or closest to the target weight Wt among the combined weights belonging to the selected weight range defined by the target weight Wt and each allowable upper limit weight Wu <q> are stored. If the answer to the determination in step S58 is yes, the value of the counter C2 is incremented by 1 (step S60). Next, it is determined whether the value of the counter C2 is equal to or greater than the number of all combinations _N C _M (step S62). If the answer to the determination is no, the process is executed again from step S44. Therefore, if the answer to the determination in step S62 is yes, the counters C1 <1> to <6> have six selections defined by the target weight Wt and the allowable upper limit weights Wu <1> to Wu <6>. The number of combination weights belonging to the weight range is counted, and the registers Wm <1> to Wm <6> include the combination weights belonging to the six selected weight ranges that are equal to or closest to the target weight Wt. Each is remembered.

Then, when the answer to the determination in step S62 is yes, the process of FIG. 6 is executed. In this process, first, the counter q is set to 1 (step S64). Then, C1 <q> is divided by _N C _M , and the selection probability index value P1 <q> which is the division value is stored (step S66). Next, the value of the counter q is incremented by 1 (step S68), and it is determined whether q is 7 or more (step S70). If the answer to this determination is no, the process is executed again from step S66. Therefore, when the answer to the determination in step S70 is yes, the selection probability index values P1 <1> to P1 <6> in the combination work up to the present are calculated.

  Next, the value of the counter C3 counting the number of times of combination work is incremented by 1 (step S72).

  The counter q is set to 1 again (step S74), and it is determined whether C1 <q> is not 0 (step S76). If the answer to this determination is yes, since there is a combination within the selected weight range specified by the counter q, Wm <q> is accumulated by ΣWm <q>, and P1 <q> is accumulated by ΣP1 <q>. The counter C4 <q> is incremented by one (step S78). Following this, or if the answer to the determination in step S76 is no, the value of the counter q is incremented by 1 (step S80), and it is determined whether the value of the counter q is 7 or more (step S82). If the answer to this determination is no, the process is executed again from step S76. When the answer to the determination in step S82 is yes, the cumulative allowable upper limit weights Wm <1> to Wm <6> of each selected weight range in the combination work up to the present, and each selected weight range in the combination work up to now Cumulative selection probability index values ΣP1 <1> to P1 <6>, and the number of times C4 <1> to C4 <6> at which at least one combination weight in each selected weight range in the combination operation up to the present is obtained. can get.

  If the answer to the determination in step S82 is yes, it is determined whether the value of C3 is equal to or greater than a predetermined combination work count Q (step S84). If the answer to the determination is no, the counters C1 <q>, C2 Is reset (step S86), and the process is executed again from step S86. Therefore, when the answer to the determination in step S84 is yes, the cumulative allowable upper limit weights Wm <1> to Wm <6> in each selected weight range in the Q combination operations and each selection in the Q combination operations. The cumulative selection probability index values ΣP1 <1> to P1 <6> of the weight range and the number of times C4 <1> to C4 <6 that at least one combination weight in each selected weight range in the Q combination operations is obtained. > Is obtained.

  If the answer to the determination in step S84 is yes, the value of the counter q is set to 1 (step S88), the value of ΣP1 <q> is divided by C3, and the selection probability index value P < q> is calculated, ΣWm <q> is divided by C4 <q>, an average combination weight A <q> is calculated in Q combination operations, and the target weight Wt is reduced from A <q> to obtain an average deviation. Ea <q> is calculated (step S90).

  Then, the value of the counter q is incremented by 1 (step S92), and it is determined whether the value of the counter q is 7 or more (step S94). If the answer to the determination is yes, the process is executed again from step S90. .

  If the answer to the determination in step S94 is yes, the average deviations Ea <1> to Ea <6> and the selection probability index value P <1> correspond to the allowable upper limit weights Wm <1> to Wm <6>, respectively. Through P <6> are calculated and displayed on the display unit 28. The operator compares the displayed average deviations Ea <1> to Ea <6> with the selection probability index values P <1> to P <6>, and sets the allowable upper limit value used during operation to the setting unit 26. The selected upper limit weight selection key is used for selection by the CPU 20.

  The above description is for automatically setting a plurality of allowable upper limit weights Wu. However, the selected weight range is set such that a plurality of target weights Wt are automatically set according to the allowable upper limit weight Wu together with the allowable upper limit weight. The width may be changed up and down.

  In the above embodiment, the combination weight Wx is generated by the combination weight random number generating means. However, the present invention is not limited to this. For example, individual articles that are normally distributed under the conditions of the average weight wa and the standard deviation ws of each individual product. Weight random number generation means is provided, M combination weights are calculated based on the weight of the individual articles generated, and the average deviation Ea and the selection probability index value P are calculated using the combination weights as described above. May be.

  In the combination weigher of the present invention, if the average weight value of the individual articles increases or decreases during the operation, how much the deviation of the combination product changes to, and how does the selection probability change at this time? As for how the value changes, if a suitable setting value, for example, a value of wa ± α is set instead of wa and an estimation calculation is performed, the result can be estimated easily.

  Even if the combination weigher is equipped with N measuring devices 2-1 to 2-N, use only N '(<N) measuring devices without using all measuring devices. , M ′ (≠ M) combinations may be selected. Even in such a case, what happens to the average deviation Ea and the selection probability index P can be easily simulated by changing the set value.

  In the above embodiment, the combination average weight is calculated and the combination average deviation is further calculated. However, the combination average weight may be used without calculating the combination average deviation. Moreover, although both the combination average deviation and the selection probability index value are calculated, only one of them may be calculated, or only the combination average weight may be calculated.

  In the above embodiment, the present invention is implemented on a manual combination weigher. However, a semi-automatic combination weigher that manually supplies articles and automatically discharges articles, and supplies and discharges articles automatically. The present invention can also be implemented in an automatic combination balance.

It is a figure which shows the change of the weight distribution of the supply article in a combination scale. It is a block diagram of the combination scale of one Embodiment of this invention. FIG. 3 is a partial flowchart of a process of calculating an estimated average deviation and a selection probability index value in the combination weigher of FIG. 2. It is a flowchart of the other part of the calculation process of the estimated average deviation and the selection probability index value in the combination weigher of FIG. It is a flowchart of a part of other example of the calculation process of the estimated average deviation and the selection probability index value in the combination weigher of FIG. It is a flowchart of the remaining part of the other example of the calculation process of the estimated average deviation and the selection probability index value in the combination weigher of FIG.

Explanation of symbols

2-1 to 2-N measuring instrument 18 control unit (average estimated value calculating means)

Claims (13)

In a combination weigher in which the weight is normally distributed, the weights of individual items consisting of one or a few solids are variously combined, and the combination total weight is within an allowable upper and lower limit range,
Based on the weight distribution of the individual items collected in advance, combined weight simulation generating means for generating various simulated combined weights of the individual items;
A simulation selection means for selecting, among the simulation combination weights, a thing that falls within a simulation allowable upper and lower limit range defined by a preset simulation allowable upper limit weight and a simulation allowable lower limit weight;
Average estimated value calculating means for calculating an average value of the selected simulated combination weights ;
Deviation calculating means for calculating a deviation between the average value and the simulation allowable lower limit value;
Display means for displaying the calculated deviation;
A combination scale equipped. In the combination weigher according to claim 1, wherein a plurality of said simulated allowable upper and lower limit range, has a first setting unit for setting either manually or automatically, for each plurality of the simulated allowable upper and lower limit range in which the set A combination weigher that calculates an average value and the deviation of the selected simulated combination weights. In the combination weigher according to claim 2, the simulated acceptable lower range corresponding to one of a plurality of said simulated allowable upper and lower limit range the selected simulated combination weight average values calculated for each, the A combination weigher comprising a second setting unit which is set in the combination weigher as an allowable upper and lower limit range . 4. The combination weigher according to claim 1, wherein the combination weight simulation generation means repeatedly generates a predetermined number of the simulation combination weights a predetermined number of times, and performs the simulation selection. Each time the predetermined number of simulated combination weights are generated, the means selects the predetermined number of simulated combination weights within the allowable upper / lower limit range and equal to or close to the allowable lower limit value. A combination weigher that performs the predetermined number of times, and wherein the average estimated value calculating means calculates an average value of simulated combination weights selected by the simulation selecting means for the predetermined number of times. 5. The combination weigher according to claim 4, wherein the predetermined number is a number having the highest probability of being selected in the combination weigher. In a combination weigher in which the weight is normally distributed, the weights of individual items consisting of one or a few solids are variously combined, and the combination total weight is within an allowable upper and lower limit range,
Based on the weight distribution of the individual items collected in advance, combined weight simulation generating means for generating various simulated combined weights of the individual items;
A simulation selection means for selecting, among the simulation combination weights, a thing that falls within a simulation allowable upper and lower limit range defined by a preset simulation allowable upper limit weight and a simulation allowable lower limit weight;
Average estimated value calculating means for calculating an average value of the selected simulated combination weights;
A combination selectivity index estimated value calculating means for calculating a selectivity index representing the difficulty of selection related to the total number or presence or absence of the selected simulated combination weight;
A combination scale equipped. 7. The combination weigher according to claim 6, further comprising: a first setting unit that manually or automatically sets a plurality of the simulation allowable upper and lower limit ranges, wherein the average estimated value calculation means includes the plurality of set simulation allowable values. wherein calculating the selected average value of a simulated combined weight for each upper and lower limit range, the combined selectivity index estimate calculation means, for each plurality of the simulated allowable upper and lower limit range in which the set, the Combination weigher that calculates selectivity index. 8. The combination weigher according to claim 7, wherein one set is selected from the set of average values of the selected simulation combination weights and the selectivity index calculated for each of the plurality of simulation allowable upper and lower limit ranges. A combination weigher comprising a second setting unit that sets the corresponding simulation allowable upper / lower limit range as the allowable upper / lower limit range in the combination weigher. 7. The combination weigher according to claim 6, wherein the average estimated value calculating means also calculates a deviation between an average value of the selected simulated combination weight and the simulation allowable lower limit weight, and the first setting unit includes a plurality of the set values. A simulation allowable upper / lower limit range is set manually or automatically, and the average value calculating means sets the average value of the selected simulated combination weight and the average value for each of the plurality of the set simulation allowable upper / lower limit ranges. A combination weigher that calculates a deviation from the simulation allowable lower limit weight, and wherein the combination selectivity index estimated value calculation means calculates the selectivity index for each of the plurality of the set simulation allowable upper and lower limit ranges. 10. The combination weigher according to claim 9, wherein a deviation between an average value of the selected simulated combined weight and the simulated allowable lower limit weight calculated for each of the plurality of simulated allowable upper and lower limit ranges, and the selectivity index. A combination weigher comprising a second setting unit that sets, in the combination weigher, the simulated allowable upper / lower limit range corresponding to one set among the sets. In a combination weigher in which the weight is normally distributed, the weights of individual items consisting of one or a few solids are variously combined, and the combination total weight is within an allowable upper and lower limit range,
Based on the weight distribution of the individual items collected in advance, combined weight simulation generating means for generating various simulated combined weights of the individual items;
Simulation selection means for selecting a simulation combination weight belonging to a preset simulation allowable upper and lower limit range,
A combination selectivity index estimated value calculating means for calculating a selectivity index representing the difficulty of selection related to the total number or presence or absence of the selected simulated combination weight;
A combination scale equipped. In the combination weigher according to claim 11, wherein a plurality of said simulated allowable upper and lower limit range, has a first setting unit for setting either manually or automatically, for each plurality of the simulated allowable upper and lower limit range in which the set A combination scale for calculating the selectivity index. The combination weigher according to claim 12, wherein the simulated allowable upper / lower limit range corresponding to one of the selectivity indices calculated for each of the plurality of simulated allowable upper / lower limit ranges is the allowable upper / lower limit range. A combination weigher comprising a second setting unit set in the combination weigher.

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