JP4137745B2 - Weighing device - Google Patents

Description

  The present invention relates to an improvement of a weighing device for weighing an article, and belongs to the technical field of article weighing.

  The combination weighing device used for automatic weighing of various articles includes, for example, an excitation type dispersion table, a plurality of radiation troughs arranged radially around the dispersion table, and a circular arrangement corresponding to the radiation troughs. A pair of upper and lower pool hoppers and weighing hoppers, each weighing the articles supplied by a plurality of weighing hoppers connected to the weight detector, and performing a combination operation based on these measured values, As a result, the combination weight is the closest to the target weight within the specified range, and the article weighed to the target weight is obtained by discharging the article only from the selected weighing hopper There is.

  In such a combination weighing device, wind is generated around the gate as the gate that opens and closes at a predetermined timing provided in the weighing hopper opens and closes the gate. In that case, as a result of the wind pressure generated by the wind acting on the weighing hopper adjacent to the weighing hopper, a low-frequency disturbance signal is output to the weighing signal output from the weight detector connected to the weighing hopper at a predetermined timing. May be superimposed. When this disturbance signal is superimposed on the measurement signal, an error is caused in the measurement value, and the measurement accuracy is lowered.

  That is, as shown in FIG. 9, each weighing signal is sampled at the current sampling time t1 while the article is held in each weighing hopper, and the current combination calculation is performed at time t2 based on these weighing signals. . As an example, when the second weighing hopper is selected as a combination, at time t3, the gate of the weighing hopper starts to open, and the force for opening the gate is applied to the weighing hopper. As a result, the weighing signal suddenly increases because the force for closing the gate starts to be applied to the weighing hopper. As a result, the weighing signal related to the second weighing hopper changes with time as shown by the solid line in the figure. It will be.

  In that case, the influence of the wind pressure generated by opening and closing the gate of the second weighing hopper is superimposed on the weighing signals of the first and third weighing hoppers adjacent to the second weighing hopper as disturbance signals indicated by symbols A and B. Sometimes. Then, at the next sampling time t5 of the measurement signal, the measurement signal on which the disturbance signal is superimposed by the magnitude Δw may be sampled. When the disturbance signal is not superimposed, the measurement signal is indicated by a two-dot chain line in the figure. The influence of the gate opening / closing of the second weighing hopper extends to the adjacent first and third weighing hoppers, but does not reach the fourth weighing hopper, and the measurement signal of the fourth weighing hopper includes a disturbance signal caused by the wind pressure. Are not superimposed. The generation timing, magnitude, and fluctuation period of the disturbance signal are confirmed to be reproducible.

  Therefore, at the next combination calculation time t6, the combination calculation is performed including the weighing signal on which the disturbance signal is superimposed by the magnitude Δw, so that the article may not be accurately weighed to the target weight. The problem becomes significant particularly when the first and third weighing hoppers are selected in the combination calculation.

  As a method for removing the disturbance signal, it is conceivable to filter the weighing signal output from the weight detector using a low-pass filter. In that case, it is necessary to use a filter with a low cut-off frequency in order to remove a low-frequency disturbance signal that overlaps with the opening and closing of the gate. However, when using a filter with a low cut-off frequency, on the other hand, the filtering time becomes long and the metering speed decreases, which may cause a problem that the metering accuracy and the metering speed, that is, the production speed are not compatible.

  As a method for solving this problem, for example, there is a method described in Patent Document 1. This method removes a disturbance signal from a weighing signal when a disturbance signal having a substantially constant waveform is superimposed on the weighing signal output from the weight detector at a predetermined timing such as power supply noise or mechanical vibration. Is.

  That is, the disturbance signal superimposed on the weighing signal output from the weight detector is sampled in advance for one period and stored in the storage means. Then, when the measurement signal output from the weight detector is sampled with the disturbance signal superimposed, the disturbance signal read from the storage means is sequentially subtracted from the measurement signal corresponding to a plurality of sampling times. As a result, the disturbance signal is accurately removed from the measurement signal, so that the measurement accuracy is improved.

Japanese Patent Publication No. 1-30083 (page 2)

  By the way, it is conceivable to apply the method described in Patent Document 1 to remove the disturbance signal caused by the wind pressure in the combination weighing device from the measurement signal. In this case, the measurement signal and the disturbance signal Since it is necessary to sequentially subtract the disturbance signal from the measurement signal at a plurality of timings after matching the time starting point, there is a problem that the apparatus and arithmetic processing are complicated and the cost is increased.

  Therefore, in view of the above situation, the present invention eliminates the disturbance from the measurement signal with a simplified configuration when the disturbance is superimposed on the measurement signal of the measurement means at a predetermined timing, thereby measuring accuracy and measurement. It is an object of the present invention to provide a weighing device that is compatible with speed.

  In order to solve the above problems, the present invention is configured as follows.

  First, the invention according to claim 1 relates to a weighing device in which a disturbance is superimposed at a predetermined timing on a weighing signal output from the weighing means, and from the reference time point within a predetermined range from the reference time point. A disturbance table in which data indicating the magnitude of the disturbance is recorded for each of a plurality of time points having different elapsed times, and a sampling timing setting means for setting a sampling timing of the measurement signal within the period, and the setting Disturbance reading means for reading from the table data indicating the magnitude of the disturbance at the time corresponding to the sampling time set by the means, and the value of the measurement signal sampled at the sampling time set by the setting means by the reading means And correction means for correcting the read data indicating the magnitude of the disturbance as a correction amount.

  Next, according to a second aspect of the present invention, in the weighing apparatus according to the first aspect, a disturbance table is provided for each of a plurality of different types of disturbances superimposed on the measurement signal. The data indicating the magnitude of each disturbance at the time corresponding to the time is read from each table, and the correction means corrects the measurement signal using the data indicating the magnitude of each disturbance signal read from each table as a correction amount. It is characterized by.

  Further, the invention according to claim 3 is the weighing device according to claim 1, wherein a disturbance table is provided for each of a plurality of different types of disturbances superimposed on the measurement signal, and any of these disturbances is detected. Disturbance selecting means for selecting whether to be corrected is provided, and the disturbance reading means indicates the magnitude of the disturbance at the time corresponding to the sampling time from the table for the disturbance signal selected by the selecting means. Along with the data reading, the correction means corrects the measurement signal using the data indicating the magnitude of the disturbance read by the reading means as a correction amount.

  According to a fourth aspect of the present invention, there is provided the weighing device according to any one of the first to third aspects, wherein a plurality of weighing means each having a hopper provided with an object discharge gate are provided adjacent to each other. The weighing device is configured such that the gate of any weighing hopper is opened and closed at a predetermined timing, and the disturbance table is opened and closed when the gate of the hopper attached to the adjacent weighing means opens and closes. The data indicating the magnitude of each time point is recorded with the influence of the wind pressure as a disturbance, and the correction means reads the sampling time read from the table when the hopper gate of the adjacent weighing means is opened and closed. The measurement signal of the measurement means is corrected by using the data indicating the magnitude of the disturbance at the time corresponding to as a correction amount.

  According to the first aspect of the present invention, when disturbance is removed from the measurement signal, one piece of data indicating the magnitude of the disturbance at the time corresponding to the measurement signal sampling time is read from the disturbance table, Since only the weighing signal is corrected using the data indicating the size as a correction amount, there is no need to use a low-pass filter or to complicate the device and arithmetic processing as in the past. A weighing device that achieves both accuracy and weighing speed is realized.

  Next, according to any of the second and third aspects of the present invention, when a plurality of different types of disturbances are superimposed on the measurement signal, a disturbance table is provided for each disturbance, so that each disturbance can be easily removed from the measurement signal. A versatile weighing device that can be implemented is realized.

  In particular, according to the invention described in claim 3, by selecting which of a plurality of disturbances is to be corrected, for example, omitting a disturbance having a small influence according to the required measurement accuracy. As a result, the load on the disturbance reading means and the correcting means is reduced.

  According to the fourth aspect of the present invention, the wind pressure generated when the gate of the weighing hopper is opened and closed acts on the adjacent weighing hopper, and the weighing signal output from the weighing means related to the weighing hopper is disturbed. In this case, the same effect as that of the above-described inventions according to claims 1 to 3 can be obtained.

  Hereinafter, a combination weighing device according to an embodiment of the present invention will be described.

  As shown in FIG. 1, the combination weighing device 1 measures an object such as a candy supplied from the upstream side to a target weight and discharges it to the downstream side, and is supported by a plurality of support legs 2. The main body case 3, an excitation-type dispersion table 4 for dispersing articles, and 12 (only two are shown in the figure) excitation-type radiation troughs 5 arranged radially around the dispersion table 4. 5 and a pair of upper and lower pool hoppers 6... 6 and weighing hoppers 7... 7 and weighing hoppers 7... 7 arranged in a circle corresponding to the radiation troughs 5. And a funnel-shaped collective chute 8 disposed below. The dispersion table 4, the radiation troughs 5, 5, the pool hoppers 6, 6, and the weighing hoppers 7, 7 are assembled in the main body case 3.

  Each pool hopper 6 is provided with a gate 6a for opening and closing the lower opening. The gate 6a is connected to a gate opening / closing drive mechanism 6b in the main body case 3 and swings as indicated by an arrow a. On the other hand, each weighing hopper 7 is provided with a gate 7a for opening and closing the lower opening, and the gate 7a is connected to a gate opening / closing drive mechanism 7b in the main body case 3 and swings as indicated by an arrow a. Each weighing hopper 7 is connected to a weight detector 7 c such as a load cell in the main body case 3.

  As a result, the articles supplied on the dispersion table 4 are distributedly supplied to the radiation troughs 5... 5 and then supplied to the weighing hoppers 7... 7 via the pool hoppers 6. Each weight is weighed by the connected weight detectors 7c... 7c and a combination calculation is performed. Then, as a result of the combination calculation, the articles are discharged from the weighing hoppers 7... 7 selected as the target weight, and the articles are collected by the collecting chute 8 and discharged to a downstream side, for example, a bag making and packaging machine. Will be.

  By the way, in this combination weighing device 1, when the gate 7a of the weighing hopper 7 opens and closes at a predetermined timing to execute discharge and holding of the article, wind is generated around the gate 7a. In this case, the wind pressure generated by the wind acts on the two weighing hoppers 7, 7 adjacent to the weighing hopper 7, and the weighing signal output from the weight detectors 7 c, 7 c connected to these weighing hoppers 7, 7 Then, a low-frequency reproducible disturbance signal is superimposed at a predetermined timing. It has been confirmed in advance that the action of the wind pressure does not reach other than the weighing hoppers 7 and 7 adjacent to the weighing hopper 7.

That is, as shown in a part of FIG. 2, among the first to seventh weighing hoppers 7 _{1 to} 7 ₇ assembled so as to be circularly arranged in the main body case 3, as an example, the second weighing hopper 7 _2. When the gate 7a ₂ swings as indicated by the arrow a by driving the gate opening / closing drive mechanism 7b ₂ , the wind pressure generated by the wind acts on the adjacent first and third weighing hoppers 7 ₁ and 7 ₃ , A disturbance signal caused by the wind pressure is superimposed on the weighing signal output from the first and third weight detectors 7c ₁ and 7c ₃ connected to the first and third weighing hoppers 7 ₁ and 7 ₃ . For the sake of clarity, in particular, the reference numerals of the weighing hopper 7, the gate 7a, the gate opening / closing drive mechanism 7b, and the weight detector 7c will be appropriately subscripted as long as they do not cause confusion.

For example, the time variation of the weight signal that is in this case the disturbance signal output from the first weight detector 7c ₁ of the first weighing hopper 7 ₁ holding no article is as shown in FIG. That is, if the time when the gate 7a ₂ of the second weighing hopper 7 ₂ begins to open as the reference point t3, disturbance signal returns to 0 after showing the minimum reduced once from 0 as indicated by the arrow A, then the gate When 7a ₂ starts to close, it increases as shown by arrow B, and then returns to 0 after showing the maximum. When the elapsed time from the reference time point t3, the time Tw as an example, the size Δw only disturbance signal from the first weight detector 7c ₁ of the first weighing hopper ₇₁ is to be outputted. In this case, the decrease or increase in the disturbance signal corresponds to the decrease or increase in the weight value. In addition, one period Th of the disturbance signal in the example is approximately 400 msec.

  Therefore, when this disturbance signal is superimposed on the measurement signal, an error is caused in the measurement value when the sampling time is set so as to sample the measurement signal on which the disturbance signal is superimposed in terms of production efficiency. As a result, the weighing accuracy is lowered. As a result, the article may not be accurately weighed to the target weight.

  Next, the control system of the combination weighing device 1 will be described.

  As shown in FIG. 4, an operation unit 11 operated by an operator to perform various settings and inputs is connected to a control unit 10 that comprehensively controls the combination weighing device 1.

  The control unit 10 outputs control signals for discharging or holding articles to the gate opening / closing drive mechanisms 6b ... 6b of the pool hoppers 6 ... 6 and the gate opening / closing drive mechanisms 7b ... 7b of the weighing hoppers 7 ... 7. The control unit 10 also controls the driving of the dispersion table 4, the radiating troughs 5 ... 5, etc., but these descriptions are omitted in FIG. 4 to avoid complication of the explanation.

  Further, the control unit 10 inputs the weighing signals output from the weight detectors 7c... 7c connected to the weighing hoppers 7... 7c, calculates the combination based on these weighing signals, and selects the combination that becomes the target weight. .

  Further, the control unit 10 has a memory 10a for storing a disturbance table as shown in Table 1 created based on FIG. 3 described above. In the disturbance table in this case, a time point when the gate 7a of the weighing hopper 7 starts to open is set as a reference time point t3, and within a predetermined range from the reference time point t3, that is, a time point when the disturbance signal shows 0 from the time point when the maximum is shown In this period, the measurement signal sampling timing is set, and during this period, the disturbance signal magnitude Δw is recorded for each of a plurality of time points tw1 to tw8 having different elapsed times Tw from the reference time point t3. ing. For example, the magnitude Δw of the disturbance signal at the time point tw5 when the elapsed time Tw is 360 msec is exemplified as 0.5 g. Further, the magnitude Δw of the disturbance signal at the time point tw1 when the elapsed time Tw is 320 msec is 0.75 g, which corresponds to the maximum value in FIG.

  For example, when an operator inputs a product code of a product produced by the combination weighing device 1 through the operation unit 11, the control unit 10 sets a sampling time according to the input product code. In this case, the sampling time is usually set based on the production capacity of the combination weighing device 1.

  Further, when the control unit 10 determines that the disturbance signal is superimposed on the measurement signal, the control unit 10 reads the magnitude Δw of the disturbance signal at the time corresponding to the sampling time from the disturbance table stored in the memory 10a, and at the same time the sampling time The disturbance signal magnitude Δw obtained by reading out the value of the measurement signal sampled in the step is corrected as a correction amount.

  Next, a control example executed by the control unit 10 will be described.

  As an example, paying attention to the control for a specific weighing hopper 7, as shown in FIG. 5, in this weighing hopper 7, when the gate 7a of the adjacent weighing hopper 7 opens and closes, the gate 7a starts to open at the reference time t3. On the other hand, when the gate 7a starts to close, as shown by the symbol A, as shown by the symbol B, a disturbance signal whose one cycle Th can be exemplified as approximately 400 msec is superimposed on the measurement signal.

  That is, when an article is supplied to the weighing hopper 7 that is empty before the reference time t3 and the weighing signal increases rapidly as indicated by the symbol C, the gate 7a of the adjacent weighing hopper 7 starts to open at the reference time t3. A disturbance signal is superimposed on the weighing signal, and once decreases and shows a minimum as shown by reference A, and then increases and shows a maximum as shown by reference B when the gate 7a starts to close, then the weighing hopper 7 When the gate 7a is opened and the article is discharged, as shown by the symbol D, the measurement signal decreases rapidly. It should be noted that the measurement signal when the disturbance signal is not superimposed shows a substantially constant value as indicated by a two-dot chain line indicated by a symbol E. In the illustrated example, when the elapsed time from the reference time point t3 is the time Tw, the disturbance signal is superimposed on the measurement signal by the magnitude Δw.

  Therefore, as shown in FIG. 6, when starting the operation of the combination weighing device 1, the control unit 10 first sets the correction flag F to 0 in step S1. The correction flag F is set to 0 when a disturbance signal caused by the wind pressure is not superimposed on the measurement signal and correction processing for the measurement signal is not performed, while a disturbance signal caused by the wind pressure is superimposed on the measurement signal and corrected. Set to 1 when processing is executed.

  Next, in step S2, the weighing hopper 7 is supplied with articles. That is, the gate 6 a of the corresponding pool hopper 6 on the upstream side is opened, and the held article is discharged toward the weighing hopper 7.

  In step S3, the system waits for the sampling timing of the weighing signal related to the article held by the weighing hopper 7, and inputs the weighing signal in step S4.

  In step S5, it is determined whether or not the correction flag F is 1. If it is determined as NO, the correction process for the weighing signal is not executed, so the process proceeds to step S6, and the combination calculation including the weighing signal of the weighing hopper 7 is performed. Do.

  In step S7, it is determined whether or not the weighing hopper 7 has been selected as a combination. If YES, the process proceeds to step S8, and the gate opening / closing drive mechanism 7b is driven to open the gate 7a to discharge the article. After that, in step S9, the gate opening / closing drive mechanism 7b is driven so as to close the gate 7a.

  In step S10, it is determined whether or not all combination weighings in the current production have been completed. If NO, the process returns to step S2. If YES, the operation of the combination weighing apparatus 1 is stopped. To do.

  If NO is determined in step S7, the process proceeds to step S11 in order to start the next combination operation while holding the article, and it is determined whether or not the weighing hoppers 7 and 7 adjacent to the weighing hopper 7 are selected as a combination. To do.

  If NO is determined in step S11, in that case, no wind pressure is generated due to the opening and closing of the gates 7a, 7a of the weighing hoppers 7, 7 adjacent to the weighing hopper 7, and the disturbance signal due to the wind pressure is not generated. Do not superimpose on the weighing signal sampled at the next sampling time. Accordingly, in this case, the process returns to step S3, and when the next measurement signal sampling timing comes and the measurement signal is input in step S4, the correction flag F remains 0, so that NO is determined in step S5, and then In step S6, a combination calculation is performed.

  On the other hand, if YES is determined in step S11, in that case, wind pressure is generated due to the opening and closing of the gates 7a and 7a of the weighing hoppers 7 and 7 adjacent to the weighing hopper 7, and the disturbance signal caused by the wind pressure is the next time. Is superimposed on the weighing signal to be sampled at the sampling time. Accordingly, in this case, the process proceeds to step S12, and the magnitude Δw of the disturbance signal at the time points tw1 to tw8 corresponding to the predetermined sampling time in the disturbance table stored in the memory 10a is read. In step S13, the correction flag F is set. After setting to 1, the process returns to step S3.

  And after performing step S3 and step S4 which were mentioned above, in step S5, since the correction flag F was set to 1 by the said step S13, it determines with YES.

  Then, in step S14, after performing a correction process using the magnitude Δw of the disturbance signal from which the measurement signal is read out, that is, a subtraction process in this case, the correction flag F is set to 0 in step S15. Then, the control after step S6 is executed. When two weighing hoppers 7 and 7 adjacent to the weighing hopper 7 are selected as a combination in step S11, the influence of wind pressure acting on the weighing hopper 7 sandwiched between the weighing hoppers 7 and 7 is selected. In step S14, the magnitude of the read disturbance signal Δw is doubled and the correction process is performed.

  Here, it demonstrates still more concretely using FIG.

First, in the state where the articles are held in the first to seventh weighing hoppers 7 _{1 to} 7 ₇ in the illustrated example, each weighing signal is sampled at the current sampling time t1, and based on these weighing signals, the current weighing signal is obtained at time t2. A combination operation is performed.

When the second weighing hopper _{7 2} and the fourth weighing hoppers _{7 4} is selected to a combination, and the time t3 begins to open the metering hopper ₇ 2, _{7 4} gates _7a 2, 7a ₄ articles discharged as an example After that, the gates 7a ₂ and 7a ₄ begin to close at time t4 and the newly supplied article is held, so that the weighing signal related to the weighing hoppers 7 ₂ and 7 ₄ changes almost as shown in the figure. become.

In that case, the weighing signal of the first and third weighing hoppers 7 _1, 7 ₃ adjacent the second weighing hopper 7 _2, the influence of the wind pressure generated along with the opening and closing of the gate 7a ₂ of the second weighing hopper 7 ₂ but also, the weight signal of the third and fifth weighing hoppers 7 _3, 7 ₅ adjacent to the fourth weighing hoppers 7 _4, the wind pressure generated along with the opening and closing of the gate 7a ₄ of the fourth weighing hoppers 7 ₄ The effect is superimposed as a disturbance signal. That is, the first and fifth weighing hoppers 7 ₁ , 7 ₅ have disturbance signals indicated by reference signs A and B in the weighing signal, and the third weighing hopper 7 ₃ has the adjacent second and fourth weighing hoppers 7 ₂ , 7. ₄ , disturbance signals indicated by codes A ′ and B ′ having a magnitude twice that of the disturbance signals indicated by codes A and B are superimposed on the measurement signal. The effect of the opening and closing of the gates 7a ₂ of the second weighing hopper _{7 2} are not inferior to other than the first and third weighing hoppers ₇ 1, _{7 3} on both sides, also in the fourth weighing hoppers _{7 4} gates 7a ₄ The influence of opening and closing does not reach other than the third and fifth weighing hoppers 7 ₃ and 7 _{5 on} both sides.

Then, the next sampling time t5, the magnitude [Delta] w only disturbance signal by twice the magnitude [Delta] w 'of the metering signal and the magnitude [Delta] w of the first and fifth weighing hoppers 7 _1, 7 ₅ superimposed weighing signal or the like according to a third weighing hoppers 7 ₃ a disturbance signal is superimposed is to be sampled. In this case, as described above, based on the disturbance table shown in Table 1, the magnitude Δw of the disturbance signal at the time points tw1 to tw8 corresponding to the elapsed time Tw from the reference time point t3 to the sampling time t5, or twice the magnitude thereof. Correction processing, that is, division processing is performed using Δw ′ as a correction amount. For example, if the elapsed time Tw until the sampling time t5 is 360Msec, for weighing signals of the first and fifth weighing hoppers ₇ 1, _{7 5,} of the disturbance signal at the time tw5 corresponding to the elapsed time Tw size Δw it the 0.5g is may be set to the correction amount, whereas, the correction amount twice for weighing signals according to the third weighing hopper 7 _3, also a size Δw of the disturbance signal point tw5 0.5g And it is sufficient. As a result, at the next combination calculation time t6, the combination calculation is performed based on the measurement signal from which the disturbance signal is corrected, that is, removed.

  Thus, when removing the disturbance signal from the measurement signal, one disturbance signal magnitude Δw at a time corresponding to the measurement signal sampling timing is read from the disturbance table, and the measurement is performed using the disturbance signal magnitude Δw as a correction amount. Since it only corrects the signal, it does not use a low-pass filter as in the past, or it does not complicate the equipment and arithmetic processing, so combined weighing that achieves both weighing accuracy and weighing speed with a simplified configuration. Apparatus 1 is realized.

  Next, an example of control executed by the control unit 10 when a plurality of disturbance signals are superimposed on the measurement signal in addition to the disturbance signal caused by the wind pressure will be described.

  In that case, as a disturbance signal other than the disturbance signal caused by the wind pressure, for example, a disturbance signal generated when the upstream radiation troughs 5... 5 are activated, or when a bag making and packaging machine is disposed downstream. It is possible to estimate in advance the generation timing and the degree of influence on the weighing signal output from the weight detectors 7c... 7c, such as a disturbance signal when the bag making and packaging machine operates in conjunction with the combination weighing device 1. A disturbance signal that is reproducible and repeatable is illustrated.

  A disturbance table is stored in the memory 10a of the control unit 10 for each of the plurality of different types of disturbance signals. In this case, each disturbance table shows the magnitude of the disturbance signal at each of a plurality of time points having different elapsed times from the reference time point within a predetermined range from the reference time point, such as the time when the gate 7a of the weighing hopper 7 starts to open. This is a record.

  As an example, paying attention to the control performed by the control unit 10 for a specific weighing hopper 7, as shown in FIG. 8, first, at the start of operation of the combination weighing apparatus 1, the operator starts the combination weighing apparatus 1 in step S21. When the product code of the product produced in 1 is input via the operation unit 11, the control unit 10 selects a disturbance signal to be corrected according to the input product code, and then sets the correction flag F in step S22. Set to 0. The correction flag F is set to 0 when the disturbance signal to be corrected is not superimposed on the measurement signal and the correction process is not performed on the measurement signal, while the disturbance signal to be corrected is superimposed on the measurement signal and the correction process is performed. Set to 1 when executing.

  Next, in step S23, the system waits for the sampling timing of the weighing signal relating to the article supplied and held by the weighing hopper 7, and in step S24, the weighing signal is input.

  Then, in step S25, it is determined whether or not the correction flag F is 1. If it is determined as NO, the correction process for the weighing signal is not executed, so the process proceeds to step S26, and the combination calculation including the weighing signal of the weighing hopper 7 is performed. Do.

  In step S27, it is determined whether or not the weighing hopper 7 has been selected as a combination. If YES, the process proceeds to step S28, and the gate opening / closing drive mechanism 7b is driven to open the gate 7a to discharge the article. After that, in step S29, the gate opening / closing drive mechanism 7b is driven so as to close the gate 7a.

  In step S30, it is determined whether or not all combination weighings in the current production have been completed. If NO, the process returns to step S23. If YES, the operation of the combination weighing apparatus 1 is stopped. To do.

  If NO is determined in step S27, the process proceeds to step S31 so that the next combination calculation can be performed while the article is held, and it is determined whether or not a disturbance signal is superimposed on the measurement signal related to the measurement hopper 7. Whether or not the disturbance signal is superimposed is, for example, whether or not the adjacent weighing hoppers 7 and 7 are selected as a combination, whether or not a control signal for starting the corresponding radiation trough 5 is output, or on the downstream side In the case where a bag making and packaging machine is provided, a determination is made based on whether or not a control signal for operating the packaging machine is output.

  If NO is determined in step S31, in this case, the disturbance signal is not superimposed on the measurement signal output from the weight detector 7c of the measurement hopper 7, and the disturbance signal is sampled at the next sampling time. Do not overlap. Therefore, in this case, the process returns to step S23, and when the next measurement signal sampling timing comes and the measurement signal is input in step S24, the correction flag F remains 0. Therefore, NO is determined in step S25, and then In step S26, the combination calculation is performed.

  On the other hand, if YES is determined in the step S31, it is predicted that a disturbance signal is superimposed on the weighing signal output from the weight detector 7c of the weighing hopper 7, and this disturbance signal is detected at the next sampling time. It is superimposed on the weighing signal to be sampled. Accordingly, in this case, the process proceeds to step S32, which corresponds to a predetermined sampling time in each disturbance table corresponding to the disturbance signal to be corrected selected in step S21 described above among the plurality of disturbance tables stored in the memory 10a. Then, the magnitude of the disturbance signal at the time of the reading is read out, the correction flag F is set to 1 in step S33, and the process returns to step S23.

  And after performing step S23 and step S24 which were mentioned above, in step S25, since the correction flag F was set to 1 by the said step S33, it determines with YES.

  Then, in step S34, correction processing is performed in which the magnitude of each disturbance signal from which the measurement signal has been read is used as a correction amount. Then, in step S35, the correction flag F is set to 0, and control in and after step S26 is performed. Execute.

  Accordingly, when a plurality of different types of disturbance signals are superimposed on the weighing signal, since the disturbance table is provided for each disturbance signal, the versatile combination weighing device 1 that can easily remove each disturbance signal from the weighing signal is provided. Realized.

  Further, since it is selected which of the plurality of disturbance signals is to be corrected, a disturbance signal having a small influence can be omitted according to the required measurement accuracy, for example, and the load of the control unit 10 is reduced. It will be reduced.

  In the above embodiment, the present invention is applied to the combination weighing device 1 in which a plurality of weighing hoppers 7 ... 7 are arranged in a circle. However, the present invention is applied to a combination weighing device in which a plurality of weighing hoppers are arranged in the horizontal direction. Also good. The present invention is also applicable to a weight sorter that measures the weight of an article and sorts the article into each weight rank based on the measurement result.

  As described above, according to the present invention, when a disturbance is superimposed on the measurement signal of the measurement means at a predetermined timing, the measurement accuracy and the measurement can be obtained by removing the disturbance from the measurement signal with a simplified configuration. A weighing device is provided that is compatible with speed. That is, the present invention relates to an improvement of a weighing device for weighing an article, and is widely suitable for the technical field of article weighing.

1 is a schematic side view of a combination weighing device according to an embodiment of the present invention. It is a partial excerpt sectional view by the II-II line of FIG. It is a figure which shows the time change of the magnitude | size of a disturbance signal. It is a block diagram of a control system. It is a figure which shows the time change of a measurement signal when the disturbance signal resulting from the wind pressure at the time of gate opening and closing is superimposed on the measurement signal. It is a flowchart for demonstrating the example of control. It is a time chart for demonstrating the influence of the disturbance signal resulting from a wind pressure, and the correction process of a measurement signal. It is a flowchart for demonstrating another example of control. It is a time chart for demonstrating the influence of the disturbance signal superimposed on a measurement signal resulting from the wind pressure at the time of gate opening and closing in the conventional combination measurement apparatus.

Explanation of symbols

1 Combination weighing device (weighing device)
7 Weighing hopper (hopper)
7a Gate 7c Weight detector (measuring means)
10 Control unit (sampling time setting means, disturbance readout means, correction means, disturbance selection means)

Claims (4)

  A weighing device in which a disturbance is superimposed on a weighing signal output from a weighing means at a predetermined timing, and the time elapses from the reference time point within a predetermined range from the reference time point at a plurality of time points. A disturbance table in which data indicating the magnitude of the disturbance is recorded, a sampling time setting means for setting the sampling time of the measurement signal within the period, and a time corresponding to the sampling time set by the setting means The disturbance reading means for reading out the data indicating the magnitude of the disturbance from the table, and the data indicating the magnitude of the disturbance read by the reading means from the measurement signal value sampled at the sampling time set by the setting means are corrected. And a correction means for correcting the quantity as a quantity.   A disturbance table is provided for each of a plurality of different types of disturbances to be superimposed on the weighing signal, and the disturbance reading means reads out the data indicating the magnitude of each disturbance at the time corresponding to the sampling time from each table and corrects it. 2. The weighing apparatus according to claim 1, wherein the means corrects the weighing signal using the data indicating the magnitude of each disturbance signal read from each table as a correction amount.   A disturbance table is provided for each of a plurality of different types of disturbances to be superimposed on the measurement signal, and disturbance selection means for selecting which of these disturbances is to be corrected is provided. The data indicating the magnitude of the disturbance at the time corresponding to the sampling time is read from the table for the disturbance signal selected by the selection means, and the correction means corrects the data indicating the magnitude of the disturbance read by the reading means. 2. The weighing device according to claim 1, wherein the weighing signal is corrected as a quantity. A weighing device is configured such that a plurality of weighing means each provided with a hopper having an object discharge gate are arranged adjacent to each other, and the gate of any weighing hopper is opened and closed at a predetermined timing. The disturbance table records the data indicating the magnitude of each time point as the disturbance due to the influence of wind pressure when the gate of the hopper attached to the adjacent weighing means opens and closes, and the correction means When the hopper gate of the weighing means is opened and closed, the weighing signal of the weighing means is corrected using the data indicating the magnitude of the disturbance at the time corresponding to the sampling time read from the table as a correction amount. The weighing device according to any one of claims 1 to 3.

Images