JP6097106B2 - Combination weighing device - Google Patents

Description

  The present invention relates to a combination weighing device that uses a measurement value of a plurality of weighing hoppers to measure a set of measurement values of an object to be measured to a target value.

  For example, there is known a combination weighing and counting device that measures an object to be weighed, such as confectionery and fruit, so as to reach a target weight or a target number. In this combination weighing device, the weight of an object to be weighed accommodated in each of a plurality of weighing hoppers is detected by a weight detection unit such as a load cell. A combination calculation is performed on the detected weight of the object to be weighed or the number obtained from the above weight, and the weighing hopper is selected so that the combined weight or number is within an allowable range. By combining the objects to be weighed in the selected weighing hopper, a desired weight or a desired number of products can be obtained (hereinafter, description of the number is omitted and referred to as “combination weighing device”).

  In such a combination weighing device, from the weight of the weighing hopper in which an object to be weighed measured by the weight detection unit is accommodated, the weight of an empty weighing hopper in which the object to be weighed is not accommodated and its supporting bracket is used. By subtracting a certain tare weight, the weight of the object to be weighed is calculated. For this purpose, the tare weight is set as the initial zero correction value.

  By the way, in the combination weighing device, a part of the object to be weighed may remain on the weighing hopper during the weighing operation. Also, the output of the load cell may fluctuate due to changes in temperature and changes with time. In such a case, a deviation occurs in the zero point correction value set as the tare weight, and an error occurs in the calculated weight of the weighing object. For this reason, it is necessary to update and set a new tare weight as the zero point correction value every predetermined period (for example, once every 10 weighing cycles). Patent Documents 1 and 2 disclose techniques related to the update setting of the zero point correction value.

Japanese Patent Laid-Open No. 61-12523 JP-A-5-77247

  However, the conventional combination weighing device has the following problems. In other words, after the zero point correction value is updated, if a part of the object to be weighed remains in the weighing hopper or the output of the load cell fluctuates due to temperature change or change over time, the zero point correction is performed next. There is a possibility that an error may occur in the weight of the object to be calculated until the value is updated.

  Therefore, a main object of the present invention is to provide a combination weighing device capable of increasing weighing accuracy.

  The combination weighing device according to one aspect of the present invention is based on a plurality of weighing hoppers that store and discharge an object to be weighed, a weight detection unit that detects the weight value of each weighing hopper, and a zero point correction value as a reference. Weighing in the state immediately before the weighing object is accommodated based on the zero point correction value based on the weighing value of the weighing object obtained from the weight value detected for the weighing hopper in the condition where the weighing object is accommodated in A weight value correction unit that calculates a corrected weight value by subtracting a weight correction value obtained from the weight value detected for the hopper, and one or more corrected weight values of the corrected weight values for each weighing hopper And a calculation unit that selects a combination of objects to be weighed so that a value obtained by combining the values in the allowable range with reference to the target value is included.

  According to this combination weighing apparatus, the zero correction value is used as a reference from the measurement value of the weighing object obtained from the weight value detected for the weighing hopper in the state where the measurement object is accommodated when the zero correction value is used as a reference. The corrected weighing value is calculated by subtracting the weight correction value obtained from the weight value detected for the weighing hopper in the state immediately before the object to be weighed is stored. The weight of the weighing hopper in the state immediately before the object to be weighed here is the weight of the weighing hopper before the object to be weighed currently accommodated, that is, the previous object to be weighed is discharged. This refers to the weight of the weighing hopper from when the current object to be weighed is received. This weight correction value is the zero point that occurs when a part of the object to be weighed remains in the weighing hopper or the output of the load cell changes due to temperature, etc., even though the object to be weighed is discharged by participating in the combination weighing. A variation value from the correction value is shown. Therefore, by subtracting this weight correction value from the measured value of the object to be calculated that is calculated based on the zero point correction value, an influence such as when a part of the object to be measured remains in the weighing hopper is eliminated. As a result, the weighing accuracy can be increased.

  The combination weighing device further includes a zero adjustment unit that resets the weight value of the weighing hopper in a state in which the object to be weighed is discharged as a zero correction value every predetermined time or every time the object is discharged a predetermined number of times. May be.

  According to this configuration, since the zero point correction value is periodically updated, the measurement accuracy can be further improved.

  In addition, when an object to be weighed is supplied to the weighing hopper and selected as a combination of objects to be weighed by the calculation unit, a series of steps for discharging the object to be weighed from the weighing hopper is regarded as one cycle. Is further provided with a control unit that stops the supply of the object to be weighed in the next cycle to the weighing hopper from which the discharge has occurred, and the measurement value correction unit is to be detected in the cycle in which the supply of the object to be weighed is stopped The weight correction value may be calculated based on the weight value of the weighing hopper in a state where the is discharged.

  According to this configuration, the weight of the weighing hopper in a state in which the object to be weighed is discharged is acquired as one cycle before the weight of the weighing hopper in a state immediately before the object to be weighed is accommodated. Thereby, the weight of the weighing hopper in a state immediately before the object to be weighed is accommodated can be easily acquired. Further, by stopping one cycle and acquiring the weight of the weighing hopper in a state where the object to be weighed is discharged, the time required for one cycle can be shortened and high-speed processing can be performed as a whole.

  Moreover, you may further provide the correction implementation control part which switches whether a correction | amendment measurement value is calculated in a measurement value correction | amendment part.

  Here, when the above correction is performed on the measurement value, a process such as detecting the weight of the weighing hopper in a state in which the object to be weighed is discharged is performed, so that it may not be possible to participate in the combination measurement of the next cycle. . As the number of weighing hoppers that cannot participate in combination weighing increases, the number of combinations when selecting the combination of objects to be weighed so that the value is within the allowable range based on the target value decreases, and the difference from the target value May increase. According to this configuration, since the number of weighing hoppers for calculating the corrected weighing value can be selectively controlled, the number of weighing hoppers that cannot participate in the combination weighing in the next cycle is reduced, and the accuracy of the combination weighing is reduced. Can be suppressed.

  The correction unit further includes a storage unit that accumulates the set and updated zero correction values, and the correction execution control unit corrects the measured values based on the standard deviation values of a predetermined number of zero correction values accumulated in the storage unit. It may be determined whether or not is calculated.

  According to this configuration, when the fluctuation of the zero correction value is relatively large and the necessity for correction is considered to be high, the measurement value calculated in the weighing hopper is corrected to calculate the correction measurement value. Can be further increased. On the other hand, it is also possible not to selectively correct the measured value for the weighing hopper considered that the fluctuation of the zero point correction value is relatively small and the need for correcting the measured value is small. Thereby, it is possible to reduce the number of weighing hoppers that cannot participate in the combination weighing, and to prevent the accuracy of the combination weighing from being lowered.

  According to the present invention, the measurement accuracy can be increased.

It is the schematic which showed typically the combination weighing | measuring device which concerns on one Embodiment. It is a block diagram for demonstrating the function which the control part of FIG. 1 has. It is drawing which each showed an example of the data memorize | stored in the memory | storage part of FIG. It is the figure which showed the weight of the to-be-measured object when the cycle which consists of supply and discharge | emission of an to-be-measured object is repeatedly performed in a certain weighing hopper. It is a block diagram for demonstrating the function which the control part which concerns on other embodiment has.

  Hereinafter, an embodiment will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The dimensional ratios in the drawings do not necessarily match those described.

  First, the configuration of the combination weighing device 1 according to an embodiment will be described. FIG. 1 is a schematic view schematically showing a combination weighing device 1 according to an embodiment. The combination weighing device 1 is a device that measures an object to be weighed having variations in individual weights so that the total weight is within an allowable range. The combination weighing device 1 mainly includes a dispersion feeder 10, a plurality of supply troughs 20, a plurality of pool hoppers 30, a plurality of weighing hoppers 40, a collecting unit 50, and a control unit 60.

  The dispersion feeder 10 receives an object to be weighed from an upper supply mechanism 100 and disperses and conveys the object to be weighed to a plurality of supply troughs 20 arranged outward. The dispersion feeder 10 has a substantially circular shape when viewed from above, and the upper surface has a conical shape with a center raised. The dispersion feeder 10 is connected to a vibration mechanism 11 using electromagnetic vibration or the like. For this reason, the upper surface of the dispersion feeder 10 can be vibrated by driving the excitation mechanism 11. The dispersion feeder 10 conveys the object to be measured while being dispersed outwardly by the vibration.

  The plurality of supply troughs 20 send the objects to be weighed dispersed by the dispersion feeder 10 to the plurality of pool hoppers 30, respectively. The plurality of supply troughs 20 are arranged radially along the outer periphery of the dispersion feeder 10, and the outer ends of the supply troughs 20 are arranged above the plurality of pool hoppers 30. Each supply trough 20 is connected to a vibration mechanism 21 using electromagnetic vibration or the like. For this reason, the conveyance surface of the supply trough can be vibrated by driving the excitation mechanism 21. The supply trough 20 moves the object to be measured outward by the vibration and sends it to the inside of the corresponding pool hopper 30.

  The plurality of pool hoppers 30 temporarily hold the objects to be weighed sent out from the supply trough 20. Each pool hopper 30 is arranged below each supply trough 20, and is arranged in an annular shape in a top view. Each pool hopper 30 has a cylindrical main body 30a that communicates vertically and a gate 30b that opens and closes its bottom. The gate 30b is connected to an opening / closing drive mechanism 31 such as a stepping motor, and the opening / closing operation of the gate 30b is realized by driving the opening / closing drive mechanism 31. Each pool hopper 30 accommodates an object to be weighed therein by closing the gate 30b, and discharges the object to be weighed to the lower weighing hopper 40 by opening the gate 30b.

  The plurality of weighing hoppers 40 store the objects to be weighed discharged from the pool hopper 30. Each weighing hopper 40 is arranged below each pool hopper 30 and is arranged in an annular shape in a top view like the pool hopper 30. Each weighing hopper 40 also has a cylindrical main body 40a that communicates vertically and a gate 40b that opens and closes its bottom. The gate 40b is connected to an opening / closing drive mechanism 41 such as a stepping motor, and the opening / closing operation of the gate 40b is realized by driving the opening / closing drive mechanism 41. Each weighing hopper 40 accommodates an object to be weighed therein by closing the gate 40b, and discharges the object to be measured to the lower collecting portion 50 by opening the gate 40b.

  Each weighing hopper 40 is connected to a weight detection unit 42 such as a load cell. Each weight detection unit 42 includes a weight value M1 of the weighing hopper 40 in a state in which the object to be weighed is accommodated in the weighing hopper 40, and a weight value of the weighing hopper 40 in a state in which the object to be weighed is not accommodated in the weighing hopper 40. M2 is detected. The weight detection unit 42 transmits the detected weight values M1 and M2 to the control unit 60. In the case of the weight detection unit 42 such as a load cell, an analog weight detection signal corresponding to the weight is output. The output analog weight detection signal is converted into a digital weighing signal (A / D count value) by the A / D converter and transmitted to the control unit 60.

  The collecting unit 50 collects and discharges the objects to be weighed discharged from the weighing hopper 40 selected by the combination calculation described later in one place. The collecting unit 50 includes a funnel-shaped sliding surface 50a that covers the lower positions of the plurality of weighing hoppers 40, and one timing hopper 50b that holds an object to be weighed down the sliding surface 50a and discharges it downward in a timely manner. Have. The timing hopper 50b is provided with a gate 50c that opens and closes its bottom. The gate 50c is connected to an opening / closing drive mechanism 51 such as a stepping motor, and the opening / closing operation of the gate 50c is realized by driving the opening / closing drive mechanism 51. While the gate hopper 50b is closed, the timing hopper 50b receives the objects to be weighed down from the sliding surface 50a, collects and holds the objects to be weighed therein, and opens the gate 50c, thereby holding the objects to be weighed. Send it down and hand it over to subsequent packaging equipment.

  The control unit 60 is a part that executes various control processes in the combination weighing device 1, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a hard disk. As shown in FIG. 2, the control unit 60 includes a measurement value calculation unit 61, a measurement value correction unit 62, and a calculation unit 63 as conceptual parts for executing various control processes in the combination weighing device 1 described in detail later. , A zero point adjustment unit 64, and a storage unit 66. The functions executed by the conceptual part shown below are executed under the control of the CPU or the like.

  The measurement value calculation unit 61 uses a weight value M1 of the weighing hopper 40 in a state in which an object to be weighed is detected, which is detected by the weight detection unit 42 when the zero correction value V0 (V1) is used as a reference. The weight (measurement value) W1 of the weighing object is calculated. In the case of the weight detector 42 such as a load cell, the tare weight digital weighing signal (A / D count value) output from the load cell is set to be zero. As a result, the weighing value calculation unit 61 converts the digital weighing signal from the load cell connected to the weighing hopper 40 in which the object to be weighed is stored, that is, the digital weighing signal from the load cell that is output based on the above-described zero value. Based on this, the weight of the object to be weighed can be obtained.

  The weighing value correction unit 62 detects the weighing object detected by the weight detection unit 42 based on the zero point correction value V0 (V1) from the weight W1 of the weighing object calculated by the weighing value calculation unit 61. The corrected weight (corrected weighing value) W2 is calculated by subtracting the weight correction value E1 obtained from the weight value M2 of the weighing hopper 40 in the state immediately before being accommodated.

  The calculation unit 63 adjusts the weight of the object to be measured so that a value obtained by combining one or a plurality of correction weights W2 of the correction weights W2 for the respective weighing hoppers 40 is within an allowable range based on the target value. This is the part for selecting a combination. Specifically, the calculation unit 63 reads the weight W1 and the correction weight W2 for each weighing hopper 40 calculated by the measurement value calculation unit 61 and the measurement value correction unit 62 from the storage unit 66, and uses the target value as a reference. The combination of the objects to be weighed is selected so as to be within the allowable range.

  The zero point adjustment unit 64 is a part that resets the zero point correction value V0 (V1) every predetermined time or every time the object to be weighed is discharged a predetermined number of times. For example, a new zero correction value V1 is reset based on the weight value of the weighing hopper 40 in a state immediately before the zero adjustment is performed (that is, the weighing hopper 40 in a state in which the object to be weighed is discharged).

  The storage unit 66 is a part that stores the weight W1 calculated by the measurement value calculation unit 61, the correction weight W2 calculated by the measurement value correction unit 62, the zero point correction values V0, V1, and the like.

  Further, the control unit 60 is electrically connected to the driving locations of the respective parts such as the vibration mechanisms 11 and 21 and the opening / closing drive mechanisms 31, 41, and 51 described above, and by sending predetermined signals, the control unit 60 The drive can be operated and adjusted.

  Next, the weighing operation of the combination weighing device 1 having the above-described configuration will be described. In addition, the following series of measurement operations are performed when the control unit 60 described above electrically operates the driving positions of the respective units. In this embodiment, a series of processes in which an object to be weighed is supplied to the weighing hopper 40 and discharged from the weighing hopper 40 when selected as a combination of objects to be weighed by the calculation unit 63 is one cycle. To do.

  The first one cycle at the time of starting (hereinafter referred to as “first cycle”) will be described. First, the objects to be weighed fall from the supply mechanism 100 located above the combination weighing device 1 and are supplied onto the dispersion feeder 10. The object to be weighed receives vibration from the upper surface of the dispersion feeder 10, moves outward on the upper surface of the dispersion feeder 10 having a conical inclination angle, and reaches a plurality of supply troughs 20.

  On the other hand, among the plurality of pool hoppers 30, when there is an empty pool hopper 30 that is discharged from the weighing hopper 40 below, the supply trough 20 corresponding to the pool hopper 30 is present. The conveying surface of the oscillating machine is vibrated. In response to this vibration, the object to be weighed is moved outward on the supply trough 20 and sent into the pool hopper 30.

  Further, among the plurality of weighing hoppers 40, when there is a weighing hopper 40 that has been emptied by discharging the objects to be gathered to the lower collecting portion 50, the pool hopper located above the weighing hopper 40. 30 opens the gate 30 b and discharges the object to be weighed to the weighing hopper 40.

When the weighing hopper 40 accommodates the object to be weighed supplied from the upper pool hopper 30, the weight value M1 of the weighing hopper 40 in the state where the object to be weighed is accommodated is measured by the weight detection unit 42 connected to the weighing hopper 40. Detected. The weight detection unit 42 transmits the weight value M1 to the control unit 60. The measured value calculation unit 61 calculates the weight W1 of the object to be measured obtained from the weight value M1 when the zero point correction value V0 is used as a reference. The measured value calculation unit 61 transmits the weight W1 to the storage unit 66. The storage unit 66 stores the weight W1 of the weighing object of each weighing hopper 40 thus calculated. For example, as shown in FIG. 3A, the storage unit 66 includes a plurality of weighing hoppers 40 (40 ₁ , 40 ₂ ,..., 40 _n ) and respective weights W1 (W1 ₁ , W1 ₂ ,. , W1 _n ) in association with each other.

  The calculation unit 63 executes a combination calculation process on the weights W1 of the plurality of objects to be measured stored in the storage unit 66, and the objects to be weighed so that the total weight is within a preset allowable range. Is selected.

  Each weighing hopper 40 selected by the combination calculation opens the gate 40b when the timing hopper 50b of the collecting unit 50 discharges the object to be measured downward to become empty, and the object to be weighed accommodated inside is opened. Drain things. The objects to be weighed sent out from the weighing hopper 40 slide down on the sliding surface 50a of the collecting unit 50 and are collected in one timing hopper 50b below. Then, the gathering unit 50 opens the gate 50c in a timely manner, and sends the objects to be weighed gathered in the timing hopper 50b to a subsequent packaging device or the like. Here, the operation of the combination weighing device 1 in the first cycle ends.

  The control unit 60 applies the weighing object in the next cycle (hereinafter referred to as “second cycle”) to the weighing hopper 40 that has participated in the combination calculation, in other words, the weighing hopper 40 that has discharged the measurement object. Stop supplying. That is, the weighing object is not supplied to the weighing hopper 40 that has opened the gate 40b and discharged the weighing object in the second cycle.

  The operation of the combination weighing device 1 in the second cycle will be described. As described above, the second cycle includes the weighing hopper 40 that has discharged the object to be weighed in the immediately preceding cycle and the weighing hopper 40 to which the object to be weighed has been supplied in the previous cycle. In other words, in the second cycle, there are the weighing hopper 40 in a state where an object to be weighed is accommodated and the weighing hopper 40 in a state where an object to be weighed is not accommodated.

In the weighing hopper 40 in the state in which the object to be weighed is accommodated, the weight detection unit 42 connected to the weighing hopper 40 is the weight value M1 of the weighing hopper 40 in the state in which the object to be weighed is accommodated, as in the first cycle. Detected by. The weight detection unit 42 transmits the weight value M1 to the control unit 60. The measured value calculation unit 61 calculates the weight W1 of the object to be measured obtained from the weight value M1 when the zero point correction value V0 is used as a reference. The measured value calculation unit 61 transmits the weight W1 to the storage unit 66. The storage unit 66 stores the weight W1 of the object to be measured thus calculated. For example, the storage unit 66 includes a plurality of weighing hoppers 40 (40 ₁ , 40 ₂ ,..., 40 _n ) and weights W1 (W1 ₁ , W1 ₂ ,...) As shown in FIG. , W1 _n ) in association with each other. However, the weight W1 (the weighing hoppers 40 ₂ and 40 ₅ ) corresponding to the weighing hopper 40 to which the object to be weighed was not supplied in the second cycle is not stored. This is different from the first cycle.

On the other hand, at the same timing when the weight value M1 of the weighing hopper 40 in the state in which the object to be weighed is accommodated is detected by the weight detection unit 42, the weight value M2 in the state in which the object to be weighed is not accommodated. Is detected by the weight detector 42 connected to the weighing hopper 40. The weight detection unit 42 transmits the weight value M2 to the control unit 60. The storage unit 66 stores a weight value M2 for each weighing hopper 40. For example, the storage unit 66 stores the weighing hoppers 40 (40 ₂ , 40 ₅ ) and the weight values M2 (M2 ₂ , M2 ₅ ) in association with each other as shown in FIG. The weight value M2 is used to calculate a weight correction value E1 for correcting the weight W1 of the object to be calculated calculated in the next cycle. Details of the calculation method of the weight correction value E1 will be described later.

  The calculation unit 63 targets the weights W1 of the plurality of objects to be weighed acquired in this cycle, that is, the weights W1 of the plurality of objects to be weighed stored in the storage unit 66 (see FIG. 3B). As in the operation in the first cycle, the combination calculation process is executed. The calculation unit 63 selects a combination of the weighing hoppers 40 that discharge the objects to be weighed so that the total weight is within a preset allowable range. Since the operation after the combination calculation process in the calculation unit 63 is the same as the operation in the first cycle, the description thereof is omitted here. Here, the operation of the combination weighing device 1 in the second cycle ends.

  The control unit 60 stops the supply of the objects to be weighed in the next cycle (hereinafter referred to as “third cycle”) to the weighing hopper 40 that participated in the combination calculation in the second cycle. In other words, the weighing hopper 40 that opens the gate 40b and discharges the object to be weighed therein is not supplied with the object to be weighed in the third cycle. In addition, the control unit 60 supplies the objects to be weighed in the third cycle to the weighing hopper 40 to which the objects to be weighed are not supplied in the second cycle.

  The operation of the combination weighing device 1 in the third cycle will be described. As described above, in the third cycle, the weighing hopper 40 that has discharged the object to be weighed in the immediately preceding cycle, the weighing hopper 40 to which the object to be weighed is supplied in the previous cycle, and the object to be weighed in the third cycle are supplied. A weighing hopper 40. In other words, in the third cycle, there are a weighing hopper 40 in a state in which an object to be weighed is accommodated and a weighing hopper 40 in a state in which an object to be weighed is not accommodated.

  In the weighing hopper 40 in the state in which the object to be weighed is accommodated, the weight detection unit 42 connected to the weighing hopper 40 is the weight value M1 of the weighing hopper 40 in the state in which the object to be weighed is accommodated, as in the first cycle. Detected by. The weight detection unit 42 transmits the weight value M1 to the control unit 60. The measured value calculation unit 61 calculates the weight W1 of the object to be measured obtained from the weight value M1 when the zero point correction value V0 is used as a reference.

Here, the weighing value correcting unit 62 is the weight of the object to be weighed in the weighing hopper 40 (here, the weighing hoppers 40 ₂ and 40 ₅ ) in which the weight value M2 is detected in the immediately preceding cycle (here, the second cycle). The weight W1 is corrected with respect to W1. Specifically, the weighing value correction unit 62 calculates the corrected weight W2 by subtracting the weight correction value E1 from the weight W1 of the object to be weighed. The weight correction value E1 is the weight value M2 of the weighing hopper 40 in a state immediately before the object is accommodated when the zero point correction value V0 is used as a reference (that is, the object to be weighed is not accommodated in the second cycle). It is obtained from the weight value M2) of the weighing hopper 40 in the state.

The storage unit 66 stores the weight W1 and the corrected weight W2 of the object to be measured thus calculated. For example, as shown in FIG. 3D, the storage unit 66 includes a weighing hopper 40 (40 ₁ , 40 ₂ ,..., 40 _n ), a weight W1, and a corrected weight W2 (W1 ₁ , W2 ₂ ,.・, W1 _n ) is stored in association with each other.

  On the other hand, at the same timing when the weight value M1 of the weighing hopper 40 in the state in which the object to be weighed is accommodated is detected by the weight detector 42, the weight value M2 in the state in which the object to be weighed is not supplied is It is detected by a weight detector 42 connected to the weighing hopper 40. Since the operation here is the same as the operation in the second cycle, the description is omitted here.

  On the other hand, at the same timing when the weight value M1 of the weighing hopper 40 in the state in which the object to be weighed is accommodated is detected by the weight detection unit 42, the weight value M2 in the state in which the object to be weighed is not accommodated. Is detected by the weight detector 42 connected to the weighing hopper 40. The operation for obtaining the weight value M2 used for correcting the weight W1 of the object to be measured calculated in the next cycle is the same as the operation in the second cycle.

  The calculation unit 63 targets the weights W1 and corrected weights W2 of the plurality of objects acquired in this cycle, that is, targets the weights W1 and the corrected weights W2 of the plurality of objects stored in the storage unit 66. As in the operations in the first and second cycles, the combination calculation process is executed. The calculation unit 63 selects a combination of the weighing hoppers 40 that discharge the objects to be weighed so that the total weight is within a preset allowable range. Since the operation after the combination calculation process in the calculation unit 63 is the same as the operation in the first and second cycles, the description thereof is omitted here. Here, the operation of the combination weighing device 1 in the third cycle ends.

  The control unit 60 stops the supply of the objects to be weighed in the next cycle to the weighing hopper 40 that has participated in the combination calculation in the third cycle. Thereafter, the control unit 60 controls each unit so as to repeatedly execute the same operation as in the third cycle described above. When the same operation as in the third cycle is repeatedly executed, all the weighing hoppers 40 are selected at least once as a combination operation. In this case, the calculation unit 63 performs the combination calculation process only on the corrected weight W2 of the plurality of objects to be weighed. That is, as shown in FIG. 3 (e), the calculation unit 63 executes the combination calculation process only for the corrected weights W <b> 2 of the plurality of objects stored in the storage unit 66.

  The zero point adjustment unit 64 resets the weight value of the weighing hopper 40 in a state in which the object to be weighed is discharged as the zero point correction value V1 for a predetermined time or a predetermined number of discharges. The zero point correction value V1 is a weight value in a state where an object to be weighed is not accommodated in the target weighing hopper 40, for example, a weight value of the weighing hopper 40 in a state in which the object to be weighed just before the zero point adjustment is discharged. can do. In the case of the weight detector 42 such as a load cell, the load cell digital weighing signal (A / D count value) connected to the weighing hopper 40 in a state where the object to be weighed is discharged is reset to zero. Thereafter, the measurement value calculation unit 61 calculates the weight W1 of the object to be obtained obtained from the weight value M1 detected by the weight detection unit 42 when the zero point correction value V1 is used as a reference. When the zero adjustment is performed on the predetermined weighing hopper 40, the weight correction value E1 corresponding to the predetermined weighing hopper 40 calculated in the previous cycle and stored in the storage unit 66 is reset. The

  According to the combination weighing device 1 having the above-described configuration, the weighing object obtained from the weight value M1 detected for the weighing hopper 40 in the state in which the object to be weighed is accommodated when the zero correction value V0 (V1) is used as a reference. The weight correction value E1 obtained from the weight value M2 detected with respect to the weighing hopper 40 immediately before the object to be weighed is stored when the zero point correction value V0 (V1) is used as a reference is subtracted from the weight W1 of the weighing object. Thus, the corrected weight W2 is calculated. The weight correction value E1 occurs when the object to be weighed is discharged by participating in the combination calculation, but when a part of the object to be weighed adheres to the weighing hopper 40 or when the output of the load cell changes due to temperature or the like. The fluctuation value from the zero point correction value V0 (V1) is shown. Moreover, the adhesion of the objects to be weighed to the weighing hopper 40 tends to accumulate. Accordingly, by subtracting the weight correction value E1 from the weight value M1 calculated with the zero point correction value V0 (V1) as a reference, a part of the object to be weighed adheres to the weighing hopper 40 after the zero point adjustment, or the temperature change Even if the output of the load cell fluctuates due to changes over time or the like, the influence is eliminated. As a result, the weighing accuracy can be increased.

  The effect of the combination weighing device 1 having the above configuration will be described in detail with reference to FIG. FIG. 4 shows the weight of an object to be weighed when a cycle consisting of supply and discharge of the object to be weighed is repeatedly performed in a certain weighing hopper 40. A portion where the weight at the time of discharge is not 0 (for example, cycles 3 and 12) indicates that a part of the object to be weighed adheres to the inner wall of the weighing hopper 40 and the object to be weighed has not been completely discharged. .

  A method for calculating an object to be weighed in cycle 1 will be described. In cycle 1, the object to be weighed of weight X2 is supplied to the weighing hopper 40 in a state where the object to be weighed is not attached. At this time, by setting the weight of the weighing hopper in a state in which the object to be weighed is not stored to 0 (by performing so-called zero point correction), the weight of the object to be weighed supplied from the value detected by the weight detection unit 42. X2 is calculated. At this time, the calculated weight X2 of the object to be weighed matches the weight of the supplied object to be weighed. The calculation of the weight X2 is a part common to the conventional combination weighing device.

  Next, a method for calculating an object to be weighed in cycle 3 will be described. In cycle 3, the object to be weighed by weight X2 is supplied to the weighing hopper 40 with the object to be weighed by weight X1 attached thereto. At this time, in the conventional combination weighing device, by setting the weight of the weighing hopper 40 in a state in which an object to be weighed is not stored to 0 (by performing so-called zero point correction), from the value detected by the weight detection unit 42, A weight X3 of the supplied object to be weighed is calculated. In this case, an error occurs between the calculated weight X3 and the weight (X3-X1) of the supplied object to be weighed. When the calculated weight X3 is used for the combination calculation, the weighing accuracy decreases.

  In the combination weighing device 1 of the present embodiment, the weight X3 calculated by the conventional method is corrected in consideration of the weighing hopper 40 in a state where an object to be weighed having a weight X1 is attached. That is, the weight X2 of the actually supplied weighing object is calculated by subtracting the weight X1 of the weighing object attached to the weighing hopper 40 from the weight X3. Specifically, in cycle 2, the weight X1 of the weighing hopper in a state where the object to be weighed is discharged is calculated by the conventional method and stored. In cycle 3, the weight X2 is calculated by correcting the weight (weight correction value) X1 from the weight X3 calculated by the conventional method. In this case, the calculated corrected weight (X3−X1) and the weight X2 of the supplied object to be weighed match. Since the corrected weight (X3-X1) calculated in this way is used for the combination calculation, the weighing accuracy does not deteriorate.

  In the combination weighing device 1 of the present embodiment, the zero point correction value is reset every predetermined time or every time the object is discharged a predetermined number of times. In FIG. 4, by setting the weight of the weighing hopper 40 with the weight X2 to be weighed to 0 (so-called zero point correction), it is supplied from the value detected by the weight detector 42 after the next cycle. The weight of the measured object is calculated. Even in the cycle after resetting the zero point correction value, as shown in cycle 12, for example, the weight X13 calculated by the conventional method is subtracted from the weight X11 of the weighing object attached to the weighing hopper 40, so that it is actually supplied. The weight X12 of the measured object is calculated.

  Although one embodiment has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.

  In the combination weighing device 1 of the above embodiment, the supply of the objects to be weighed in the next cycle is stopped for all the weighing hoppers 40 participating in the combination calculation, and the weight value M2 for calculating the weight correction value E1 is obtained. An example of obtaining, that is, an example in which the weight W1 is corrected and the corrected weight W2 is calculated (hereinafter referred to as “adhesion correction”) has been described, but the present invention is not limited to this.

  For example, the correction execution control unit 67 (see FIG. 5) is provided, and the measurement value calculation unit 61 and the measurement are performed so that the adhesion correction is performed every time the object to be weighed is discharged a plurality of times (for example, twice) or every predetermined time. The value correction unit 62 may be controlled.

  Further, the correction execution control unit 67 may select, for example, the weighing hopper 40 that performs adhesion correction from the weighing hoppers 40 that have participated in the combination calculation. Selection of the weighing hopper 40 in the correction execution control unit 67 may be performed based on an input from the input unit 70 (see FIG. 5). The input unit 70 can be realized by a known keyboard and touch panel. At this time, for example, if there is a means for displaying the elapsed time from the previous zero correction, the number of discharges, etc. for each weighing hopper 40, the user can assist in selecting the weighing hopper 40 to perform the adhesion correction. It can be performed.

  Further, the selection of the weighing hopper 40 in the correction execution control unit 67 may be performed based on an input from a correction determination unit 68 (see FIG. 5) described in detail below. Hereinafter, an example of whether or not adhesion correction can be performed in the correction determination unit 68 will be described.

  First, the zero correction value V <b> 1 updated in the weighing hopper 40 is stored in the storage unit 66. Next, when a plurality of (for example, 20) zero correction values V1 are accumulated, the correction determination unit 68 adds up these zero correction values V1 and calculates a standard deviation. The summation of the zero point correction values V1 here is not the summation of the zero point correction values V1 for each weighing hopper 40, but the zero point correction values V1 updated in the plurality of weighing hoppers 40 are summed in time series. The correction determination unit 68 may determine whether or not to perform adhesion correction based on the standard deviation calculated in this way.

  By providing such a correction determination unit 68, it is possible to automatically perform adhesion correction when the standard deviation exceeds a threshold value. Further, when the standard deviation becomes less than the threshold value, the adhesion correction can be automatically stopped. According to this configuration, the weight W1 is corrected when the fluctuation of the zero point correction value is relatively large and the necessity of adhesion correction is considered high, so that the weighing accuracy can be further improved. On the other hand, the weight hopper 40 is not corrected when the fluctuation of the zero point correction value is relatively small and the necessity of the adhesion correction is considered to be low, that is, for obtaining the weight correction value E1. On the other hand, since it is not necessary to stop the supply of the objects to be weighed, it is possible to reduce the number of weighing hoppers that cannot participate in the combination weighing, and to suppress the deterioration of the accuracy of the combination calculation.

  Further, the correction determination unit 68 may rank the standard deviation values and select the number of weighing hoppers 40 that perform the adhesion correction for each rank. For example, ranks are divided into three ranges based on the standard deviation, and “adhesion correction is not performed on all weighing hoppers 40” and “adhesion correction is performed only on a predetermined number of weighing hoppers 40” according to each rank. Determinations such as “Yes” or “Perform adhesion correction on all weighing hoppers 40”.

  Further, the correction determination unit 68 checks whether or not the ability to participate in the combination calculation stably every cycle by measuring the interlocking signal interval from the subsequent packaging device, and determines whether or not the adhesion correction can be performed. May be.

  Further, the correction determination unit 68 may total the zero point correction values V1 for each weighing hopper 40, and may determine whether or not the adhesion correction can be performed for each weighing hopper 40 based on these total values and standard deviation.

  In the modification of the above-described embodiment, the process in which the adhesion correction is not performed every time has been described. Even in this case, the calculation unit 63 uses the target value as a reference when the value obtained by combining one or a plurality of correction weights W2 among the correction weights W2 for the respective weighing hoppers 40 is used at least once. The combination of the objects to be weighed is selected so as to be within the allowable range.

  In the embodiment and the modification described above, in order to obtain the weight M2 of the weighing hopper 40 immediately before the object to be weighed is stored, the supply of the object to be weighed in the next cycle is stopped, and in the next cycle Although an example of acquiring the weight value M2 has been described, the present invention is not limited to this. Even if the supply of the weighing object is not stopped in the next cycle, the weight value M2 of the weighing hopper 40 in a state where the weighing object is discharged may be acquired at the timing when the weighing object is discharged. Further, the weight of the weighing hopper 40 in a state immediately before the object to be weighed is supplied to the weighing hopper 40 may be acquired within the same cycle in which the object to be weighed is supplied.

  In the above embodiment, the combination calculation of the weights of the objects to be weighed accommodated in the weighing hopper 40 is performed. However, the number combination weighing device that divides the weight value M1 of each weighing hopper 40 by the unit weight and converts it into the number. Even so, the present invention can be applied.

  The weight (measurement) performed by the measurement value calculation unit 61, the measurement value correction unit 62, the calculation unit 63, the zero point adjustment unit 64, the storage unit 66, the correction execution control unit 67, and the correction determination unit 68 included in the control unit 60. The value correction method can also be realized as a program executed by a computer.

  DESCRIPTION OF SYMBOLS 1 ... Combination weighing device, 40 ... Weighing hopper, 42 ... Weight detection part, 60 ... Control part, 61 ... Measurement value calculation part, 62 ... Measurement value correction part, 63 ... Calculation part, 64 ... Zero point adjustment part, 66 ... Memory | storage Unit, 67... Correction execution control unit, 68.

Claims (4)

A plurality of weighing hoppers for receiving and discharging the objects to be weighed;
A weight detector for detecting a weight value of each of the weighing hoppers;
A zero point adjustment unit for setting a zero point correction value every predetermined time or every time the measurement object is discharged a predetermined number of times;
From the measured value of the weighing object obtained from the weight value detected for the weighing hopper in a state in which the weighing object is accommodated when the zero point correction value set by the zero point adjustment unit is used as a reference, Weighing value correction for calculating a corrected weighing value by subtracting a weight correction value obtained from the weight value detected for the weighing hopper in a state immediately before the object is accommodated when the zero point correction value is used as a reference And
The combination of the objects to be weighed is set so that a value obtained by combining one or more of the corrected measurement values of each of the weighing hoppers is within an allowable range based on a target value. A computing unit to select;
A combination weighing device. When the object to be weighed is supplied to the weighing hopper and selected as a combination of the objects to be weighed by the calculation unit, a series of steps for discharging the object to be weighed from the weighing hopper is one cycle. ,
A control unit for stopping the supply of the objects to be weighed in the next cycle to the weighing hopper from which the objects to be weighed have been discharged;
The weighing value correction unit calculates the weight correction value based on a weight value of the weighing hopper in a state where the weighing object is discharged, which is detected in a cycle in which the supply of the weighing object is stopped. Item 3. The combination weighing device according to Item 1 . Further comprising a correction execution control unit that switches whether to calculate the corrected weight values in the weighing value correcting unit, the combination weighing apparatus according to claim 1 or 2. A storage unit for storing the set and updated zero point correction value;
The correction execution control unit based on the value of the standard deviation of the zero-point correction value of said predetermined stored in the storage unit number, determines whether to calculate the correction metric, according to claim 3 Combination weighing device.

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