Metering device

Abstract

To provide a weighing device for weighing an article during conveyance, capable of calculating an appropriate correction value while suppressing an operation time of the weighing device required for calculating the correction value for correcting a weight measured by a measuring part and an actual weight of the article.SOLUTION: The weighing device includes a second conveyor, a load cell, and a control unit. The second conveyor receives and conveys the article. The load cell detects the weight of the second conveyor, or when the second conveyor is conveying an article, the weight of the second conveyor and the weight of the article on the second conveyor, and outputs a weighing signal. The control unit calculates a correction value for correcting the weight of the article detected by the load cell based on the weighing signal output by the load cell when the reference sample is conveyed by the second conveyor for the number of times of weighing the reference sample. The control unit calculates the reference number of sample weighings based on the weighing signal output by the load cell when the second conveyor is driven.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a weighing device. [Background technology]

[0002] Weighing devices that weigh items while they are being transported are known. In such weighing devices, items may float due to air currents or other factors during transport, which can result in an error between the actual weight of the items and the measured weight.

[0003] In response to this, Patent Document 1 (JP 2013-76661 A) describes a method of collecting a preset number of weighing results (dynamic weighing values) (a number of tests recommended by the manufacturer) of sample articles with known weights while they are being transported, excluding outliers, and calculating a correction value using the collected weighing results.Then, it describes a method of obtaining the weight value of an article by correcting the dynamic weighing values ​​with the calculated correction value when actually weighing an article. Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the degree of variation in the weight measurement results (dynamic weighing values) of a weighing device varies depending on the environment in which the weighing device is installed, etc. Therefore, the number of sample item weighing results required to obtain an appropriate correction value varies depending on the weighing device. In other words, the appropriate number of tests in Patent Document 1 (JP 2013-76661 A) varies depending on the weighing device.

[0005] When calculating a correction value, if the set number of tests is smaller than the appropriate value, the calculated correction value may not be an appropriate value. If the set number of tests is large enough, the possibility that the calculated correction value will be inappropriate can be reduced. However, in this case, an excessive number of tests may be performed, which may unnecessarily increase the work time required to calculate the correction value.

[0006] The object of the present invention is to provide a weighing device that weighs items while transporting them, and that can calculate an appropriate correction value while reducing the operating time of the weighing device required to calculate a correction value for correcting the weight measured by the measuring unit and the actual weight of the item. [Means for solving the problem]

[0007] A weighing device according to a first aspect includes a conveying unit, a detecting unit, and a control unit. The conveying unit receives and conveys an object. The detecting unit detects the weight of the conveying unit, or, if the conveying unit is conveying an object, the weight of the conveying unit and the weight of the object on the conveying unit, and outputs a weighing signal. The control unit calculates a correction value for correcting the weight of the object detected by the detecting unit based on the weighing signal output by the detecting unit when the conveying unit conveys a reference sample a predetermined number of times. The control unit calculates the predetermined number of times based on the weighing signal output by the detecting unit when driving the conveying unit.

[0008] In the weighing device of the first aspect, the number of times the reference sample should be run to calculate the correction value is calculated based on the weighing signal output by the detection unit when the transport unit is driven, so it is possible to prevent the occurrence of a situation in which the reference sample is weighed too few times to calculate an appropriate correction value, or conversely, the reference sample is weighed too many times.As a result, the weighing device of the first aspect can calculate an appropriate correction value while reducing the operating time of the weighing device required to calculate the correction value (the time required to calculate the correction value).

[0009] A weighing device according to a second aspect is the weighing device according to the first aspect, wherein the control unit calculates the predetermined number of times based on a weighing signal output by the detection unit when the transport unit is driven to transport the articles.

[0010] In the weighing device of the second aspect, the predetermined number of times is calculated based on the weighing signal output by the detection unit when an item is transported, so that an appropriate predetermined number of times can be calculated for calculating the correction value, taking into account the characteristics of the weighing device itself, the influence of the installation environment, and the influence of item transport.

[0011] A weighing device according to a third aspect is the weighing device according to the second aspect, wherein the control unit calculates the predetermined number of times based on a weighing signal output by the detection unit when the transport unit is driven to transport the reference sample.

[0012] In the weighing device of the third aspect, the predetermined number of times is calculated based on the weighing signal output by the detection unit while transporting the reference sample used to calculate the correction value, so that an appropriate predetermined number of times can be calculated for calculating the correction value, taking into account the characteristics of the reference sample actually weighed by the weighing device.

[0013] A weighing device of a fourth aspect is the weighing device of the first aspect, wherein the control unit calculates the predetermined number of times based on the weighing signal output by the detection unit when the conveying unit is driven but is not conveying any items.

[0014] In the weighing device according to the fourth aspect, it is possible to calculate a predetermined number of times appropriate for calculating a correction value in a short period of time without transporting articles using the transport section.

[0015] A weighing device according to a fifth aspect is the weighing device according to any one of the first to fourth aspects, further comprising an output unit that outputs the predetermined number of times calculated by the control unit.

[0016] In the weighing device of the fifth aspect, the calculated predetermined number of times is output, so that an operator or the like operating the weighing device can check whether the calculated number of times is an appropriate value.

[0017] A weighing device according to a sixth aspect is the weighing device according to any one of the first to fifth aspects, further comprising a memory unit that stores the predetermined number of times. The control unit stores the calculated predetermined number of times in the memory unit. The control unit calculates a correction value for correcting the weight of the item detected by the detection unit based on the weighing signals output by the detection unit when the transport unit transports the reference sample the predetermined number of times stored in the memory unit.

[0018] In the weighing device of the sixth aspect, the calculated predetermined number of times is automatically set in the weighing device, thereby eliminating the need for an operator to manually set the predetermined number of times. [Effects of the Invention]

[0019] The weighing device of the present invention calculates the number of times the reference sample should be run to calculate the correction value based on the weighing signal output by the detection unit when the conveying unit is driven, thereby preventing the occurrence of a situation where the reference sample is weighed too few times to calculate an appropriate correction value, or conversely, where the reference sample is weighed too many times. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic front view of a weighing device according to one embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram of the weighing device of FIG. 1. [Figure 3] 2 is a schematic plan view of the main part of the weighing device of FIG. 1 as seen from above. [Figure 4] 2 is a schematic diagram of the weighing device and a second conveyor of the transport device of the weighing device of FIG. 1. FIG. [Figure 5] 2 is a block diagram of a configuration for weight calculation processing of a control device of the weighing device of FIG. 1. FIG. [Figure 6] 2 is a diagram schematically showing a detection signal of a load cell of the weighing device of FIG. 1 and a detection signal after filtering. FIG. [Figure 7] 2 is an example of a flowchart of a process for calculating a correction value in the weighing device of FIG. 1. [Figure 8] 10 is a flowchart of a first embodiment of a process for calculating the number of times a reference sample is measured in a process for calculating a correction value. [Figure 9] 10 is a flowchart of a second embodiment of the process for calculating the number of times of measuring a reference sample in the process for calculating a correction value. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be described with reference to the accompanying drawings, in which: Fig. 1 is a diagram showing a weighing device according to an embodiment of the present invention;

[0022] (1) Overall structure A weighing device 100 according to a first embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a schematic front view of the weighing device 100. Figure 2 is a block diagram of the weighing device 100. Figure 3 is a schematic plan view of the main parts of the weighing device 100 as seen from above.

[0023] The weighing device 100 is a weighing device that weighs an object P while transporting the object P.

[0024] 1, the weighing device 100 mainly includes a conveying device 10 and a detecting device 20. The weighing device 100 also includes a control device 80 that controls the operations of the conveying device 10 and the detecting device 20, as shown in FIG.

[0025] The conveying device 10 receives and conveys the objects P to be weighed, which are supplied from an upstream process (not shown, for example, a manufacturing process for the objects P). Specifically, the conveying device 10 conveys the objects P to a location where the weight is detected by the detection device 20.

[0026] The detection device 20 detects the weight of the object P to be weighed transported by the transport device 10 and outputs a weighing signal corresponding to the detected weight to the control device 80. The control device 80 calculates the weight W of the object P to be weighed based on the weighing signal output by the detection device 20 when detecting the weight of the object P to be weighed. Furthermore, the control device 80 determines whether the calculated weight W of the object P to be weighed is within the allowable weight range. When the weight W of the object P is within the allowable weight range, it means that the weight of the object P is equal to or greater than the allowable minimum weight and equal to or less than the allowable maximum weight.

[0027] It should be noted that, for example, a sorting device (not shown) is disposed downstream of the weighing device 100. The sorting device sorts the objects P based on the weight W of the objects P calculated by the control device 80. For example, if the weight W of the objects P is outside the allowable weight range, the sorting device removes the objects P from the conveying line for the objects P.

[0028] (2) Detailed configuration The details of the weighing device 100 will be described in detail below.

[0029] In the following, expressions such as "front," "rear," "up," "down," "left," and "right" may be used when describing directions and positional relationships, but these expressions are for the convenience of explanation and do not limit the content of the present invention. Expressions such as "front," "rear," "up," "down," "left," and "right" refer to the directions indicated by the arrows in the drawings unless otherwise specified.

[0030] (2-1) Conveyor The conveying device 10 conveys the objects to be weighed P along a conveying direction A (see FIGS. 1 and 3).

[0031] The transport device 10 includes a first conveyor 12, a second conveyor 14, a first drive unit 18a, and a second drive unit 18b. The first drive unit 18a and the second drive unit 18b are, for example, motors.

[0032] As shown in FIGS. 1 and 3, in the conveying device 10, a first conveyor 12 and a second conveyor 14 are arranged in this order from the upstream side in a conveying direction A of the objects P to be weighed.

[0033] 3, the first conveyor 12 is disposed upstream of the first conveyor 12 and the second conveyor 14 in the conveying direction A. The first conveyor 12 functions as an intake conveyor that takes in the objects P to be weighed that are conveyed from a process upstream of the weighing device 100 into the weighing device 100. The first conveyor 12 conveys the objects P to be weighed in the conveying direction A and hands over the objects P to the second conveyor 14.

[0034] The first conveyor 12 includes a first conveyor belt 12a (see FIG. 1). The first drive unit 18a drives the drive roller 122a of the drive roller 122a and the driven roller 122b around which the first conveyor belt 12a is wound, causing the first conveyor 12 to transport the objects to be weighed P on the first conveyor belt 12a in the transport direction A.

[0035] As shown in Figure 3, the second conveyor 14 is disposed downstream in the conveying direction A of the first conveyor 12 and the second conveyor 14. The second conveyor 14 receives and conveys the objects P to be weighed conveyed by the first conveyor 12. The detection device 20 detects the weight of the objects P being conveyed by the second conveyor 14 and outputs a weighing signal. The second conveyor 14 conveys the objects P to be weighed in the conveying direction A and delivers the objects P to a subsequent process of the weighing device 100 (for example, a sorting device not shown).

[0036] The second conveyor 14 includes a second conveyor belt 14a (see FIG. 1). The second drive unit 18b drives the roller (drive roller) 144a of the rollers 144a, 144b around which the second conveyor belt 14a is wound, causing the second conveyor 14 to convey the objects to be weighed P on the second conveyor belt 14a in the conveying direction A.

[0037] (2-2) Detection device The detection device 20 will be described with further reference to Fig. 4. Fig. 4 is a schematic diagram of the second conveyor 14 of the transport device 10 and the detection device 20.

[0038] As shown in FIGS. 3 and 4, the detection device 20 mainly includes a sensor 25 and a load cell 28 as an example of a detection unit.

[0039] The sensor 25 detects that the objects P to be weighed, being transported by the first conveyor 12, have reached the second conveyor 14. The sensor 25 is, for example, a photoelectric sensor. However, the type of the sensor 25 is not limited to a photoelectric sensor, and any type of sensor can be used as long as it is capable of detecting the arrival of the objects P to be weighed on the second conveyor 14.

[0040] The control device 80 detects the timing when the entire object P is present on the second conveyor belt 14a based on the detection result of the sensor 25, the conveying speed V of the conveying device 10, and the length L1 of the object P in the conveying direction A. The control device 80 calculates the weight W of the object P based on the weighing signal output by the load cell 28 while the entire object P is present on the second conveyor belt 14a.

[0041] The load cell 28 includes a strain element 28a that distorts in proportion to the force acting on it, and a strain gauge (not shown) that is attached to the strain element 28a and converts the strain into an electrical signal (called a measurement signal) and outputs it. In short, the load cell 28 transmits a measurement signal that corresponds to the force acting on it. The load cell 28 is housed inside a case 26 disposed below the second conveyor 14 (see FIG. 4).

[0042] The detection of weight by the load cell 28 will be described below. Before describing the detection of weight by the load cell 28, the structure of the second conveyor 14 of the transport device 10 will first be described in detail.

[0043] In addition to the second conveyor belt 14a described above, the second conveyor 14 mainly includes a frame 142, a driving roller 144a, and a driven roller 144b (see FIG. 4).

[0044] The frame 142 of the second conveyor 14 is supported by brackets 24 that extend upward from the case 26. The case 26 is fixed to the frame 50 of the weighing device 100, as shown in FIG.

[0045] As shown in Fig. 4, the drive roller 144a and the driven roller 144b are provided at both ends of the frame 142. The drive roller 144a and the driven roller 144b are rotatably supported by the frame 142. The second conveyor belt 14a is wound around the drive roller 144a and the driven roller 144b. When the second drive unit 18b drives the drive roller 144a, the second conveyor belt 14a rotates, and the second conveyor 14 conveys the objects to be weighed P on the second conveyor belt 14a in the conveying direction A.

[0046] Due to the above structure, when no objects to be weighed P are present on the second conveyor belt 14a, the load cell 28 detects the weight of the second conveyor 14 as a transport unit (the force that the second conveyor 14 applies to the load cell 28) and outputs a weighing signal. Note that the weight of the second conveyor 14 here is roughly the total weight of the frame 142, the drive roller 144a and the driven roller 144b, and the second conveyor belt 14a. Furthermore, when the second conveyor belt 14a is transporting objects to be weighed P, the load cell 28 detects the weight of the second conveyor 14 and the weight of the objects to be weighed P on the second conveyor 14 and outputs a weighing signal.

[0047] (2-3) Control device The control device 80 controls the operation of each part of the weighing device 100. The control device 80 also performs a process of calculating the weight W of the object P to be weighed based on the weighing signal transmitted by the detection device 20.

[0048] The control device 80 of this embodiment mainly includes a CPU, memory consisting of a RON, a RAN, an auxiliary storage device (e.g., a flash memory), and various electronic circuits. The control device 80 controls the operation of each part of the weighing device 100 and performs various processes by the CPU reading and executing programs stored in the memory.

[0049] The configuration of the control device 80 described here is merely one example of the configuration of the control device 80, and functions similar to those of the control device 80 of this embodiment may be realized by hardware such as a logic circuit, or may be realized by a combination of hardware and software. Furthermore, the control device 80 may be realized by one device or by multiple devices.

[0050] The control device 80 is electrically connected to the first driving unit 18a and the second driving unit 18b of the transport device 10, and the sensor 25 and the load cell 28 of the detection device 20.

[0051] The control device 80 is also electrically connected to the input device 60 and the output device 70 (see FIG. 2). The input device 60 receives various commands and information input by the operator of the weighing device 100. For example, the input device 60 is a touch panel display. Information input to the input device 60 includes, for example, the specified weight Wt of the object P to be weighed, the length L1 of the object P, and the conveying speed V of the object P by the conveying device 10. The commands and information input to the input device 60 are sent to the control device 80. The output device 70 is controlled by the control device 80 to output various information. For example, the output device 70 is a display that displays various information. That is, in this embodiment, a touch panel display functions as the input device 60 and the output device 70.

[0052] The input device and output device are not limited to the above devices. For example, the input device may be a communication unit 86 that receives commands and information transmitted from an external device 90 (for example, a portable terminal operated by an operator of the weighing device 100, or a central control unit that is higher than the weighing device 100). The output device may be a communication unit 86 that outputs (transmits) various information to an external device 90 (for example, a portable terminal held by an operator of the weighing device 100, or a central control unit that is higher than the weighing device 100). In FIG. 2, the external device 90 and the communication unit 86 are indicated by dashed lines.

[0053] The memory of the control device 80 includes a storage unit 82 that stores various types of information. Examples of information stored in the storage unit 82 will be described later.

[0054] The CPU of the control device 80 functions as a control unit 84 by reading and executing a program stored in the memory.

[0055] (2-4-1) Control Unit The control unit 84 controls the operation of the weighing device 100 based on commands input to the input device 60, and information input to the input device 60, such as the specified weight Wt of the object to be weighed P, the length L1 of the object to be weighed P in the conveying direction A as it is conveyed in the conveying direction A by the conveying device 10, and the conveying speed V of the object to be weighed P by the conveying device 10.

[0056] For example, when an operating command is input to the input device 60, the control unit 84 controls the operation of the first drive unit 18a and the second drive unit 18b so that the transport speed of the item P to be weighed by the first conveyor 12 and the second conveyor 14 becomes the transport speed V.

[0057] Furthermore, for example, the control unit 84 calculates the weight W of a certain object P to be weighed based on the weighing signal output by the load cell 28 while the object P is being transported by the second conveyor 14. Specifically, the control unit 84 detects the timing when the entire object P is present on the second conveyor belt 14a based on the detection result of the sensor 25, the transport speed V, and the length L1 of the object P. The control unit 84 calculates the weight W of the object P to be weighed based on the weighing signal output by the load cell 28 while the entire object P is present on the second conveyor belt 14a. The calculation of the weight W of the object P by the control unit 84 will be described later.

[0058] Furthermore, for example, the control unit 84 determines whether the calculated weight of the object P to be weighed is within the allowable weight range. For example, the control unit 84 determines whether the calculated weight W of the object P to be weighed is a value between the allowable minimum weight (specified weight Wt of the object P - α) and the allowable maximum weight (specified weight Wt of the object P + β) (α and β are preset numerical values). If the calculated weight W of the object P to be weighed is within the allowable weight range, the control unit 84 determines that the object P to be weighed is an acceptable product, and if the calculated weight W of the object P to be weighed is outside the allowable weight range, the control unit 84 determines that the object P to be weighed is an unacceptable product.

[0059] (A) Calculation of the weight of the item The calculation process of the weight W of the object to be weighed P by the control unit 84 will be described below. First, the configuration of the control device 80 for the weight calculation process will be described with reference to Fig. 5. Fig. 5 is a block diagram of the configuration of the control device 80 for the weight calculation process.

[0060] The control device 80 includes an amplifier 182, an analog filter 184, and an A / D converter 186. The control unit 84 also includes a signal processing unit 188 as a functional unit for calculating the weight of the object P to be weighed.

[0061] The amplifier 182 amplifies the weighing signal input from the load cell 28 and outputs it as an amplified signal to the analog filter 184. The analog filter 184 removes unnecessary high-frequency components from the amplified signal and outputs it as an analog signal. The A / D converter 186 converts the analog signal output from the analog filter 184 into a digital signal and outputs it to the signal processing unit 188. The signal processing unit 188 filters the digital signal using a predetermined finite impulse response (FIR) filter (hereinafter simply referred to as a filter), although the type of filter is not limited thereto. In short, the signal processing unit 188 filters the weighing signal preprocessed by the amplifier 182, analog filter 184, and A / D converter 186 (hereinafter the preprocessed weighing signal is referred to as the weighing signal of the load cell 28) using a predetermined filter. The control unit 84 calculates the weight W of the object to be weighed P based on the weighing signal of the load cell 28 filtered by the signal processing unit 188. Specifically, the control unit 84 calculates the dynamic weight of the object P based on the weighing signal of the load cell 28 filtered by the signal processing unit 188. The control unit 84 calculates the weight W of the object P by multiplying the dynamic weight by a correction value. The dynamic weight and the correction value will be described later.

[0062] As described above, when the second conveyor belt 14a is carrying the objects P, the load cell 28 detects the weight of the second conveyor 14 and the weight of the objects P on the second conveyor 14 and outputs a weighing signal. Therefore, if the control unit 84 were to calculate the weight directly based on the weighing signal from the load cell 28 when the second conveyor belt 14a is carrying the objects P, the control unit 84 would calculate the total weight of the second conveyor 14 and the objects P. Therefore, before actually starting to measure the weight of the objects P, the control unit 84 performs a process of deriving the zero point based on the weighing signal output by the load cell 28 when the objects P are not present on the second conveyor belt 14a. In other words, before actually starting to weigh the weight of the object to be weighed P, the control unit 84 performs a process in advance to calculate the weight of the second conveyor 14 to be subtracted from the total weight of the second conveyor 14 and the object to be weighed P on the second conveyor 14.

[0063] The reason why the signal processing unit 188 filters the weighing signal of the load cell 28 is that the weighing signal of the load cell 28 contains noise caused by the inherent vibration of the weighing device 100 and the rotational vibration of the motor (e.g., the motor used as the second drive unit 18b) and rollers (e.g., the drive roller 144a and driven roller 144b of the second conveyor 14) used by the weighing device 100.

[0064] Explaining this with reference to Fig. 6, the weighing signal of the load cell 28 is a signal that contains vibration components (noise) with a relatively large amplitude, as shown by the dashed line in Fig. 6. The weight of the object to be weighed P cannot be calculated with high accuracy from a weighing signal that contains such vibration components. Therefore, the signal processing unit 188 uses a predetermined filter to filter the weighing signal of the load cell 28 (to reduce noise) and extracts a signal with little noise (a signal that generally indicates only the force that the object to be weighed P applies to the load cell 28), as shown by the solid line in Fig. 6.

[0065] The control unit 84 calculates the dynamic weight of the object P based on the difference between the zero point and the weighing signal after filtering (noise reduction) by the signal processing unit 188. Specifically, the control unit 84 calculates the dynamic weight of the object P based on the difference between the weighing signal during the period when the entire object P is present on the second conveyor belt 14a (the weighing signal at the plateau portion of the solid line in FIG. 6) and the weighing signal during the period when the object P is not present on the second conveyor belt 14a (the value indicated by DW in FIG. 6).

[0066] (B) Dynamic weight and correction value When weighing an object being transported, an event may occur in which the object floats up due to air resistance. Therefore, the dynamic weight of the object P to be weighed calculated by the control unit 84 based on the weighing signal of the load cell 28 filtered by the signal processing unit 188 may differ from the actual weight of the object. Therefore, the control unit 84 calculates the weight W of the object P to be weighed by multiplying the dynamic weight by a correction value so that the dynamic weight is converted into the actual weight of the object.

[0067] An example of a method for calculating the correction value will be described with reference to an example flowchart of the correction value calculation process in Figure 7. Note that the calculation method described here is merely an example and is not intended to be limiting. For example, the order of the processes in the flowchart may be changed as appropriate within a consistent range.

[0068] The calculation of the correction value is premised on the existence of a reference sample S whose accurate weight is known. The reference sample S is preferably, but not limited to, the same type of article as the object P to be weighed actually by the weighing device 100.

[0069] The accurate weight of the reference sample S is, for example, the weight (static weight) SW calculated based on the calibration signal output by the load cell 28 when the reference sample S is placed on the second conveyor belt 14a with the conveying device 10 stopped. Note that when the conveying device 10 is stopped, air resistance does not affect the detection of the weight of the reference sample S, so no correction value is required to calculate the weight SW of the reference sample S. Note that the weight SW of the reference sample S may be measured by a weighing device separate from the weighing device 100.

[0070] Assuming that a reference sample S exists, an operator who intends to calculate a correction value operates, for example, the input device 60 to operate the weighing device 100 in a correction value calculation mode (step S1).

[0071] When operating the weighing device 100 in the correction value calculation mode, the operator also inputs the value of the weight SW of the reference sample S as information into the input device 60. The weight SW of the reference sample S input into the input device 60 is stored in the memory unit 82. When the weight of the reference sample S is measured by the weighing device 100, the weight calculated by the control unit 84 may be stored directly as the weight SW in the memory unit 82, rather than the weight SW of the reference sample S input into the input device 60 by the operator.

[0072] In the correction value calculation mode, the control device 80 operates the conveying device 10 and the detection device 20. Preferably, in the correction value calculation mode, the control device 80 controls the operation of the conveying device 10 so that the reference sample S is conveyed at a conveying speed (the conveying speed V described above) when the weighing device 10 actually weighs the object P (the actual item to be weighed). In this state, when the reference sample S is placed on the first conveyor 12 of the conveying device 10, the first conveyor 12 conveys the reference sample S to the second conveyor 14, and the control unit 84 calculates the dynamic weight based on the weighing signal output by the load cell 28 of the detection device 20 while the reference sample S is being conveyed on the second conveyor 14 (step S2). The control unit 84 stores the calculated dynamic weight in the memory unit 82 (step S3). The control device 80 continues to operate the conveying device 10 and the detection device 20 until the number of dynamic weight data stored in the memory unit 82 reaches a predetermined number (for the N number of reference sample weighings described below) (step S4). In other words, an operator who intends to calculate a correction value places the reference sample S on the first conveyor 12 of the conveying device 10 for the N number of reference sample weighings, thereby causing the control unit 84 to calculate the dynamic weight of the reference sample S for the N number of reference sample weighings.

[0073] The storage unit 82 stores the dynamic weights DW1, DW2, . . . DW for the number of times N the reference samples were weighed. N When the number of the particles reaches a certain level, the control unit 84 stops the operation of the transport device 10 (step S5).

[0074] Then, the control unit 84 calculates the correction value k using the following formula 1 (step S6).

[0075]

number

[0076] When actually calculating the weight W of the object to be weighed P, the control unit 84 calculates the weight W by multiplying the dynamic weight of the object to be weighed P, which is calculated based on the weighing signal of the load cell 28 filtered by the signal processing unit 188, by the correction value k. In short, the control unit 84 calculates the correction value k for correcting the weight of the object to be weighed P detected by the load cell 28, based on the weighing signal output by the load cell 28 when the reference sample S is transported by the second conveyor 14 a predetermined number N of times.

[0077] The variation in the dynamic weight value calculated by the control unit 84 (in other words, the effect of noise remaining in the weighing signal after filtering) varies depending on the characteristics of the weighing device 100 itself, as well as the environment of the site where the weighing device 100 is installed. For example, if there is a device that generates vibrations near the location where the weighing device 100 is installed, or if the location where the weighing device 100 is installed is susceptible to the influence of wind generated by an air conditioning device, the variation in the dynamic weight value calculated by the control unit 84 is likely to be large.

[0078] If the number of reference sample weighings N is set to a constant value and is set to a small value, the correction value k calculated by the weighing device 100 installed in such an environment may not be an appropriate value. Conversely, if the number of reference sample weighings N is set to a large value in anticipation of the possibility that the weighing device 100 may be installed in such an environment, the possibility that the calculated correction value k will be an inappropriate value can be reduced. However, in this case, there is a possibility that an excessive number of tests will be performed, which may unnecessarily increase the work time required to calculate the correction value.

[0079] Therefore, the control unit 84 calculates the number of reference sample weighings N suitable for each weighing device 100 based on the weighing signal output by the load cell 28 when driving the conveying device 10 (particularly the second conveyor 14), for example, in a manner as exemplified below.

[0080] (C) Calculation process of the number of times the reference sample is weighed <First Example> A first embodiment of the calculation process for the reference sample measurement count N in the calculation process for the correction value will be described with reference to the flowchart of FIG.

[0081] In the first embodiment, the control unit 84 calculates the reference sample weighing count N based on the weighing signal output by the load cell 28 when driving the conveying device 10 to convey an article. The article to be conveyed by the conveying device 10 when calculating the reference sample weighing count N may be selected arbitrarily, but is preferably the reference sample S. Here, the explanation will be given under the assumption that the article to be conveyed by the conveying device 10 when calculating the reference sample weighing count N is the reference sample S, the weight of which is known.

[0082] An operator who wishes to calculate the reference sample weighing count N operates the input device 60, for example, to operate the weighing device 100 in the measurement count calculation mode (step S11).

[0083] When operating the weighing device 100 in the measurement count calculation mode, the operator also inputs the value of the weight SW of the reference sample S as information into the input device 60. The weight SW of the reference sample S input into the input device 60 is stored in the memory unit 82. When the weight of the reference sample S is measured by the weighing device 100, the weight calculated by the control unit 84 may be automatically stored in the memory unit 82 as the weight SW, instead of the weight SW of the reference sample S input into the input device 60 by the operator.

[0084] In the measurement count calculation mode, the control device 80 operates the conveying device 10 and the detection device 20 in the same manner as in the correction value calculation mode. Preferably, in the measurement count calculation mode, the control device 80 controls the operation of the conveying device 10 so that the reference sample S is conveyed at the conveying speed (the conveying speed V described above) when the weighing device 10 actually weighs the object P (the actual item to be weighed). In this state, when the reference sample S is placed on the first conveyor 12 of the conveying device 10, the first conveyor 12 conveys the reference sample S to the second conveyor 14, and the control unit 84 calculates the dynamic weight based on the weighing signal output from the load cell 28 of the detection device 20 while the reference sample S is being conveyed on the second conveyor 14 (step S12). The control unit 84 stores the calculated dynamic weight in the memory unit 82 (step S13). The control device 80 continues to operate the conveying device 10 and the detection device 20 until the number of dynamic weight data stored in the memory unit 82 reaches a predetermined number B (e.g., 5) (step S14). In other words, an operator who wishes to calculate the number of times the reference sample is weighed places the reference sample S on the first conveyor 12 of the conveying device 10 B times, thereby causing the control unit 84 to calculate the dynamic weight of the reference sample S B times. The value of B is selected in step S16 as a number that allows calculation of the variance of the dynamic weight and is as small as possible.

[0085] The memory unit 82 stores B dynamic weights DW1, DW2, . . . DW B When the number of the particles has reached the maximum, the control unit 84 stops the operation of the transport device 10 (step S15).

[0086] The control unit 84 calculates the variance due to noise using the following formula: TIFF2026020317000003.tif3954 is calculated (step S16).

[0087]

number

[0088] In addition, when the number of times the standard sample is measured is M, the sample average TIFF2026020317000005.tif4752 is variance due to noise. If TIFF2026020317000006.tif4052 is known, it follows the normal distribution expressed by Equation 3 and Equation 4.

[0089]

number

[0090]

number

[0091] Therefore, for example, if you want to keep μ within the scale interval ±e at a 95% confidence interval, you can estimate the interval using the standard normal distribution as follows:

[0092]

number

[0093]

number

[0094] Therefore, the control unit 84 determines the smallest integer greater than the value of M calculated using Equation 6 as the reference sample weighing count N (step S17).

[0095] The control unit 84 may output the reference sample weighing count N calculated by the control unit 84 to the output device 70 (step S18). Specifically, the control unit 84 displays the reference sample weighing count N on a display as an example of the output device 70, for example.

[0096] 8, the control unit 84 may, for example, cause a display (as an example of the output device 70) to display a message prompting the input device 60 to input whether or not to adopt the reference sample weighing count N. If the input device 60 receives an input indicating that the reference sample weighing count N should be adopted, the process may proceed to step S19. If the input device 60 receives an input indicating that the reference sample weighing count N should not be adopted, the process may be repeated from step S11. This configuration can prevent a situation in which, for example, if the reference sample weighing count N is an obviously abnormal value for some reason, this value is used as the reference sample weighing count N.

[0097] In addition, the processing of step S18, the step of prompting the output device 70 to input whether or not to adopt the reference sample weighing number N to the input device 60, and the step of inputting to the input device 60 that the reference sample weighing number N should be adopted may be omitted.

[0098] Next, the control unit 84 stores the calculated number of times N to weigh the reference sample in the memory unit 82 (step S19). When calculating the correction value k based on the flow sheet shown in Fig. 7, the control unit 84 calculates the correction value k to correct the dynamic weight of the object to be weighed P detected by the load cell 28 based on the weighing signal output by the load cell 28 when the reference sample S is transported by the second conveyor 14 for the number of times N to weigh the reference sample stored in the memory unit 82.

[0099] The dynamic weights DW1, DW2, DW of the reference sample S obtained when calculating the number of times N the reference sample was weighed are B may be used as the dynamic weight data of the reference sample S for calculating the correction value k. The dynamic weights DW1, DW2, ... DW of the reference sample S obtained when calculating the number of times N the reference sample is weighed may be used as the dynamic weight data of the reference sample S for calculating the correction value k. B By using the data on the dynamic weight of the reference sample S for calculating the correction value k, the time required to calculate the correction value k can be reduced.

[0100] <Second Example> A second embodiment of the process for calculating the number of times of measuring the reference sample in the process for calculating the correction value will be described with reference to the flowchart of FIG.

[0101] In the second embodiment, the control unit 84 calculates the number of reference sample weighings N based on the weighing signal output by the load cell 28 when the conveying device 10 is driven and the second conveyor 14 is not transporting any items (when nothing is being transported).

[0102] Here, no article such as the reference sample S is required to calculate the number of times N that the reference sample is weighed.

[0103] An operator who wishes to calculate the reference sample weighing count N operates, for example, the input device 60 to operate the weighing device 100 in the measurement count calculation mode (step S11a).

[0104] In the measurement count calculation mode of the second embodiment, the control device 80 operates the conveying device 10 and the detection device 20 in the same manner as in the first embodiment. Preferably, in the measurement count calculation mode, the control device 80 controls the rotation speeds of the motors of the first drive unit 18a and the second drive unit 18b to a rotation speed that achieves the conveying speed V when the weighing device 100 actually weighs the object P (the actual item to be weighed). In this state, the control unit 84 acquires a weighing signal output by the load cell 28 while the second conveyor 14 is operating (step S12a) and stores the weighing signal in the memory unit 82 (step S13a). The control device 80 continues operating the conveying device 10 and the detection device 20 until a predetermined time has elapsed, and continues acquiring the weighing signal output by the load cell 28 and storing the weighing signal in the memory unit 82 (step S14a).

[0105] When the weighing signal for a predetermined period of time is stored in the memory unit 82, the control unit 84 The operation is stopped (step S15a).

[0106] Then, the control unit 84 calculates the noise variance of the weighing signal stored in the memory unit 82. TIFF2026020317000011.tif4353 is calculated (step S16a).

[0107] The processing from step S17 to step S19 is the same as the processing from step S17 to step S19 in the first embodiment, and therefore a description thereof will be omitted here.

[0108] (3) Features (3-1) A weighing device 100 according to an example of a weighing device includes a second conveyor 14 as an example of a transport unit, a load cell 28 as an example of a detection unit, and a control unit 84. The second conveyor 14 receives and transports articles. The load cell 28 detects the weight of the second conveyor 14, or, if the second conveyor 14 is transporting articles, the weight of the second conveyor 14 and the weight of the articles on the second conveyor 14, and outputs a weighing signal. The control unit 84 calculates a correction value k for correcting the weight (dynamic weight) of the article detected by the load cell 28 based on the weighing signal output by the load cell 28 when the second conveyor 14 transports the reference sample S the number of times N for the reference sample weighing. The control unit 84 calculates the number of times N for the reference sample weighing based on the weighing signal output by the load cell 28 when driving the second conveyor 14.

[0109] In the weighing device 100, the number of times the reference sample S should be run to calculate the correction value k is calculated based on the weighing signal output by the load cell 28 when the second conveyor 14 is driven, so that it is possible to prevent the occurrence of a situation in which the reference sample S is weighed too few times to calculate an appropriate correction value k, or conversely, the reference sample S is weighed too many times. As a result, the weighing device 100 can calculate an appropriate correction value k while reducing the operating time of the weighing device 100 required to calculate the correction value k (the time required to calculate the correction value k).

[0110] (3-2) In the first embodiment described above, the control unit 84 calculates the reference sample weighing count N based on the weighing signal output by the load cell 28 when the second conveyor 14 is driven to transport the articles.

[0111] Here, the reference sample weighing count N is calculated based on the weighing signal output by the load cell 28 when transporting an item, so that an appropriate reference sample weighing count N for calculating the correction value k can be calculated taking into account the characteristics of the weighing device 100 itself, the influence of the installation environment, and the influence of item transport.

[0112] Preferably, the control unit 84 calculates the number of times N that the reference sample is weighed based on the weighing signal output by the load cell 28 when the second conveyor 14 is driven to transport the reference sample S.

[0113] In the weighing device 100 configured in this manner, the number of times N the reference sample is weighed is calculated based on the weighing signal output by the load cell 28 while transporting the reference sample S used to calculate the correction value k. Therefore, the number of times N the reference sample is weighed can be calculated as appropriate for calculating the correction value k, taking into account the characteristics of the reference sample S actually weighed by the weighing device 100.

[0114] (3-3) In the second embodiment described above, the control unit 84 calculates the number of reference sample weighings N based on the weighing signal output by the load cell 28 when the second conveyor 14 is driven and is not transporting any items.

[0115] Here, the number of times N of weighing the reference sample is appropriate for calculating the correction value k can be calculated in a short time without transporting articles on the second conveyor 14.

[0116] (3-4) The weighing device 100 preferably includes an output device 70 that outputs the number of times N the reference sample is weighed calculated by the control unit 84.

[0117] The weighing device 100 outputs the calculated number of times N to weigh the reference sample, so that the worker operating the weighing device 100 can check whether the calculated number is an appropriate value (whether the value is clearly too small or too large from a technical standpoint).

[0118] (3-5) The weighing device 100 includes a memory unit 82 that stores the number of times N the reference sample is weighed. The control unit 84 stores the calculated number of times N the reference sample is weighed in the memory unit 82. The control unit 84 calculates a correction value k for correcting the weight (dynamic weight) of the article detected by the load cell 28 based on the weighing signals output by the load cell 28 when the reference sample is transported by the second conveyor 14 for the number N of times the reference sample is weighed that are stored in the memory unit 82.

[0119] In the weighing device 100, the calculated number of times N to weigh the reference sample is automatically set in the weighing device 100, which saves the operator the trouble of manually setting the number of times N to weigh the reference sample.

[0120] However, this is not limited to this, and the operator may manually input the calculated number of times N to weigh the reference sample (for example, the number of times N to weigh the reference sample output by the output device 70) via the input device 60.

[0121] (4) Variations Modifications of this embodiment are described below. The modifications described below may be combined as appropriate within the scope of not contradicting each other.

[0122] (4-1) Variation A The weighing device 100 is composed of a conveying device 10, a detecting device 20, and a control device 80, but the weighing device 100 may be a device having other configurations. For example, in the above embodiment, an example is described in which a sorting device separate from the weighing device 100 is placed downstream of the weighing device 100, but the weighing device 100 may also have a sorting mechanism that sorts the objects P to be weighed based on the weighing results of the objects P to be weighed. [Industrial Applicability]

[0123] The present invention is widely applicable and useful to weighing devices that weigh items while being transported. [Explanation of symbols]

[0124] 14 Second conveyor (transport section) 28 Load cell (detection part) 70 Output device (output section) 82 Memory section 84 Control Unit 86 Communication unit (output unit) 100 Weighing device S Reference sample [Prior art documents] [Patent documents]

[0125] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-76661

Claims

1. a conveying unit that receives and conveys the article; a detection unit that detects the weight of the conveying unit, or, when the conveying unit is conveying the item, the weight of the conveying unit and the weight of the item on the conveying unit, and outputs a weighing signal; a control unit that calculates a correction value for correcting the weight of the object detected by the detection unit based on the weighing signal output by the detection unit when the reference sample is transported by the transport unit a predetermined number of times, the control unit calculates the predetermined number of times based on the weighing signal output by the detection unit when the conveying unit is driven to convey the articles. Weighing device.

2. the control unit calculates the predetermined number of times based on the measurement signal output by the detection unit when driving the transport unit to transport the reference sample. The weighing device according to claim 1 .

3. An output unit that outputs the predetermined number of times calculated by the control unit is further provided.

3. A weighing device according to claim 1 or 2.

4. Further, a storage unit that stores the predetermined number of times is provided, The control unit stores the calculated predetermined number of times in the storage unit, the control unit calculates the correction value for correcting the weight of the object detected by the detection unit based on the weighing signal output by the detection unit when the reference sample is transported by the transport unit the predetermined number of times stored in the memory unit. A weighing device according to any one of claims 1 to 3.

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