Weighing device and calibration method

Abstract

To provide a weighing device and a calibration device, capable of improving weighing accuracy of a weighing device comprising a plurality of load cells.SOLUTION: A weighing device comprises: a weighing unit that weighs a weight of an object to be weighed based on a plurality of ports for connecting load cells and a detection result of each load cell individually connected to the plurality of ports; and a storage unit that stores a correction value related to the detection of the weight derived for each load cell, in association with a port identifier that can identify the port to which the load cell is connected. The weighing unit weighs the weight of the object to be weighed based on the result of correcting the detection result of the weight detected by each load cell with the correction value corresponding to the port identifier of the port to which the load cell is connected.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] Embodiments of the present invention relate to a weighing device and a calibration method.

Background Art

[0002] As a device for weighing the weight of articles such as products, there is a weighing device including a pedestal on which an article is placed and a load cell that weighs the weight of the article placed on the pedestal. In addition, there is a weighing device in which a plurality of load cells are provided for one pedestal. For example, conventionally, a technique has been proposed in which, for each of a plurality of load cells connected in series, an initial load at the time of power supply is evaluated using an initial load corresponding to a load signal in a no-load state when the weighing device is adjusted (see, for example, Patent Document 1).

[0003] By the way, in order to improve the weighing accuracy of a weighing device including a plurality of load cells, it is necessary to make the weighing accuracy of each load cell high. Therefore, a calibration process (hereinafter also referred to as calibration) is performed on the load cell.

[0004] However, in a weighing device including a plurality of load cells, it is necessary to perform calibration for each load cell in order to confirm the weighing accuracy.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a weighing device and a calibration method capable of improving the weighing accuracy of a weighing device including a plurality of load cells.

Means for Solving the Problems

[0006] The weighing device according to the embodiment includes a plurality of ports for connecting load cells, and a weighing unit that weighs the weight of the object to be weighed based on the detection results of each of the load cells individually connected to the plurality of ports, and a storage unit that stores correction values related to the detection of the weight derived for each load cell in association with a port identifier capable of identifying the port to which the load cell is connected. The weighing unit weighs the weight of the object to be weighed based on the result of correcting the detection result of the weight detected by each of the load cells with the correction value corresponding to the port identifier of the port to which the load cell is connected.

Brief Description of Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the weighing device 1 will be described with reference to the drawings. Note that the present invention is not limited by the following embodiments. The components in the following embodiments include those that can be easily conceived by those skilled in the art, substantially identical components, and those within the so-called equivalent scope. Furthermore, various omissions, substitutions, changes, and combinations of the components can be made without departing from the gist of the following embodiments.

[0009] FIG. 1 is a schematic diagram showing a schematic configuration of the weighing device 1 according to the embodiment. As shown in FIG. 1, the weighing device 1 includes an I / O port 2, a load cell 3, and a weighing table 4.

[0010] The weighing device 1 is an example of a weighing device. The weighing device 1 weighs the weight of the object to be weighed placed on the upper surface of the weighing table 4 based on the output of the load cell 3 connected to the I / O port 2 described later.

[0011] The I / O port 2 is an example of a port. The I / O port 2 is an interface for electrically connecting the control unit 100 (see FIG. 2) of the weighing device 1 and the load cell 3. The weighing device 1 includes a plurality of I / O ports 2. In FIG. 1, the weighing device 1 is configured to include six I / O ports 2, but the number of I / O ports 2 is not limited to this.

[0012] The load cell 3 is an example of a load cell. The load cell 3 is electrically connected to the control unit 100 (see FIG. 2) of the weighing device 1 by being connected to the I / O port 2. In the weighing device 1 of the present embodiment, a plurality of load cells 3 are connected to the I / O port 2. Note that the number of load cells 3 is not limited to the illustrated example.

[0013] The load cell 3 is, for example, a load cell composed of a metal called a strain body, a resistance wire (hereinafter also referred to as a strain gauge) adhered to the strain body, and a circuit attached to the strain body. When a weight (hereinafter also referred to as a load) acts on the strain body, the strain gauge deforms together with the strain body, causing a change in the resistance value of the strain gauge. Then, a voltage (analog signal) is output according to the change in the resistance value of the strain gauge. That is, an analog signal is output according to the load acting on the load cell 3.

[0014] Note that the load cell 3 may be a digital load cell integrated with the A / D conversion unit 5 described later. Also, the load cell 3 may be a load cell that converts the load acting on the load cell 3 into an analog signal by a mechanism different from the mechanism described above.

[0015] The weighing platform 4 is a pedestal that supports the object to be weighed weighed by the weighing device 1. As shown in FIG. 1, the weighing platform 4 is arranged to be grounded on the upper surface of the load cell 3. Then, the weighing platform 4 causes the weight of the object to be weighed placed on the upper surface of the weighing platform 4 to act on the load cell 3.

[0016] Next, with reference to FIG. 2, the configuration of the weighing device 1 described above will be described. FIG. 2 is a block diagram showing an example of the hardware configuration of the weighing device 1 according to the embodiment. As shown in FIG. 2, the weighing device 1 includes a CPU (Central Processing Unit) 101 which is an example of a processor, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and a memory unit 104, etc.

[0017] The CPU 201 comprehensively controls each part of the weighing device 1. The ROM 102 stores various programs. The RAM 103 is a workspace for expanding programs and various data. The memory unit 104 stores various programs.

[0018] The CPU 101, ROM 102, RAM 103, and memory unit 104 are connected to each other via a bus 111. The CPU 101, ROM 102, and RAM 103 constitute a control unit 100 of a computer configuration. That is, the control unit 100 executes control processing of the weighing device 1 described later by operating according to a control program unit 105 stored in the ROM 102 or memory unit 104 and expanded in the RAM 103.

[0019] The memory unit 104 is a non-volatile memory such as an HDD (Hard Disc Drive) or a flash memory that retains stored information even when the power is turned off. The memory unit 104 includes a control program unit 105, a correction value DB 106, and a calibration setting DB 107.

[0020] The correction value DB 106 is an example of a storage unit. The correction value DB 106 is a database that stores correction values used in processing related to calibration of the load cell 3 described later (hereinafter also referred to as calibration processing). Further, the correction value DB 106 stores, for example, an identification number of an I / O port 2 to which the load cell 3 is connected (hereinafter also referred to as a port number) and a correction value related to detection of weight derived for each load cell 3 associated with the port number in association with each other.

[0021] The calibration setting DB 107 is a database that stores values referred to as correction references (hereinafter also referred to as masters) in calibration processing. The calibration setting DB 107 stores, for example, an AD value at zero weight (hereinafter also referred to as a zero point). Further, the calibration setting DB 107 stores, for example, an AD value at the weight of a weight (hereinafter also referred to as a calibration load) used in calibration processing. Further, the calibration setting DB 107 stores, for example, a threshold value (hereinafter also simply referred to as a threshold value) used for abnormality determination of the load cell 3 in calibration processing.

[0022] Here, the threshold value stored in the calibration setting DB 107 is the master of the change characteristics of the AD value when the load cell 3 changes in weight in the calibration process of the load cell 3 described later. Hereinafter, for the sake of convenience, the AD value stored in the calibration setting DB 107 is defined as the master AD value, and the change characteristics of the AD value when the load cell 3 stored in the calibration setting DB 107 changes in weight are defined as the master change characteristics.

[0023] Here, the AD value is the output value when the analog signal output from the load cell 3 in response to the load is converted into a digital signal by the A / D conversion unit 5 described later. That is, the AD value increases in proportion to the load acting on the load cell 3.

[0024] Next, the correction value will be described with reference to FIG. 3. FIG. 3 is an example of a graph showing the relationship between the AD value output by the load cell 3 according to the embodiment and the weight.

[0025] FIG. 3 is an example of a graph with the weight on the horizontal axis and the AD value on the vertical axis. Note that the values described on each axis are examples, and the scale of the axis is not limited. For example, in FIG. 3, a straight line A and a straight line B corresponding to the load cell A that is the master in the calibration process and the load cell B before the calibration process are described. Here, the change characteristics of the AD value when the load cell 3 changes in weight are defined as the slope of the straight line in FIG. 3. The correction value is defined as the difference between the master change characteristics stored in the calibration setting DB 107, that is, the slope of the straight line A, and the change characteristics of the AD value when the load cell 3 before the calibration process changes in weight, that is, the slope of the straight line B.

[0026] As shown in FIG. 3, for example, on straight line A and straight line B, the AD value at the zero point is 20 for both straight line A and straight line B. Taking the calibration load as a weight of 20, when the AD value at a weight of 20 is 40 for straight line A and 30 for straight line B, the correction value is the difference between the slope of straight line A and the slope of straight line B, that is, 0.5. The calculated correction value is an index indicating how much adjustment is required for any load cell 3 that performs the calibration process with respect to the master load cell 3.

[0027] Returning to FIG. 2, the control unit 100 is connected to the I / O port 2, the display unit 109, and the operation unit 110 via the I / O controller 108 and the bus 111. The I / O controller 108 is connected to the display unit 109 and the operation unit 110. Then, the I / O controller 108 controls each connected unit based on a command from the control unit 100.

[0028] The display unit 109 is a display device such as an LCD (Liquid Crystal Display). The display unit 109 displays various information under the control of the CPU 101. The operation unit 110 is an input device such as a keyboard or a pointing device. The operation unit 110 outputs the operation content input via the input device to the CPU 101. Note that the operation unit 110 may be a touch panel provided on the display unit 109.

[0029] The A / D conversion unit 5 converts the analog signal output from the load cell 3 connected to the I / O port 2 into a digital signal. The load cell 3 is connected to the I / O port 2. That is, the analog signal from the load cell 3 is converted into a digital signal by the A / D conversion unit 5 and input to the CPU 101.

[0030] Then, the control unit 100 (CPU 101) can obtain the load acting on the load cell 3 by calculation based on the AD value output by the load cell 3 input to the I / O port 2.

[0031] Next, referring to FIG. 4, the control unit 100 of the weighing device 1 will be described. FIG. 4 is a block diagram showing an example of the functional configuration of the control unit 100 in the weighing device 1 according to the embodiment. As shown in FIG. 4, the control unit 100 includes a calibration processing unit 1001, a weight detection unit 1002, and a display control unit 1003 as functional configurations.

[0032] Specifically, the control unit 100 (CPU 101) of the weighing device 1 realizes the above-described functional configuration by executing the control program unit 105 stored in the memory unit 104. In this embodiment, the above-described functional configuration is a software configuration realized by the cooperation of the processor and the program of the weighing device 1. However, the present invention is not limited thereto, and a part or all of the functional configuration may be a hardware configuration realized by a dedicated circuit or the like.

[0033] The calibration processing unit 1001 is an example of a derivation means and a storage control means. Specifically, the calibration processing unit 1001 performs a calibration process for adjusting (also referred to as calibration or the like) the load cell 3 connected to the I / O port 2. The method of the calibration process is not particularly limited, and a publicly known and commonly used method can be adopted. The calibration processing unit 1001 performs the calibration process for each load cell 3 by, for example, the method shown below.

[0034] For each load cell 3 connected to the I / O port 2, the calibration processing unit 1001 calculates a correction value related to weight detection based on the AD value output by the load cell 3 with the calibration load attached to the load cell 3 and the AD value output by the load cell 3 with the calibration load removed. Further, the calibration processing unit 1001 stores the correction value for each load cell 3 in the correction value DB 106 in association with the port number of the I / O port 2 to which the load cell 3 is connected.

[0035] Further, when the calibration processing unit 1001 receives an instruction to execute calibration processing via the operation unit 110, for example, it checks the electrical connection state of each of the I / O ports 2. Next, the calibration processing unit 1001 sequentially sets each of the I / O ports 2 to which the load cell 3 is connected as a processing target, and sequentially executes calibration processing.

[0036] First, the calibration processing unit 1001 acquires the AD value at the zero point for the load cell 3 connected to the I / O port 2 to be processed. Next, the calibration processing unit 1001 extracts the AD value at the zero point stored in the calibration setting DB 107, that is, the master AD value. Subsequently, the calibration processing unit 1001 calculates a correction value (hereinafter, also referred to as the correction value at the zero point) for correcting the acquired AD value to the master AD value based on the acquired AD value and the extracted master AD value.

[0037] The calibration processing unit 1001 determines whether the calculated correction value at the zero point is within the threshold range stored in the calibration setting DB 107. When the calculated correction value at the zero point is within the threshold range stored in the calibration setting DB 107, the calibration processing unit 1001 stores the calculated correction value at the zero point in association with the port number of the I / O port 2 to be processed in the correction value DB 106, that is, executes zero point correction.

[0038] Note that when the calibration processing unit 1001 performs zero point correction, it determines whether the acquired AD value is within the threshold range of the master AD value at the zero point stored in the calibration setting DB 107. If it is outside the threshold range, the calibration processing unit 1001 determines that the target I / O port 2 is in an invalid state, and in cooperation with the display control unit 1003 described later, it displays the port number of the I / O port 2 to which the load cell 3 corresponding to the acquired AD value is connected on the display unit 109. For example, the calibration processing unit 1001 displays, on the display unit 109, a message notifying that there is an abnormality in the load cell 3 together with the port number of the I / O port 2 to which the load cell 3 is connected. Here, the state where the target I / O port 2 is invalid means that the I / O port 2 is in a state where it cannot be used and is not subject to calibration processing.

[0039] When the calibration processing unit 1001 has performed zero point correction for all the I / O ports 2 to be processed, it extracts the master change characteristics stored in the calibration setting DB 107. Next, the calibration processing unit 1001 causes the display unit 109 to display a message instructing to attach a weight of a predetermined weight (for example, calibration load) to any one of the load cells 3. At this time, it is preferable that the display control unit 1003 causes the display unit 109 to display a message instructing to directly apply a predetermined weight, such as removing the weighing platform 4 from the weighing device 1 and attaching a weight to the load cell 3, to the load cell 3.

[0040] When the calibration processing unit 1001 and the weight detection unit 1002 described later detect that a weight has been placed on one of the load cells 3 due to a change in the AD value, they acquire the AD value corresponding to the weight of the detected weight. Subsequently, the calibration processing unit 1001 calculates the change characteristics of the AD value when the weight changes from the master AD value at the zero point and the AD value corresponding to the weight of the weight detected by the weight detection unit 1002 described later.

[0041] Next, the calibration processing unit 1001 calculates a correction value related to the change characteristic based on the difference between the master change characteristic extracted from the calibration setting DB 107 and the calculated change characteristic.

[0042] Next, the calibration processing unit 1001 determines whether the correction value related to the calculated change characteristic is within the threshold range stored in the calibration setting DB 107. When the correction value related to the change characteristic is within the threshold range stored in the calibration setting DB 107, the calibration processing unit 1001 associates the correction value related to the change characteristic with the port number of the I / O port 2 to be processed and stores it in the correction value DB 106, that is, executes the calibration process.

[0043] On the other hand, when the correction value related to the change characteristic is outside the threshold range, the calibration processing unit 1001 determines that the target I / O port 2 is in an invalid state, and in cooperation with the display control unit 1003 described later, displays the port number of the I / O port 2 to which the load cell 3 corresponding to the acquired AD value is connected on the display unit 109. For example, the calibration processing unit 1001 displays on the display unit 109 a message notifying that there is an abnormality in the load cell 3 together with the port number of the I / O port 2 to which the load cell 3 is connected.

[0044] It should be noted that it is desirable to perform the above-described series of calibration processes in a configuration excluding the weighing table 4 from the configuration of the weighing device 1 in order to improve the accuracy of the calibration process of the load cell 3.

[0045] The weight detection unit 1002 is an example of a weighing unit. Specifically, the weight detection unit 1002 weighs the load acting on each of the load cells 3. More specifically, the weight detection unit 1002 weighs the weight of the object to be weighed based on the AD value output by the load cell 3 connected to the I / O port 2.

[0046] Further, when the weight detection unit 1002 detects that a weight is placed on one load cell 3 based on the change in the AD value output by the load cell 3, the weight detection unit 1002 outputs an AD value corresponding to the weight of the detected weight.

[0047] Further, the weight detection unit 1002 measures the weight of the object to be measured placed on the weighing platform 4 of the weighing device 1. Then, the weight detection unit 1004 applies the correction value calculated for each load cell 3 to the AD value output by each of the load cells 3 individually connected to the I / O port 2. Then, the weight detection unit 1002 measures the weight of the object to be measured based on the AD value to which the correction value has been applied.

[0048] The display control unit 1003 causes various information to be displayed on the display unit 109. Specifically, when the calibration processing unit 1001 checks the electrical connection state for each I / O port 2 and determines that the I / O port 2 to be checked is in an invalid state, the display control unit 1003 causes the display unit 109 to display the port number of the I / O port 2 determined to be in the invalid state and a message indicating that the I / O port 2 to be checked is in the invalid state.

[0049] Further, the display control unit 1003 causes various information to be displayed on the display unit 109 by cooperating with the calibration processing unit 1001.

[0050] Further, in the process related to measuring the weight of the object to be measured, the display control unit 1003 causes the display unit 109 to display an instruction to place the object to be measured on the upper surface of the weighing platform 4. Further, the display control unit 1003 calculates the total weight of the object to be measured from the weight of the object to be measured calculated for each load cell 3 and causes the display unit 109 to display it.

[0051] Hereinafter, a processing example performed by the above-described weighing device 1 will be described.

[0052] FIG. 5 is a flowchart showing an example of processing performed by the control unit 100 of the weighing device 1 according to the embodiment.

[0053] First, the calibration processing unit 1001 waits via the operation unit 110 until the execution of the calibration process (step S101; No). When the calibration processing unit 1001 receives the execution of the calibration process via the operation unit 110 (step S101; Yes), it sequentially checks the electrical connection state of each of the I / O ports 2 (step S102).

[0054] When it is confirmed that the load cell 3 is electrically connected to the I / O port 2 to be checked (step S102; Yes), the calibration processing unit 1001 determines that the I / O port 2 to be checked is in a valid state and proceeds to step S104.

[0055] Also, when it cannot be confirmed that the load cell 3 is electrically connected to the I / O port 2 to be checked (step S102; No), the calibration processing unit 1001 determines that the I / O port 2 to be checked is in an invalid state. In this case, the calibration processing unit 1001 collaborates with the display control unit 1003 described later to display a message indicating that the I / O port 2 to be checked is in an invalid state on the display unit 109 (step S103) and proceeds to step S104.

[0056] In the subsequent step S104, it is determined whether the state of all the I / O ports 2 has been checked (step S104). When there is an unconfirmed I / O port 2 (step S104; No), the calibration processing unit 1001 returns the process to step S102 and determines the validity of the unconfirmed I / O port 2. Also, when it is determined that the state of all the I / O ports 2 has been checked (step S104; Yes), the calibration processing unit 1001 sets the load cell 3 connected to the I / O port 2 in a valid state as the processing target of the calibration process and sequentially executes the calibration process (step S105).

[0057] Next, with reference to FIG. 6, an example of the processing performed by the weighing device 1 will be described. FIG. 6 is a flowchart showing an example of the calibration process of the load cell 3 performed by the control unit 100 of the weighing device 1 according to the embodiment. Note that the series of steps shown in FIG. 6 corresponds to the subroutine processing of step S105 shown in FIG. 5.

[0058] First, the calibration processing unit 1001 extracts the AD value at the zero point stored in the calibration setting DB 107, that is, the master AD value (step S201).

[0059] Next, the calibration processing unit 1001 acquires the AD value at the zero point of the load cell 3 connected to the I / O port 2 to be processed (step S202). At this time, the upper surface of the weighing table 4 is in a state where nothing is placed. Note that the calibration processing unit 1001 preferably performs the operation in a state where the weighing table 4 and the load cell 3 are separated by removing the weighing table 4 or the like.

[0060] Subsequently, the calibration processing unit 1001 calculates a correction value (hereinafter also referred to as a correction value at the zero point) for correcting the acquired AD value to the master AD value based on the acquired AD value and the extracted master AD value (step S203). Then, the calibration processing unit 1001 determines whether the calculated correction value at the zero point is within the threshold range stored in the calibration setting DB 107 (step S204).

[0061] When the calculated correction value at the zero point is within the threshold range stored in the calibration setting DB 107 (step S204; Yes), the calibration processing unit 1001 stores the calculated correction value at the zero point in association with the port number of the I / O port 2 to be processed in the correction value DB 106 (step S206). Next, the calibration processing unit 1001 proceeds to step S207.

[0062] Also, when the correction value at the calculated zero point is outside the threshold range stored in the calibration setting DB107 (step S204; No), the calibration processing unit 1001, in cooperation with the display control unit 1003 described later, displays a message on the display unit 109 indicating that the target I / O port 2 is in an invalid state (step S205), and proceeds to step S207.

[0063] In the subsequent step S207, the calibration processing unit 1001 determines whether the processing of steps S202 to S206 has been executed for all valid I / O ports 2 (step S207). If there is an unprocessed I / O port 2 (step S207; No), the calibration processing unit 1001 returns the processing to step S202. Also, when all the I / O ports 2 have been processed (step S207; Yes), the calibration processing unit 1001 extracts the master change characteristics stored in the calibration setting DB107 (step S208).

[0064] Next, the calibration processing unit 1001, in cooperation with the display control unit 1003 described later, causes the display unit 109 to display a message instructing to place a weight of a predetermined weight (for example, calibration load) on any one of the load cells 3 (step S209). Also, at this time, a message instructing to directly apply the predetermined weight to the load cell 3, such as removing the weighing platform 4 and then attaching a weight to the load cell 3, is displayed on the display unit 109.

[0065] The calibration processing unit 1001 waits until the weight detection unit 1002 detects that a weight has been placed on one of the load cells 3 due to a change in the AD value (step S210; No). When it detects that a weight has been placed on one of the load cells 3 (step S210; Yes), it acquires the AD value corresponding to the weight of the detected weight (step S211).

[0066] In step S210, although the process proceeds to the processes after step S211 with the load cell 3 connected to the I / O port 2 that detected the installation of the weight as the processing target, the processing target load cell 3 may be specified by inputting the port number from the operation unit 110 or the like.

[0067] Subsequently, the calibration processing unit 1001 calculates the change characteristics of the AD value when the weight changes from the master AD value at the zero point and the AD value corresponding to the weight of the weight detected by the weight detection unit 1002 (step S212). Subsequently, the calibration processing unit 1001 calculates a correction value related to the change characteristics from the difference between the master change characteristics extracted from the calibration setting DB107 and the calculated change characteristics (step S213). Then, the calibration processing unit 1001 determines whether the correction value related to the calculated change characteristics is within the threshold range stored in the calibration setting DB107 (step S214).

[0068] When the correction value related to the calculated change characteristics is within the threshold range stored in the calibration setting DB107 (step S214; Yes), the calibration processing unit 1001 associates the correction value related to the calculated change characteristics with the port number of the I / O port 2 to be processed and stores it in the correction value DB106 (step S216). Next, the calibration processing unit 1001 proceeds to step S217.

[0069] Also, when the correction value related to the calculated change characteristics is outside the threshold range stored in the calibration setting DB107 (step S214; No), the calibration processing unit 1001 collaborates with the display control unit 1003 described later to display a message on the display unit 109 indicating that the target I / O port 2 is in an invalid state (step S215) and proceeds to step S217.

[0070] In the subsequent step S217, the calibration processing unit 1001 determines whether the processing of steps S209 to S216 has been executed for all the I / O ports 2 in the valid state (step S217). If there is an unprocessed I / O port 2 (step S217; No), the calibration processing unit 1001 returns the processing to step S209. Also, when all the I / O ports 2 have been processed (step S217; Yes), the processing ends by returning to the processing of FIG. 5.

[0071] By executing the series of calibration processes described with reference to FIG. 6 above, the connection state of the load cell 3 can be confirmed in units of the I / O port 2, and calibration of the load cell 3 can be performed. Therefore, the acquisition and management of correction values related to each of the load cells 3 can be efficiently performed. Also, by applying the correction value calculated in the calibration process to the AD value output by the load cell 3 with the corresponding port number, each of the load cells 3 can have the same measurement accuracy.

[0072] Next, with reference to FIG. 7, an example of the processing performed by the weighing device 1 will be described. FIG. 7 is a flowchart showing an example of the processing related to the weighing of the object to be weighed of the load cell 3 performed by the control unit 100 of the weighing device 1 according to the embodiment.

[0073] First, the calibration processing unit 1001 waits via the operation unit 110 until execution of the calibration process (step S101; No). When the calibration processing unit 1001 receives the execution of the calibration process via the operation unit 110 (step S101; Yes), it sequentially checks the electrical connection state of each of the I / O ports 2 (step S102).

[0074] When it is confirmed that the load cell 3 is electrically connected to the I / O port 2 to be checked (step S102; Yes), the calibration processing unit 1001 determines that the I / O port 2 to be checked is in a valid state and proceeds to step S104.

[0075] Also, if it cannot be confirmed that the load cell 3 is electrically connected to the I / O port 2 to be confirmed (step S102; No), the calibration processing unit 1001 determines that the I / O port 2 to be confirmed is in an invalid state. In this case, the calibration processing unit 1001 collaborates with the display control unit 1003 described later to display a message indicating that the I / O port 2 to be confirmed is in an invalid state on the display unit 109 (step S103), and then proceeds to step S104.

[0076] In the subsequent step S104, it is determined whether the states of all the I / O ports 2 have been confirmed (step S104). If there is an unconfirmed I / O port 2 (step S104; No), the calibration processing unit 1001 returns the process to step S102 and determines whether the unconfirmed I / O port 2 is valid or invalid. Also, if it is determined that the states of all the I / O ports 2 have been confirmed (step S104; Yes), the calibration processing unit 1001 sets the load cell 3 connected to the I / O port 2 in a valid state as the processing target of the calibration process and executes the calibration process (step S105).

[0077] First, the calibration processing unit 1001 sequentially checks the electrical connection states of each of the I / O ports 2 (step S301). If it is confirmed that the load cell 3 is electrically connected to the I / O port 2 to be confirmed (step S301; Yes), the calibration processing unit 1001 determines that the I / O port 2 to be confirmed is in a valid state and proceeds to step S303.

[0078] Also, if it cannot be confirmed that the load cell 3 is electrically connected to the I / O port 2 to be confirmed (step S301; No), the calibration processing unit 1001 determines that the I / O port 2 to be confirmed is in an invalid state. In this case, the calibration processing unit 1001 collaborates with the display control unit 1003 described later to display a message indicating that the I / O port 2 to be confirmed is in an invalid state on the display unit 109 (step S302), and then proceeds to step S303.

[0079] In the subsequent step S303, it is determined whether the states of all the I / O ports 2 have been confirmed (step S303). If there is an unconfirmed I / O port 2 (step S303; No), the calibration processing unit 1001 returns the process to step S301 and determines whether it is valid / invalid for the unconfirmed I / O port 2.

[0080] Also, when it is determined that the states of all the I / O ports 2 have been confirmed (step S303; Yes), the display control unit 1003, in cooperation with the calibration processing unit 1001, displays an instruction to place the object to be weighed on the upper surface of the weighing platform 4 on the display unit 109 (step S304).

[0081] Note that the processes from step S301 to step S303 are not necessarily required to be performed, and the process may be started from step S304.

[0082] Next, the calibration processing unit 1001 waits until the weight detection unit 1002 detects the weight of the object to be weighed by one load cell 3 due to a change in the AD value (step S305; No). When one load cell 3 detects the weight of the object to be weighed (step S305; Yes), the calibration processing unit 1001 acquires the AD value corresponding to the weight of the object to be weighed detected for each load cell 3 connected to the I / O port 2 in an effective state (step S306).

[0083] Subsequently, the calibration processing unit 1001 refers to the correction value DB106 and extracts the port number stored in the correction value DB106 and the correction value associated with the port number. Then, the calibration processing unit 1001 applies the correction value corresponding to the port number of the I / O port 2 to which the load cell 3 is connected to the AD value corresponding to the weight of the object to be weighed detected by the load cell 3 connected to the I / O port 2 in an effective state (step S307).

[0084] Next, the calibration processing unit 1001 detects the load cell 3 connected to the I / O port 2 in an effective state, and calculates the weight of the object to be measured from the AD value to which the correction value is applied (step S308). Subsequently, the calibration processing unit 1001, in cooperation with the display control unit 1003, calculates the total weight of the object to be measured from the weight of the object to be measured calculated for each load cell 3, and displays it on the display unit 109 (step S309).

[0085] As described above, in the weighing device 1 of the present embodiment, for one or a plurality of load cells 3 connected to the I / O port 2, each load cell 3 determines whether it is connected to the I / O port 2. Next, the weighing device 1 performs zero point correction on the load cell 3 in a state where the connection between the load cell 3 and the I / O port 2 is effective by receiving an execution instruction from the operation unit 110. Subsequently, the weighing device 1 calculates the change characteristic of the AD value when the weight changes, that is, the correction value, for the load cell 3 in a state where the connection between the load cell 3 and the I / O port 2 is effective. Then, when the calculated correction value is within the threshold range, after performing calibration, the identification number of the I / O port 2 and the calculated correction value are stored in the database.

[0086] Thereby, it is possible to calculate the correction value related to the weighing accuracy for each load cell 3 and perform calibration of one or a plurality of load cells 3. Therefore, it is possible to improve the weighing accuracy of the weighing device 1 including a plurality of load cells 3.

[0087] Note that the above-described embodiment can be appropriately modified and implemented by changing a part of the configuration or function of each of the above-described devices. Therefore, below, some modification examples according to the above-described embodiment will be described as other embodiments. Note that below, mainly the points different from the above-described embodiment will be described, and detailed description of the points common to the already described content will be omitted. Also, the modification examples described below may be implemented individually or in appropriate combination.

[0088] (Modification Example 1) The weighing device 1 described in the above embodiment may be applied, for example, to a sales data processing device used in the field of commercial transactions. In this case, as the sales data processing device, for example, it can be applied to a weighing device that weighs products to be registered and / or registered products in semi-self or full-self POS.

[0089] (Modification 2) In the above embodiment, the calibration process is executed with the load cell 3 attached to the weighing device 1. However, the present invention is not limited to this, and the calibration process may be executed after removing the load cell 3 from the weighing device 1. Further, the calibration process may be executed before attaching the load cell 3 to the weighing device 1.

[0090] Note that the program executed by the weighing device 1 in the embodiment and the modification may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the program executed by the weighing device 1 in the embodiment and the modification may be configured to be provided or distributed via a network such as the Internet.

[0091] Note that the program executed by each device in the above embodiment is provided in a state pre-embedded in a ROM, a storage unit, etc. The program executed by each device in the above embodiment may be configured to be recorded on a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk) in an installable format or an executable format file and provided.

[0092] Furthermore, the program executed by each device in the above embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the program executed by each device in the above embodiment may be configured to be provided or distributed via a network such as the Internet.

[0093] As described above, the embodiments of the present invention have been described. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments and their modifications can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0094] 1 Measuring device 2 I / O port 3 Load cell 4 Measuring table 106 Correction value DB 107 Calibration setting DB 1001 Calibration processing unit 1002 Weight detection unit 1003 Display control unit

Prior Art Documents

Patent Documents

[0095]

Patent Document 1

Claims

1. A plurality of ports for connecting load cells, and a weighing unit that weighs the weight of an object to be weighed based on the detection results of each of the load cells individually connected to the plurality of ports; a storage unit that stores, in association with a port identifier capable of identifying the port to which the load cell is connected, a correction value related to the detection of the weight derived for each load cell; comprising The weighing unit weighs the weight of the object to be weighed based on the result of correcting the detection result of the weight detected by each of the load cells with the correction value corresponding to the port identifier of the port to which the load cell is connected. A weighing device.

2. further comprising a pedestal for supporting the object to be weighed, each of the load cells connected to the plurality of ports is provided on the common pedestal, The weighing device according to claim 1.

3. For each load cell connected to the port, based on the detection result in a state where a weighing object of a predetermined weight is attached to the load cell and the detection result of the load cell in a state where the weighing object is removed, Deriving means for deriving a correction value related to weight detection; Storage control means for storing, in the storage unit, the correction value for each load cell derived by the derivation means in association with the port identifier of the port to which the load cell is connected; The weighing device according to claim 1, further comprising.

4. When the detection result of the load cell in a state where the weighing object is removed deviates from the first threshold range, the deriving means notifies the port identifier of the port to which the load cell is connected. The weighing device according to claim 3.

5. When the characteristics of the load cell derived based on the detection result of the load cell in a state where the weighing object is removed, the detection result of the load cell in a state where the weighing object is attached, and the weight of the weighing object deviate from the second threshold range, the deriving means invalidates the port to which the load cell is connected. The weighing device according to claim 3 or 4.

6. A calibration method for a load cell attached to a weighing device, The weighing device includes a plurality of ports for connecting the load cells, an acquisition step of acquiring, for each load cell individually connected to the plurality of ports, a detection result in a state where a weighing object of a predetermined weight is attached to the load cell and a detection result of the load cell in a state where the weighing object is removed; A derivation step of deriving a correction value related to weight detection for each load cell based on the detection result obtained in the acquisition step; A storage step of storing the correction value derived for each load cell in association with a port identifier capable of identifying the port to which the load cell is connected; A calibration method including the above steps.

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