JP2021148718A - Measurement device - Google Patents

Abstract

To provide a measurement device that can suppress reduction of the productivity caused by reduction of the measurement accuracy over time.SOLUTION: A measurement device 1 includes: a carrying unit for carrying an item; a measurement unit for outputting a raw signal for a measurement component of a force applied on the carrying unit; and a processing unit for generating a measurement signal by applying a digital filter to the raw signal, and performing measurement processing on the basis of the measurement signal. The processing unit generates first accuracy information for evaluating a measurement accuracy based on the measurement signal if an object is not on the carrying unit when the carrying unit is working, and detects an abnormality in the measurement unit on the basis of the generated first accuracy information.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a weighing device.

Conventionally, a transport unit capable of transporting an article, a metering unit that outputs an original signal corresponding to a measurement component of a force applied to the transport unit, and a digital filter applied to the original signal to generate a measurement signal, which is used as a measurement signal. A weighing device including a processing unit that performs weighing processing based on the above is known (for example, Patent Document 1).

Special Table 2015-141670

In the weighing device as described above, when the measuring device is installed at the installation site, for example, the zero point is acquired before the start of the inspection. After the zero point is acquired, the measuring device and its surrounding conditions (for example, abnormalities in the measuring part, vibration of the measuring device itself, vibration transmitted from the outside to the measuring device, etc.) change over time after being installed at the installation location. By doing so, an abnormality of the measuring part such as a deviation of a certain amount or more from the initially acquired zero point or an exacerbation of variation may occur. Such an abnormality of the measuring unit may affect the yield of the production of the article, for example, when the measuring device is applied to the production line of the article. As described above, it is desired to prevent the measurement accuracy of the measuring device from decreasing with time.

An object of the present disclosure is to provide a measuring device capable of suppressing a decrease in productivity due to a decrease in measurement accuracy over time.

The weighing device according to the present disclosure includes a transporting unit capable of transporting an article, a measuring unit that outputs an original signal corresponding to a measuring component of a force applied to the transporting unit, and a measuring signal by applying a digital filter to the original signal. It includes a processing unit that generates and performs weighing processing based on the weighing signal, and the processing unit evaluates the weighing accuracy based on the weighing signal when the article is not located on the transport unit during the operation of the transport unit. First accuracy information is generated, and an abnormality in the measuring unit is detected based on the generated first accuracy information.

According to this weighing device, when the article is not located on the transport unit during the operation of the transport unit, the first accuracy information for evaluating the measurement accuracy is generated based on the measurement signal. An abnormality in the measuring unit is detected based on the generated first accuracy information. In this way, using the first accuracy information when the article is not located on the transport unit during the operation of the transport unit as a reference, changes over time in the weighing device and its surrounding conditions (for example, the vibration of the floor). By catching (increase) as a change in accuracy information with respect to the standard, it is possible to detect an abnormality in the measuring unit at an early stage as compared with the case where the detection based on the standard is not performed. As a result, it is possible to eliminate the abnormality of the measuring unit at an early stage and restart the measuring process, so that it is possible to suppress a decrease in productivity due to a decrease in measurement accuracy with time.

After generating the first accuracy information, the processing unit further generates the second accuracy information for evaluating the change with time of the measurement accuracy, and performs an abnormality based on the comparison result between the first accuracy information and the second accuracy information. It may be detected. In this case, by evaluating the second accuracy information with the first accuracy information as a reference, it is possible to easily evaluate the change over time in the measurement accuracy even if the person is not an expert.

The processing unit stores a plurality of digital filters in advance, and when an abnormality is detected, a digital filter different from the digital filter applied to generate the first accuracy information is applied, and the measurement accuracy of the different digital filter is applied. A third accuracy information for evaluating the above is generated, and based on the comparison result between the first accuracy information and the third accuracy information, either the different digital filter or a predetermined default digital filter is selected for weighing processing. May be done. In this case, by automatically switching the digital filter based on the comparison result between the first accuracy information and the third accuracy information, an abnormality in the measurement accuracy is detected by using the digital filter applied to generate the first accuracy information. Even in such a case, the measurement process can be restarted by using the digital filter applied to the generation of the third accuracy information. As a result, the interruption time of the weighing process can be shortened.

When an abnormality is detected, the weighing device may further include a notification unit for notifying the occurrence of the abnormality. In this case, the user of the weighing device can be made aware of the occurrence of an abnormality in the weighing unit. As a result, the user of the weighing device is urged to eliminate the abnormality of the weighing unit, and the weighing process can be restarted at an early stage.

The weighing device includes a storage unit that stores processing information including at least the date and time when the first accuracy information was generated, the type of digital filter applied to the generation of the first accuracy information, or the detection result information regarding the abnormality detection result. A display unit for displaying processing information may be further provided. In this case, the user of the weighing device can easily confirm the processing information.

According to the present disclosure, it is possible to suppress a decrease in productivity due to a decrease in measurement accuracy over time.

It is a schematic block diagram of the measuring apparatus which concerns on embodiment. It is a figure which shows the functional structure of the control part. It is a flowchart which shows the 1st precision information generation processing of the measuring apparatus of FIG. It is a flowchart which shows the abnormality detection processing of the weighing apparatus of FIG. It is a flowchart which shows the digital filter switching process of the measuring apparatus of FIG. FIG. 6A is a diagram showing a waveform included in the original signal. FIG. 6B is a diagram showing a waveform after filtering the waveform shown in FIG. 6A. FIG. 7A is an example of the time-dependent change of the standard deviation in the abnormality detection process. FIG. 7B is an example of the time-dependent change of the standard deviation in the measurement process. It is a schematic block diagram of the measuring apparatus which concerns on a modification.

Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a schematic configuration diagram of a weighing device according to an embodiment. The weighing device 1 shown in FIG. 1 is a device that weighs an object to be measured while transporting it in the direction of the arrow in FIG. 1 (hereinafter, simply referred to as “transportation direction”). The weighing device 1 is, for example, a device arranged on the final line of the production line. The object to be measured is, for example, an article P extending along the transport direction. The weighing device 1 includes a transport unit 2, a gantry 3, a measuring unit 4, and an operating unit 6.

The transport unit 2 is a transport device capable of transporting the article P along the transport direction, and is, for example, a conveyor. The transport unit 2 transports the article P at a designated transport speed, for example, via the operation unit 6. The transport speed is specified via the operation unit 6. The transport unit 2 includes a first conveyor unit 2a, a second conveyor unit 2b, and a third conveyor unit 2c. Each of the first conveyor unit 2a, the second conveyor unit 2b, and the third conveyor unit 2c has, for example, a roller, a rotating body such as a motor, a transport belt, and the like. The first conveyor section 2a, the second conveyor section 2b, and the third conveyor section 2c are arranged in order from the upstream side in the transport direction. That is, the second conveyor portion 2b is located between the first conveyor portion 2a and the third conveyor portion 2c in the transport direction. The first conveyor section 2a is a conveyor that carries the article P into the second conveyor section 2b. The first conveyor unit 2a may have, for example, a metal detector (not shown) or the like. The second conveyor section 2b is a conveyor that carries the article P conveyed from the first conveyor section 2a into the third conveyor section 2c. The third conveyor unit 2c is a conveyor that carries out the article P from the second conveyor unit 2b. The third conveyor unit 2c has, for example, a sorting machine (not shown) that sorts articles P whose weight deviates from an appropriate range.

The measuring unit 4 is mounted on the second conveyor unit 2b. Therefore, the article P transported by the transport unit 2 is weighed on the second conveyor unit 2b. Further, sensors for detecting the presence or absence of the article P may be provided on each of the upstream side and the downstream side of the second conveyor portion 2b. In this case, it can be easily determined whether or not the entire article P is located on the second conveyor portion 2b.

The gantry 3 is a member that accommodates the measuring unit 4, and is fixed to the floor F below the transport unit 2. The gantry 3 has a main body 3a for accommodating the measuring unit 4 and a plurality of legs 3b located between the main body 3a and the floor F. In FIG. 1, the main body 3a is shown by a broken line.

The measuring unit 4 is a detector that measures the weight of the article P located on the second conveyor unit 2b, and is located, for example, in the central portion of the transport unit 2. The measuring unit 4 includes a strain generating body 11 that receives compression and tension according to a load, and a measuring cell 12 that measures the article P located on the second conveyor unit 2b. The strain-causing body 11 has a movable rigid body portion 11a that supports the second conveyor portion 2b, and a fixed rigid body portion 11b that is fixed to the gantry 3. Each of the movable rigid body portion 11a and the fixed rigid body portion 11b is, for example, a member extending in the vertical direction. One end of the movable rigid body portion 11a is connected to the upstream end portion of the second conveyor portion 2b, and the other end of the movable rigid body portion 11a is connected to the measuring cell 12. One end of the fixed rigid body portion 11b is connected to the measuring cell 12, and the other end of the fixed rigid body portion 11b is connected to the main body 3a of the gantry 3. Although not shown, in the weighing cell 12, a plurality of strain gauges attached to the strain generating body 11 are connected to a Wheatstone bridge circuit.

In the present embodiment, the measuring unit 4 has an A / D conversion unit in addition to the strain generating body 11 and the measuring cell 12. The measuring cell 12 extracts an electric signal corresponding to the load transmitted from the strain generating body 11 from the Wheatstone bridge circuit. This electric signal is an analog original signal corresponding to the measurement component of the force applied to the second conveyor portion 2b. This analog original signal is converted into a digital original signal by the A / D conversion unit. The measuring unit 4 outputs the digital original signal to the outside (hereinafter, simply referred to as "original signal"). As a result, the amount of data output from the measuring unit 4 to the operating unit 6 can be reduced.

The measuring unit 4 outputs an original signal corresponding to the measuring component of the force applied to the second conveyor unit 2b. The measuring component is a component in the vertical downward direction of the force (load) applied to the second conveyor portion 2b. When the article P is not located on the second conveyor unit 2b during the operation of the transport unit 2, the force due to the vibration generated by the weighing device 1 and the force due to the vibration generated by the surroundings of the measuring device 1 are second. Join the conveyor section 2b. The vibration generated by the measuring device 1 includes the vibration caused by the operation of the transport unit 2, the vibration generated when the article P is transported to the transport unit 2, and the like. , Vibration (floor vibration) transmitted from the floor surface on which the weighing device 1 is placed is included. The floor vibration is, for example, vibration caused by a device installed on a production line of an article P including a measuring device 1, a device not included in the production line, or the like. When the article P is located on the second conveyor unit 2b during the operation of the transport unit 2, in addition to the force due to the vibration generated by the weighing device 1 and the force generated by the vibration generated around the measuring device 1, in addition to the force generated by the vibration generated by the surroundings of the measuring device 1. The force due to gravity acting on the article P is applied to the second conveyor portion 2b.

The operation unit 6 is a control panel for operating the transport unit 2 and the measuring unit 4, and is installed in the vicinity of, for example, the second conveyor unit 2b. The operation unit 6 includes a display interface 7, a control unit 8, a notification light 9, and a speaker 10.

The display interface 7 is a member (display unit) that displays various information output from the control unit 8. The display interface 7 is, for example, a measured value indicating the weight of the weighed article P, accuracy information indicating the weighing accuracy of the article P, the conveying speed of the conveying unit 2, the dimensions of the article P along the conveying direction, and the conveying of the article P. The frequency, the weighing pitch of the article P, and the like are displayed. The various information output from the control unit 8 includes the date and time when the first accuracy information (described later) for evaluating the measurement accuracy based on the measurement signal was generated, the type of digital filter applied to the generation of the first accuracy information, and so on. In addition, processing information such as detection result information regarding the detection result of the abnormality of the measuring unit 4 is included. The detection result information includes at least the information that the detection result of the abnormality of the measuring unit 4 is "the abnormality of the measuring unit 4 is detected" or "the abnormality of the measuring unit 4 is not detected". In the present embodiment, the display interface 7 has a touch panel 7a that functions as an external input unit. As a result, when the display interface 7 receives the input from the operator (user), the input information indicating the input content is output to the control unit 8. The input information is, for example, data regarding the transport speed of the transport unit 2, the dimensions of the article P along the transport direction, the type of the article P, the transport frequency of the article P, and the like. The transport frequency of the article P is set, for example, based on the capacity of the production machine located upstream of the weighing device 1.

Each of the measurement value of the article P and the accuracy information is data obtained based on the measurement signal output from the measurement unit 4 to the operation unit 6. Further, the weighing pitch of the article P is calculated by the control unit 8 based on the transport speed of the transport unit 2, the above-mentioned dimensions of the article P, and the transport frequency of the article P.

The control unit 8 is a controller that controls each member included in the weighing device 1, and is built in the operation unit 6. The control unit 8 is composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The control unit 8 outputs, for example, an operation signal for controlling the transfer speed of the transfer unit 2 designated via the display interface 7 to the transfer unit 2. Further, for example, when the distribution machine is provided in the third conveyor unit 2c and the control unit 8 determines that the weight of the article P deviates from a preset appropriate range, the control unit 8 Outputs an operation signal to the sorter so as to sort (exclude from the line) the article P. The control unit 8 not only controls each member included in the weighing device 1, but also receives / calculates / transmits various signals, records / reads various signals, and the like. As an example of the calculation of various signals by the control unit 8, the derivation of the measurement result of the article P can be mentioned. The control unit 8 is, for example, a drive circuit for outputting a control signal to the transport unit 2, a drive circuit for calculating the measurement value of the article P from the measurement signal generated by the measurement unit 4, and the above measurement signal. It has a drive circuit for calculating accuracy information, a storage circuit for storing each signal and each information, and the like. That is, the control unit 8 is a processing unit that applies a digital filter to the original signal to generate a measurement signal and performs measurement processing based on the measurement signal. The weighing process means a process of generating a weighing value of the article P when the article P is located on the second conveyor portion 2b during the operation of the transport unit 2.

The notification light 9 is a signal tower that emits light according to the operating condition of the measuring device 1. The alarm light 9 can emit, for example, red, yellow, and green light. The speaker 10 emits a sound (for example, a buzzer sound) according to the operating condition of the weighing device 1. The display interface 7 and the notification light 9 function as a notification unit that emits light according to the operating status of the measuring device 1 and the like. The speaker 10 functions as a notification unit that emits a sound according to the operating condition of the weighing device 1.

The operating status of the measuring device 1 includes an abnormality of the measuring unit 4 that occurs after the generation of the first accuracy information. The abnormality of the measuring unit 4 includes an abnormality of the weight value (so-called zero point) which is a reference for weighing. The first accuracy information is generated before the production and weighing of the article P (for example, before the start of the weight inspection) when the weighing device 1 is installed at the installation location (for example, the production line of the article P including the weighing device 1). ). The abnormality of the measuring unit 4 may be, for example, a state in which the accuracy information varies beyond the permissible range in which a predetermined margin is expected with respect to the generated first accuracy information. When an abnormality occurs in the measuring unit 4, the measuring accuracy of the measuring device 1 deteriorates with time.

FIG. 2 is a diagram showing a functional configuration of the control unit. As shown in FIG. 2, the control unit 8 includes a reception unit 21, a filter unit 22, a calculation unit 23, an output unit 24, and a storage unit 25.

The receiving unit 21 is, for example, a part that receives the weighing signal output from the weighing unit 4 and the input information transmitted from the display interface 7. The output of the weighing signal from the measuring unit 4 to the receiving unit 21 and the transmission of the input information from the display interface 7 to the receiving unit 21 may be performed via wire or wirelessly, respectively. You may. The receiving unit 21 may receive data other than the measurement signal and the input information.

The filter unit 22 is a portion that filters the original signal by using a plurality of digital filters stored in advance. Each of the plurality of digital filters is composed of a low-pass filter that attenuates frequency components exceeding a predetermined frequency, a notch filter (band stop filter) that attenuates frequency noise of a rotating body included in the transport unit 2, and the like. .. That is, when at least a part of the plurality of digital filters is selected, the filter unit 22 can perform multi-step filtering processing on the original signal. Each digital filter may include one or more low pass filters, one or more notch filters. Each of the plurality of digital filters may include a low-pass filter that attenuates different frequency bands from each other, or may include a notch filter that attenuates different frequency bands from each other. The plurality of low-pass filters may be, for example, the variable filter described in Japanese Patent No. 5901126.

As a weighing process, the filter unit 22 filters the original signal by using one digital filter selected in advance from the plurality of digital filters during the operation of the transport unit 2 and the transport of the article P. .. Then, the filter unit 22 generates a signal (measurement signal) after the filtering process. The obtained measurement signal is output to, for example, a calculation unit 23, a storage unit 25, etc. included in the control unit 8 shown in FIG. The weighing signal has a waveform arranged for performing a weighing process for calculating the weight of the article P.

The filter unit 22 refers to the original signal obtained when the article P is not transported by the transport unit 2 during the operation of the transport unit 2 (hereinafter, also referred to as “idle operation of the transport unit 2”). Apply each of multiple digital filters. In other words, the filter unit 22 performs a filtering process in which each of the plurality of digital filters is applied to the original signal while the transport unit 2 is idle. As a result, the filter unit 22 generates a plurality of measurement signals that are the result of applying each of the plurality of digital filters to the original signal obtained during the idle operation of the transport unit 2. Then, the filter unit 22 outputs a plurality of measurement signals to the calculation unit 23, the storage unit 25, and the like. Whether or not the transport unit 2 is idle may be determined by the operator or may be automatically determined. For example, when the transport unit 2 is in operation and the non-detection state of the article detection sensor provided in the weighing device 1 continues for a predetermined time or longer, the transport unit 2 is automatically operated when it is idle. May be judged by.

In the present embodiment, the signal output from the measuring unit 4 when the transport unit 2 is idle-operated at the transfer speed specified to be implemented via the display interface 7 is conveyed while the transfer unit 2 is in operation. It corresponds to the original signal obtained when the article P is not conveyed by the part 2. For example, when a plurality of digital filters have a first filter to a third filter, the original signal is filtered by each of the first filter to the third filter. As a result, the first metric signal obtained by applying the first filter, the second metric signal obtained by applying the second filter, and the third metric signal obtained by applying the third filter. A weighing signal is obtained.

The calculation unit 23 is a part that performs calculation processing of various input information. As a weighing process, the calculation unit 23 calculates the weight of the article P based on the weighing signal output from the filter unit 22 when the article P is located on the second conveyor unit 2b during the operation of the transport unit 2. Perform weighing process. As a result, the calculation unit 23 generates the measured value of the article P. The calculation unit 23 outputs the generated measurement value to the output unit 24. The calculation unit 23 calculates the measurement pitch (measurement interval) of the article P based on the input transfer speed of the transfer unit 2, the dimensions of the article P, and the transfer frequency. Based on the measured value, the calculation unit 23 determines whether or not the weight of the article P deviates from the preset appropriate range. Depending on the determination result, the calculation unit 23 outputs an operation signal to, for example, a distributor.

The calculation unit 23 obtains the product P when the product P is not being transported by the transport unit 2 while the transport unit 2 is in operation before the production and weighing of the article P when the article P is installed at the installation location of the weighing device 1. One of the plurality of digital filters is selected based on the result of applying each of the plurality of digital filters to the obtained original signal. In the present embodiment, the calculation unit 23 is based on a plurality of measurement signals obtained during the idle operation of the transport unit 2 before the manufacture and measurement of the article P when it is installed at the installation location of the measurement device 1. Generate multiple accuracy information. Subsequently, the calculation unit 23 compares a plurality of accuracy information. Here, the first accuracy information, which is the most appropriate accuracy information among the plurality of measurement signals, is the accuracy information for evaluating the measurement accuracy based on the measurement signals. The calculation unit 23 determines the most appropriate accuracy information as the first accuracy information. Subsequently, the calculation unit 23 selects the digital filter corresponding to the first accuracy information.

The accuracy information is calculated based on, for example, the standard deviation of the amplitude of the waveform included in the measurement signal. The calculation result may be the standard deviation of the amplitude of the waveform itself, or may be a parameter based on the standard deviation. The first precision information here is the standard deviation σ _a of the amplitude of the waveform included in the measurement signal. The calculation unit 23 compares the standard deviations of the amplitudes for each waveform obtained by applying each of the plurality of digital filters to the original signal, and selects the digital filter that obtains the smallest standard deviation as the first accuracy information. .. For example, when a plurality of digital filters have the first filter to the third filter, the calculation unit 23 determines the first standard deviation of the amplitude of the waveform included in the first measurement signal and the amplitude of the waveform included in the second measurement signal. The second standard deviation of the above and the third standard deviation of the amplitude of the waveform included in the third measurement signal are calculated. _{Subsequently, the calculation unit 23 specifies the standard deviation σ a} , which is the smallest value among the first standard deviation, the second standard deviation, and the third standard deviation, as the first accuracy information. Then, the calculation unit 23 selects the digital filter applied by the measurement signal having the first accuracy information. Then, the calculation unit 23 outputs to the storage unit 25 the date and time when the first accuracy information was generated and the type of the digital filter applied to the generation of the first accuracy information as the first accuracy information and the information regarding the selected digital filter. do. The storage unit 25 stores the date and time when the first accuracy information was generated and the type of the digital filter applied to the generation of the first accuracy information.

The waveform included in the measurement signal includes vibration generated by the measurement device 1 and its surroundings. The vibration becomes noise with respect to the weighing of the article P. Therefore, it can be determined that the smaller the standard deviation of the amplitude of the waveform, the smaller the noise with respect to the weighing of the article P.

Here, the calculation unit 23 performs an abnormality detection process for detecting an abnormality in the measurement unit 4 that occurs after the generation of the first accuracy information based on the stored first accuracy information. The weighing signal used for the abnormality detection process may be a period during the operation of the transport unit 2 after the start of production of the article P and while the article P is not located on the second conveyor portion 2b. For example, a plurality of types of measurement signals may be used. The period between the weight inspections of the article P is applicable.

After the generation of the first accuracy information, the calculation unit 23 further generates the second accuracy information for evaluating the change with time of the measurement accuracy, for example. The second accuracy information is accuracy information for detecting an abnormality in the measuring unit 4 using the first accuracy information as a reference. The second precision information is calculated based on, for example, the standard deviation of the amplitude of the waveform included in the measurement signal after the generation of the first precision information. The calculation result may be the standard deviation of the amplitude of the waveform itself, or may be a parameter based on the standard deviation. _{The second precision information is the standard deviation σ b} of the amplitude of the waveform included in the measurement signal after the generation of the first precision information. _{The standard deviation σ b} of the second precision information is the standard of the amplitude of the waveform included in the measurement signal in the preset constant standard deviation acquisition period after the generation of the first precision information (for example, after the start of production of the article P). It can be a deviation. The constant standard deviation acquisition period is continuous or continuous during the operation of the transport unit 2 after the start of production of the article P after the generation of the first accuracy information and while the article P is not located on the second conveyor portion 2b. It corresponds to an intermittent total period, and is not particularly limited, but may be, for example, a total of 30 minutes. As an example, the standard deviation σ _b can also be used as the standard deviation calculated using data (here, 3000 pieces) obtained by sampling the amplitude values of the waveforms included in the measurement signal 100 times per minute during the standard deviation acquisition period. good.

As the abnormality detection process, the calculation unit 23 may detect the abnormality of the measurement unit 4 based on the comparison result between the first accuracy information and the second accuracy information. The calculation unit 23 compares, for example, the standard deviation σ _a of the first accuracy information and the standard deviation σ _b of the second accuracy information, and has a _{standard deviation σ b} than the threshold value Th1 obtained by multiplying the _{standard deviation σ a by a predetermined margin.} If is large, an abnormality in the measuring unit 4 is detected. The calculation unit 23 does not detect an abnormality in the measurement unit 4, for example, when the standard deviation σ _b is equal to or less than the threshold value Th1. The predetermined margin may be, for example, a predetermined coefficient of about 1.5 to 3.0. When the calculation unit 23 detects an abnormality in the measuring unit 4, the output unit 24 may or may not stop the measuring device 1. Further, the output unit 24 may _{graph the standard deviation σ b} of the second precision information and display it on the touch panel 7a. In this case, the output unit 24 may _{further display the standard deviation σ a} of the first precision information on the touch panel 7 a.

When the calculation unit 23 detects an abnormality in the measurement unit 4 by the abnormality detection process, the calculation unit 23 may automatically switch from the digital filter applied to generate the first accuracy information to a digital filter that does not detect the abnormality in the measurement unit 4. good. For example, when the calculation unit 23 detects an abnormality in the measuring unit 4 by an abnormality detection process, the conveying unit 2 is in operation after the production of the article P after detecting the abnormality in the measuring unit 4 is started, and the article P is in the second conveyor unit. To evaluate the measurement accuracy of the different digital filter by applying a digital filter different from the digital filter applied to generate the first accuracy information based on the original signal of the period while not located on 2b. Generate third accuracy information. The original signal in this case may be an original signal after the time when the abnormality of the measuring unit 4 is detected.

The calculation unit 23 selects, for example, either the different digital filter or the predetermined default digital filter based on the comparison result between the first accuracy information and the third accuracy information, and performs the weighing process. The third accuracy information is accuracy information for evaluating the measurement accuracy with a digital filter different from the digital filter applied to generate the first accuracy information when the abnormality of the measurement unit 4 is detected. The third accuracy information is, for example, a measurement signal during the period during which the transport unit 2 is operating after the production of the article P is started after the abnormality of the measurement unit 4 is detected and the article P is not located on the second conveyor unit 2b. Calculated based on the standard deviation of the amplitude of the waveform contained in. The calculation result may be the standard deviation of the amplitude of the waveform itself, or may be a parameter based on the standard deviation. The third accuracy information is included in the measurement signal during the period during which the transport unit 2 is operating after the production of the article P is started after the abnormality of the measurement unit 4 is detected and the article P is not located on the second conveyor unit 2b. It is the standard deviation σ _c of the amplitude of the waveform. _{The standard deviation σ c} of the third accuracy information is, for example, after the abnormality of the measuring unit 4 is detected, _{and in the same manner as the method for the standard deviation σ b} described above, the transport unit 2 is operating and the article is in operation after the production of the article P is started. It can be the standard deviation of the amplitude of the waveform included in the measurement signal during the standard deviation acquisition period during the period when P is not located on the second conveyor portion 2b.

Calculation unit 23, for example, by comparing the standard deviation of the first accuracy information sigma _a and a standard deviation sigma _c of the third accuracy information, when the standard deviation sigma _c is equal to or less than the standard deviation sigma _a, third accuracy information Switch to the digital filter applied to the generation of. For example, when the standard deviation σ _c is larger than the standard deviation σ _a , the calculation unit 23 switches to the default digital filter. The default digital filter is a digital filter used in the standard setting among a plurality of digital filters, and is generally used under a wide range of conditions rather than giving priority to the convergence of the measurement signal under specific conditions. It is a digital filter with possible convergence. The digital filter switching process by the calculation unit 23 described above may be performed automatically, or may be performed in response to an input operation on the touch panel 7a or the like by the operator. When the input operation is performed, the output unit 24 may display, for example, a predetermined character and / or an image on the touch panel 7a to urge the operator of the weighing device 1 to perform the input operation.

The output unit 24 outputs, for example, various information and various signals generated by the control unit 8 and various information and various signals stored in the storage unit 25 to the outside. The output unit 24 outputs, for example, the measurement value, accuracy information, first accuracy information, measurement pitch, and the like of the article P to the display interface 7 as display information. The output unit 24 displays, for example, the date and time when the first accuracy information was generated, the type of the digital filter applied to the generation of the first accuracy information, or the processing information including at least the detection result information regarding the abnormality detection result as display information. Output to interface 7. The output unit 24 outputs an operation signal for controlling the transfer speed of the transfer unit 2 to the transfer unit 2, and outputs an operation signal for the distributor to the distributor. The output of the operation signal from the output unit 24 to the transport unit 2 may be performed via wire or wirelessly.

When an abnormality of the measuring unit 4 is detected by the abnormality detection process, the output unit 24 outputs to at least one of the display interface 7, the notification light 9, and the speaker 10 to notify the occurrence of the abnormality of the measuring unit 4. May be good. The notification of the occurrence of an abnormality in the measuring unit 4 can be performed, for example, by turning on the notification light 9, the buzzer sound of the speaker 10, the screen display of the touch panel 7a, the notification to the remote terminal, or the like.

The storage unit 25 stores the input information input via the display interface 7 and various information and various signals generated by the control unit 8. The storage unit 25 stores a plurality of digital filters in advance. The storage unit 25 stores, for example, processing information including at least the date and time when the first accuracy information was generated, the type of the digital filter applied to the generation of the first accuracy information, or the detection result information regarding the abnormality detection result. The storage unit 25 stores, for example, the standard deviation σ _a of the first precision information. Storage unit 25 may store the standard deviation sigma _b and the standard deviation sigma _c of the third accuracy information of the second accuracy information.

Next, each process by the control unit 8 of the weighing device 1 will be described with reference to FIGS. 3 to 5. FIG. 3 is a flowchart showing the first accuracy information generation process of the measuring device 1. The process of FIG. 3 is performed before the production and weighing of the article P (for example, before the start of the weight inspection) when the weighing device 1 is installed at the installation location (for example, the production line of the article P including the weighing device 1). Will be done.

First, the transport speed of the transport unit 2 is determined (step S01). In step S01, the transfer speed of the transfer unit 2 is specified via the display interface 7. At this time, the operator may input the transport speed itself of the transport unit 2 via the display interface 7, or may input the transport frequency of the article P.

The original signal when the transport unit 2 is operated in a state where the article P is not transported (when the transport unit 2 is idle) is acquired (step S02). In step S02, for example, the measuring unit 4 acquires the original signal when the transport unit 2 is idle-operated for about 5 seconds at a designated transport speed before weighing the article P. The acquired original signal is output to the control unit 8.

Each of the plurality of digital filters is applied to the acquired original signal (step S03). In step S03, the filter unit 22 applies each of the plurality of digital filters to the original signal to perform filtering processing. As a result, the filter unit 22 acquires a plurality of measurement signals.

The standard deviations of the amplitudes of each waveform after the filtering process are compared (step S04). In step S04, first, the calculation unit 23 calculates the standard deviation of the amplitude of the waveform included in each of the plurality of measurement signals. Subsequently, the calculation unit 23 compares the magnitude of each standard deviation. Here, the calculation unit 23 determines a waveform from which the smallest standard deviation (standard deviation σ _{a of the first precision information) is obtained among the plurality of standard deviations.}

One of the plurality of digital filters is selected (step S05). In step S05, the calculation unit 23 selects the digital filter used to generate the metric signal having the waveform with the smallest standard deviation. After that, the first accuracy information is stored (step S06). In step S06, the storage unit 25 stores the standard deviation σ _a as the first precision information. As described above, the digital filter used when measuring the article P at the designated transport speed is automatically set and reserved.

FIG. 4 is a flowchart showing an abnormality detection process of the weighing device 1. The process of FIG. 4 is performed during the period during which the transport unit 2 is in operation after the first accuracy information is generated, for example, after the production of the article P after the generation of the first accuracy information is started.

The original signal when the transport unit 2 is operated in a state where the article P is not transported is acquired (step S11). In step S11, for example, the measuring unit 4 is the source of the period when the transport unit 2 is operated at the above-designated transport speed for about 5 seconds and the article P is not located on the second conveyor portion 2b. Get the signal. The acquired original signal is output to the control unit 8.

The second accuracy information is generated by applying, for example, the same digital filter as that used for generating the first accuracy information to the original signal (step S12). In step S12, the calculation unit 23 receives the original signal during the period during which the transport unit 2 is operating and the product P is not located on the second conveyor unit 2b after the production of the article P is started after the first accuracy information is generated. Based on the above, the same digital filter as that used for generating the first accuracy information is applied to generate the second accuracy information.

A comparison is made between the first standard deviation (standard deviation σ _a of the first accuracy information) and the second standard deviation (standard deviation σ _b of the second accuracy information) (step S13). In step S13, the calculation unit 23 compares, for example, _{the threshold value Th1 obtained by multiplying the standard deviation σ a} by a predetermined margin with the standard deviation σ _b .

It is determined whether or not the second standard deviation is larger than the threshold Th1 obtained by multiplying the first standard deviation by a predetermined margin (step S14). The calculation unit 23 detects an abnormality (step S15), for example, when the second standard deviation is larger than the threshold Th1 obtained by multiplying the first standard deviation by a predetermined margin (step S14: YES). On the other hand, when the second standard deviation is, for example, the threshold value Th1 or less (step S14: NO), the calculation unit 23 ends the process of FIG. 4 as it is without detecting an abnormality.

Here, the digital filter is automatically switched according to the detection of the abnormality (step S16). Specifically, in step S16, the digital filter switching process shown in FIG. 5 is performed.

FIG. 5 is a flowchart showing a digital filter switching process of the weighing device 1. As shown in FIG. 5, the original signal is acquired during the period during which the transport unit 2 is operating and the article P is not located on the second conveyor unit 2b after the abnormality is detected (step S21). In step S21, for example, the measuring unit 4 is the source of the period when the transport unit 2 is operated at the above-designated transport speed for about 5 seconds and the article P is not located on the second conveyor portion 2b. Get the signal. The acquired original signal is output to the control unit 8.

A digital filter different from that used for generating the first precision information is applied to the original signal to generate the third precision information (step S22). In step S22, the calculation unit 23 generates the first accuracy information based on the original signal during the period during which the transport unit 2 is operating and the article P is not located on the second conveyor unit 2b after the abnormality is detected. A digital filter different from that used in is applied to generate the third accuracy information.

A comparison is made between the first standard deviation (standard deviation σ _a of the first accuracy information) and the third standard deviation (standard deviation σ _c of the third accuracy information) (step S23). In step S23, the calculation unit 23 compares, for example, the standard deviation σ _a of the first precision information and the standard deviation σ _c of the third precision information.

It is determined whether or not the third standard deviation is equal to or less than the first standard deviation (step S24). For example, when the third standard deviation is equal to or less than the first standard deviation (step S24: YES), the calculation unit 23 switches to the digital filter applied to the third accuracy information (step S25). On the other hand, when the third standard deviation is larger than the first standard deviation, for example, the calculation unit 23 switches to the default digital filter (step S24: NO).

Returning to FIG. 4, the occurrence of an abnormality in the measuring unit 4 is notified (step S17). In step S17, the output unit 24 outputs to at least one of the display interface 7, the notification light 9, and the speaker 10, for example, to notify the occurrence of an abnormality in the measuring unit 4. As notification of the occurrence of an abnormality in the measuring unit 4, for example, the notification light 9 is turned on, the buzzer sound of the speaker 10, the screen display of the touch panel 7a, the notification to the remote terminal, and the like are performed.

Next, the operation of the weighing device 1 will be described with reference to FIGS. 6 and 7. FIG. 6A is a diagram showing a waveform included in the original signal. FIG. 6B is a diagram showing a waveform after filtering the waveform shown in FIG. 6A.

FIG. 6A shows a waveform 51 of the original signal for calculating the weight of the article P acquired by the weighing unit 4 of the weighing device 1 when the transporting unit 2 is transported at a predetermined speed. The waveform includes noise and the like caused by the measuring device 1 and its surroundings. Therefore, usually, the noise is removed by performing a filtering process on the waveform.

FIG. 6B shows waveforms 52 and 53 after the waveform 51 is filtered by a plurality of digital filters. The waveform 52 is a waveform obtained by applying one of a plurality of digital filters. The waveform 53 is a waveform of a measurement signal obtained by applying a digital filter different from the digital filter applied to the waveform 52 among the plurality of digital filters. According to FIG. 6B, the noise of the waveform 53 tends to be removed more than that of the waveform 52. Therefore, when the weighing device 1 weighs the article P at the predetermined speed, the digital filter applied to the waveform 53 is more appropriate than the digital filter applied to the waveform 52 under the conditions of FIG. , It is presumed that the variation in the weight of the article P is small and weighed. Therefore, the digital filter applied to the waveform 53 is selected as the digital filter corresponding to the first accuracy information, and the standard deviation of the amplitude of the waveform 53 is stored in the storage unit 25 as _{the standard deviation σ a of the first accuracy information.}

FIG. 7A is an example of the time-dependent change of the standard deviation in the abnormality detection process. FIG. 7A shows a standard deviation σ _a of the first precision information, a threshold Th1 obtained by multiplying the standard deviation σ _a by a predetermined margin, and a standard deviation σ _b of the second precision information. Times t1 to t6 are included in the period after the generation of the first accuracy information, during the operation of the transport unit 2 after the start of production of the article P, and while the article P is not located on the second conveyor unit 2b, respectively. It is the time to be The times t1 to t6 may be, for example, the time when the idle operation ends in the period of the idle operation between a plurality of weight inspections (the time when the sensor for detecting an article is in the detection state).

In FIG. 7A, at times t1 to t5, the standard deviation σ _b of the second precision information is equal to or less than the threshold Th1 obtained by multiplying the standard deviation σ _{a by a predetermined margin.} Therefore, no abnormality is detected in the measuring unit 4 at times t1 to t5. However, after being installed at the installation location, the weighing device 1 and its surroundings (for example, an abnormality in the measuring unit 4, vibration of the measuring device 1 itself, vibration transmitted from the outside to the measuring device 1, etc.) have changed over time. By increasing, the standard deviation σ _b of the second accuracy information increases with time. As a result, at time t6, the standard deviation σ _{b corresponding to the variation in the accuracy information from the zero point increases by a} certain amount or more from the initially acquired standard deviation σ a and exceeds the threshold Th1. That is, at time t6, the standard deviation σ _b of the second precision information becomes larger than the threshold Th1 obtained by multiplying the standard deviation σ _a by a predetermined margin, and as a result, an abnormality of the measuring unit 4 is detected at time t6.

By the way, apart from the detection of the abnormality of the measuring unit 4 focusing on the idle operation of the transport unit 2, the control unit 8 is in the measurement process (that is, during the operation of the transport unit 2 and during the transport of the article P). (In) Abnormal increase in transfer noise of article P conveyed from the first conveyor section 2a to the second conveyor section 2b (abnormality that the digital filter setting is inappropriate) and abnormality in article weight variation (for example, weighing). An abnormality in increasing variation in the weight of the article P itself due to an abnormality in the production machine located upstream of the device 1) may be detected. For these abnormalities, for example, the standard deviation of the amplitude of the waveform included in the measurement signal generated based on the original signal during the operation of the transport unit 2 and the transport of the article P is more than a certain value from the _{initially acquired standard deviation σ a.} If it increases, it may be detected.

FIG. 7B is an example of the time-dependent change of the standard deviation in the measurement process. FIG. 7B shows the standard deviation of the first accuracy information obtained based on the original signal when the transport unit 2 is in operation and the article P is not transported by the transport unit 2 (during idle operation). and sigma _a, resulting in a standard deviation sigma _a with a threshold Th2 which is multiplied by a predetermined margin, after acquisition of the first accuracy information based on the original signal during the transport operation in and article P conveying portion 2 of the first accuracy information The standard deviation σ _Pb is shown.

In FIG. 7B, as an example, the standard deviation σ _Pb is calculated for each transportation of the article P. For example, the times t10, t12, t14, and t16 correspond to the times when the sensor for detecting the article is in the detection state, and the times t11, t13, t15, and t17 are the times when the sensor for detecting the article is in the non-detection state, respectively. Corresponds to the time. That is, the article P is located on the second conveyor portion 2b during each period of time t10 to t11, t12 to t13, t14 to t15, and t16 to t17. The calculation timing of the standard deviation σ _Pb is not limited to this.

_{In FIG. 7B, the standard deviation σ Pb} calculated at the times t11, t13, and t15 is equal to or less than the threshold value Th2. Therefore, at time t11, t13, and t15, an abnormality of increase in transit noise and an abnormality of article weight variation were not detected. However, the transfer noise of the article P conveyed from the first conveyor portion 2a to the second conveyor portion 2b and / or the variation in the weight of the article P itself in the production machine located upstream of the weighing device 1 over time. By increasing, the standard deviation σ _Pb increases with time. As a result, at time t17, the standard deviation σ _Pb exceeds the threshold value Th2. That is, the article measurement abnormality is detected at time t17.

As described above, according to the weighing device 1, when the article P is not located on the second conveyor unit 2b during the operation of the transport unit 2, the first measuring accuracy is evaluated based on the measuring signal. Accuracy information is generated. An abnormality of the measuring unit 4 is detected based on the generated first accuracy information. In this way, using the first accuracy information when the article P is not located on the second conveyor unit 2b during the operation of the transport unit 2 as a reference, changes over time in the weighing device 1 and its surroundings. By capturing (for example, an increase in floor vibration) as a change in accuracy information with respect to the reference, it is possible to detect an abnormality in the measuring unit 4 earlier than in the case where the detection based on the reference is not performed. As a result, it is possible to eliminate the abnormality of the measuring unit 4 at an early stage and restart the measuring process, so that it is possible to suppress a decrease in productivity due to a decrease in measurement accuracy with time.

After the first accuracy information is generated, the control unit 8 further generates the second accuracy information for evaluating the change with time of the measurement accuracy, and the abnormality is based on the comparison result between the first accuracy information and the second accuracy information. Is detected. As a result, by evaluating the second accuracy information with the first accuracy information as a reference, it is possible to easily evaluate the change over time in the measurement accuracy even if the person is not an expert.

The control unit 8 stores a plurality of digital filters in advance, and when an abnormality is detected, the control unit 8 applies a digital filter different from the digital filter applied to generate the first accuracy information, and measures with the different digital filter. A third accuracy information for evaluating the accuracy is generated, and based on the comparison result between the first accuracy information and the third accuracy information, either the different digital filter or a predetermined default digital filter is selected and weighed. Perform processing. As a result, by automatically switching the digital filter based on the comparison result between the first accuracy information and the third accuracy information, an abnormality in the measurement accuracy is detected when the digital filter applied to the generation of the first accuracy information is used. Even in such a case, the measurement process can be restarted by using the digital filter applied to the generation of the third accuracy information. As a result, the interruption time of the weighing process can be shortened.

When an abnormality is detected, the weighing device 1 further includes a notification light 9 and a speaker 10 as a notification unit for notifying the occurrence of the abnormality. As a result, the user of the measuring device 1 can be made to recognize the occurrence of the abnormality of the measuring unit 4. As a result, the user of the weighing device 1 is urged to eliminate the abnormality of the measuring unit 4, and the weighing process can be restarted at an early stage.

The measuring device 1 includes a storage unit 25 that stores processing information including at least the date and time when the first accuracy information was generated, the type of the digital filter applied to the generation of the first accuracy information, or the detection result information regarding the abnormality detection result. Further, the touch panel 7a of the display interface 7 for displaying the processing information is further provided. As a result, the user of the weighing device 1 can easily confirm the processing information.

Although the embodiment of the measuring device and the modified example thereof according to the present disclosure have been described above, the present disclosure is not limited to the above-described embodiment and the above-mentioned modified example. For example, the weighing device 1 can be deformed as in the weighing device 1A shown in FIG. In the description of the measuring device 1A, the description of the portion overlapping with the above embodiment will be omitted. Therefore, in the following, the parts different from the above-described embodiment will be mainly described.

FIG. 8 is a schematic configuration diagram of the weighing device 1A according to the modified example. As shown in FIG. 8, the weighing device 1A is a device for measuring the weight of the long article P1 along the transport direction, and has a first measuring unit 4A and a second measuring unit 5. The first measuring unit 4A is located on the upstream side of the second conveyor unit 2b. The second measuring unit 5 is located on the downstream side of the second conveyor unit 2b and has a strain generating body 31 and a measuring cell 32. Like the strain-causing body 11, the strain-causing body 31 has a movable rigid body portion 31a that supports the second conveyor portion 2b and a fixed rigid body portion 31b that is fixed to the gantry 3.

When the article P1 is not transported by the transport unit 2 during the operation of the transport unit 2, the filter unit 22 of the control unit 8 has, for example, the first original signal output from the first measuring unit 4A and the second original signal. One of a plurality of digital filters is selected for each of the second original signal output from the measuring unit 5. In this case, the digital filter selected based on the first original signal and the digital filter selected based on the second original signal may be the same as each other or may be different from each other. In this case, the weighing signal obtained by filtering the original signal output from the first measuring unit 4A while the transporting unit 2 is operating and the article P1 is being transported by the transporting unit 2 and the measuring signal obtained from the second measuring unit 5 The output original signal is filtered and the measurement signal obtained is added up. Based on the total measurement signal obtained by this, the standard deviation σ _a of the first precision information, the standard deviation σ _b of the second precision information, and the standard deviation σ _c of the third precision information are calculated, and the same as in the above embodiment. Then, the first precision information generation process, the abnormality detection process, and the digital filter switching process are performed. Further, the calculation unit 23 of the control unit 8 generates the measurement value of the article P1 based on the total measurement signal.

Alternatively, the filter unit 22 of the control unit 8 may, for example, refer to the total original signal of the first original signal output from the first measuring unit 4A and the second original signal output from the second measuring unit 5. Select one of the multiple digital filters. In this case, the control unit 8 first generates a total original signal that is the sum of the first original signal output from the first measurement unit 4A and the second original signal output from the second measurement unit 5. Then, the calculation unit 23 selects one of the plurality of digital filters for the total original signal. In this case, the original signal output from the first measuring unit 4A and the original signal output from the second measuring unit 5 are added up while the transporting unit 2 is operating and the article P1 is being conveyed by the transporting unit 2. .. Based on the metric signal obtained by filtering the total original signal obtained from this, the standard deviation σ _a of the first precision information, the standard deviation σ _b of the second precision information, and the standard deviation σ of the third precision information. _c is calculated, and the first precision information generation process, the abnormality detection process, and the digital filter switching process are performed in the same manner as in the above embodiment. Further, the calculation unit 23 of the control unit 8 generates the measurement value of the article P based on the measurement signal obtained by filtering the total original signal.

Even in such a measuring device 1A, the same action and effect as those of the above-described embodiment are exhibited. In addition, according to the weighing device 1A, the weight of the long article P1 can be accurately weighed along the transport direction.

In the above embodiment and the above modification, the accuracy information is calculated based on, but is not limited to, the standard deviation of the amplitude of the waveform obtained by applying a digital filter to the original signal. For example, the accuracy information may be calculated based on the value of an arbitrary point of the waveform obtained by applying a digital filter to the original signal. Further, for example, the accuracy information may be calculated based on the deviation of the zero point (for example, the average value of the measurement signal) of the waveform included in the measurement signal obtained by applying a digital filter to the original signal, or may be calculated as a standard. It may be calculated based on both deviations and biases. Further, for example, the accuracy information may be calculated based on the standard deviation of the differential value of the amplitude of the waveform obtained by applying a digital filter to the original signal. This calculation result may be the standard deviation itself of the differential value of the amplitude of the waveform. In these cases, the influence of vibration generated when the article is conveyed to the weighing device can be reduced. Therefore, it becomes easier to automatically select a digital filter suitable for the weighing device and its surroundings. Alternatively, the accuracy information may be calculated based on the standard deviation of the second derivative of the amplitude of the waveform obtained by applying a digital filter to the original signal. The calculation result may be the standard deviation itself of the second derivative of the amplitude of the waveform. Alternatively, the accuracy information may be calculated by subtracting the minimum value of the amplitude from the maximum value of the amplitude of the waveform. In this case, the accuracy information can be easily calculated.

In the above embodiment and the above modification, the measuring unit uses the digital signal as the original signal and outputs it to the outside, but the present invention is not limited to this. The measuring unit may output the acquired analog signal as an original signal to the outside. In this case, for example, the control unit may digitally convert the analog signal.

In the above-described embodiment and the above-described modification, the second accuracy information is generated for the measurement signal obtained by applying the same digital filter as that applied to the generation of the first accuracy information to the original signal, and the first accuracy information is used. An abnormality was detected based on the comparison result with the second accuracy information, but the present invention is not limited to this. For example, when generating the second accuracy information, a digital filter different from the one applied to generate the first accuracy information may be applied to the original signal, or the digital filter may not be applied to the original signal.

In the above embodiment and the above modification, the third accuracy information is generated for the measurement signal obtained by applying the digital filter different from the one applied to the generation of the first accuracy information to the original signal, and the first accuracy information is used. The digital filter switching process was performed based on the comparison result with the third accuracy information, but the present invention is not limited to this. For example, it is not always necessary to generate the third accuracy information. In this case, it may be automatically switched to the default digital filter. Alternatively, the digital filter switching process itself may be omitted. In this case, the processes of steps S16 and 5 in FIG. 4 may be omitted.

In the above-described embodiment and the above-described modification, the measuring devices 1 and 1A include a touch panel 7a, a notification light 9, and a speaker 10 as notification units, but some of them may be omitted. Moreover, all of these may be omitted. In this case, step S17 in FIG. 4 may be omitted.

1,1A ... Weighing device, 2 ... Conveying unit, 3 ... Stand, 4 ... Weighing unit, 4A ... First measuring unit (weighing unit), 5 ... Second measuring unit (weighing unit), 6 ... Operating unit, 7 ... Display interface (display unit), 8 ... Control unit (processing unit), 9 ... Notification light (notification unit), 10 ... Speaker (notification unit), 11, 31 ... Distortion body, 11a, 31a ... Movable rigid body, 11b , 31b ... Fixed rigid body unit, 12, 32 ... Weighing cell, 21 ... Receiver unit, 22 ... Filter unit (processing unit), 23 ... Calculation unit (processing unit), 24 ... Output unit, 25 ... Storage unit, P, P1 … Goods.

Claims (5)

A transport unit that can transport goods and
A measuring unit that outputs an original signal corresponding to the measuring component of the force applied to the transport unit, and a measuring unit.
A processing unit that applies a digital filter to the original signal to generate a weighing signal and performs weighing processing based on the weighing signal is provided.
When the article is not located on the transport unit during the operation of the transport unit, the processing unit generates first accuracy information for evaluating the measurement accuracy based on the measurement signal, and the generated first accuracy information is generated. A weighing device that detects an abnormality in the measuring unit based on the first accuracy information. After the generation of the first accuracy information, the processing unit further generates the second accuracy information for evaluating the change with time of the measurement accuracy, and the comparison result between the first accuracy information and the second accuracy information. The weighing device according to claim 1, wherein the abnormality is detected based on the above. The processing unit
Multiple digital filters are stored in advance,
When the abnormality is detected, the third accuracy information for evaluating the measurement accuracy in the different digital filter by applying the digital filter different from the digital filter applied to generate the first accuracy information. To generate
Claim 1 or 2 in which the weighing process is performed by selecting either the different digital filter or the predetermined default digital filter based on the comparison result between the first accuracy information and the third accuracy information. The weighing device described in. The weighing device according to any one of claims 1 to 3, further comprising a notification unit for notifying the occurrence of the abnormality when the abnormality is detected. A storage unit that stores at least processing information including at least the date and time when the first accuracy information was generated, the type of the digital filter applied to the generation of the first accuracy information, or the detection result information regarding the detection result of the abnormality.
The measuring device according to any one of claims 1 to 4, further comprising a display unit for displaying the processing information.

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