JP2014025831A - Weighing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weighing apparatus capable of reducing a measurement error by correcting deviation in dynamic measurement in accordance with a conveyance interval and a length in a conveyance direction of an object to be measured.SOLUTION: In a weighing apparatus 1, weighing means 72 includes dynamic correction coefficient storage means for previously storing therein plural dynamic correction coefficients set for each measurement point and signal processing condition and dynamic correction means for correcting a weighing signal using the dynamic correction coefficients, and control means 74 controls the dynamic correction means to read out from the dynamic correction coefficient storage means a dynamic correction coefficient according to a length in a conveyance direction and a conveyance interval determined by conveyance state determination means and signal processing conditions used by signal processing means 71 and to use the read out dynamic correction coefficient to correct the weighing signal.

Description

  The present invention relates to a weighing device that measures quality by weighing an object to be weighed such as meat, fish, processed food, and medicine.

  2. Description of the Related Art Conventionally, in a production line for foods, etc., articles that are incorporated into the production line are sequentially carried in from the front stage, weighed while transporting the carried-in articles, and are removed from the production line by carrying out or sorting to the subsequent stage. A weighing device is used.

  This type of weighing device employs dynamic weighing that performs weighing while conveying the object to be weighed, so it depends on factors such as the impact of the object being weighed from the run-up conveyor to the weighing conveyor and air resistance during conveyance. An error (bias) may occur in the measured value.

  In a weighing device that performs dynamic weighing, the object to be weighed (master work) as a master is measured a plurality of times in advance, and the weight of the object to be weighed is determined by correcting the bias in dynamic weighing with the correction coefficient calculated at the time of measurement. There is a technique (see, for example, Patent Document 1).

  In addition, this type of weighing device is known to perform measurement while changing the measurement timing and filter characteristics according to the conveyance interval of the object to be weighed (see, for example, Patent Document 2).

Japanese Patent No. 270638 Japanese Patent No. 3644680

  However, the technique described in Patent Document 1 has a problem in that the measurement value varies depending on the correction using one dynamic correction coefficient because the weighing data used for weighing differs depending on the conveyance interval of the object to be weighed.

  For example, as a state at the time of weighing, the object to be weighed is loaded into the weighing conveyor at intervals not to ride on two, and the object to be weighed is loaded onto the weighing conveyor at intervals of becoming two. In addition, there is a state in which weighing is performed in a state including residual vibration due to a transfer impact of the object to be weighed, but an error (bias) of the weighing value is often different for each object to be weighed due to the influence of the residual vibration.

  Here, paying attention to the influence of the residual vibration due to the connection, there is a method of performing measurement in a state without the influence of the residual vibration. However, in this case, there is a possibility that the measurement may be delayed or the accuracy may be deteriorated. For example, if measurement is started from the time when the residual vibration has converged, the attenuation band by the low-pass filter (low-pass filter) becomes narrow, leading to deterioration in accuracy.

  There is also a method of removing the residual vibration component by using a specific band elimination filter, but in this case, a delay occurs in the measurement due to the filter delay, leading to a decrease in measurement capability (measurable number per time).

  Therefore, the present invention has been made to solve the above-described conventional problems, and by correcting the deviation during dynamic weighing according to the conveyance interval and the length in the conveyance direction of the object to be weighed, a measurement error can be obtained. An object of the present invention is to provide a weighing device capable of reducing the above.

  The weighing device according to the present invention includes a conveyance means (32) that conveys the objects to be weighed (W) sequentially carried in accordance with predetermined conveyance conditions, and the measurement object that is supported by the conveyance means and is being conveyed by the conveyance means. Weighing means (21) for outputting a weighing signal based on the load of the object, and detecting the carry-in of the object to be weighed into the conveying means, the length of the object in the conveying direction, the object to be weighed and the subsequent A conveyance status determination means for determining a conveyance interval with the object to be weighed, a signal processing means (71) for receiving the weighing signal and outputting a measurement signal obtained by processing the weighing signal based on a predetermined signal processing condition; Based on the measured value of the measurement signal at a measurement point and a dynamic correction coefficient for correction at a measurement point after a predetermined time has elapsed since the conveyance status determination unit detected the conveyance of the object to be conveyed to the conveyance unit. Calculate the weighing value of an object A weighing means (72) for comparing, a quality value calculated by the weighing means and a quality judgment criterion to judge the quality of the object to be weighed (76), and a control means for controlling the weighing means ( 74), wherein the weighing means stores in advance a plurality of dynamic correction coefficients set for each of the measurement points and the signal processing conditions, and a dynamic correction coefficient storage means (113), Dynamic correction means (103) for correcting the weighing signal using a dynamic correction coefficient, the control means for the dynamic correction means with respect to the conveyance direction length and the conveyance determined by the conveyance status determination means When the dynamic correction coefficient corresponding to the interval and the signal processing condition used by the signal processing means is read from the dynamic correction coefficient storage means Moni, and controlling so as to correct the weighing signal by using the read dynamic correction factor.

  With this configuration, the dynamic correction coefficient is read from the dynamic correction coefficient storage unit by the dynamic correction unit according to the conveyance direction length and the conveyance interval determined by the conveyance state determination unit and the signal processing conditions used by the signal processing unit. Since the weighing signal is corrected using the read dynamic correction coefficient, the weighing error is reduced by correcting the bias at the time of dynamic weighing according to the conveyance interval and the length in the conveyance direction of the object to be weighed. be able to.

  In the weighing device according to the present invention, the weighing unit calculates a dynamic correction coefficient according to the measurement point and the signal processing condition while changing both the measurement point and the signal processing condition. The calculation unit (112) is provided, and the dynamic correction coefficient storage unit stores in advance a plurality of dynamic correction coefficients calculated by the dynamic correction coefficient calculation unit.

  With this configuration, the dynamic correction coefficient calculated by the dynamic correction coefficient calculation unit according to the conveyance direction length and the conveyance interval determined by the conveyance condition determination unit and the signal processing condition used by the signal processing unit is determined by the dynamic correction unit. Is read from the dynamic correction coefficient storage means, and the weighing signal is corrected using the read dynamic correction coefficient. Therefore, the bias during dynamic weighing is corrected according to the conveyance interval and conveyance direction length of the object to be weighed. By doing so, the measurement error can be reduced.

  The weighing device according to the present invention switches an operation mode between an operation mode for determining the quality of the object to be weighed and a learning mode for storing the plurality of dynamic correction coefficients in the dynamic correction coefficient storage means. A mode switching unit (77), and the control unit is configured to determine the transport direction determined by the transport state determination unit with respect to the dynamic correction unit when the operation mode is switched to the operation mode by the mode switching unit. The dynamic correction coefficient corresponding to the length and the conveyance interval and the signal processing condition used by the signal processing means is read from the dynamic correction coefficient storage means, and the weighing signal is corrected using the read dynamic correction coefficient. And the operation mode is switched to the learning mode by the mode switching means. And controlling the dynamic correction coefficient calculating means to calculate a dynamic correction coefficient according to the measurement point and the signal processing condition while changing both the measurement point and the signal processing condition. The dynamic correction coefficient storage means is controlled to store a plurality of dynamic correction coefficients calculated by the dynamic correction coefficient calculation means.

  With this configuration, in the operation mode, the control unit responds to the dynamic correction unit according to the conveyance direction length and the conveyance interval determined by the conveyance state determination unit, and the signal processing conditions used by the signal processing unit. The dynamic correction coefficient is read from the dynamic correction coefficient storage means, and the weighing signal is controlled to be corrected using the read dynamic correction coefficient, and the measurement is performed with respect to the dynamic correction coefficient calculation means in the learning mode. While changing both the point and the signal processing condition, control is performed to calculate a dynamic correction coefficient according to the measurement point and the signal processing condition, and the dynamic correction coefficient calculation is performed with respect to the dynamic correction coefficient storage unit The dynamic correction coefficient calculated by And controls to store, calculate a dynamic compensation coefficient for each individual metering devices, by storing and use, it is possible to reduce the weighing error based on individual differences of the metering device.

  In the weighing apparatus according to the present invention, the signal processing unit includes a plurality of low-pass filters (LPF1, LPF2, LPFn), and the conveyance direction length determined by the conveyance state determination unit from the plurality of low-pass filters. Signal processing is performed by a low-pass filter selected as a signal processing condition based on the length and the conveyance interval.

  With this configuration, the dynamic correction coefficient according to the conveyance direction length and the conveyance interval determined by the conveyance condition determination unit and the low-pass filter used as the signal processing condition by the signal processing unit is dynamically corrected by the dynamic correction unit. Since the weighing signal is corrected using the read dynamic correction coefficient, the weighing error is corrected by correcting the bias during dynamic weighing according to the conveyance interval and the length in the conveyance direction of the object to be weighed. Can be reduced.

  The present invention can provide a weighing device that can reduce a measurement error by correcting a bias at the time of dynamic weighing according to a conveyance interval and a conveyance direction length of an object to be weighed.

It is a perspective view which shows the outline | summary of the weighing | measuring device which concerns on one embodiment of this invention. It is a block diagram which shows the internal structure of the weighing | measuring device which concerns on one embodiment of this invention. It is a block diagram which shows the detailed structure of the signal processing means of the measuring apparatus which concerns on one embodiment of this invention, and a measuring means. It is a figure which shows the dynamic correction coefficient of the measuring device which concerns on one embodiment of this invention. It is a block diagram which shows the structural requirements regarding the operation | movement in the learning mode of the measuring device which concerns on one embodiment of this invention. It is a flowchart which shows operation | movement in the learning mode of the measuring device which concerns on one embodiment of this invention. It is a block diagram which shows the structural requirements regarding the operation | movement in the operation mode of the measuring device which concerns on one embodiment of this invention. It is a flowchart which shows the operation | movement in the operation mode of the measuring device which concerns on one embodiment of this invention. It is a timing chart which shows the operation | movement in the operation mode of the measuring apparatus which concerns on one embodiment of this invention.

  Hereinafter, embodiments of a weighing device according to the present invention will be described with reference to the drawings. 1 to 9 show an embodiment of a weighing device according to the present invention.

  As shown in FIGS. 1 and 2, the weighing device 1 is configured to include an apparatus main body 2, a transport unit 3, and a carry-in detection sensor 4. A sorting unit 5 is connected to the subsequent stage of the weighing device 1.

  The weighing device 1 is installed on the downstream side of the belt conveyor 14 constituting a part of the production line, and is to be weighed for meat, fish, processed foods, pharmaceuticals, etc. that are sequentially carried in the direction of arrow A at predetermined intervals. The weight of the object W is measured, and the measurement result is output.

  Furthermore, it compares with the reference value of the upper limit and the lower limit of the preset weight respectively, and determines whether or not the measured value obtained as the weight of the object W is within the range of the reference value. May be determined as non-defective and those out of the range as defective, and the weight rank may be determined corresponding to a plurality of reference values.

  In addition, the measurement result, the pass / fail determination result, and the weight rank determination result are displayed on the display unit 10 and are output to the selection unit 5 connected to the subsequent stage of the weighing device 1. The sorting unit 5 distributes the objects to be weighed W according to the measurement result, the pass / fail determination result, and the weight rank determination result output from the weighing device 1.

  The apparatus main body 2 includes a weighing unit 21, a general control unit 7, a display unit 10, a setting unit 11, and a housing 2a that houses these units.

  The conveyance unit 3 is configured to convey the object W to be weighed in from the belt conveyor 14 in the direction of arrow A under predetermined conveyance conditions. The object to be weighed W is conveyed by being accelerated or decelerated so as to have an optimum speed for measurement by the run-up conveyor 31, further conveyed by the weighing conveyor 32, and the weight is measured by the weighing means 21 while being conveyed. It has become so. The weighing conveyor 32 is configured to convey an object to be weighed according to predetermined conveyance conditions. In addition, the object to be weighed W is further transported to the sorting unit 5 in the subsequent stage after the weighing and is distributed.

  The transport unit 3 includes a running conveyor 31 and a weighing conveyor 32. The run-up conveyor 31 performs the run-up of the object to be weighed W before the object to be weighed W conveyed from the preceding belt conveyor 14 moves to the weighing conveyor 32, and includes two rollers 31a and 31c, And an endless conveying belt 31b wound around the roller.

  The weighing conveyor 32 is supported by the upper part of the weighing means 21 for weighing the workpiece W, and is composed of two rollers 32a and 32c and an endless conveying belt 32b wound around these rollers. Yes.

  The carry-in detection sensor 4 is configured by a transmission photoelectric sensor including a pair of light projecting units 4 a and light receiving units 4 b, and is disposed between the run-up conveyor 31 and the weighing conveyor 32. Specifically, the light projecting unit 4a is disposed on the apparatus main body 2 side of the transport belt 32b, and the light receiving unit 4b is disposed on the other side of the transport belt 32b so as to face the light projecting unit 4a. When the object to be weighed W passes between the light projecting unit 4a and the light receiving unit 4b, the light receiving unit 4b is shielded from light by the object to be weighed, so that the carry-in of the object to be weighed W is detected.

  The carry-in detection sensor 4 outputs, as a carry-in detection signal, a signal corresponding to light shielding or non-light shielding when the object W passes through the carry-in detection sensor 4 to the general control unit 7 in the apparatus main body 2. It has become.

  The weighing means 21 is a load sensor that supports the weighing conveyor 32 and outputs a weighing signal based on the load of the object to be weighed. For example, the weighing means 21 has a configuration of an electromagnetic balance type balance, and the object to be weighed W is the weighing conveyor 32. The load applied to the weighing means 21 is measured while being conveyed.

  When the weighing means 21 is configured as an electromagnetic balance type balance, although not shown in the figure, the suspension plate that moves up and down together with the weighing conveyor 32, a parallel spring that suspends the suspension plate, and one end that is fixed to the suspension plate. A fulcrum that supports the cage, a position sensor that detects the position of the other end of the cage and outputs a displacement detection signal, an electromagnetic coil with a magnet that applies a force to the other end of the cage, and an electromagnetic coil A coil application unit for driving, and a servo control unit for controlling the coil application unit so as to maintain the balance in accordance with a displacement detection signal from the position sensor.

  The weighing means 21 as an electromagnetic balance type balance is balanced when no load is applied. When the object W is placed on the weighing conveyor 32, the balance around the fulcrum is lost, and the balance rises to the right in the figure. Although this inclination is detected by a position sensor and a current is passed through the electromagnetic coil so that the inclination is zero, this current is proportional to the weight of the object to be weighed. Can be converted into a weighing signal.

  That is, the load caused by the mass of the object W to be measured and the force generated by the current flowing through the magnet and the electromagnetic coil are balanced, and the current value flowing through the electromagnetic coil at this time is measured as the weight of the object W to be inspected.

  The comprehensive control unit 7 includes a signal processing unit 71, a weighing unit 72, a storage unit 73, a control unit 74, a quality determination unit 76, and a mode switching unit 77.

  The signal processing means 71 is adapted to receive a weighing signal from the weighing means 21 and output a signal-processed measurement signal that has been signal-processed based on predetermined signal processing conditions, and converts an analog signal into a digital signal. A / D converter is provided.

  Further, as will be described later with reference to FIG. 3, the signal processing means 71 includes a plurality of low-pass filters of different types and characteristics, and these low-pass filters allow only low-frequency components of the weighing signal to pass therethrough. It is designed to output.

  The signal processing means 71 may select one low-pass filter or a combination of a plurality of low-pass filters.

  The low-pass filter provided in the signal processing means 71 includes an FIR (Finite Impulse Response) filter and an IIR (Infinite Impulse Response) filter.

  Here, the FIR filter is a finite impulse response filter that outputs an output for a predetermined time (finite time) when an impulse response waveform is input, and the IIR filter outputs an attenuation waveform of the impulse response waveform infinitely. This is an infinite impulse response filter.

  Specifically, the FIR filter constitutes a low-pass filter that passes a predetermined low-frequency component with respect to the weighing signal converted into a digital signal by the A / D converter, and performs a simple averaging process or a known window function. Is used to perform weighted averaging processing.

  The IIR filter is composed of an analog filter that directly receives a weighing signal (analog weighing signal) from the weighing means 21 and outputs it to an A / D converter using hardware whose characteristics can be changed, such as a switched capacitor filter. Alternatively, a digital filter that receives a digital weighing signal (not shown) from the A / D converter may be used.

  The weighing means 72 is configured to calculate (convert to weight) the measurement value of the object W based on the measurement signal obtained by signal-processing the weighing signal output from the signal processing means 71. Further, in the weighing means 72, it is detected after the carry-in detection sensor 4 detects that the object to be weighed W has been carried into the weighing conveyor 32 with respect to the object W to which the weighing signal is output from the weighing means 21. The measured value of the object W is calculated at a predetermined timing (hereinafter also referred to as a measurement point).

  In the present embodiment, the measurement point for calculating the measurement value of the workpiece W varies according to the conveyance interval of the workpiece W. In addition, the weighing means 72 converts the weight based on the measurement signal in order to calculate the measured value for the workpiece W moving on the weighing conveyor 32, and further calculates a dynamic correction coefficient optimum for the converted value. The measured value is calculated by correcting the converted value converted into the weight by multiplication.

  The weight of each weighing result calculated by the weighing means 72 is stored in the storage means 73 as calculation data. Detailed configurations of the measuring means 72 and the signal processing means 71 will be described later.

  The storage means 73 is composed of a storage medium and the like, and the condition parameters including the predetermined transport condition of the object W to be weighed by the weighing conveyor 32 and the predetermined signal processing condition in the signal processing means 71 are the types of the object W to be weighed. It corresponds to memorize.

  The storage unit 73 stores a conveyance speed and LPF (Low Pass Filter) characteristics corresponding to each type number assigned to each type of the object to be weighed W. Further, the storage means 73 stores a non-defective range for determining the quality of the object W to be weighed.

  The conveyance speed is the speed of the conveyance unit 3 that conveys the workpiece W, the LPF characteristic indicates what characteristic the low-pass filter is, and the non-defective range is the non-defective product range. This is the range of the weight of the weighing object W.

  The stored information is stored in advance by a setting operation from the setting unit 11 or connection with an external device. The storage means 73 stores various data such as measurement values and non-defective product determination results.

  The control means 74 reads out a predetermined transport condition and a predetermined signal processing condition from the storage means 73 in accordance with the type of the object to be weighed W, and controls the weighing conveyor 32 and the signal processing means 71, respectively.

  Further, the transport unit 3 and the signal processing unit 71 are controlled by sequentially switching condition parameters corresponding to a plurality of types stored in the storage unit 73. Further, the control means 74 is configured to drive and control the rotational speed (rpm) of a motor (not shown) so as to control the transport speed of the workpiece W by the transport unit 3.

  The pass / fail judgment means 76 is for judging pass / fail of the object to be weighed W. The pass / fail judgment means 76 is constituted by a judgment circuit and the like, and compares the weight value calculated by the weighing means 72 with the pass / fail judgment criteria to determine the pass / fail of the object W It comes to judge.

  Specifically, when the quality determination unit 76 receives the weight signal of the weighing result of the object W output from the weighing unit 72, the upper limit value Ga and the lower limit value Gb of the weight stored in advance in the storage unit 73. , And the calculated weight of the object to be weighed is compared with the upper limit value Ga and the lower limit value Gb, respectively, and the weight of the object to be weighed is within the allowable range determined by the upper limit value Ga and the lower limit value Gb. It is determined whether or not.

  The determination result determined by the quality determination unit 76 is output to the display unit 10 and displayed as a non-defective product or a defective product. The determination result is output to the sorting unit 5 connected to the subsequent stage of the weighing device 1 so that the object to be weighed W is sorted as a non-defective product or a defective product. Further, the determination result is output to the storage means 73, and the determination result for each object W is stored.

  The mode switching unit 77 issues a command to the control unit 74 and switches the operation mode of the weighing device 1 between the operation mode and the learning mode. Here, the operation mode is a normal operation mode in which the weighing device 1 measures the object W, calculates the weight, and determines pass / fail, and the learning mode is an operation in the operation mode. This is an operation mode for calculating and storing a dynamic coefficient to be used.

  The mode switching unit 77 switches the operation mode to either the operation mode or the learning mode in accordance with an input operation from the setting unit 11.

  As shown in FIG. 1, the display unit 10 is provided at the upper end of the apparatus main body 2 on the transport unit 3 side, and is configured by a display device such as a liquid crystal display. When the operation mode of the weighing device 1 is the operation mode, the display means 10 displays the operation state of the weighing device 1, the measured value of the object W, and the pass / fail judgment result, and the operation mode of the weighing device 1 is the setting mode. In this case, display related to parameter setting and operation confirmation is performed.

  The display unit 10 may be configured as a touch panel in which displayed numbers, characters, and the like are input by a touch operation, and may be configured to be integrated with the setting unit 11.

  The sorting unit 5 is connected to the subsequent stage of the weighing device 1 and includes a sorting mechanism unit 5a and a conveyor belt 5b. The sorting mechanism unit 5a is configured by, for example, an extrusion type sorting mechanism. The sorting mechanism unit 5a only needs to be able to sort good products and defective products, and may be configured by a sorting mechanism such as a flipper mechanism, a dropout mechanism, or an air jet mechanism.

  The sorting mechanism unit 5a is configured to transfer the workpiece belt W to the workpiece W determined to be defective while the workpiece W transported from the upstream weighing conveyor 32 is being transported in the arrow B direction by the transport belt 5b. 5b is pushed out in the lateral direction and jet air is sprayed, and the defective object W is discharged from the conveying belt 5b and is distinguished from the non-defective object W by sorting. Yes.

  The conveyor belt 5b is composed of a roller 5c, a roller (not shown) disposed opposite to the roller 5c, and an endless conveyor belt wound around these rollers. The weighing object W is conveyed downstream at a predetermined speed.

  Next, detailed configurations of the weighing unit 72 and the signal processing unit 71 will be described.

  As shown in FIG. 3, the signal processing means 71 includes a first low-pass filter LPF1, a second low-pass filter LPF2, and an n-th low-pass filter LPFn as a plurality of low-pass filters. Note that n is a positive integer.

  The plurality of low-pass filters are connected to the weighing means 21 in parallel, and the weighing signal from the weighing means 21 is input to all of the plurality of low-pass filters.

  The weighing unit 72 includes a filter selection unit 101, a measurement point selection unit 102, a dynamic correction unit 103, and a conveyance status determination unit 104 as constituent requirements used when the operation mode of the weighing device 1 is the operation mode. ing.

  In addition, the weighing unit 72 includes a measurement value acquisition unit 111, a dynamic correction coefficient calculation unit 112, and a dynamic correction coefficient storage unit 113 as constituent elements used when the operation mode of the weighing device 1 is the learning mode. Yes.

  The filter selection unit 101 outputs any one of the signals input from the plurality of low-pass filters of the signal processing unit 71 to the subsequent stage, and thereby selects any of the plurality of low-pass filters of the signal processing unit 71. Whether to use a low-pass filter is substantially selected.

  The measurement point selection means 102 measures the object to be weighed after it is detected by the carry-in detection sensor 4 that the object to be weighed W has been carried into the weighing conveyor 32 with respect to the object W to which the weighing signal is output from the weighing means 21. A measurement point that is a timing for calculating a measurement value of the object W is selected.

  The dynamic correction unit 103 applies the dynamic correction coefficient read from the dynamic correction coefficient storage unit 113 to perform dynamic correction of the measurement value.

  The measurement value acquisition unit 111 acquires measurement values at a first measurement point, a second measurement point, and an nth measurement point as a plurality of different measurement points. That is, the measurement value acquisition unit 111 acquires measurement values at a plurality of different measurement points from the measurement values output from the plurality of low-pass filters of the signal processing unit 71, respectively. The plurality of measurement values for each low-pass filter and each measurement point acquired by the measurement value acquisition unit 111 are output to the dynamic correction coefficient calculation unit 112.

  The dynamic correction coefficient calculation unit 112 calculates a dynamic correction coefficient based on the measurement values for each of the plurality of low-pass filters and the plurality of measurement points acquired by the measurement value acquisition unit 111.

  As shown in FIG. 4, the dynamic correction coefficient calculated by the dynamic correction coefficient calculation unit 112 becomes matrix-like data for each of a plurality of low-pass filters and a plurality of measurement points. These dynamic correction coefficients are dynamic correction coefficients. It is stored in the storage means 113.

  The conveyance status determination means 104 determines the conveyance interval between the preceding object to be weighed W and the subsequent object to be weighed W based on the carry-in detection signal from the carry-in detection sensor 4, and the length of the object to be weighed W in the conveying direction. Judgment is made.

  The weighing apparatus 1 according to the present embodiment selects an optimum low-pass filter from a plurality of low-pass filters having different attenuation bands according to the conveyance interval and the length in the conveyance direction of the object W, and calculates a plurality of pre-calculated plural low-pass filters. A measurement value is calculated by correcting with a dynamic correction coefficient for correcting a dynamic measurement error (bias).

  Here, the dynamic correction coefficient is calculated in advance in the learning mode by the dynamic correction coefficient calculation unit 112 for each conveyance interval or measurement point of the object W. Note that the dynamic correction coefficient for every transport interval may be calculated from the correction coefficients for a plurality of measurement points instead of every transport interval.

  Next, the operation in the learning mode and the operation mode of the weighing device 1 according to the present embodiment will be described.

[Operation in learning mode]
The operation when the operation mode is the learning mode will be described with reference to FIG. 5 and the flowchart of FIG. FIG. 5 shows only the configuration requirements used in the learning mode from the configuration diagram of FIG.

  As shown in FIG. 6, first, the operation mode is set to the learning mode by the user (step S11), the master work mass is inputted by the operation input of the setting means 11 (step S12), and the master work is transferred to the belt conveyor 14 or It is placed on the run-up conveyor 31 and conveyed and weighed on the weighing conveyor 32 (step S13).

  Here, the master work used in step S13 is an article whose accurate mass has been determined by prior measurement, and is an object W for calculating a dynamic correction coefficient. In step S12, the mass of the master work that has been determined in advance is input.

  In step S14, the signal processing unit 71 performs signal processing with a plurality of low-pass filters, and the measurement value acquisition unit 111 captures (acquires) measurement values at a plurality of measurement points.

  In step S15, it is determined whether or not each measured value is within a predetermined allowable range. When this determination is “NO” (not within the allowable range), the process proceeds to step S16 to determine whether or not the condition is met. If the determination in step S16 is “YES” (a condition that satisfies the measurement), the master work is again flowed in step S13. If the determination is “NO” (the condition that does not satisfy the measurement), the process proceeds to step S19. Error handling. When the determination in step S16 is “YES” and the master work is run again in step S13, a message such as “Please run the master work again” is displayed on the display means. When the determination in step S15 is “YES” (within the allowable range), the process proceeds to step S17.

  In step S17, the dynamic correction coefficient calculation means 112 calculates the dynamic correction coefficient Ak (n) for each low-pass filter and each measurement point from the master work mass and each measurement value.

  In step S18, the dynamic correction coefficient storage unit 113 determines whether or not the coefficient A of the calculated dynamic correction coefficient is within the allowable range.

  When the determination in step S18 is “NO” (not within the allowable range), the process proceeds to step S19, and error processing is performed. When the determination is “YES” (within the allowable range), the process proceeds to step S20. The process proceeds to store each calculated dynamic correction coefficient.

  The dynamic correction coefficient stored in the dynamic correction coefficient storage unit 113 is a matrix value corresponding to each of a plurality of low-pass filters and a plurality of measurement points, as shown in FIG.

  When the dynamic correction coefficient is stored in step S20, the learning mode is exited in step S21, and these processes are terminated.

[Operation in operation mode]
The operation when the operation mode is the operation mode will be described with reference to FIGS. 7 and 9 and based on the flowchart of FIG. FIG. 7 shows only the configuration requirements used in the operation mode from the configuration diagram of FIG.

  As shown in FIG. 8, first, the object W to be transferred from the running conveyor 31 to the weighing conveyor 32 is detected by the carry-in detection sensor 4 (step S31).

  In step S32, a timer for the measurement delay time Ta is started, and it is determined whether or not the measurable time Ta has ended (step S33). If the determination in step S33 is "YES" (measurable time Ta has ended), a timer for measurable time Tb is started (step S34).

  Next, before the end of the measurement possible time Tb, it is determined whether or not the next object to be weighed W is detected by the carry-in detection sensor 4 (step S35), and this determination is “YES” (the next object to be weighed W). Is detected) (step S36), the process proceeds to step S38, and the determination in step S35 is "NO" (the next object to be weighed W is not detected). If so, the measurement of the measurable time Tb is ended (step S37), and the process proceeds to step S38.

  In step S38, the filter selection unit 101 selects a low-pass filter corresponding to the measurable time Tb. In step S39, the measurement point selection unit 102 selects the end time of the measurable time Tb as the measurement point.

  In step S40, the weight converted value at the measurement point selected in step S39 and the low-pass filter selected in step S38 is output.

  In step S41, the dynamic correction coefficient at the measurement point selected in step S39 and the low-pass filter selected in step S38 is read from the dynamic correction coefficient storage unit 113.

  In step S42, a measured value is calculated from the weight converted value and the dynamic correction coefficient read in step S41. In step S43, the measurement value calculated in step S42 is output.

  On the other hand, after the object to be weighed W is detected in step S31, it is determined whether or not the two-passage monitoring time Tc timer has already been activated (step S44). That is, it is determined whether or not the next object to be weighed W that has been detected during the two-passenger monitoring time Tc is detected. If this determination is “YES”, a two-passenger determination is output (step S45). ). “Two-piece” is a state in which two objects to be weighed W are simultaneously on the weighing conveyor 32 because the conveyance interval of the objects to be weighed back and forth in the conveying direction is short.

  When the determination in step S45 is “NO” (not two-seater), the timer for the two-seater monitoring time Tc is started (step S46) and the two-seater is monitored (step S47).

  As described above, in the weighing apparatus 1 according to the present embodiment, the weighing unit 72 includes the dynamic correction coefficient storage unit 113 that stores in advance a plurality of dynamic correction coefficients set for each measurement point and signal processing condition, and the dynamic correction coefficient storage unit 113. Dynamic correction means 103 that corrects the weighing signal using a correction coefficient, and the control means 74 has the conveyance direction length and conveyance interval determined by the conveyance status determination means 104 to the dynamic correction means 103, and a signal. A dynamic correction coefficient corresponding to the signal processing conditions used by the processing means 71 is read from the dynamic correction coefficient storage means 113, and control is performed so as to correct the weighing signal using the read dynamic correction coefficient.

  With this configuration, the dynamic correction coefficient according to the conveyance direction length and the conveyance interval determined by the conveyance condition determination unit 104 and the signal processing condition used by the signal processing unit 71 is dynamic correction coefficient storage unit. 113, and the weighing signal is corrected using the read dynamic correction coefficient. Therefore, by correcting the deviation during dynamic weighing according to the conveyance interval and the length in the conveyance direction of the object W, Weighing error can be reduced.

  Further, in the weighing device 1 according to the present embodiment, the weighing unit 72 calculates the dynamic correction coefficient that calculates the dynamic correction coefficient according to the measurement point and the signal processing condition while changing both the measurement point and the signal processing condition. And a dynamic correction coefficient storage unit 113 that stores a plurality of dynamic correction coefficients calculated by the dynamic correction coefficient calculation unit 112 in advance.

  With this configuration, the dynamic correction unit 103 calculates the dynamic correction coefficient calculation unit 112 according to the conveyance direction length and conveyance interval determined by the conveyance state determination unit 104 and the signal processing conditions used by the signal processing unit 71. The dynamic correction coefficient is read from the dynamic correction coefficient storage means 113, and the weighing signal is corrected using the read dynamic correction coefficient. Therefore, the dynamic correction coefficient is dynamically changed according to the conveyance interval and the conveyance direction length of the object W. The measurement error can be reduced by correcting the bias at the time of measurement.

  In addition, the weighing device 1 according to the present embodiment has an operation mode between an operation mode for determining pass / fail of the object to be weighed W and a learning mode for storing a plurality of dynamic correction coefficients in the dynamic correction coefficient storage unit 113. The mode switching means 77 is provided for switching the operation direction to the dynamic correction means 103 when the operation mode is switched to the operation mode by the mode switching means 77. The dynamic correction coefficient corresponding to the length and the conveyance interval and the signal processing condition used by the signal processing means 71 is read out from the dynamic correction coefficient storage means 113 and controlled so as to correct the weighing signal using the read dynamic correction coefficient. When the operation mode is switched to the learning mode by the mode switching means 77 The dynamic correction coefficient calculation unit 112 is controlled to calculate a dynamic correction coefficient corresponding to the measurement point and the signal processing condition while changing both the measurement point and the signal processing condition, and the dynamic correction coefficient storage unit 113. On the other hand, control is performed to store a plurality of dynamic correction coefficients calculated by the dynamic correction coefficient calculation means 112.

  With this configuration, in the operation mode, the control unit 74 determines the conveyance direction length and the conveyance interval determined by the conveyance state determination unit 104 and the signal processing conditions used by the signal processing unit 71 with respect to the dynamic correction unit 103. The corresponding dynamic correction coefficient is read out from the dynamic correction coefficient storage means 113, and the weighing signal is controlled to be corrected using the read dynamic correction coefficient. In the learning mode, the measurement point and the dynamic correction coefficient calculation means 112 are controlled. While changing both of the signal processing conditions, control is performed to calculate a dynamic correction coefficient corresponding to the measurement point and the signal processing condition, and the dynamic correction coefficient storage unit 113 calculates the dynamic correction coefficient by the dynamic correction coefficient calculation unit 112. Memorize multiple dynamic correction factors Because so that control, the dynamic correction factor for each individual metering device 1 calculates, by storing and use, it is possible to reduce the weighing error based on individual differences of the metering device 1.

  Further, in the weighing apparatus 1 according to the present embodiment, the signal processing unit 71 includes a plurality of low-pass filters LPF1, LPF2, and LPFn, and the conveyance status determination unit 104 among the plurality of low-pass filters LPF1, LPF2, and LPFn. Signal processing is performed by a low-pass filter selected as a signal processing condition based on the determined conveyance direction length and conveyance interval.

  With this configuration, the dynamic correction unit 103 dynamically corrects the dynamic correction coefficient according to the conveyance direction length and the conveyance interval determined by the conveyance state determination unit 104 and the low-pass filter used as the signal processing condition by the signal processing unit 71. Since the weighing signal is read from the coefficient storage means 113 and the weighing signal is corrected using the read dynamic correction coefficient, the bias at the time of dynamic weighing is corrected according to the conveyance interval and the conveyance direction length of the object W. Thus, the measurement error can be reduced.

  As described above, the weighing device according to the present invention has an effect that the measurement error can be reduced by correcting the bias at the time of dynamic weighing according to the conveyance interval and the conveyance direction length of the object to be weighed. In addition, it is useful as a weighing device that measures the quality of objects to be weighed such as meat, fish, processed foods, and pharmaceuticals.

DESCRIPTION OF SYMBOLS 1 Weighing device 3 Conveying part 4 Carry-in detection sensor 5 Sorting part 7 General control part 10 Display means 11 Setting means 14 Belt conveyor 21 Weighing means 31 Advancing conveyor 32 Weighing conveyor (conveying means)
Reference Signs List 71 Signal processing means 72 Measuring means 73 Storage means 74 Control means 76 Pass / fail judgment means 77 Mode switching means 101 Filter selection means 102 Measurement point selection means 103 Dynamic correction means 104 Transport status judgment means 111 Measurement value acquisition means 112 Dynamic correction coefficient calculation means 113 dynamic correction coefficient storage means LPF1 first low-pass filter LPF2 second low-pass filter LPFn n-th low-pass filter W object to be weighed

Claims (4)

Transport means (32) for transporting the objects to be weighed (W) sequentially carried in accordance with predetermined transport conditions;
Weighing means (21) for supporting the conveying means and outputting a weighing signal based on the load of the object to be weighed being conveyed by the conveying means;
A conveyance status determination means for detecting the carry-in of the object to be weighed into the conveyance means, and for determining a conveyance direction length of the object to be weighed, a conveyance interval between the object to be weighed and a subsequent object to be weighed,
Signal processing means (71) for receiving the weighing signal and outputting a measurement signal obtained by subjecting the weighing signal to signal processing based on a predetermined signal processing condition;
Based on the measured value of the measurement signal at a measurement point and a dynamic correction coefficient for correction at a measurement point after a predetermined time has elapsed since the conveyance status determination unit detected the conveyance of the object to be conveyed to the conveyance unit. Weighing means (72) for calculating a weighing value of the object;
Pass / fail judgment means (76) for comparing the measured value calculated by the weighing means and the pass / fail judgment criteria to judge pass / fail of the object to be weighed;
Control means (74) for controlling the weighing means,
The weighing means stores dynamic correction coefficient storage means (113) for storing in advance a plurality of dynamic correction coefficients set for each of the measurement points and the signal processing conditions, and dynamic for correcting the weighing signal using the dynamic correction coefficients. Correction means (103),
The control means assigns a dynamic correction coefficient to the dynamic correction means in accordance with the conveyance direction length and conveyance interval determined by the conveyance status determination means and the signal processing conditions used by the signal processing means. A weighing apparatus that reads out from the correction coefficient storage means and performs control to correct the weighing signal using the read dynamic correction coefficient. The weighing means includes dynamic correction coefficient calculation means (112) for calculating a dynamic correction coefficient according to the measurement point and the signal processing condition while changing both the measurement point and the signal processing condition,
The weighing apparatus according to claim 1, wherein the dynamic correction coefficient storage unit stores in advance a plurality of dynamic correction coefficients calculated by the dynamic correction coefficient calculation unit. A mode switching means (77) for switching an operation mode between an operation mode for determining pass / fail of the object to be measured and a learning mode for storing the plurality of dynamic correction coefficients in the dynamic correction coefficient storage means;
The control means includes
When the operation mode is switched to the operation mode by the mode switching unit, the conveyance direction length and the conveyance interval determined by the conveyance state determination unit and the signal used by the signal processing unit to the dynamic correction unit. A dynamic correction coefficient corresponding to the processing conditions is read from the dynamic correction coefficient storage means, and the weighing signal is controlled to be corrected using the read dynamic correction coefficient.
When the operation mode is switched to the learning mode by the mode switching unit, the measurement point and the signal processing are changed while changing both the measurement point and the signal processing condition with respect to the dynamic correction coefficient calculation unit. Control is performed to calculate a dynamic correction coefficient according to conditions, and control is performed to store a plurality of dynamic correction coefficients calculated by the dynamic correction coefficient calculation unit in the dynamic correction coefficient storage unit. The weighing device according to claim 2.   The signal processing means has a plurality of low-pass filters (LPF1, LPF2, LPFn), and a signal processing condition based on a conveyance direction length and a conveyance interval determined by the conveyance condition determination means from the plurality of low-pass filters. 4. The weighing device according to claim 1, wherein signal processing is performed by a low-pass filter selected as.

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