JP2012208082A - Measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring device capable of maintaining exact measurement by determining that it becomes an abnormal state that the exact measurement cannot be performed such as block of a vent hole, etc.SOLUTION: A measuring device includes: a belt conveyor 14 which conveys objects W to be measured to be sequentially thrown on a weighing conveyor 32 under a predetermined conveyance condition; weighing means 21 for outputting a weighing signal according to load weight of the objects W to be measured to be conveyed on the weighing conveyor 32; abnormal weighing signal storage means 101 for storing a weighing signal which can be output from the weighing means 21 when the weighing means 21 is at an abnormal state as an abnormal weighing signal; and abnormality diagnosis means 102 for comparing the weighing signal output from the weighing means 21 with the abnormal weighing signal which is stored by the abnormal weighing signal storage means 101 to determine that the weighing signal is abnormal when the weighing signal and the abnormal weighing signal have a common feature.

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 has a waterproof structure in which a hole is provided in a part of the housing of the scale main body and a weight-sensitive part from the weighing platform protrudes upward from this hole. In addition to sealing the gap with a stretchable body, and providing a vent hole for circulating air to eliminate the pressure difference between the outside air due to the expansion and contraction of the stretchable body and the inside air of the chassis in a portion other than the hole of the chassis, A technique is known in which pressure in the casing is released through a vent (see, for example, Patent Document 1).

  Further, as this type of measuring device, a cylindrical member having one end opened to the outside of the bottom of the casing of the scale main body and the other end opened to the upper portion of the casing is provided. A technique is known in which water splash reaching the upper part of the casing from the bottom opening of the casing of the scale body is reduced by releasing the pressure so as to improve waterproofness (for example, see Patent Document 2). ).

JP-A-3-285125 Japanese Patent Laid-Open No. 11-258032

  However, in the conventional weighing device, there is a risk that water will be put on the vent hole due to surface tension after washing the balance, etc., and the balance may be sealed. In this case, there is a problem that accurate weighing cannot be performed. there were.

  Therefore, the present invention has been made to solve the above-described conventional problems, and by determining that an abnormal state where accurate measurement cannot be performed, such as blocking of a vent hole, has occurred. An object of the present invention is to provide a weighing device capable of maintaining accurate weighing.

  The weighing device according to the present invention has a conveying means for conveying the objects to be weighed sequentially on the weighing table under a predetermined conveying condition, and a weighing signal corresponding to the load of the objects to be weighed conveyed on the weighing table. A weighing means for outputting; an abnormal weighing signal storage means for storing a weighing signal that can be outputted from the weighing means when the weighing means is in an abnormal state as an abnormal weighing signal; a weighing signal output from the weighing means; An abnormality diagnosing means for comparing the abnormal weighing signal stored in the abnormal weighing signal storage means and determining that the weighing signal is abnormal when the weighing signal and the abnormal weighing signal have a common feature; It is characterized by having.

  With this configuration, when the weighing signal having the same characteristics as the abnormal weighing signal stored in the abnormal weighing signal storage means is output from the weighing means, the abnormality diagnosis means determines that the weighing signal is abnormal. It is possible to maintain accurate weighing by determining that

  Therefore, it is possible to maintain accurate measurement by determining that an abnormal state in which accurate measurement cannot be performed, such as blocking of a vent hole, has occurred.

  The weighing device according to the present invention includes a pseudo input signal generating unit that generates a pseudo input signal, and an abnormal transfer function storage that stores in advance, as an abnormal transfer function, a transfer function of the weighing unit when the weighing unit is in an abnormal state. And an abnormal weighing signal generating means for generating an abnormal weighing signal by inputting the pseudo input signal generated by the pseudo input signal generating means to the abnormal transfer function stored in the abnormal transfer function storage means, The abnormal weighing signal storage means stores the abnormal weighing signal generated by the abnormal weighing signal generation means.

  With this configuration, the abnormal weighing signal stored in the abnormal weighing signal storage means is generated by inputting the pseudo input signal generated by the pseudo input signal generating means to the abnormal transfer function stored in the abnormal transfer function storage means. Therefore, by handling the characteristics of the abnormal weighing signal as a transfer function, an abnormality diagnosis corresponding to various abnormal states of the weighing means can be performed.

  The weighing device according to the present invention is characterized in that the casing of the weighing means has an elastic member that seals a gap between the weighing table and an air to eliminate a pressure difference between the inside and outside of the casing due to expansion and contraction of the elastic member. And the abnormal state is a state in which the vent hole is closed.

  With this configuration, it is possible to determine that an abnormal state where accurate measurement cannot be performed due to the blockage of the vent hole is made, and accurate measurement can be maintained.

  Further, the weighing device according to the present invention is characterized in that the abnormality diagnosis unit diagnoses that the weighing signal is abnormal when a waveform shape or a natural frequency of the weighing signal and the abnormal weighing signal are approximated. And

  With this configuration, when the weighing signal whose waveform shape or natural frequency approximates the abnormal weighing signal is output from the weighing means, the abnormality diagnosing means determines that the weighing signal is abnormal. Therefore, accurate weighing can be maintained.

  The weighing device according to the present invention further includes a loading detection unit that detects loading of the object to be weighed into the weighing table, and the loading detection unit detects loading of the object to be weighed into the weighing table. In addition, the pseudo input signal generating unit generates a pseudo input signal, and the abnormality diagnosis unit compares the weighing signal output from the weighing unit with the abnormal weighing signal stored in the abnormal weighing signal storage unit. It is characterized by that.

  With this configuration, the generation of the pseudo input signal, the generation and storage of the abnormal weighing signal, and the comparison of the weighing signal are performed in accordance with the timing at which the loading detection means detects the loading of the object to be measured and the weighing signal is output from the weighing means. Since it is performed, the timings of the weighing signal and the abnormal weighing signal compared by the abnormality diagnosis means can be matched.

  The present invention can provide a weighing device capable of maintaining accurate weighing by determining that an abnormal state in which accurate weighing cannot be performed, such as blocking of a vent hole, has occurred.

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 side view which shows the conveyance part of the weighing | measuring device which concerns on one embodiment of this invention. (A)-(c) is a figure which shows the specific example of the weighing means of the measuring apparatus which concerns on one embodiment of this invention. (A) is a figure which shows the structure which approximates a load cell balance with a secondary delay system transfer function, (b) is an approximation of the transfer function of an electromagnetic balance type balance with a feedback system such as a secondary delay system and PID control. It is a figure which shows the structure to do. It is a timing chart which shows each signal of the measuring device concerning one embodiment of the present invention, (a) shows a carrying-in detection signal, (b) shows a pseudo input signal, and (c) is at the time of abnormality. (D) shows the actually measured weighing signal.

  Hereinafter, embodiments of a weighing device according to the present invention will be described with reference to the drawings.

  1 to 4 show an embodiment of a weighing device according to the present invention. As shown in FIGS. 1 to 4, the weighing device 1 includes a device main body 2, a transport unit 3, and a carry-in 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 obtained measurement value is output as a measurement result. Furthermore, it compares with the reference value of the upper limit and the lower limit of the preset weight, respectively, determines whether or not the obtained measurement value is within the range of the reference value, makes the one in the range a non-defective product, and out of the range It may be determined whether the product is defective or not, or the weight rank is 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 output from the weighing device 1, the pass / fail determination result, and the weight rank determination result.

  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 weighing conveyor 32 can be replaced with a different type of conveyor by a user at the operation site or an operator in the assembly process at the time of manufacture.

  The carry-in 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 part 4a and the light receiving part 4b, the light receiving part 4b is shielded by the object to be weighed, so that it is detected that the carry-in of the object to be weighed W is started. It has become. The carry-in detection signal output from the carry-in sensor 4 is input to the general control unit 7 in the apparatus main body 2.

  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 weighing object W. While the weighing object W is being conveyed by the weighing conveyor 32, The applied load is measured.

  The weighing means 21 is an electromagnetic balance type balance (force balance) shown in FIG. 4 (a), an electric resistance wire type balance (load cell) shown in FIG. 4 (b), or a differential transformer type shown in FIG. 4 (c). It is configured as one of the scales.

  Here, when the weighing means 21 is configured as an electromagnetic balance-type balance as shown in FIG. 4A, the weighing means 21 includes a load due to the mass of the object W on the weighing conveyor 32, a magnet and an electromagnetic wave. The force generated by the current flowing through the coil is balanced, and the value of the current flowing through the electromagnetic coil at this time is measured as the mass of the workpiece W. In this electromagnetic balance type balance (force balance), the transfer function of the balance can be approximated by a secondary delay system and a feedback system such as PID control as shown in FIG.

Further, when the weighing means 21 is configured as an electric resistance wire type scale as shown in FIG. 4B, the weighing means 21 is a load cell generated by a load due to the mass of the object W to be weighed on the weighing conveyor 32. By measuring the strain as a change in the resistance value of the electric resistance wire attached to the load cell, the mass of the object W is measured. In this electric resistance wire type balance (load cell), the transfer function of the balance can be approximated by a second order lag transfer function as shown in FIG. In FIG. 5 (a), when the balance is in a sealed state, the measured value fluctuates due to the internal pressure of the balance, but in the no-load state, whether the cause of the fluctuation in the measured value is the influence of the water after washing. It is difficult to identify the cause, such as whether the object is touching or due to the influence of electrical noise. On the other hand, when a large load is applied to the balance as in measurement, the natural vibration of the balance can be confirmed on the waveform. It is possible to specify the cause of the fluctuation of the measured value. Since the state where the balance is sealed with water can be approximated to a system in which the balance has an air damper, the balance in the sealed state can be expressed as a damping coefficient ζ = ζb, and the transfer function of the balance is ω ² / ( s2 + 2ζbω _n s + ω ² ).

  In addition, when the weighing means 21 is configured as a differential transformer type scale as shown in FIG. 4C, the weighing means 21 detects the displacement generated by the load due to the mass of the object W to be weighed on the weighing conveyor 32. The mass of the object to be weighed W is measured by converting it into an electric signal with an operating transformer.

  On the upper surface of the casing 124 of the weighing means 21, a support 120 that receives the load of the weighing conveyor 32 and the object to be weighed W penetrates, and a gap between the support 120 and the casing 124 is sealed in this support 120. A bellows-shaped elastic member 121 is provided to prevent liquid such as water from entering the inside of the casing 124. The elastic member 121 expands and contracts as the support column 120 is displaced in the vertical direction. By following the displacement of the support column 120, the gap between the support column 120 and the housing 124 is always sealed.

  At the bottom of the casing 124 of the weighing means 21, a vent hole 122 that penetrates the casing 124 is provided in order to eliminate the pressure difference between the inside and the outside of the casing 124 caused by the displacement of the column 120 and the expansion and contraction of the elastic member 121. .

  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 receives the weighing signal from the weighing means 21 and performs signal processing based on predetermined signal processing conditions to output a signal-processed weighing signal. The signal processing means 71 converts an analog signal into a digital signal. A / D converter is provided. Specifically, the signal processing means 71 has signal-processed only the low-frequency component of the weighing signal using a filter selected from a plurality of low-pass filters of different types and characteristics with respect to the weighing signal from the weighing means 21. It passes through as a weighing signal. The signal processing means 71 may select one low-pass filter or a combination of a plurality of low-pass filters. As this low-pass filter, there are a 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.

  Here, the FIR filter constitutes a low-pass filter that passes a predetermined low-frequency component for the weighing signal converted into a digital signal by the A / D converter, and uses a simple averaging process or a known window function. Weighted averaging processing is performed. The IIR filter is an analog filter that directly receives a weighing signal (analog weighing signal) from the weighing means 21 and outputs a processed signal to the A / D converter using hardware whose characteristics can be changed, such as a switched capacitor filter. Or a digital filter that receives a digital weighing signal (not shown) from the A / D converter.

  The weighing means 72 calculates (measured in grams) the measured value of the object W based on the signal-processed weighing signal output from the signal processing means 71. Further, in the weighing means 72, a predetermined reference time Tk has elapsed after the carry-in sensor 4 detects that the object to be weighed W has been carried into the weighing conveyor 32, and the weighing signal from which the weighing signal has been output from the weighing means 21. A measurement value is calculated for the object W. Individual weights calculated by the weighing means 72 are stored in the storage means 73 as calculation data.

The weighing unit 72 performs weighing when a preset reference time Tk has elapsed after the carry-in sensor 4 detects that the workpiece W has been carried into the weighing conveyor 32. Here, the reference time Tk is detected by the loading sensor 4 that the object to be weighed W has started to be loaded onto the weighing conveyor 32, and then the weighing object W is completely transferred to the weighing conveyor 32, and further from the weighing means 21. This means the time required for the output weighing signal to stabilize. Specifically, the reference time Tk is the speed of the weighing conveyor 32 (m / min), the length of the weighing conveyor 32 in the direction of arrow B (mm), and the length of the weighing object W in the direction of arrow B, which is the conveyance direction. (Mm), the size of the workpiece W, the processing capacity of the line, and other conditions. Further, as shown in FIG. 3, the reference time Tk has elapsed, the objects to be weighed W is moved by L ₁ reaches the mass measuring position P _S from the loading start detection position P _O, metering is performed.

  In the weighing means 72, inspection conditions (parameters) such as the measurement range, measurement capability, and inspection accuracy are selected according to the type (particularly size) of the object to be weighed W. Depending on the type of the weighing object W, for example, the measurement range is selected from 6 g to 600 g, and the measurement capability is selected at a maximum of 150 pieces / min. In this case, the reference time Tk per object W is set to a minimum of 400 msec, and the reference time Tk may be 400 msec or more. It is set according to capacity, production and other conditions. Since the reference time Tk is measured in a shorter time as it is closer to 400 msec, the inspection efficiency is increased, and as the distance is longer, the inspection time is longer, but the weighing accuracy is increased because it is stably conveyed on the weighing conveyor 32. Become.

  Further, according to the type of the object to be weighed W, for example, the measurement range is selected from 1 g to 300 g, and the measurement capability is selected at a maximum of 600 pieces / min. If the measurement capacity is 600 pieces / min at the maximum, the measurement time per piece of the object to be weighed W is set to a minimum of 100 msec, and the size of the object to be weighed W, the processing capacity of the line, production, etc. It is set according to the conditions. Since the reference time Tk is measured in a shorter time as it is closer to 100 msec, the inspection efficiency is increased. As the distance is longer, the inspection time is longer, but the weighing accuracy is increased because the weighing conveyor 32 is stably conveyed. In this way, in the weighing means 72, the inspection conditions (parameters) such as the range and capability are selected according to the type of the object to be weighed W.

  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. Further, the control means 74 controls the operation of an abnormal weighing signal storage means 101, an abnormality diagnosis means 102, a pseudo input signal generation means 103, an abnormal transfer function storage means 104, and an abnormal weighing signal generation means 105, which will be described later. Yes.

  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, the quality determination unit 76, when receiving the weight signal of the object W output from the weighing unit 72, reads the upper limit value Ga and the lower limit value Gb of the weight stored in advance in the storage unit 73, 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 whether the weight of the object to be weighed W is within the allowable range determined by the upper limit value Ga and the lower limit value Gb. It is to judge whether.

  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 setting mode. Here, the operation mode is a normal operation mode in which the weighing apparatus 1 performs weighing, weight calculation, and pass / fail judgment of the object to be weighed. The setting mode refers to various parameters for operation in the operation mode. This is an operation mode for confirming whether or not the automatic setting or manual setting can be performed or whether the operation in the operation mode can be normally performed. The mode switching unit 77 switches the operation mode to the setting mode according to an input operation from the setting unit 11 or switches the operation mode to the setting mode at the start of operation of the apparatus.

  The overall control unit 7 includes an abnormal weighing signal storage unit 101, an abnormality diagnosis unit 102, a pseudo input signal generation unit 103, an abnormal transfer function storage unit 104, and an abnormal weighing signal generation unit 105.

  The abnormal weighing signal storage means 101 stores a weighing signal that can be output from the weighing means 21 when the weighing means 21 is in an abnormal state as an abnormal weighing signal shown in FIG. The abnormal state of the weighing means 21 is, for example, a state in which the ventilation hole 122 at the bottom of the casing 124 of the weighing means 21 is blocked by water adhering to the surface tension when the weighing device 1 is cleaned, and the casing 124 is sealed. is there.

  The weighing signal output from the weighing means 21 is a waveform having the form shown on the left side (first waveform) in FIG. 6D when the weighing means 21 is in a normal state. In the state, for example, the waveform shown in the right side (second waveform) in FIG.

  Specifically, the normal weighing signal shown on the left side of FIG. 6D is a period from when the workpiece W is carried in until the carry-in detection signal in FIG. 6A is output until it is carried out. The signal has overshoot converged to a constant value immediately after a predetermined time.

  On the other hand, the weighing signal at the time of abnormality shown on the right side of FIG. 6D is a constant value between the time when the workpiece W is carried in and the carry-in detection signal shown in FIG. It is a wobbling signal that does not converge.

  The abnormality diagnosis unit 102 compares the weighing signal output from the weighing unit 21 with the abnormal weighing signal stored in the abnormal weighing signal storage unit 101, and the weighing signal and the abnormal weighing signal have common characteristics (for example, When the waveform shapes match, the weighing signal is determined to be abnormal. For example, when the waveform of the actually measured weighing signal shown on the right side of FIG. 6D matches the waveform of the abnormal weighing signal on the right side of FIG. 6C, the abnormality diagnosing means 102 has an abnormal weighing signal. When the waveform of the actually measured weighing signal shown on the left side of FIG. 6 (d) does not match the waveform of the abnormal weighing signal on the left side of FIG. 6 (c), the abnormality diagnosis means 102 indicates that the weighing signal is normal. It is determined that

  The diagnosis result by the abnormality diagnosis unit 102 is displayed on the display unit 10 and notified to the user. Here, the case where the weighing signal and the abnormal weighing signal have common characteristics is, for example, the case where the waveform shape or the natural frequency of the weighing signal and the abnormal weighing signal are approximated.

  The abnormality diagnosing means 102 includes a weighing signal output from the weighing means 21 and an abnormal weighing signal stored in the abnormal weighing signal storage means 101 when the carry-in sensor 4 detects the loading of the workpiece W into the weighing conveyor 32. To compare.

  That is, the abnormality diagnosing means 102 reads the abnormal weighing signal from the abnormal weighing signal storage means 101 in accordance with the timing when the loading sensor 4 detects the loading of the object W and the weighing signal is output from the weighing means 21. The weighing signal is compared with the abnormal weighing signal.

  As a result, the weighing signal and the abnormal weighing signal compared by the abnormality diagnosis unit 102 have the same timing, that is, the position in the horizontal axis direction in the waveform graph.

  As the abnormal weighing signal, the operation mode of the weighing device 1 is switched to the setting mode, and water is intentionally attached to the ventilation holes 122 of the casing 124 of the weighing means 21 to close the casing 124 so that the casing 124 is sealed. The abnormal weighing signal acquired and stored in the abnormal weighing signal storage means 101 is used. Alternatively, a weighing signal generated by the pseudo input signal generation unit 103, the abnormal transfer function storage unit 104, and the abnormal weighing signal generation unit 105 described below and temporarily stored in the abnormal weighing signal storage unit 101 may be used.

  The pseudo input signal generation means 103 generates a pseudo input signal, and this pseudo input signal is a signal having a waveform shown in FIG. 6B, and is carried out after the workpiece W is carried in. The signal input to the weighing means 21 is generated from the carry-in detection signal and the belt speed.

  The abnormal transfer function storage means 104 stores in advance the transfer function of the weighing means 21 when the weighing means 21 is in an abnormal state as an abnormal transfer function. Here, when water is attached to the vent hole 122 of the casing 124 of the weighing means 21 and the vent hole 122 is closed, and the weighing means 21 becomes abnormal, the abnormal transfer function in this case is normal. A damping component (air damper component) due to the air hole 122 being blocked is added to the transfer function of the weighing means 21 in the state.

  The abnormal weighing signal generation means 105 inputs the pseudo input signal generated by the pseudo input signal generation means 103 to the abnormal transfer function stored in the abnormal transfer function storage means 104 and generates the abnormal weighing signal shown in FIG. It is supposed to be. The abnormal weighing signal generated by the abnormal weighing signal generation unit 105 is stored in the abnormal weighing signal storage unit 101.

  The pseudo input signal generation unit 103 generates a pseudo input signal at the timing when the carry-in sensor 4 detects the carry-in of the workpiece W to the weighing conveyor 32 and outputs the carry-in detection signal in FIG. It has become. That is, in accordance with the timing when the carry-in sensor 4 detects the carry-in of the workpiece W and the weighing signal is output from the weighing means 21, the pseudo input signal is generated, the abnormal weighing signal is generated and stored, and the weighing signal is compared. Done. As a result, the weighing signal and the abnormal weighing signal compared by the abnormality diagnosing means 102 have the same timing, that is, the position in the horizontal axis direction in the waveform graph as shown in the relationship between FIG. 6D and FIG. 6C. Will be.

  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.

  An operation (operation 1) of the weighing device 1 according to the present embodiment will be described.

  The operation when a pseudo input signal is input to the abnormal transfer function to generate an abnormal weighing signal will be described.

  First, when the objects W to be weighed sequentially are conveyed by the belt conveyor 14 and are carried into the weighing conveyor 32, the carry-in sensor 4 detects the carry-in of the objects W to be weighed.

  Next, in accordance with the carry-in detection signal from the carry-in sensor 4, the pseudo input signal generating unit 103 generates a pseudo input signal, and the abnormal weighing signal generating unit 105 converts the abnormal transfer function stored in the abnormal transfer function storage unit 104 into the abnormal transfer function. A pseudo input signal is input to generate an abnormal weighing signal and stored in the abnormal weighing signal storage means 11.

  Next, the weighing means 21 outputs a weighing signal corresponding to the load of the workpiece W conveyed on the weighing conveyor 32.

  Next, the abnormality diagnosing means 102 reads the abnormal weighing signal stored in the abnormal weighing signal storage means 101, matches the timing of the weighing signal output from the weighing means 21 with the detection signal from the carry-in sensor 4, and the abnormal weighing signal and Compare with the weighing signal. The abnormality diagnosis unit 102 determines that the weighing signal is abnormal when the weighing signal has characteristics common to the abnormal weighing signal, for example, when the waveform shape or the natural frequency approximates.

  Next, an operation when the abnormal weighing signal is stored in advance in the abnormal weighing signal storage means 11 (operation 2) will be described.

  First, when the objects W to be weighed sequentially are conveyed by the belt conveyor 14 and are carried into the weighing conveyor 32, the carry-in sensor 4 detects the carry-in of the objects W to be weighed.

  Next, the weighing means 21 outputs a weighing signal corresponding to the load of the workpiece W conveyed on the weighing conveyor 32.

  Next, the abnormality diagnosing means 102 reads the abnormal weighing signal stored in the abnormal weighing signal storage means 101, matches the timing of the weighing signal output from the weighing means 21 with the detection signal from the carry-in sensor 4, and the abnormal weighing signal and Compare with the weighing signal. The abnormality diagnosis unit 102 determines that the weighing signal is abnormal when the weighing signal has characteristics common to the abnormal weighing signal, for example, when the waveform shape or the natural frequency approximates.

  Note that the time from when the carry-in detection signal is output from the carry-in sensor 4 until the abnormal weighing signal is generated is extremely short, and the operation when the abnormal weighing signal storage means 11 stores the abnormal weighing signal in advance. In contrast to (Operation 2), when an abnormal weighing signal is generated by inputting a pseudo input signal to the abnormal transfer function (Operation 1), the comparison between the weighing signal and the abnormal weighing signal is performed in the abnormality diagnosis means 102. There will be no deviation in timing.

  As described above, the weighing device 1 according to the present embodiment is conveyed on the weighing conveyor 32 and the belt conveyor 14 that conveys the objects W to be sequentially loaded on the weighing conveyor 32 under predetermined conveying conditions. Weighing means 21 for outputting a weighing signal corresponding to the load of the weighing object W, and an abnormal weighing signal storage means for storing a weighing signal that can be output from the weighing means 21 when the weighing means 21 is in an abnormal state as an abnormal weighing signal. 101, the weighing signal output from the weighing means 21 and the abnormal weighing signal stored in the abnormal weighing signal storage means 101 are compared, and when the weighing signal and the abnormal weighing signal have common characteristics, the weighing signal is And an abnormality diagnosis means 102 for determining that there is an abnormality.

  With this configuration, when the weighing signal having characteristics common to the abnormal weighing signal stored in the abnormal weighing signal storage means 101 is output from the weighing means 21, the abnormality diagnosis means 102 determines that the weighing signal is abnormal. By determining that an abnormal state has occurred, accurate weighing can be maintained.

  Therefore, it is possible to maintain accurate measurement by determining that an abnormal state in which accurate measurement cannot be performed, such as obstruction of the vent hole 122, has occurred.

  Further, the weighing apparatus 1 according to the present embodiment stores in advance, as an abnormal transfer function, a pseudo input signal generating unit 103 that generates a pseudo input signal and a transfer function of the weighing unit 21 when the weighing unit 21 is in an abnormal state. An abnormal transfer function storage means 104 and an abnormal weighing signal generation means for generating an abnormal weighing signal by inputting the pseudo input signal generated by the pseudo input signal generating means 103 to the abnormal transfer function stored in the abnormal transfer function storage means 104 105, and the abnormal weighing signal storage means 101 stores the abnormal weighing signal generated by the abnormal weighing signal generation means 105.

  With this configuration, the abnormal weighing signal stored in the abnormal weighing signal storage unit 101 is generated by inputting the pseudo input signal generated by the pseudo input signal generation unit 103 to the abnormal transfer function stored in the abnormal transfer function storage unit 104. Therefore, the abnormality diagnosis corresponding to various abnormal states of the weighing means can be performed by handling the characteristic of the abnormal weighing signal as a transfer function.

  Further, in the weighing device 1 according to the present embodiment, the housing 124 of the weighing means 21 has an elastic member 121 that seals a gap between the weighing conveyor 32 and the pressure difference between the inside and outside of the housing 124 due to the expansion and contraction of the elastic member 121. In order to eliminate the problem, the air hole 122 for circulating air is provided, and the abnormal state is a state where the air hole 122 is closed.

  With this configuration, it is possible to determine that an abnormal state where accurate measurement cannot be performed due to the blockage of the vent hole 122 is made, and accurate measurement can be maintained.

  In addition, the weighing apparatus 1 according to the present embodiment is characterized in that the abnormality diagnosis unit 102 diagnoses that the weighing signal is abnormal when the waveform shape or the natural frequency of the weighing signal and the abnormal weighing signal approximate. And

  With this configuration, when the weighing signal whose waveform shape or natural frequency approximates the abnormal weighing signal is output from the weighing means 21, the abnormality diagnosing means 102 determines that the weighing signal is abnormal. By measuring this, accurate weighing can be maintained.

  The weighing device 1 according to the present embodiment includes a carry-in sensor 4 that detects the carry-in of the object to be weighed W to the weighing conveyor 32, and the carry-in sensor 4 detects the carry-in of the object to be weighed W to the weighing conveyor 32. The pseudo input signal generation means 103 generates a pseudo input signal, and the abnormality diagnosis means 102 outputs the weighing signal output from the weighing means 21 and the abnormal weighing signal stored in the abnormal weighing signal storage means 11. It is characterized by comparing.

  With this configuration, in accordance with the timing when the carry-in sensor 4 detects the carry-in of the workpiece W and the weighing signal is output from the weighing means 21, the generation of the pseudo input signal, the generation and storage of the abnormal weighing signal, and the weighing signal Since the comparison is performed, the timings of the weighing signal and the abnormal weighing signal compared by the abnormality diagnosis unit 102 can be matched.

  As described above, the weighing device according to the present invention can maintain accurate weighing by determining that an abnormal state in which accurate weighing cannot be performed, such as the blockage of the vent hole 122, is made. It has the effect of being able to be made, and is useful as a measuring device for measuring 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 sensor (carry-in detection means)
DESCRIPTION OF SYMBOLS 5 Sorting part 7 General control part 10 Display means 11 Setting means 14 Belt conveyor 21 Weighing means 31 Run-up conveyor 32 Weighing conveyor (weighing stand)
71 Signal processing means 72 Weighing means 73 Storage means 74 Control means 76 Pass / fail judgment means 77 Mode switching means 101 Abnormal weighing signal storage means 102 Abnormality diagnosis means 103 Pseudo input signal generation means 104 Abnormal transfer function storage means 105 Abnormal weighing signal generation means 120 Prop 121 Elastic member 122 Vent hole 124 Housing W Object to be weighed

Claims (5)

Conveying means (14) for conveying the objects to be weighed (W) sequentially put on the weighing table (32) under predetermined conveying conditions;
Weighing means (21) for outputting a weighing signal according to the load of the object to be weighed conveyed on the weighing table;
An abnormal weighing signal storage means (101) for storing, as an abnormal weighing signal, a weighing signal that can be output from the weighing means when the weighing means is in an abnormal state;
When the weighing signal output from the weighing means and the abnormal weighing signal stored in the abnormal weighing signal storage means are compared, and the weighing signal and the abnormal weighing signal have common characteristics, the weighing signal is An abnormality diagnosis means (102) for determining an abnormality. Pseudo input signal generation means (103) for generating a pseudo input signal;
An abnormal transfer function storage means (104) for preliminarily storing a transfer function of the weighing means when the weighing means is in an abnormal state as an abnormal transfer function;
An abnormal weighing signal generating means (105) for generating an abnormal weighing signal by inputting the pseudo input signal generated by the pseudo input signal generating means to the abnormal transfer function stored in the abnormal transfer function storage means;
The weighing apparatus according to claim 1, wherein the abnormal weighing signal storage unit stores the abnormal weighing signal generated by the abnormal weighing signal generation unit. The casing (124) of the weighing means has an elastic member (121) that seals the gap between the weighing platform and a passage through which air is circulated to eliminate the pressure difference between the inside and outside of the casing due to expansion and contraction of the elastic member. A pore (122),
The weighing apparatus according to claim 1, wherein the abnormal state is a state where the vent hole is closed.   The abnormality diagnosis means diagnoses that the weighing signal is abnormal when a waveform shape or a natural frequency of the weighing signal and the abnormal weighing signal approximate to each other. A weighing device according to any one of the above. A loading detection means for detecting loading of the object to be weighed into the weighing platform;
When the carry-in detection means detects the carry-in of the object to be weighed into the weighing platform, the pseudo input signal generating means generates a pseudo input signal, and the abnormality diagnosis means is output from the weighing means. 5. The weighing apparatus according to claim 1, wherein the weighing signal is compared with an abnormal weighing signal stored in the abnormal weighing signal storage means.

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