JP5545748B2 - Conveyor scale - Google Patents

Description

  The present invention relates to a conveyor scale for obtaining a transport amount of a thin (rose-shaped) transported object continuously transported by a belt conveyor.

  Conventionally, for example, this type of conveyor scale is disclosed in Patent Document 1. According to this prior art, a pulse signal is output from the pulse generator each time the belt conveyor travels a unit length. In addition, the belt conveyor is provided with a load cell as a load detector so as to support the carrier side belt. The output of the load cell is accumulated every time a pulse signal is output from the pulse generator. Then, by dividing the accumulated value by a predetermined span value, the transport amount of the transported object is obtained. It should be noted that after the output of the load cell is divided by the span coefficient, the divided value may be accumulated to determine the transport amount of the transported object.

  Apart from this, there is also one disclosed in Patent Document 2, for example. That is, the conveyor scale disclosed in the above-mentioned Patent Document 1 is a so-called weight measurement method in which the weight of a transported object is measured using load detection means such as a load cell, and the transport amount is obtained based on the measured value. However, according to the conveyor scale disclosed in Patent Document 2, not a load detecting means but a non-contact type distance measuring means is used. Specifically, the distance measuring means is arranged above the carrier side belt of the belt conveyor. The distance measuring means is a distance from itself to the surface of the transported object (solid raw material) on the carrier side belt, specifically, a distance to a plurality of positions on the surface of the transported object in a direction crossing the traveling direction of the carrier side belt, Is measured without contact. Then, the coordinates of each position on the surface of the object to be transported are obtained based on the measurement values by the distance measuring means, and further, the loading shape of the object to be transported is determined based on the coordinate values. Then, based on the determined loading shape and the shape of the carrier side belt when in an unloaded state, the transport amount (transport volume) of the transported object is obtained.

JP 58-95220 A JP 2004-144463 A

  However, in the conveyor scale of the weight measurement method disclosed in Patent Document 1, a vibration load or an impact load is always applied to a load measuring means or a so-called weight measurement system such as a weighing roller accompanied therewith. For this reason, there exists a problem that a weight measurement system tends to fail especially.

  On the other hand, according to the so-called non-contact measurement type conveyor scale disclosed in Patent Document 2, the above-described vibration load or impact load is directly applied to the non-contact type measurement system including the distance measuring means. Therefore, it is less prone to failure compared to the gravimetric conveyor scale. However, the surface of the object to be transported, which is the target of the distance measuring means, usually has an unspecified number of irregularities, and a large lump portion exists depending on the property. Therefore, it is extremely difficult to accurately determine the shape of the surface of the transported object in such a state using a non-contact type distance measuring means. Therefore, the non-contact measurement type conveyor scale cannot accurately determine the transport amount of the transported object. In other words, the weight measurement type conveyor scale is more suitable than the non-contact measurement type conveyor scale in order to accurately determine the transport amount of the object to be transported.

  Therefore, the present invention includes both elements of the weight measurement method and the non-contact measurement method, thereby reliably ensuring the original function of the conveyor scale for obtaining the transport amount of the object to be transported, and in particular for the weight measurement method. An object of the present invention is to provide a conveyor scale capable of detecting an abnormality such as a failure in an element with a simple configuration.

  In order to achieve this object, the present invention provides a load to be applied via a carrier side belt of a belt conveyor in a conveyor scale for determining a transport amount of a thin transport object continuously transported by a belt conveyor. A weight measuring unit is included which includes a load detecting unit for detecting, and obtains the weight per predetermined unit of the transported object related to the transport amount based on the load detection value by the load detecting unit. In addition, the position detecting means includes a position detecting means for detecting, in a non-contact manner, the position of the upper surface of the transported object that corresponds to the line of intersection between the orthogonal plane substantially orthogonal to the traveling direction of the carrier side belt and the upper surface of the transported object And a volume measuring means for determining a volume per predetermined unit of the transported object related to the transport amount based on the position detection value by. And the determination means which compares the weight measurement value by a weight measurement means with the volume measurement value by a volume measurement means, and determines the presence or absence of the abnormality of the said weight measurement means is comprised.

  That is, according to the present invention, the weight per predetermined unit of the object to be transported is obtained by the weight measuring means including the load detecting means. And based on the weight measurement value by this weight measurement means, the transport amount of a to-be-transported object is calculated | required. In addition, the volume per predetermined unit of the transported object is obtained by the volume measuring means including the non-contact type position detecting means. The transport amount of the transported object can also be obtained based on the volume measurement value by the volume measuring means. That is, both a weight measurement type element and a non-contact measurement type element are provided. Therefore, the original function of the conveyor scale for determining the transport amount of the transported object is reliably ensured. Here, for example, it is assumed that the weight measuring means is normal. In this case, the so-called first transport amount obtained based on the weight measurement value obtained by the weight measurement means and the so-called second transport amount obtained based on the volume measurement value obtained by the volume measurement means are substantially equivalent. On the other hand, when an abnormality occurs in the weight measuring means, both of them become unequal. Paying attention to this point, the determination means compares the weight measurement value by the weight measurement means with the volume measurement value by the volume measurement means, and determines the presence or absence of abnormality of the weight measurement means based on the comparison result. . In other words, the volume measuring means is also used as a comparison means for determining whether or not the weight measuring means is abnormal.

  The volume measuring means may obtain the volume measurement value in the following manner. First, a first function expression representing the upper surface position of the transported object is obtained based on the position detection value by the position detection means. Subsequently, based on the second function expression representing the upper surface position of the carrier side belt corresponding to the line of intersection between the orthogonal plane and the upper surface of the carrier side belt, and the first function expression obtained earlier, the orthogonal function Find the cross-sectional area of the object to be transported by a plane Based on this cross-sectional area, a volume measurement value is obtained. The second function expression referred to here is obtained, for example, based on the actual measurement result of the shape and dimensions of the upper surface of the carrier side belt or the design values thereof. The second function equation can also be obtained based on the position detection value obtained by the position detection means when the carrier-side belt is not loaded with the object to be transported.

  Further, the position detecting means may detect a plurality of locations (partial portions) of the upper surface position of the transported object. In this case, the volume measuring means subdivides the cross section of the transported object by the above-described orthogonal plane based on the plurality of detection points by the position detecting means, and calculates the first function for each subdivided area. You may ask for it. Then, an area for each area is obtained based on the first function expression for each area and the second function expression for each area, and an orthogonal plane is calculated based on the total area for each area. Alternatively, the total cross-sectional area of the object to be transported may be obtained, and thus the volume measurement value may be obtained.

  Further, the determination means may determine whether or not the weight measurement means is abnormal based on an apparent specific gravity value of the transported object, which is a ratio between the weight measurement value and the volume measurement value.

  Specifically, the determination unit compares the apparent specific gravity value with a reference specific gravity value that is a reference for the apparent specific gravity value, and when the degree of difference between the two exceeds a predetermined first threshold value. The weight measuring unit may be determined to be abnormal. According to this determination procedure, when the apparent specific gravity value changes excessively, that is, particularly when it changes over a relatively long period of time, this can be detected accurately. That is, it is possible to accurately detect an abnormality in the weight measuring means that induces such a situation.

  Separately from this, the determination means obtains the degree of change in the apparent specific gravity value every predetermined interval, for example, every certain period or every time the carrier side belt travels a certain distance, and this degree of change is determined in advance. When the second threshold value is exceeded, it may be determined that the weight measuring means is abnormal. According to this determination procedure, when the apparent specific gravity value changes excessively within a certain period of the predetermined interval (including a period required for the carrier side belt to travel a certain distance), a particularly short period This can be accurately detected when it changes excessively.

  Furthermore, a warning output means for outputting a predetermined warning when the weight measurement value is determined to be abnormal by the determination means may be provided. The warning referred to here may be output in a visual manner such as lighting on or displaying characters on the display, or may be output in an auditory manner such as a buzzer sound or sound emission from a speaker. Good.

  In addition, a first transport amount calculation means for obtaining the first transport amount based on the weight measurement value by the weight measurement means, and a second transport amount calculation for obtaining the second transport amount based on the volume measurement value by the volume measurement means. Means and transportation amount information output means for outputting information on one or both of the first transportation amount and the second transportation amount may be further provided.

  In this case, the transport amount information output means outputs information on the first transport amount when the determination means determines that the weight measurement means is normal, and the weight measurement means is determined to be abnormal. When it is, information on the second transportation amount may be output. According to this configuration, when the weight measuring means is normal, information on the accurate transport amount, which is the first transport amount, is output. Then, when the weight measuring means is abnormal, a kind of information regarding the second transport amount, which is so called secondary accurate transport amount, is temporarily output.

  Moreover, it is desirable that the first transport amount and the second transport amount are physical quantities in the same unit. For example, when the first transport amount is a physical quantity including a weight (mass) as a unit, the second transport operation means calculates the weight measurement value and the volume measurement value so that the second transport amount is the same physical quantity. The weight per predetermined unit of the transported object may be estimated based on the reference value of the ratio and the volume measurement value, and the second transport amount may be obtained based on the estimated value. The ratio of the weight measurement value and the volume measurement value referred to here may be the apparent specific gravity value described above. The reference value may be the above-described reference specific gravity value.

  As described above, according to the present invention, both a weight measuring element called a weight measuring means including a load detecting means and a non-contact measuring element called a volume measuring means including a non-contact type position detecting means are provided. Therefore, the original function of the conveyor scale for obtaining the transport amount of the transported object is surely guaranteed. In addition, since the volume measuring means is also used as a comparison control means when determining the presence or absence of an abnormality in the weight measuring means, a special means for detecting that an abnormality has occurred in the weight measuring means. There is no need to provide it separately. That is, when an abnormality occurs in the weight measuring means, the original function of the conveyor scale can be reliably guaranteed, and this can be detected with a simple configuration.

It is the schematic which shows the whole structure of one Embodiment of this invention. It is an illustration figure which shows the installation state of the load cell and distance sensor in the embodiment. It is a block diagram which shows the detailed structure of the control apparatus in the embodiment. It is an illustration figure for demonstrating the volume measuring point of the to-be-transported object in the same embodiment. It is an illustration figure which shows the extreme example of FIG. It is an illustration figure which shows an example different from FIG. It is a flowchart which shows the flow of the adjustment task which CPU performs in the same embodiment. It is a flowchart which shows the flow of the operation | work task which the same CPU performs. It is a flowchart following FIG.

  An embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the conveyor scale 10 according to this embodiment includes a belt conveyor 12. The belt conveyor 12 is installed outdoors, for example, and a thin transport object 100 such as coke or limestone is continuously supplied onto the carrier side belt 14. Then, the carrier-side belt 14 travels in the direction indicated by the thick solid arrow 16 in FIG. 1 (from the left side to the right side in FIG. 1), so that the object 100 to be transported on the carrier-side belt 14 continuously in the same direction 16. To be transported to.

  The carrier side belt 14 is supported by a plurality of free rotation rollers (pulleys) 18, 18,... Arranged in parallel along the horizontal direction that is the traveling direction 16. A part of the plurality of rollers 18, 18,..., For example, one roller 20 located in the center in FIG. 1 is a measuring roller with two load cells 22 and 24 as load detecting means attached thereto, for example. In addition, a roller 18 adjacent to the upstream side (left side in FIG. 1) of the metering roller 20 other than the metering roller 20, for example, a travel distance for detecting the travel distance of the carrier side belt 14. A rotary pulse generator (PG) 28 as a detecting means is attached. Further, a plurality of, for example, seven, non-contacts as position detecting means are provided above the carrier side belt 14 at positions where the carrier side belt 14 (and the transported object 100) is opposed to the measuring roller 20. Mold distance sensors 30, 32, 34, 36, 38, 40 and 42 are arranged. These distance sensors 30 to 42 are, for example, of the infrared reflection type, and emit an infrared beam toward the surface (upper surface) of the object to be transported 100 as indicated by a dashed arrow 44 in FIG. Receives the reflected light of the infrared beam reflected by the surface of the object to be transported 100 as indicated by a reverse arrow 46, and the distance from each installation position to the surface of the object to be transported 100 based on the time between them Measure.

  Specifically, as shown in FIG. 2, each of the distance sensors 30 to 42 is a plane orthogonal to the traveling direction of the carrier side belt 14 (the front and back direction of the paper surface of FIG. 2) (a plane along the paper surface of FIG. 2: In the horizontal plane (the left-right direction in FIG. 2) at regular intervals u. Of these, the distance sensor 36 located at the center is substantially directly above the center O of the carrier side belt 14. The distance sensors 30 and 42 located at both ends are slightly closer to the inside (close to the center O) than both side edges of the carrier side belt 14. Each of the distance sensors 30 to 42 is fixed to a base (not shown) of the belt conveyor 12 via an appropriate support member (not shown).

  As can be seen from FIG. 2, the metering roller 20 has three individual rollers 20a and 20b arranged in series so as to form a generally concave shape (generally convex shape downward) in the above-described virtual plane. And 20 c. Similarly, the other rollers 18, 18,... Including the travel distance detection roller 26 are also three tank rollers. The carrier side belt 14 is supported by these three tank rollers 18, 18,..., So that the cross section of the virtual plane is curved in a generally concave shape (generally convex shape in the downward direction) upward. In other words, the object to be transported 100 is shaped so as not to spill out. The metering roller 20 is fixed to the base of the belt conveyor 12 via two load cells 22 and 24 attached thereto and an appropriate support member (not shown) different from the above. The other rollers 18, 18,... Including the travel distance detecting roller 26 are fixed to the base of the belt conveyor 12 via another support member (not shown).

  Returning to FIG. 1, each load cell 22 and 24 generates analog load detection signals Sw <b> 1 and Sw <b> 2 having a DC voltage value corresponding to the magnitude of the load applied thereto. The analog load detection signals Sw <b> 1 and Sw <b> 2 are input to a control device 50 installed in a place away from the belt conveyor 12, for example, a management room. The pulse generator 28 generates the pulse signal Sp each time the carrier side belt 14 travels a relatively short predetermined distance of ΔLp. This pulse signal Sp is also input to the control device 50. Furthermore, each distance sensor 30-42 produces | generates the distance measurement signal Sd1-Sd7 of the digital aspect showing each distance measurement value. These distance measurement signals Sd1 to Sd7 are also input to the control device 50.

  As shown in FIG. 3, the control device 50 has an adder circuit 52 to which analog load detection signals Sw1 and Sw2 from the load cells 22 and 24 are input. The adder circuit 52 adds the input analog load detection signals Sw1 and Sw2. The added analog load detection signal Sw (= Sw1 + Sw2) is appropriately amplified by the amplifier circuit 54 and then input to the A / D conversion circuit 56. Although not shown in the figure, a noise component in a relatively high frequency band, mainly a noise component mainly due to an electrical factor, included in the analog load detection signal Sw is removed from the front stage or the rear stage of the amplifier circuit 54. An analog low-pass filter circuit is provided.

  The A / D conversion circuit 56 samples the input analog load detection signal Sw in accordance with the rising edge (or falling edge) of the clock pulse CLK supplied from the clock pulse generation circuit 58 as the clock pulse generation means. As a result, the analog load detection signal Sw is converted into a digital signal (hereinafter also represented by the symbol Sw). The sampling period by the A / D conversion circuit 56, that is, the period ΔTs of the clock pulse CLK is much shorter than the period of the pulse signal Sp generated from the pulse generator 28, for example, 1 ms.

  The digital load detection signal Sw after conversion by the A / D conversion circuit 56 is input to a CPU (Central Processing Unit) 62 as a calculation means via the input / output interface circuit 60. A clock pulse CLK is also input to the CPU 62 via the input / output interface circuit 60. In addition, the CPU 62 receives the pulse signal Sp from the pulse generator 28 via the input / output interface circuit 60 and also receives the distance measurement signals Sd1 to Sd7 from the distance sensors 30 to 42. However, since the mode of the pulse signal Sp, in particular, the voltage value does not conform to the input specification of the CPU 62, it is appropriately shaped by the pulse shaping circuit 64 and then inputted to the CPU 62.

  Based on the digital load detection signal Sw and the pulse signal Sp, the CPU 62 obtains a transport weight value W that represents the transport amount of the transported object 100 by weight. At the same time, the CPU 62 obtains a transport volume value V that represents the transport amount of the transported object 100 by volume based on the distance measurement signals Sd1 to Sd7 and the pulse signal Sp.

  The specific calculation procedure of the transport weight value W and the transport volume value V will be described in detail later. However, when both are compared, the transport weight value W is more accurate than the transport volume value V for the reason described later. It is. On the other hand, the weight measuring system including the load cells 22 and 24 and the measuring roller 20 which are calculation elements of the transport weight value W is always in a state of receiving a vibration load or an impact load via the carrier side belt 14. On the other hand, the non-contact type measurement system including the distance sensors 30 to 42 which are the calculation elements of the transport volume value V does not receive such vibration load or impact load. For this reason, the weight measurement system is more likely to fail than the non-contact type measurement system. In addition, the signal levels of the analog load detection signals Sw1 and Sw2 output from the load cells 22 and 24 that are components of the weight measurement system are extremely small. Therefore, each distance that is a component of the non-contact type measurement system. There is also a problem that the stability of the load cells 22 and 24 at the time of performance deterioration is lacking compared to the digital distance measurement signals Sd1 to Sd7 output from the sensors 30 to 42. In other words, the weight measurement system including the load cells 22 and 24 generally tends to deteriorate in performance as compared with the non-contact measurement system including the distance sensors 30 to 42.

  Therefore, the CPU 62 treats the transportation weight value W as the main transportation amount, and treats the transportation volume value V as the secondary transportation amount. That is, when the weight measurement system is normal, the transport weight value W, which is an accurate transport amount, is displayed on the display 66 as information output means. When an abnormality such as a failure occurs in the weight measurement system, the transport volume value V that is a secondary transport amount is converted into an estimated weight value W ′ that will be described later, which is the same unit as the transport weight value W. Thus, it is temporarily displayed on the display 66. The display 66 is connected to the CPU 62 via the input / output interface 60.

  Whether or not the weight measurement system is normal is determined based on a comparison between the transport weight value W and the transport volume value V. That is, the CPU 62 compares the transport weight value W and the transport volume value V, and strictly monitors the apparent specific gravity value K represented by the following expression 1, and an excessive change is observed in the apparent specific gravity value K. When this occurs, it is determined that an abnormality has occurred in the weight measurement system.

<< Formula 1 >>
K = W / V

  The apparent specific gravity value K expressed by the equation 1 is substantially constant when the weight measurement system is normal. If an abnormality occurs in the weight measurement system, the transport weight value W becomes an abnormal value, and the apparent specific gravity value K changes excessively. Of course, an abnormality such as a failure may occur in the non-contact type measurement system, but the probability is extremely lower than that in the weight measurement system. In addition, if the components of the weight measurement system and the non-contact type measurement system are appropriately replaced by regular maintenance and inspection work, etc., the probability of occurrence of abnormalities is further increased for the long-life non-contact type measurement system. Lower. Therefore, here, it is assumed that an abnormality may occur only in the weight measurement system of the weight measurement system and the non-contact measurement system, and that the non-contact measurement system is always normal. .

  That is, the CPU 62 determines that the weight measurement system is normal when the apparent specific gravity value K is substantially constant. In this case, the transport weight value W is displayed on the display 66 as described above. When the apparent specific gravity value K changes excessively, it is determined that an abnormality has occurred in the weight measurement system. In this case, the estimated weight value W ′ is calculated based on the following Equation 2 using the transport volume value V as a variable, and the estimated weight value W ′ is displayed on the display 62. Note that Ks in Equation 2 is a reference specific gravity value that is a standard value of the apparent specific gravity value K. This reference specific gravity value Ks will also be described in detail later.

<< Formula 2 >>
W '= Ks · V

  As described above, according to the present embodiment, when the weight measurement system is normal, the information regarding the accurate transport amount of the transport weight value W is displayed on the display 66. When an abnormality occurs in the weight measurement system, an estimated weight value W ′ obtained based on a secondary accurate transportation amount called a transportation volume value V is displayed on the display 66. That is, even if an abnormality occurs in the weight measurement system, the original function of the conveyor scale 10 for obtaining the transport amount of the transported object 100 is reliably ensured. This is particularly effective in a situation where the operation of the conveyor scale 10 cannot be stopped immediately. Whether or not the weight measurement system is normal is determined based on an apparent specific gravity value K which is a ratio between the transport weight value W and the transport volume value V. That is, the non-contact type measurement system that is a calculation element of the transport volume value V also functions as a comparison unit when determining whether or not the weight measurement system is normal. Therefore, it is not necessary to separately provide a special means for checking whether or not the weight measuring system is normal, and therefore the configuration of the entire conveyor scale 10 is simplified.

  The CPU 62 is also connected with an operation key 68 as a command input means for inputting various commands to the CPU 62 via the input / output interface circuit 60. The operation keys 68 may be integrated with the display 66, and may be realized by a touch screen, for example. The CPU 62 is connected to a memory circuit 70 as a storage unit. The memory circuit 70 stores a control program for controlling the operation of the CPU 62.

  Now, CPU62 calculates | requires the transportation weight value W specifically in the following way.

  That is, every time one pulse of the above-mentioned pulse signal Sp is input (strictly, every time the rising or falling of the pulse signal Sp is detected), that is, every time the carrier side belt 14 travels by the predetermined distance ΔLp. Then, based on the digital load detection signal Sw, the weight of the transported object 100 on the working length Ld, so-called instantaneous load Wd [n] (n: an index indicating the input order of the pulse signal Sp) is obtained. Note that the definition of the working length Ld and the method of obtaining the instantaneous load Wd [n] are well known, and thus the description thereof is omitted here. Then, the CPU 62 obtains the transport weight value W [n] of the transported object 100 for a predetermined distance ΔLp based on the following expression 3.

<< Formula 3 >>
W [n] = Wd [n] · (ΔLp / Ld)

  Further, every time the pulse signal Sp is input with N (N: integer greater than or equal to 1) pulses, the CPU 62 sets the period as one section, and based on the following equation 4, the section m (m: number of the section) The transport weight value W [m] for the index) is obtained.

<< Formula 4 >>
W [m] = ΣW [n] where n = 1 to N

  The CPU 62 displays the transport weight value W [m] obtained based on the equation 4 on the display 66. Then, the transport weight value W [m] is obtained for each division m in the same manner and displayed on the display 66, that is, the transport weight value W [m] displayed on the display 66 is updated. Note that the value of the index n indicating the input order of the pulse signal Sp is reset (n = 1) every time the section m is updated. Further, the CPU 62 can accumulate the weight measurement value W [m] and display the accumulated value on the display 66.

  At the same time, the CPU 62 obtains the transport volume value V and, in turn, obtains the estimated weight value W ′ in the following manner.

  First, the CPU 62 forms XY orthogonal coordinates as shown in FIG. 4 on the above-described virtual plane. Specifically, the center O of the carrier side belt 14 is the origin. A horizontal straight line passing through the origin O is taken as the X axis, and a vertical line passing through the origin O is taken as the Y axis. FIG. 4 is a view of the virtual plane viewed from the downstream side of the carrier side belt 14 toward the upstream side of the carrier side belt 14. In FIG. 4, the right side of the Y axis is the X axis. The left side of the Y axis is the negative area of the X axis. The area above the X axis is the Y axis positive area, and the area below the X axis is the Y axis negative area.

  On such orthogonal coordinates, the CPU 62 represents a curve formed by the upper surface of the carrier side belt 14 by a functional expression fb (x). The function formula fb (x) is obtained based on, for example, an actual measurement result of the shape and dimensions of the upper surface of the carrier side belt 14 or a design value thereof. Then, the CPU 62 sets the X axis value of the left side edge of the carrier side belt 14 to −α, and sets the X axis value of the right side edge to α.

  Here, when attention is paid to the arrangement positions of the distance sensors 30 to 42, the X-axis values of the arrangement positions of the distance sensors 30 to 42 are respectively -3 · u, -2 · u, -u, 0, u, 2 · u and 3 · u. Therefore, for example, the distance sensor 30 at the left end in FIG. 4 measures the distance H1 from its installation position to the surface position P1 of the transported object 100 on the X axis value of −3 · u. Similarly, the distance sensor 32 measures the distance H2 from its installation position to the surface position P2 of the transported object 100 on the X axis value of −2 · u. The distance sensor 34 measures the distance H3 from the installation position to the surface position P3 of the transported object 100 on the X axis value −u, and the center distance sensor 36 determines the Y axis from the installation position. A distance H4 to the surface position P4 of the transported object 100 is measured. Furthermore, the distance sensor 38 measures a distance H5 from the installation position to the surface position P5 of the transported object 100 on the X-axis value u, and the distance sensor 40 measures 2 · u from the installation position of X. The distance H6 to the surface position P6 of the transported object 100 on the axis value is measured. The distance sensor 42 at the right end measures the distance H7 from the installation position of the distance sensor 42 to the surface position P7 of the transported object 100 on the X axis value of 3 · u.

  Each time the pulse signal Sp is input by one pulse, that is, every time the carrier side belt 14 travels by the predetermined distance ΔLp, the CPU 62 determines each of the relevant values based on the distance measurement signals Sd1 to Sd7 from the distance sensors 30 to 40. The distances H1 to H7 from the installation positions of the distance sensors 30 to 40 to the surface positions P1 to P7 of the transported object 100 are recognized. Then, by subtracting these distances H1 to H7 from the Y-axis value Hs of the installation positions of the distance sensors 30 to 40, that is, based on the following equation 5, Y of each surface position P1 to P7 of the transported object 100 The axis values y1 [n] to y7 [n] are obtained.

<< Formula 5 >>
y1 [n] = Hs−H1
y2 [n] = Hs−H2
y3 [n] = Hs−H3
y4 [n] = Hs−H4
y5 [n] = Hs−H5
y6 [n] = Hs−H6
y7 [n] = Hs−H7

  Further, the CPU 62 specifies the midpoint on the X axis between the left side edge of the carrier side belt 14 and the arrangement position of the distance sensor 30 at the left end, and sets the X axis value of this midpoint to −u ′ (= − ( α + 3 · u) / 2). The upper surface position of the carrier side belt 14 on the X-axis value −u ′ is P0. The Y-axis value at this position P0 is obtained by substituting the X-axis value −u ′ at the midpoint into the above-mentioned quadratic function expression fb (x) representing the upper surface shape of the carrier side belt 14, that is, fb ( −u ′).

  Similarly, the CPU 62 specifies the midpoint on the X axis between the right side edge of the carrier side belt 14 and the position of the distance sensor 42 at the right end, and sets the X axis value of this midpoint to u ′ (= (Α + 3 · u) / 2). The upper surface position of the carrier side belt 14 on the X-axis value u ′ is P8. The Y-axis value at this position P8 is also obtained by substituting the X-axis value u ′ at the middle point into a quadratic function expression fb (x) representing the upper surface shape of the carrier side belt 14, that is, fb (u ′ )

  CPU62 calculates | requires the average value y1a [m] -y7a [m] of Y-axis value y1 [n] -y7 [n] of each surface position P1-P7 of the to-be-transported object 100 for every 1 division m mentioned above. Specifically, the average values y1a [m] to y7a [m] at the time point when the pulse signal Sp is input by N pulses are obtained based on the following Expression 6.

<< Formula 6 >>
y1a [m] = {Σy1 [n]} / N
y2a [m] = {Σy2 [n]} / N
y3a [m] = {Σy3 [n]} / N
y4a [m] = {Σy4 [n]} / N
y5a [m] = {Σy5 [n]} / N
y6a [m] = {Σy6 [n]} / N
y7a [m] = {Σy7 [n]} / N
where n = 1 to N

  Then, the CPU 62 hypothesizes a line segment P0P1 that connects the position P0 on the X-axis value of -u ′ described above and the target position P1 by the left end distance sensor 30, and this line segment P0P1 is referred to as f0p (x). It is expressed by a linear function formula. Similarly, a line segment P1P2 connecting the target position P1 by the left end distance sensor 30 and the target position P2 by the adjacent distance sensor 32 is hypothesized, and this line segment P1P2 is a linear function expression f1p (x). Represented by Further, a line segment P2P3 connecting the target position P2 by the distance sensor 32 and the target position P3 by the distance sensor 34 adjacent on the right side is hypothesized, and this line segment P2P3 is expressed by a linear function expression f2p (x). A line segment P3P4 connecting the target position P3 by the distance sensor 34 and the target position P4 by the central distance sensor 36 adjacent to the right side is hypothesized, and this line segment P3P4 is expressed by a linear function expression f3p (x). . A line segment P4P5 connecting the target position P4 by the center distance sensor 36 and the target position P5 by the distance sensor 38 adjacent on the right side is hypothesized, and this line segment P4P5 is expressed by a linear function expression f4 (x). In addition, a line segment P5P6 connecting the target position P5 by the distance sensor 38 and the target position P6 by the distance sensor 40 adjacent to the right side is hypothesized, and this line segment P5P6 is expressed by a linear function expression f5p (x). . Then, a line segment P6P7 connecting the target position P6 by the distance sensor 40 and the target position P7 by the right end distance sensor 42 adjacent to the right side is hypothesized, and this line segment P6P7 is expressed by a linear function expression of f6p (x). In addition, a line segment P7P8 connecting the target position P7 by the distance sensor 43 at the right end and the above-described position P8 on the X-axis value u ′ is hypothesized, and this line segment P7P8 is a linear function f7p (x). Represented by a formula. That is, the surface shape of the transported object 100 on the virtual plane is represented by eight linear function expressions of f0p (x) to f7p (x). In FIG. 4, eight line segments P0P1 to P7P8 representing these eight linear function expressions f0p (x) to f7p (x) are collected by one code fp (x) due to space constraints. It is shown.

  In addition, the CPU 62 divides the cross section of the transported object 100 in a virtual plane into eight regions with the vertical lines passing through the positions P0 to P8 as boundaries. And each cross-sectional area A0-A7 of these eight area | regions is calculated based on following Formula 7. FIG. Note that the function formula fb (x) representing the shape of the upper surface of the carrier side belt 14 in Formula 7 may also be determined individually for each region.

<< Formula 7 >>
^{_{A0 = ∫ -u '-3 · u}} {f0p (x) -fb (x)} · dx
A1 = ∫− _{3 · u} ^{−2 · u} {f1p (x) −fb (x)} · dx
A2 = ∫− _{2 · u} ^−u {f2p (x) −fb (x)} · dx
A3 = ∫− _u ⁰ {f3p (x) −fb (x)} · dx
A4 = ∫ ₀ ^u {f4p (x) −fb (x)} · dx
A5 = ∫ _u ^{2 · u} {f5p (x) −fb (x)} · dx
A6 = ∫ _{2 · u} ^{3 · u} {f6p (x) −fb (x)} · dx
A7 = ∫ _{3 · u} ^{u ′} {f7p (x) −fb (x)} · dx

  Further, the CPU 62 calculates the total cross-sectional area A [m] of the transported object 100 in the virtual plane by summing the cross-sectional areas A0 to A7 of these eight regions, that is, based on the following Expression 8.

<< Formula 8 >>
A [m] = A0 + A1 + A2 + A3 + A4 + A5 + A6 + A7

  According to the calculation procedure of the cross-sectional area A [m] of the transported object 100, for example, the amount of the transported object 100 is small as shown in FIG. 5, or the transported object 100 as shown in FIG. Even when a part of the target positions P1 to P7 by the distance sensors 30 to 42 deviates from the surface of the transported object 100, that is, on the upper surface of the carrier side belt 14. Even in the case of direct contact, the cross-sectional area A [m] of the transported object 100 is obtained with a certain degree of accuracy.

  Then, the CPU 62 multiplies the cross-sectional area A [m] of the transported object 100 thus obtained by the traveling distance (= N · ΔLp) of the carrier side belt 14 for one section m, that is, Based on Equation 9, the transport volume V [m] of the transported object 100 for the one division m is obtained.

<< Formula 9 >>
V [m] = A [m] · N · ΔLp

  The CPU 62 obtains the transport volume value V [m] for each section m as well as the transport weight value W [m] described above.

  As can be seen from the calculation procedure for the transport volume value V [m], in the calculation procedure, seven discrete positions P1 to P7 on the surface of the transported object 100 and P0 and P8 are assumed. Based on the set two positions, functional expressions f0p (x) to f7p (x) representing the surface shape of the transported object 100 are established, and as a result, the surface area A [m] of the transported object 100 is calculated. Further, the transport volume value V [m] is obtained. Therefore, as shown in FIG. 2 and FIG. 4, in the extreme, as shown in FIG. 5 and FIG. The value V [m] is inferior in accuracy compared to the transport weight value W [m] based on the weight measurement system. However, the transport volume value V [m] is sufficiently useful in the secondary significance in place of the transport weight value W [m].

  In addition, the CPU 62 obtains an apparent specific gravity value K [m] for each section m based on the following equation 10 based on the above-described equation 1.

<< Formula 10 >>
K [m] = W [m] / V [m]

  Then, the CPU 62 monitors the apparent specific gravity value K [m] and determines whether or not it changes excessively, that is, whether or not the weight measurement system is normal.

  Specifically, the CPU 62 compares the apparent specific gravity value K [m] with the reference specific gravity value Ks described above. Then, the degree of difference between the two is obtained. In short, the absolute degree of variation of the apparent specific gravity value K [m] with respect to the reference specific gravity value Ks is obtained. Specifically, the absolute variation amount E [m] is obtained based on the following equation 11.

<< Formula 11 >>
E [m] = | K [m] −Ks |

  The reference specific gravity value Ks is determined at the time of prior adjustment operation. Specifically, the transported object 100 is transported under the same conditions as in actual operation during the adjustment operation in advance. In this state, an apparent specific gravity value K [m] is obtained over a predetermined M (M: an integer equal to or greater than 1) section. Then, the average value of the apparent specific gravity values K [m] (m = 1 to M) over the M section is determined as the reference specific gravity value Ks. That is, the reference specific gravity value Ks is determined based on the following Expression 12. Apart from this, a known value may be set as the reference specific gravity value Ks.

<< Formula 12 >>
Ks = {ΣK [m]} / M where m = 1 to M

  Further, the CPU 62 compares the absolute fluctuation amount E [m] obtained based on Expression 11 with a predetermined allowable absolute fluctuation amount Emax. The allowable absolute fluctuation amount Emax referred to here is a limit value that is allowed as an absolute fluctuation amount of the apparent specific gravity value K [m], and this allowable absolute fluctuation amount Emax is also determined during the prior adjustment operation. Specifically, when the apparent specific gravity value K [m] is expected to fluctuate by e% at the maximum, the allowable variation rate e is multiplied by the reference specific gravity value Ks, that is, based on the following equation (13). The allowable absolute variation amount Emax is determined. Note that the value of the allowable variation rate e can be arbitrarily set.

<< Formula 13 >>
Emax = (e / 100) · Ks

  As a result of comparing the allowable absolute fluctuation amount Emax and the absolute fluctuation amount E [m] obtained based on Expression 11, when the absolute fluctuation amount E [m] is equal to or smaller than the allowable absolute fluctuation amount Emax, that is, When the following expression 14 is satisfied, the CPU 62 determines that the weight measurement system is normal. On the other hand, when Expression 14 is not satisfied, it is determined that an abnormality has occurred in the weight measurement system.

<< Formula 14 >>
E [m] ≦ Emax

  As described above, the CPU 62 monitors whether or not the apparent specific gravity value K [m] is excessively changed as compared with the reference specific gravity value Ks that is an absolute reference, so that the weight measurement system is normal. It is determined whether or not. According to this monitoring procedure, even when the apparent specific gravity value K [m] changes over a relatively long period, this can be detected accurately. In short, it is possible to accurately detect an abnormality in the weight measurement system that induces such a situation. Normally, the actual weight of the transported object 100 conveyed on the belt conveyor 12 (carrier side belt 14) and the actual volume of the transported object 100 correspond to each other. Even if the actual volume increases or decreases, the actual apparent specific gravity, which is the ratio between the two, is generally constant and does not vary greatly. Due to such a property, by monitoring the apparent specific gravity value K [m] as described above, the presence or absence of an abnormality in the weight measurement system is accurately detected.

  As another monitoring procedure, the CPU 62 also monitors the fluctuation amount ΔK [m] of the apparent specific gravity value K [m] for each section m. That is, the apparent specific gravity values K [m] and K [m-1] are compared for each section m with the previous section m-1. Then, based on the following Expression 15, a difference between the two, that is, a relative fluctuation amount ΔK [m] representing a relative change degree is obtained.

<< Formula 15 >>
ΔK [m] = | K [m] −K [m−1] |

  Further, the CPU 62 compares the relative fluctuation amount ΔK [m] obtained based on the equation 15 with a predetermined allowable relative fluctuation amount ΔKmax. The allowable relative fluctuation amount ΔKmax here is a limit value that is allowed as a fluctuation amount of the apparent specific gravity value K [m] within a certain period of one section, and this allowable relative fluctuation amount ΔKmax is also adjusted in advance. Determined during operation. Specifically, the standard deviation σk of the apparent specific gravity value K [m] (m = 1 to M) over the above-described M sections is obtained on the assumption that the apparent specific gravity value K [m] has a certain variation. And between two adjacent sections m and m−1, there is a difference of β (β: positive number) times the standard deviation σk at maximum in the apparent specific gravity values K [m] and K [m−1]. On the basis of this, the allowable relative fluctuation amount ΔKmax is determined based on the following equation (16). As the value of the coefficient β mentioned here, for example, β = about 3 to 4 is appropriate.

<< Formula 16 >>
ΔKmax = β · σ where β = 3-4

  As a result of comparing the allowable relative fluctuation amount ΔKmax with the relative fluctuation amount ΔK [m] obtained based on Expression 15, when the relative fluctuation amount ΔK [m] is equal to or smaller than the allowable relative fluctuation amount ΔKmax, that is, When the following expression 17 is satisfied, the CPU 62 determines that the weight measurement system is normal on condition that the above expression 14 is satisfied. On the other hand, when Expression 17 is not satisfied, it is determined that an abnormality has occurred in the weight measurement system.

<Equation 17>
ΔK [m] ≦ ΔKmax

  As described above, the CPU 62 determines whether or not the weight measurement system is normal by monitoring the fluctuation amount ΔK [m] of the apparent specific gravity value K [m] for each section m. According to this monitoring procedure, even if the change occurs within a relatively short period of each section m, this can be detected accurately. In short, it is possible to accurately detect an abnormality in the weight measurement system that induces such a situation.

  The CPU 62 displays the transport weight value W [m] on the display 66 as described above when the weight measurement system is normal, that is, when both of the expressions 14 and 17 are satisfied. At this time, a message indicating that the weight measurement system is normal may be displayed on the display 66.

  On the other hand, when an abnormality has occurred in the weight measurement system, that is, when at least one of Expressions 14 and 17 is not satisfied, a warning message indicating that fact is displayed on the display 66. At the time of this abnormality, an estimated weight value W ′ [m] is calculated based on the following equation 18 based on the above-described equation 2, and the estimated weight value W ′ [m] is displayed on the display 66. This temporary state is continued until the abnormality of the weight measurement system is resolved.

<< Formula 18 >>
W ′ [m] = Ks · V [m]

  As described above, the operation of the CPU 62 is controlled by the control program stored in the memory circuit 70. Specifically, the operation is as follows.

  First, when the adjustment mode is selected by operating the operation key 68 during the prior adjustment operation, the CPU 62 executes the adjustment task shown in the flowchart of FIG. Prior to the execution of this adjustment task, the function formula fb (x) representing the surface shape of the carrier-side belt 14, the allowable variation rate e, and the coefficient β are set as appropriate. In addition, the number of pulses N for one section m and the number of repeated execution sections M in the adjustment task are set. Needless to say, the X-axis values −3 · u, −2 · u, −u, 0, u, 2 · u, and 3 · u of the arrangement positions of the distance sensors 30 to 42 are already known. The Y-axis value Hs of the arrangement positions of the distance sensors 30 to 42 is also known.

  In this adjustment task, the CPU 62 first performs an initial setting in step S1. Specifically, the index value n representing the pulse number of the pulse signal Sp described above is reset and the index value m representing the section m is reset. That is, “1” is set as the index values n and m.

  Then, the CPU 62 proceeds to step S3 and waits until a pulse signal Sp for one pulse is input. When the pulse signal Sp is input, the CPU 62 proceeds to step S5. In this step S5, the CPU 62 acquires the distance measurement signals Sd1 to Sd7 from the distance sensors 30 to 42, and then proceeds to step S7, where the target position by each of the distance sensors 30 to 42 is based on the above equation 5. Y-axis values y1 [n] to y7 [n] of P1 to P7 are calculated. Note that the Y-axis values fb (−u ′) and fb (u ′) of the two virtual positions P0 and P8 set further outward from the target positions P1 to P7 at both ends represent the surface shape of the carrier belt 14. It is determined when the functional expression fb (x) is set.

  Further, the CPU 62 proceeds to step S9 and acquires the digital load detection signal Sw. And it progresses to step S11, and based on Formula 3, the transport weight value W [n] of the to-be-transported object 100 for predetermined distance (DELTA) Lp is calculated, and it progresses to step S13 after that.

  In step S13, the CPU 62 compares the index value n representing the pulse number of the pulse signal Sp with the total pulse number N for one section m. That is, it is determined whether or not the end of one division m has arrived. Here, for example, when the index value n is smaller than the total number of pulses N for one section m (n <N), the CPU 62 determines that the end of one section m has not yet arrived, and the step Proceed to S15. In step S15, after the index value n is incremented by “1”, the process returns to step S3 to wait for the next pulse signal Sp to be input. On the other hand, in step S13, when the index value n is equal to or greater than the total number of pulses N for one section m (n ≧ N), strictly, the index value n is equivalent to the total number of pulses N for one section m. In the case (n = N), it is determined that the end of one division m has arrived, and the process proceeds to step S17.

  In step S <b> 17, the CPU 62 calculates Y-axis average values y <b> 1 a [n] to y <b> 7 a [n] of the target positions P <b> 1 to P <b> 7 by the distance sensors 30 to 42 based on Expression 6. And it progresses to step S19 and eight linear function formulas f0p (x) -f7p (x) showing the surface shape of the to-be-transported object 100 are derived. Further, the CPU 62 proceeds to step S21, and obtains cross-sectional areas A0 to A7 of each of the eight subdivided regions of the cross section of the transported object 100 based on the virtual plane based on Expression 7. And it progresses to step S23, calculates | requires the total cross-sectional area A [m] of the to-be-transported object 100 by the said virtual plane based on Formula 8, Then, it progresses to step S25 and based on Formula 9, for one division m The transport volume value V [m] is obtained.

  After execution of step S25, the CPU 62 proceeds to step S27, and obtains the transport weight value W [m] for one division m based on Equation 4. Then, the process proceeds to step S29, the apparent specific gravity value K [m] is obtained based on Expression 10, and then the process proceeds to step S31, where the index value m representing the section m and the number of repeated execution sections M in this adjustment task are determined. And compare. In short, it is determined whether or not the apparent specific gravity value K [m] for the number M of repeated execution sections has been obtained, in other words, whether or not the apparent specific gravity value K [M] of the section M has been obtained.

  In step S31, for example, when the index value m representing the section m is smaller than the number of repeated execution sections M (m <M), the CPU 62 still has no apparent specific gravity value K [m] for the number of repeated execution sections M. It determines with having not been carried out, and progresses to step S33. In step S33, the index value m representing the division m is incremented by “1”. Further, in step S35, the index value n representing the pulse number of the pulse signal Sp is reset, and then the new pulse signal Sp The process returns to step S3 to wait for input. On the other hand, in step S31, when the index value m representing the section m is greater than or equal to the number of repeated execution sections M (m ≧ M), strictly speaking, when the index value m is equivalent to the number of repeated execution sections M (m = M) determines that the apparent specific gravity value K [m] corresponding to the number M of repeated execution sections has been obtained, and proceeds to step S37.

  In step S <b> 37, the CPU 62 obtains a reference specific gravity value Ks based on Expression 12. Then, the process proceeds to step S39, where the allowable absolute fluctuation amount Emax is obtained based on the equation 13, and further proceeds to step S41, where the allowable relative fluctuation amount ΔKmax is obtained based on the equation 16. In step S43, a message indicating that a series of processing in the adjustment mode has been completed is displayed on the display 66 for a certain period (about several seconds), and then this adjustment task is ended.

  Subsequently, when the operation mode is selected by operating the operation key 68 during actual operation, the CPU 62 executes the operation task shown in the flowcharts of FIGS. 8 and 9.

  In this operation task, the CPU 62 first proceeds to step S101 in FIG. 8 and performs initial setting. Specifically, the index value n representing the pulse number of the pulse signal Sp is reset, and the index value m representing the section m is reset. At the same time, “0 (zero)” is set in a flag F as an index indicating whether or not the weight measurement system is normal. The flag F indicates that the weight measuring system is normal when it is “0”, and indicates that an abnormality such as a failure has occurred in the weight measuring system when it is “1”.

  After executing the initial setting in step S101, the CPU 62 proceeds to step S103. The processing in steps S103 to S125 is exactly the same as the processing in steps S3 to S25 in the adjustment task shown in FIG. Therefore, detailed description of steps S103 to S125 is omitted.

  In step S127 following step S125, the CPU 62 determines whether or not “0” is set in the flag F, that is, whether or not the weight measurement system is normal. Here, for example, when “0” is set in the flag F, that is, when the weight measurement system is normal, the CPU 62 proceeds to step S129 of FIG. In step S129, the transport weight value W [m] for one section m is obtained based on Equation 4, and then the process proceeds to step S131 to display the transport weight value W [m] for one section m. 66. Note that the display of the transport weight value W [m] on the display 66 is continued, for example, until the next step S131 is executed. However, if “1” is set in the above-mentioned flag F after execution of step S131, step S131 is not executed next, as will be described later. In this case, the display of the transport weight value W [m] in step S131 is ended when step S163 described later is executed.

  After execution of step S131, the CPU 62 proceeds to step S133, and obtains an apparent specific gravity value K [m] based on equation (10). Further, the CPU 62 proceeds to step S135, and obtains the absolute fluctuation amount E [m] of the apparent specific gravity value K [m] based on Expression 11. In step S137, the absolute variation E [m] is compared with the allowable absolute variation Emax.

  In this step S137, for example, when the absolute variation E [m] of the apparent specific gravity value K [m] is equal to or smaller than the allowable absolute variation Emax (E [m] ≦ Emax), that is, when Expression 14 is satisfied, The CPU 62 determines that the weight measurement system is normal, strictly speaking, the absolute variation E [m] is within the normal value range. Then, the process proceeds to step S141.

  On the other hand, if the absolute variation E [m] of the apparent specific gravity value K [m] is larger than the allowable absolute variation Emax (E [m]> Emax) in step S137, that is, if the equation 14 is not satisfied, the CPU 62 It is determined that the weight measurement system is abnormal, strictly speaking, the absolute variation E [m] is an abnormal value. In this case, the process proceeds from step S137 to step S143. In step S143, a message indicating that the weight measurement system is abnormal is displayed on the display 66. At this time, the fact that the absolute fluctuation amount E [m] is an abnormal value is also displayed. The display of the message in step S143 is continued until the operation of the conveyor scale 10 is temporarily stopped, for example, until the abnormality of the weight measurement system is resolved. Then, the CPU 62 proceeds to step S145, sets “1” in the flag F, and then proceeds to step S141.

  In step S141, the CPU 62 determines whether or not the index value m representing the section m is m = 1, that is, whether or not the current section m is the first. If the index value m is m = 1, that is, if the current segment m is the first, the process proceeds to step S14, and the index value m is incremented by “1”. Further, the process proceeds to step S149, the index value n indicating the pulse number of the pulse signal Sp is set, and then the process returns to step S103 in FIG. 8 to wait for the input of a new pulse signal Sp. On the other hand, if the index value m representing the section m is not m = 1 in step S141, that is, if the current section m is at least the second or later, the process proceeds to step S151.

  In step S151, the CPU 62 obtains the fluctuation amount ΔK [m] of the apparent specific gravity value K [m] for each section m based on Expression 15. In step S153, the fluctuation amount ΔK [m] is compared with the allowable relative fluctuation amount ΔKmax. Here, for example, when the fluctuation amount ΔK [m] of the apparent specific gravity value K [m] is equal to or less than the allowable relative fluctuation amount ΔKmax (ΔK [m] ≦ ΔKmax), that is, when Expression 17 is satisfied, the CPU 62 It is determined that the weight measurement system is normal, strictly speaking, the fluctuation amount ΔK [m] is within a normal value range. Then, the process proceeds to step S147.

  On the other hand, when the fluctuation amount ΔK [m] of the apparent specific gravity value K [m] for each section m is larger than the allowable relative fluctuation amount ΔKmax (ΔK [m]> ΔKmax) in step S153, that is, Expression 17 is not satisfied. In this case, the CPU 62 determines that the weight measurement system is abnormal, strictly speaking, the fluctuation amount ΔK [m] is an abnormal value. In step S157, a message indicating that the weight measurement system is abnormal is displayed on the display 66. At this time, the fact that the fluctuation amount ΔK [m] of the apparent specific gravity value K [m] for each category m is an abnormal value is also displayed. The message display in step S157 is continued until, for example, the operation of the conveyor scale 10 is temporarily stopped until the abnormality of the weight measurement system is resolved. Then, the CPU 62 proceeds to step S159, sets “1” in the flag F, and then proceeds to step S147.

  Furthermore, if “1” is set in the flag F in step S127 of FIG. 8, that is, if an abnormality has occurred in the weight measurement system, the CPU 62 proceeds to step S161. In step S161, the weight estimated value W ′ [m] is obtained based on Expression 18, and then the process proceeds to step S163, where the weight estimated value W ′ [m] is displayed on the display 66. The display of the estimated weight value W ′ [m] on the display 66 is continued until, for example, step S163 is executed next. Then, the CPU 62 proceeds from step S163 to step S147 in FIG. That is, when “1” is set in the flag F, steps S129 to S145 and steps S151 to S159 in FIG. 9 are skipped and not executed.

  In the present embodiment, the single measuring roller 20 is supported by the two load cells 22 and 24. However, the present invention is not limited to this. For example, a plurality of measuring rollers may be provided, or one or three or more load cells may be provided. Further, a digital load cell may be employed instead of the analog type as in the present embodiment.

  The carrier-side belt 14 travels along the horizontal direction, but may travel with an inclination angle. Further, the carrier side belt 14 is supported by the three tank rollers 18, 18,... So that the cross section of the imaginary plane is shaped so as to be curved in a substantially concave shape upward. If there is no such shaping, such shaping may not be performed. That is, each roller 18, 18,... Is not limited to the three tanks. In other words, the carrier side belt 14 (conveyor belt) may be a so-called flat belt.

  In addition, although the rotary pulse generator 28 is employed as the travel distance detecting means, the present invention is not limited to this. For example, an appropriate mark is attached to the conveyor belt including the carrier side belt 14 at regular intervals along the running direction, and this mark is detected by an appropriate sensor such as an optical sensor. The travel distance may be detected. Further, as disclosed in Japanese Patent Application Laid-Open No. 2004-144463 as Patent Document 2 described above, a distance sensor having the same specifications is provided on either the upstream side or the downstream side of each of the distance sensors 30 to 42, The travel distance of the carrier side belt 14 may be obtained based on the time difference when the same target position is detected by these two sensors.

  Further, although the seven distance sensors 30 to 42 are used, other number of distance sensors may be used. Moreover, although the infrared reflective type thing was employ | adopted as the said distance sensors 30-42, things other than the said infrared reflective types, such as a laser type and an ultrasonic type, may be employ | adopted. In an extreme case, the surface shape of the transported object 100 may be obtained by employing a surveillance camera and analyzing the captured image.

  And about the functional formula fb (x) showing the upper surface shape of the carrier side belt 14, it is from each distance sensor 30-42 when it exists in the empty state in which the to-be-transported object 100 is not loaded on the said carrier side belt 14. FIG. You may obtain | require based on distance measurement signal Sd1-Sd7.

  Further, when the weight measurement system is normal, the transport weight value W [m] is displayed on the display 66, and when an abnormality occurs in the weight measurement system, the estimated weight value W ′ [m] is displayed on the display 66. However, it is not limited to this. For example, when the weight measurement system is normal, an estimated weight value W ′ [m] may be displayed in addition to the transport weight value W [m]. Regardless of whether the weight measurement system is normal, the transport volume value V [m] may be always displayed. Alternatively, a part or all of the transport weight value W [m], the transport volume value V [m], and the estimated weight value W ′ [m] are selectively displayed by an operation with the operation key 68 (that is, manual operation). It may be. Furthermore, not only the display on the display 66 but also such information may be output to an external device such as a management personal computer or a printing device.

  Then, when an abnormality occurs in the weight measurement system, a warning message is displayed on the display 66. However, the present invention is not limited to this. For example, illumination such as an appropriate lamp may be turned on, or an appropriate alarm device such as a buzzer or a bell may be sounded. Further, the warning message may be output by voice from a speaker.

  Further, the absolute variation E [m] of the apparent specific gravity value K [m] based on Expression 11 is determined for each division m, but is not limited thereto. For example, the absolute variation E [m] may be obtained every certain number of sections q (q: an integer of 1 or more). Moreover, you may obtain | require the said absolute variation | change_quantity E [m] irregularly not regularly.

Further, instead of the absolute variation amount E [m] based on the equation 11, for example, an absolute variation rate E ′ [m] is obtained based on the following equation 19, and this absolute variation rate E ′ [m]: It may be determined whether or not the weight measurement system is normal by comparing the allowable absolute variation rate Emax ′ based on Equation 20.
You may decline.

<Formula 19>
E ′ [m] = | (K [m] −Ks) / Ks |

<< Formula 20 >>
Emax '= e / 100

  Further, the relative variation ΔK [m] of the apparent specific gravity value K [m] based on Expression 15 is obtained for each section, that is, the apparent specific gravity value K [m] between the adjacent sections m and m−1. However, the present invention is not limited to this. For example, based on the difference between the apparent specific gravity values K [m] and K [m] between two sections m and mr that are separated from each other by a certain number of sections r (r: an integer of 2 or more), the relative variation amount ΔK [m] may be obtained. That is, the relative variation ΔK [m] may be obtained based on the following equation 21 instead of the equation 15.

<< Formula 21 >>
ΔK [m] = | K [m] −K [m−r] |

  Then, instead of the relative fluctuation amount ΔK [m] based on the formula 21 or the above-described formula 15, the relative fluctuation rate ΔK ′ [m] is obtained based on the following formula 22, for example, and the relative fluctuation rate ΔK ′ [ m] and the allowable relative fluctuation rate ΔKmax ′ based on Expression 23 may be compared to determine whether or not the weight measurement system is normal. In Equation 23, γ is an allowable variation rate (%) that can be arbitrarily set.

<< Formula 22 >>
ΔK ′ [m] = | (K [m] −K [m−1]) / K [m] |

<< Formula 23 >>
ΔKmax ′ = γ / 100

  In addition, as described with reference to FIG. 4, the surface shape of the transported object 100 on the virtual plane is expressed by eight linear function expressions of f0p (x) to f7p (x). Not exclusively. For example, it may be expressed by a quadratic function expression. In this case, one of the two adjacent Y-axis values among the positions P0 to P8 is the maximum value, and the other Y-axis value is the minimum value. In any case, any function expression that can be appropriately determined based on two adjacent Y-axis values may be used.

  In determining the transport volume value V [m] for each section m, first, an average cross-sectional area A [m] of the transported object 100 over the section m is determined, and this cross-sectional area A [m] is obtained. The transport volume value V [m] is obtained by multiplying the travel distance (= N · ΔLp) of the carrier side belt 14 for the one division m, but is not limited thereto. For example, every time the pulse signal Sp is input, that is, every time the carrier-side belt 14 travels a predetermined distance ΔLp, a transport volume value corresponding to the predetermined distance ΔLp is obtained and integrated over one section m. Thus, the transport volume value V [m] for each section m may be obtained.

DESCRIPTION OF SYMBOLS 10 Conveyor scale 12 Belt conveyor 14 Carrier side belt 20 Measuring roller 22, 24 Load cell 28 Pulse generator 30-42 Distance sensor 50 Control apparatus 62 CPU
100 Transported goods

Claims (10)

In a conveyor scale that calculates the transport amount of thin objects to be transported continuously by a belt conveyor,
A load detecting means for detecting a load applied via the carrier side belt of the belt conveyor, and a weight per predetermined unit of the transported object related to the transport amount based on a load detection value by the load detecting means; A weight measuring means for determining,
Position detecting means for detecting, in a non-contact manner, the position of the upper surface of the object to be transported that corresponds to the line of intersection between the plane perpendicular to the traveling direction of the carrier side belt and the upper surface of the object to be transported; Volume measuring means for obtaining a volume per unit of the transported object related to the transport amount based on a position detection value by:
A determination means for comparing the weight measurement value by the weight measurement means and the volume measurement value by the volume measurement means to determine the presence or absence of abnormality of the weight measurement means;
Conveyor scale characterized by comprising. The volume measuring unit obtains a first function expression representing the upper surface position of the transported object based on the position detection value, and the carrier side belt corresponding to the intersection line of the orthogonal plane and the upper surface of the carrier side belt. Obtaining the area of the cross section of the transported object by the orthogonal plane based on the second function expression representing the upper surface position and the first function expression, and further obtaining the volume measurement value based on the area
The conveyor scale according to claim 1. The position detection means detects a plurality of locations of the upper surface position of the transported object,
The volume measuring means subdivides the cross section into a plurality of regions based on the plurality of locations, obtains the first function equation for each of the subdivided regions, and the first function equation for each region. And determining the area for each region based on the second function formula for each region, and further determining the volume measurement based on the total area for each region,
The conveyor scale according to claim 2. The determination means determines the presence or absence of abnormality of the weight measurement means based on the apparent specific gravity value of the transported object which is a ratio of the weight measurement value and the volume measurement value.
The conveyor scale according to any one of claims 1 to 3. The determination means determines that the weight measurement means is abnormal when a difference between the apparent specific gravity value and a reference specific gravity value that is a reference of the apparent specific gravity value exceeds a predetermined first threshold value.
The conveyor scale according to claim 4. The determination unit determines that the weight measurement unit is abnormal when the degree of change in the apparent specific gravity value at predetermined intervals exceeds a predetermined second threshold value.
The conveyor scale according to claim 4 or 5. A warning output means for outputting a warning when the determination means determines that the weight measurement means is abnormal;
The conveyor scale according to any one of claims 1 to 6. First transportation amount calculating means for obtaining the transportation amount based on the weight measurement value;
Second transportation amount calculating means for obtaining the transportation amount based on the volume measurement value;
Transport amount information output means for outputting information relating to one or both of the first transport amount determined by the first transport amount calculation means and the second transport amount determined by the second transport amount calculation means;
The conveyor scale according to any one of claims 1 to 7, further comprising: The transport amount information output means outputs information on the first transport amount when the determination means determines that the weight measurement means is normal, and the determination means determines that the weight measurement means is abnormal. When it is determined, information on the second transportation amount is output.
The conveyor scale according to claim 8. The second transport amount calculation means estimates the weight per predetermined unit of the transported object based on the reference value of the ratio between the weight measurement value and the volume measurement value and the volume measurement value, and is estimated Obtaining the second transportation amount based on the estimated weight value;
The conveyor scale according to claim 8 or 9.

Images