JPH06317458A - Combination register - Google Patents

Abstract

PURPOSE:To correct the detection signal of a metric unit by regarding the output signals from a plurality of metric units, deviated from the previous combinational operation, as dummy signals and detecting vibration of the floor on which the metric units are disposed based on the components of vibration and then calculating the vertical displacement. CONSTITUTION:Metric units 11-1n weigh objects at weight detecting sections 271-27n thereof to produce signals W1-Wn which are fed to a multiplexer 2 through amplifiers 31-3n. A selected output is then fed through an A/D converter 4 to a CPU 5. A combinational operating means in the CPU 5 then performs combinational operation on the signals W1-Wn to select a combination of total weight values closest to a target value thus driving the gate driving sections 281-28n correspondingly. Metric signals W1-Wn from the metric units 1i-1n not employed in the combinational operation are regarded as dummy signals and the oscillation mode of the floor F is detected based on the components of vibration thus calculating the vertical displacement. The calculated displacement is then subtracted from the signals Wi-Wn thus removing the influence of the vibration of floor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, for weighing food and industrial parts, and calculates the target value by combining the weighing signals of a plurality of weighing instruments installed on the same floor. Regarding the combination weighing device that discharges the objects to be weighed from the weighing machine that is a close combination, in detail, the vertical displacement of the floor is calculated using the weighing signal from the weighing machine not selected for the combination, and this displacement The present invention relates to a combination weighing device configured to eliminate a measurement error caused by the measurement.

[0002]

2. Description of the Related Art In a combination weighing device of this type, a weighing signal output from a plurality of weighing devices that has not been selected in a previous combination calculation is used as a dummy signal, and the dummy signals are added to obtain an average value. It is known that the output fluctuation caused by the floor vibration is removed by correcting the measured value by the measuring instrument selected in (1) (for example, see JP-A-64-32122).

Since the floor vibration generally has a lower frequency than the vibration generated when the object to be weighed is placed on the weighing device, when the floor vibration component is removed from the weighing signal by a filter, the cutoff frequency of the filter is lowered. Since it needs to be set, the filtering time becomes long and the weighing speed is reduced. Therefore, as described above, the floor vibration component is separately removed by correction, so that the cutoff frequency of the filter can be set high, thereby achieving high-speed weighing.

[0004]

However, in the conventional combination weighing device having the above-mentioned configuration, the vibration characteristic of the floor is obtained by the average value of the output signals of the plurality of weighing devices which are not selected in the previous combination calculation. Then, the output value of the weighing instrument selected for the combination is corrected. In other words, assuming that the vibration state of the floor at the position where multiple measuring instruments are installed is the same,
Since the correction is performed, if the vibration state of the floor part where each measuring instrument is installed is different, even if the floor vibration component obtained by the above average value from the output value of the selected measuring instrument is removed. Accurate correction cannot be performed, and in some cases, the error may become larger due to the correction. In any case, the measurement error due to floor vibration was inevitable.

The present invention has been made in view of the above-mentioned circumstances, and eliminates the need for using a special dummy cell, an amplifier or the like to reduce the equipment cost and to reduce the cost of the position where a plurality of measuring instruments are installed. An object of the present invention is to provide a combination weighing device capable of accurately removing a vibration component included in a weighing signal to realize highly accurate weighing even when the vibration state of the floor portion is different. .

[0006]

In order to achieve the above object, a combination weighing device according to claim 1 of the present invention measures a plurality of objects to be weighed and outputs a plurality of weighing signals corresponding to the weights. When the measuring instruments are installed on the same floor and the weighing signals of these weighing instruments are combined and calculated to discharge the objects to be weighed from the weighing instruments that have a combination close to the target value, it is not selected in the previous combination calculation. Using the weighing signals output from multiple weighing instruments as dummy signals, the vibration mode of the floor is detected based on the vibration components of these dummy signals, and the vertical displacement of the floor at the position where each weighing instrument is installed is calculated. And a floor vibration correction means for generating a vibration corrected signal by removing the floor vibration component from the weighing signal by the calculated displacement.

In addition to the configuration of claim 1, the combination weighing device according to claim 2 further comprises a spring constant of each weighing device and a load of each weighing device when no object is placed on the weighing device. From this, cell sensitivity setting means for setting the cell sensitivity ratio between the measuring instruments, and cell sensitivity correcting means for correcting at least one of the weighing signal and the dummy signal with the cell sensitivity ratio to generate a cell sensitivity corrected signal. It has and.

Further, in addition to the structure of claim 1, the combination weighing device according to claim 3 further comprises a weight sensitivity calculating means for calculating a weight sensitivity ratio between the weighing devices according to the weight of the object to be weighed.
Weight sensitivity correction means for correcting at least one of the weighing signal and the dummy signal with the weight sensitivity ratio to generate a weight sensitivity corrected signal.

[0009]

According to the structure of claim 1 of the present invention, the weighing signals corresponding to the weights of the objects to be weighed, which are obtained by the plurality of weighing devices, are combined and calculated, and the weighing devices having the combination close to the target value are measured. Discharge things. At this time, by using the weighing signal output from the weighing instrument that was not selected in the previous combination operation as a dummy signal, a special dummy cell with the same performance as the weighing instrument for eliminating measurement error due to floor vibration. It is not necessary to install an amplifier or an amplifier and the equipment cost can be reduced.

Further, the vibration mode of the floor is detected based on the vibration components of the plurality of dummy signals, and the vertical displacement in the floor portion where the weighing machine selected for the combination is installed is calculated. Then, the measured signal is corrected by the calculated displacement in the vertical direction to generate a vibration corrected signal in which the influence of floor vibration is removed. That is, by subtracting the vertical displacement in the floor part where the weighing instrument is installed from the weighing signal of the selected weighing instrument, the selected weighing instrument and the unselected weighing instrument are installed. Even if the vibration state of the floor portion at a different position is different, the weighing signal can be accurately corrected, and highly accurate weighing can be realized.

Further, according to the second aspect of the present invention, the cell sensitivity ratio between the measuring instruments is used to correct at least one of the weighing signal and the dummy signal to generate the cell sensitivity corrected signal, and thereby the floor vibration is corrected. It is possible to prevent the occurrence of a weighing error due to the difference in the sensitivity of the weighing instrument and further improve the weighing accuracy.

Further, according to the third aspect of the invention, the cell sensitivity ratio between the respective weighing devices with the object to be weighed placed thereon, that is, the weight sensitivity ratio is calculated, and the weighing signal is calculated based on the calculated weight sensitivity ratio. Also, by correcting at least one of the dummy signal and the dummy signal to generate a weight sensitivity corrected signal, it is possible to prevent weighing errors due to changes in the sensitivity of the weighing instrument due to the load of the object to be weighed, and to further improve weighing accuracy. Can be made.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a combination weighing device according to an embodiment of the present invention. In the figure, reference numeral 20 denotes a vibrating and conveying type dispersion table, in which objects to be weighed (mainly powder particles in this case) that are dropped from above are radially dispersed and are radially arranged around the table 20. The objects to be weighed are dispersedly supplied to the plurality of weighing sections 21 _{1 to} 21 _n . Each of these metering sections 21 _{1 to} 21 _n has a distributed supply device 22 _{1 to} 22 _n having electromagnetic vibrating portions 22a1 to 22a1 and troughs 22b2 to 22bn and a pool hopper 23 _1.
˜23 _n , pool hopper gates 24 _{1 to} 24 _n , weighing hoppers 25 _{1 to} 25 _n , weighing hopper gates 26 ₁ to
26 _n , a weight detection unit 27 _{1 to} 27 _n, and a hopper gate drive unit 28 _{1 to} 28 _n . The weighing hoppers 25 _{1 to} 25 _n and the weight detection units 27 _{1 to} 27 _n provide a plurality of weighing devices. 1 ₁ to 1 _n are configured.

[0014] 29 is a collecting chute for collecting the objects to be weighed which have been discharged from the weighing hopper 25 ₁ to 25 _n in each meter 1 ₁ to 1 _n downward central portion, and a funnel-shaped conical or polygonal There is. 30 is a base and is on the same floor F
Installed and supported by.

FIG. 2 is a block diagram showing a schematic configuration of a signal processing system of the combination weighing device as described above. In FIG. 2, reference numerals ₁₁ to 1n _denote the plurality of weighing devices, and the weights of the objects to be weighed. Are weighed by the weight detectors 27 _{1 to} 27 _n , and analog weighing signals W1 to Wn corresponding to the respective weights are output.
A multiplexer 2 receives the weighing signals W1 to Wn output from the weighing devices 1 ₁ to 1 _n after being amplified by the amplifiers 3 _{1 to} 3 _n . 4 is an A / D converter, which will be described later in CP.
The analog weighing signals W1 to Wn selectively output from the multiplexer 2 by the switching signal c from U5.
To a digital signal.

Reference numeral 5 denotes a CPU which constitutes an arithmetic means and the like, which executes a predetermined vibration correction and a combination operation based on the digital weighing signals W1 to Wn inputted through the A / D converter 4 to obtain a target value. The open signal OS for selectively opening the weighing hoppers 25 _{1 to} 25 _n that are the closest combination is output.

[0017] FIG. 3 is a block diagram showing the configuration of the interior of the CPU 5, in FIG, 6 ₁ to 6 _n are each digital filter of FIG. 2 multiplexer 2
The weighing signals W1 to Wn selectively output from the A / D converter 4 and converted into digital signals by the A / D converter 4 are passed through the switching circuit 7 of FIG.
By passing the object to be weighed _{1 to} 6 _n , the relatively high vibration component having the same wave number, which is generated when the object to be weighed is put into the weighing hoppers 25 _{1 to} 25 _n of the weighing devices ₁₁ to 1 _n , is mainly removed.

Reference numeral 8 denotes a combination calculating means, which receives the digital weighing signals W1 to Wn which have passed through the digital filters 6 _{1 to} 6 _{n and} which has been passed through a floor vibration correcting means 10 which will be described later, and then inputs them as corrected weighing signals BS1 to BSn. Then, they are combined and calculated, and the weighing machine that becomes the combination of the total weight values closest to the target value, for example, 1 ₁ , 1 ₂ , 1 ₃ is selected,
The hopper gate driver 28 _{1-28 3} in the meter ₁ 1 to 1 ₃ of the selected 2 outputs a gate open signal OS, weighing hoppers 25 ₁ thereof meter ₁ 1 to 1 ₃
The object to be weighed is discharged from 25 ₃ to the collecting chute 29.

Normally, in the combination calculation in the combination calculation means 8, a plurality of measuring instruments remain without being selected. For example, if the weighing devices 1 _i to 1 _n are not selected, the objects to be weighed remain in the weighing hoppers 26 i to 26 n. Corresponding to the pool hopper 23i
The object to be weighed is not supplied from ~ 23n. Therefore, vibrations due to the supply (drop) of the objects to be weighed do not occur in the weighing hoppers 26i to 26n. As a result, these measuring instruments 1 _i to 1 _n only vibrate under the vibration of the floor F, so that the vibration components of the weighing signals Wi to Wn shown in FIG. 3 become equal to the floor vibration component. The scales 1 _i to 1 _n include
Of course, the scales 1 _{1 to} 3 ₃ selected in this combination calculation
May be included.

Reference numeral 9 denotes a floor vibration calculating means, which converts the weighing signals Wi to Wn output from the plurality of weighing instruments 1 _i to 1 _n not selected in the previous combination calculation into the digital dummy signal D.
i to Dn, these digital dummy signals Di to Dn
Based on the vibration component by detecting the floor vibration mode, it calculates the vertical displacement of the floor at the position measuring instrument 1 ₁ to 1 ₃ is installed.

[0021] 10 in the floor vibration correcting means by vertical displacement signals S1~Sn each meter ₁ 1 to 1 _n calculated by the floor vibration calculating means 9, is output from the meter ₁ 1 to 1 _n The measured signals W1 to Wn are corrected, that is, the vertical displacement signals S1 to S from the measured signals W1 to Wn.
By subtracting the displacement amount by n, the vibration-corrected weighing signals BS1 to BSn from which the influence of floor vibration is removed are generated and output. In this way, by correcting the low-frequency floor vibration component, it is possible to set the cutoff frequency of the filters 6 _{1 to} 6 _n high and realize high-speed weighing. The vibration-corrected weighing signals BS1 to BSn are input to the combination calculating means 8 to select a plurality of signals BS1 to BSn that are the combination closest to the target value, and the signals BS1 to BSn are selected.
A selection signal OS for opening the weighing hoppers 25 _{1 to} 25 _n outputting n is output.

As described above, among the plurality of weighing scales 1 ₁ to 1 _n installed on the same floor F, the plurality of weighing scales 1 _i to 1 _n not selected in the previous combination calculation are used as dummy cells. The measurement signals Wi to Wn and the dummy signal D
When i to Dn, the vibration mode is detected based on the vibration components of these dummy signals Di to Dn, and the vertical displacement of the installation position of the measuring instruments 1 ₁ to 1 _{n on} the floor F is calculated,
By subtracting (cancelling) the calculated displacement from the weighing signals W1 to Wn, corrected weighing signals BS1 to BSn from which the influence of floor vibration is removed are output. here,
In this embodiment, since the correction calculation is performed digitally, it is possible to perform the correction with higher accuracy as compared with the case of using an analog circuit in which the characteristics of individual parts and elements have variations.

As described above, the weight detecting units (hereinafter referred to as "load cells") 27 _{1 to} 27 _n of a plurality of weighing devices detect the mode of floor vibration and cancel the vibration component of the load cell at an arbitrary position. Is a floor vibration cancellation method (hereinafter referred to as multi-point AFV (Anti- Floor Vibration) method)
Say. When the load cell is arranged on the floor in a plane, that is, two-dimensionally, the floor vibration at three or more points that are not on the floor is detected by the dummy cell, and the vibration mode of the floor is detected from the detected vibrations. Then, the floor vibration component at the position where the arbitrary load cell is installed is obtained from this vibration mode, and the floor vibration component is subtracted from the output of the load cell installed at that position. On the other hand, when the load cells are linearly arranged on the floor, that is, one-dimensionally arranged, floor vibrations at two or more points on the straight line are detected by the dummy cells, and from the detected vibrations, in the case of the above planar arrangement. Similarly to, the floor vibration component at the position where an arbitrary load cell is installed is obtained, and the floor vibration component is subtracted from the output of the load cell installed at that position.

FIG. 4 shows a load cell 27 used in the above combination weighing device. This type of load cell 2
The strain gauge 32 attached to each of the four notch portions 31 detects the deformed state of the load cell 27 as the strain amount. Furthermore, these four strain gauges 32 constitute a Wheatstone bridge, and the output changes only when the load cell 27 is deformed to the Roverval (parallelogram) state as shown by the broken line, and in other deformed states, The output does not change. Therefore, the fixed (floor) side 27a of the load cell 27
Of the relative displacement on the load (weight) side 27b, only the Roberval deformation component is detected. Therefore, when used in the combination weighing device described above, only the vertical component for the floor vibration state of each mode is detected. It turns out that you should consider.

Now, as shown in FIG. 5, it is assumed that the load cell 27 is fixed at the position of the point (x, y) on the XY plane. The behavior of the XY plane consists of rotation about the X axis, rotation about the Y axis, and movement in the axis (Z axis) direction perpendicular to the XY plane. Other motions are not detected by the load cell 27 used here, and therefore will not be discussed here.

Here, the vertical (Z-axis) component movement generated by the rotational movement about the X-axis is B (t), and the vertical (Z-axis) component movement generated by the rotation movement about the Y-axis is A (t). ), Z
If the axial motion is C (t), the floor vibration component Vp (t) in the output signal of the load cell at the position of the point P is Vp (t) = x · A (t) + y · B (T) + C (t) (1)

By the way, for the vibration mode of the floor, A (t), B (t), and C (t) in the equation (1) may be obtained. Therefore, in order to obtain this, three points that are not on a straight line are used. It suffices to detect the motion of the floor, that is, solve the three-dimensional linear simultaneous equations. In reality, since the output of each measuring instrument contains an error, it is detected at three or more points and A (t), B (t), and C (t) are obtained by using the least square method or the like. Is good. The calculation of the vibration component Vp (t) based on the equation (1) is performed by the floor vibration calculation means 9 in FIG.

In the above embodiment, it is preferable to add the following functions. In order to extract only the vibration component from the output signal of the vibration detection dummy cell, a filter having a very low cutoff frequency and a long stabilization time is used in parallel with a normal filter. Although this filter is very effective, it is not stable in the time of one weighing cycle. Therefore, when the weighing instrument continuously participates in the combination calculation, the data obtained by correcting the floor vibration is used as the output signal, but when the weighing device does not continuously participate and the stable time of the strong filter can be secured, The filter result is automatically switched to be used as the output signal.

When a head that has not participated in the combination calculation last time is used as a dummy cell for vibration detection, the vibration mode of the floor can be determined with at least three points, but the vibration mode is only used with dummy cells that are adjacent to each other. If you decide, the error is large. Therefore, a load cell pattern in which the error is equal to or less than a predetermined value is obtained in advance, and a combination is determined every time so that the load cells in the pattern are preferentially left.

FIG. 6 is a block diagram showing the configuration of the CPU 5 in the weighing device according to another embodiment of the present invention.
In the figure, the following two points are different from the internal configuration of the CPU 5 of the above embodiment shown in FIG. First the first point, the meter 1 ₁ to 1 and the spring constant of the load cell 27 ₁ ~ 27 _n for _n, each meter from the load of the load cell 27 ₁ ~ 27 _n in a state where objects to be weighed is not placed The cell sensitivity setting means 15 for setting the cell sensitivity ratio between the dummy signals Di to D with the cell sensitivity ratio based on one of the weighing devices.
The cell sensitivity correction means 16 for correcting n to generate the cell sensitivity corrected signals CSi to CSn is provided.

The second point is to correct the change in sensitivity to floor vibration due to different load weights, and to calculate the weight sensitivity ratio between the weighing devices according to the weight of the object to be weighed. The weight sensitivity calculation means 17 and the weight sensitivity ratio calculated by the weight sensitivity calculation means 17 are used to correct the displacement signals S1 to Sn output from the floor vibration calculation means 9 to obtain the weight sensitivity corrected signals WS1 to WSn. And a weight sensitivity correction means 18 for generating

The cell sensitivity is corrected by the cell sensitivity correcting means 16 and the dummy signals Di to Dn are measured signals W1 to Wi _-1.
The floor vibration is calculated by the floor vibration calculating means 9 based on the converted signals (cell sensitivity corrected signals) CSi to CSn. Further, the weight sensitivity correction means 18 performs sensitivity correction according to the weight of the objects to be weighed loaded on the weighing devices 1 ₁ to 1 _n , and the weight sensitivity corrected signals WS 1 to W.
The floor vibration correcting means 10 uses Sn to measure signals W1 to W1.
Vibration-corrected signal BS1 by subtracting the floor vibration component from n
Obtain ~ BSn. Since other configurations are the same as those in FIG. 3, the same reference numerals are given to corresponding portions, and detailed description thereof will be omitted.

The formula for sensitivity correction in the embodiment shown in FIG. 6 will be briefly described. The case of FIG. 6 can be represented by the vibration model of FIG. If we call all the load cells used for the combination calculation in this weighing, that is, all the load cells, and the load cells that are not selected in the combination calculation in the previous weighing, the dummy cells. The equation of motion of the dummy cell (floor vibration detection side) is as shown in equations (11) and (12). In both equations (11) and (12), M
0 and M1 are loads (mass) attached to the free ends of the dummy cell and the weighing cell in the state where the object to be weighed is not placed,
m is the mass of the object to be weighed, k0, k1 are the spring constants of the dummy cell and the weighing cell, x0, x1 are the displacements of the free ends of both cells, x
_B is the displacement of the floor F.

[0034]

[Equation 1]

Since the relative displacement between the floor side and the load side is the output of each cell, the above equations (11) and (12) are given.
Can be transformed into equations (13) and (14).

[0036]

[Equation 2]

Using the above equations (13) and (14), the displacement of the floor is taken as the input of the system, and the output of the cell is taken as the output of the system, the transfer function which is the relation of the input and output thereof is obtained, and the frequency characteristic of the amplitude is further obtained. When G1 (jω) and Go (jω) are calculated, equation (15)
And it becomes Formula (16). Expression (15) and Expression (16)
In, ω ₁ is the natural frequency of the weighing cell, and ω ₀ is the natural frequency of the dummy cell. As described above, the weighing cell and the dummy cell may be the same, and in that case, of course,
ω ₁ = ω ₀ .

[0038]

[Equation 3]

Therefore, the ratio β of the sensitivity between the metering cell side and the dummy cell side is given by the following equation (17).

[0040]

[Equation 4]

Here, 1 >> (ω / ω _o ) ² , 1 >> (ω / ω
₁ ) ² , that is, when the frequency to be corrected has a sufficiently high natural frequency on both the measurement cell side and the dummy cell side, formula (18) is obtained.

[0042]

[Equation 5]

In this equation (18), the part of is m
= 0, that is, the sensitivity ratio of both cells in the state where the object to be weighed is not placed, and the part of shows how much the sensitivity of the weighing cell changes due to the placement of the object to be weighed. That is, it represents the weight sensitivity ratio of both cells.

The spring constants of the weighing device, that is, the spring constants k0 and k1 of the weighing cell and the dummy cell, the load M1 of the weighing cell in the state where the object to be weighed is not placed, and were not selected in the previous combination calculation. Based on the load M0 of the dummy cell, the cell sensitivity ratio is obtained in advance by the simple equation shown by the above equation (18), and the cell sensitivity setting means 1 of FIG.
This cell sensitivity ratio is set in step 5, and the cell sensitivity correction means 16
Correct the cell sensitivity with. On the other hand, the weight sensitivity calculation means 17
Then, the weight sensitivity ratio is obtained by a simple equation represented by the above equation (18), and the weight sensitivity correction means 18 corrects the weight sensitivity. In this way, the correction of the weighing signal can be performed extremely accurately.

In the embodiment shown in FIG. 6, the cell sensitivity correction and the weight sensitivity correction are performed not only for the dummy cell but also for the weighing cell, thereby further improving the weighing accuracy.

The cell sensitivity correction means 16 and the weight sensitivity correction means 18 perform the cell sensitivity correction and the weight sensitivity correction of only the weighing signals W1 to Wn to obtain the dummy signals Di to.
The floor vibration correction may be performed after converting the level to Dn, but in that case, it is necessary to perform the correction to convert the sensitivity-corrected weighing signals W1 to Wn to the level before correction again. In other words, the cell sensitivity correction means 16 and the weight sensitivity correction means 18 use the dummy signal D from the combination calculation means 8.
i-Dn or the weighing signals W1 to Wn, or both of the signals Di to Dn, W1 to Wn, that is, at least one of the dummy signals Di to Dn or the weighing signals W1 to Wn is subjected to sensitivity correction.

Further, since the digital filters 6 _{1 to} 6 _n are used in each of the above-mentioned embodiments, the cut-off characteristics are different from those in the case of using the analog filters in which the characteristics of individual parts and elements are also varied. Since the error becomes small, it becomes possible to set the cutoff frequency of each of the filters 6 _{1 to} 6 _n high, and as a result, the response is further improved and the weighing is speeded up.

[0048] However, digital filters 6 ₁ -
An analog filter may be used instead of or together with 6 _n , in which case the analog filter 19 is connected at the position shown by the phantom line in FIG.

Further, in the embodiment shown in FIG. 6, it is preferable to add the following functions. In order to reduce the error after the floor vibration correction, the weight sensitivity correction is performed when the object to be weighed is loaded, but the mass m of the object to be weighed used in the correction formula is the final desired result. Is an undetermined value. Therefore, first, floor vibration correction is performed without weight sensitivity correction, and the result (mass m of the object to be weighed) is calculated.
Floor vibration correction with weight sensitivity correction is performed again using that value. This is repeated multiple times to obtain high weighing accuracy.

If the floor vibration is small, the floor vibration may be corrected due to a calculation error or the like, which may rather reduce the weighing accuracy. Therefore, if the vibration component of the dummy cell output for vibration detection is below a certain standard, floor vibration correction is automatically stopped to prevent deterioration of accuracy.

The present invention can also be applied to a combination weighing device in which a plurality of weighing devices are linearly arranged.

[0052]

As described above, according to the first aspect of the present invention, by using the weighing signal output from the weighing machine not selected in the previous combination calculation as a dummy signal, the weighing error due to floor vibration is generated. Therefore, it is not necessary to install a special dummy cell or amplifier having the same performance as that of the measuring instrument, and the equipment cost can be reduced. Moreover, by detecting the vibration mode of the floor based on the vibration components of the plurality of dummy signals, the vertical vibration component, that is, the vertical displacement, in the floor portion where the weighing instrument is installed is calculated and corrected. Therefore, even if the vibration state of the floor portion at the position where the weighing instrument that outputs the dummy signal and the weighing instrument that outputs the weighing signal are different, Even when the combination is selected, the weighing signal can be accurately corrected to realize the highly accurate combined weighing.

According to the second aspect of the present invention, it is possible to prevent the measurement error from occurring due to the difference in the sensitivity of the measuring instrument to the floor vibration, thereby further improving the measuring accuracy.

Further, according to the third aspect of the present invention, it is possible to prevent the occurrence of a weighing error due to the change of the weight sensitivity due to the load of the object to be weighed, so that the weighing accuracy is further improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a combination weighing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a signal processing system of the above combination weighing device.

FIG. 3 is a block diagram showing a configuration of a CPU of FIG.

FIG. 4 is a diagram showing a model of a load cell for explaining the theory of AFV technology.

FIG. 5 is a diagram showing an arrangement of the load cells of the above.

FIG. 6 is a block diagram showing a configuration of a CPU in a combination weighing device according to another embodiment of the present invention.

FIG. 7 is a diagram showing a model in the case of FIG.

[Explanation of symbols]

1 ₁ to 1 _n ... Measuring instrument, 5 ... CPU, 8 ... Computing means, 9 ...
Floor vibration calculation means, 10 ... Floor vibration correction means, 16 ... Weight sensitivity calculation means, 17 ... Weight sensitivity correction means, W1-Wn (D
1 to Dn) ... Metering signal (dummy signal), BS1 to BSn
... vibration corrected signal, WS1-WSn ... weight sensitivity corrected signal, F ... floor.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hidekatsu Tokumaru 5-7 Mizukamidacho, Shugakuin, Sakyo Ward, Kyoto City, Kyoto Prefecture

Claims (3)

[Claims] 1. A plurality of weighing instruments for weighing an object to be weighed and outputting a weighing signal corresponding to the weight are installed on the same floor, and the weighing signals of these weighing instruments are combined and calculated to obtain a target value. In a combination weighing device that discharges objects to be weighed from weighing instruments that are close to each other in combination, the weighing signals output from multiple weighing instruments that were not selected in the previous combination calculation are used as dummy signals and based on the vibration components of these dummy signals. Floor vibration calculation means for detecting the floor vibration mode and calculating the vertical displacement of the floor at the position where each measuring instrument is installed, and the floor vibration component is removed from the weighing signal by the calculated displacement. A combination weighing device, comprising: floor vibration correction means for generating a vibration corrected signal. 2. The cell according to claim 1, wherein a cell sensitivity ratio between the respective weighing devices is set based on a spring constant of each of the weighing devices and a load of each of the weighing devices when an object to be weighed is not placed. A combination weighing device comprising sensitivity setting means and cell sensitivity correction means for correcting at least one of the weighing signal and the dummy signal with the cell sensitivity ratio to generate a cell sensitivity corrected signal. 3. The weight sensitivity calculating means for calculating the weight sensitivity ratio between the weighing devices according to the weight of the object to be weighed according to claim 1, and at least one of the weighing signal and the dummy signal being the weight sensitivity ratio. A combination weighing device, comprising: a weight sensitivity correction unit that corrects and generates a weight sensitivity corrected signal.