JP5535661B2 - Weighing device - Google Patents

Description

  The present invention relates to a weighing device including a filter that filters a load signal output from a load sensor according to a load applied to a weighing unit of an object to be measured and outputs a response measurement value.

Conventionally, the timing at which an object is supplied to the weighing unit is detected by an article sensor, the time is counted from the detected timing, and the time at which a weight measurement value is obtained from the weight signal output from the filter is determined. There is known a weighing device that evaluates filter characteristics with each weight measurement value (see Patent Document 1).
Also, in weighing devices with multiple different filters, every time an object is measured while the weighing device is in operation, the weighing data in response is detected and evaluated, so that the most stable (transient response) There is one in which a filter having a fast signal convergence is selected (see Patent Document 2).
Further, in a weighing device having a floor vibration correction comprising a first digital filter that removes a relatively high frequency vibration component and a second digital filter that removes a low frequency vibration component, the amplitude of the floor vibration component is a reference value. Is exceeded, the correction processing circuit including the second digital filter is operated to perform vibration correction. On the other hand, when the amplitude of the vibration component of the floor is below the reference value, the correction processing circuit is operated. There is one in which unnecessary vibration correction is stopped by stopping it (see Patent Document 3).
In the weighing signal processing apparatus including digital filters having different filter characteristics corresponding to the weight rank of the article, the filter characteristics having the shortest filtering time are sequentially switched to the filter characteristics having the long filtering time corresponding to the weight rank. There is one that processes the weighing signal (see Patent Document 4).

JP-A-6-43011 JP 7-333045 A Japanese Patent Laid-Open No. 7-198469 Japanese Patent Laid-Open No. 8-170928

However, in the weighing device according to Patent Document 1, although the variation in time from the supply timing of the object to be weighed to the weighing unit until the load signal starts rising is not related to the filter characteristic, the response characteristic of the filter Therefore, there is a problem that the filter characteristics cannot be correctly evaluated and the optimum filter cannot be determined.
Further, in the weighing device according to Patent Document 2, since the true weight value of the object to be weighed (the weight measurement value after a sufficient amount of time has elapsed = the final stable value) is not known, in other words, the difference from the final stable value is calculated. Since it cannot be evaluated, the weight measurement based on the filter with the fastest convergence in the course of the transient response at a certain weighing time does not always have the smallest error with respect to the true weight value, ie the earliest final stable value. It is not always converged to. In a filter with a large response delay, even if convergence to the final stable value is slower than other filters, convergence as metric data during response may be the fastest. Therefore, just because a filter with fast convergence of the transient response signal is selected, there is a problem that a filter that quickly converges the transient response signal to the final stable value is not necessarily selected.
Further, in each device according to each of Patent Documents 2 to 3, when setting a plurality of filters in advance, a device that is optimal for the device or that has characteristics in the vicinity thereof is not always set. There is a point.

  The present invention has been made in view of the above-described problems, and can accurately determine an optimum filter by appropriately evaluating the filter characteristics without being affected by the supply timing of the object to be weighed. The object is to provide a weighing device.

In order to achieve the above object, the weighing device according to the first invention comprises:
In a weighing device comprising a plurality of filters having different filter characteristics from each other for filtering a load signal output from a load sensor according to a load applied to a weighing unit of an object to be weighed,
A filter calculation means for calculating a response measurement value by executing a filter calculation algorithm according to the plurality of different filters;
Response measurement value acquisition means for acquiring response measurement values of the filter calculation means at a plurality of different response waiting times starting from the timing near the rising edge of the load signal;
Based on the response measurement value acquired by the response measurement value acquisition means when the measurement is performed a plurality of times, the response measurement of the response measurement value at the different response waiting time for each of the plurality of different response waiting times. An average deviation calculating means for obtaining an average deviation which is an average value of deviations from the final stable value of the value;
Filter determining means for determining a filter in which the average deviation is smaller than a preset allowable value at the shortest response waiting time among the plurality of different response waiting times as a filter to be used during the actual operation. It is characterized by this .

The weighing device according to the second invention is
In a weighing device comprising a plurality of filters having different filter characteristics from each other for filtering a load signal output from a load sensor according to a load applied to a weighing unit of an object to be weighed,
A filter calculation means for calculating a response measurement value by executing a filter calculation algorithm according to the plurality of different filters;
Response measurement value acquisition means for acquiring response measurement values of the filter calculation means at a plurality of different response waiting times starting from the timing near the rising edge of the load signal;
Based on the response measurement value acquired by the response measurement value acquisition means when the measurement is performed a plurality of times, a variation amount of the response measurement value in the different response waiting time is obtained for each of the plurality of different response waiting times. A variation amount calculating means and an average deviation calculating means for calculating an average deviation of the response measurement values;
A filter in which the variation amount and the average deviation simultaneously become smaller than a preset allowable value at the shortest response waiting time among the plurality of different response waiting times is determined as a filter to be used in actual operation. And a filter determining means.

In the first invention or the second invention, the filter determined by the filter determining means is defined as a filter candidate that can be used during actual operation according to the weighing condition, and the display means for displaying the filter candidate, and the display Preferably, filter setting means is provided for selecting and setting the filter candidates displayed on the means as filters to be used during actual operation ( third invention).

In the first aspect of the invention , it is preferable that display means for displaying the average deviation and filter setting means for selecting and setting a filter to be used during actual operation based on the display content of the display means are provided (first). 4 invention).
In the second aspect of the invention, there are provided display means for displaying the variation amount and the average deviation, and filter setting means for selecting and setting a filter to be used during the actual operation based on the display content of the display means. Preferred (5th invention).

In the present invention, the timing in the vicinity of the rising edge of the load signal is used as a starting point for time measurement of a plurality of different response waiting times for evaluating the response measurement value. For this reason, the variation of the time from the supply timing of the object to be weighed to the weighing unit until the load signal starts rising is considered as the response characteristic of the filter regardless of the filter characteristic in the past. Can be eliminated. Then, by evaluating response measurement values at a plurality of different response waiting times, a filter to be used during the actual operation is selectively determined from a plurality of different filters. Therefore, the filter characteristics can be properly evaluated without being affected by the supply timing of the object to be weighed, and the optimum filter can be accurately determined.
Further, the load signal varies depending on the weighing conditions such as the type of the object to be weighed, the supply amount, and the measurement allowable time. Therefore, the optimum filter can be accurately determined according to the measurement conditions.

1 is a schematic system configuration diagram of a combination weigher according to an embodiment of the present invention. Block diagram showing schematic configuration of load signal processing system Load signal graph (a) and response measurement graph (b)

  Next, specific embodiments of the weighing device according to the present invention will be described with reference to the drawings. The embodiment described below is an example in which the present invention is applied to an automatic combination weigher as a weighing device. However, the present invention is not limited to this, and the present invention is applied to other types of weighing devices. Of course, it is also possible.

<Description of schematic configuration of combination weigher>
A combination scale 1 shown in FIG. 1 includes an article supply device 2, a dispersion feeder 3, a linear feeder 4, a supply hopper 5, a weighing hopper 6, a memory hopper 7, a control device 8, and a display device 9. The operation device 10 is provided.
In FIG. 1, only one linear feeder 4, supply hopper 5, weighing hopper 6, and memory hopper 7 are shown.

<Description of article supply device, distributed feeder, straight feeder>
The article supply device 2 drops and supplies the objects to be weighed stored in the device to the dispersion feeder 3.
The dispersion feeder 3 includes an object receiving unit 11 having a circular shape and an umbrella-like periphery, and all objects to be weighed from the article supply device 2 dropped and supplied onto the object receiving unit 11 are vibrated. It is distributed radially over the circumference, and is fed and supplied onto k linearly-feeding feeders 4 arranged around the object receiving portion 11.
The rectilinear feeder 4 sends and supplies the objects to be weighed and supplied from the dispersion feeder 3 toward the supply hopper 5 arranged on the front end side by the vibration operation. If the target weight of the combination calculation is Wt (g) and the target number of combinations is M, the supply hopper 5 is generally adjusted so that Wt / M (g) is supplied. In the adjustment of the supply amount by vibration, it is difficult to supply just Wt / M (g) to each supply hopper 5, and the weight value varies.

<Description of supply hopper, weighing hopper, memory hopper>
The supply hopper 5 temporarily stores the objects to be weighed and supplied from the linear feeder 4 in the hopper, and drops and supplies the objects to be weighed in the hopper to the weighing hopper 6 disposed below.
The weighing hopper 6 temporarily stores the object to be weighed and supplied from the supply hopper 5 in the hopper, detects the weight of the object to be weighed in the hopper with the load sensor 12, and then weighs the object in the hopper. An object is dropped and supplied to the memory hopper 7 disposed below.
The memory hopper 7 temporarily stores the objects to be weighed and supplied from the weighing hopper 6 in the hopper, and collects the objects to be weighed in the hopper as needed via a collecting chute 13 disposed below. Drop to 14.

<Description of amplifier and A / D converter>
An amplifier 15 and an A / D converter 16 are provided between the load sensor 12 and the control device 8, respectively.
Amplifier 15 amplifies the analog load signal from load sensor 12 to a signal large enough to digitize.
The A / D converter 16 converts the analog load signal from the load sensor 12 amplified by the amplifier 15 into a digital load signal.

<Description of control device>
The control device 8 controls the operations of the article supply device 2, the rectilinear feeder 4, the supply hopper 5, the weighing hopper 6, and the memory hopper 7.
The control device 8 is mainly composed of a microcomputer, and as shown in FIG. 2, the filter device 17, the dynamic weight measurement value acquisition means 18, the static weight measurement value acquisition means 19, and the dynamic response measurement. Value acquisition means 20, static response measurement value acquisition means 21, storage means 22, variation amount calculation means 23, average deviation calculation means 24, dynamic weight measurement value acquisition time determination means 25, filter determination means 26, a stable waiting time timer 27, and a response waiting time timer 28.
In the control device 8, by executing a predetermined program, the filter device 17, the dynamic weight measurement value acquisition means 18, the static weight measurement value acquisition means 19, the dynamic response measurement value acquisition means 20, the static response measurement. Each of value acquisition means 21, storage means 22, variation amount calculation means 23, average deviation calculation means 24, dynamic weight measurement value acquisition time determination means 25, filter determination means 26, stable waiting time timer 27, and response waiting time timer 28 The function is realized.

<Description of filter device>
The filter device 17 executes a plurality of filters 17a (filter A1, filter A2,..., Filter Ag) having different filter characteristics and a filter operation algorithm corresponding to the plurality of different filters 17a (filters A1 to Ag). And an output suitable for acquiring a weight measurement value by attenuating a vibration noise component included in the digital load signal from the A / D converter 16. Smooth to response signal.

<Description of dynamic weight measurement value acquisition means>
The dynamic weight measurement value acquisition means 18 outputs from the filter device 17 at each of a plurality of different dynamic weight measurement value acquisition times after the time when the object to be weighed is supplied from the supply hopper 5 to the weighing hopper 6. It has a function of acquiring a dynamic weight measurement value from the response signal.

<Description of static weight measurement value acquisition means>
The static weight measurement value acquisition means 19 has a function of acquiring a static weight measurement value from an output response signal from the filter device 17 at a static weight measurement value acquisition time after a plurality of different dynamic weight measurement value acquisition times. Have.

<Description of Dynamic Response Measurement Value Acquisition Unit>
The dynamic response measurement value acquisition means 20 is a final response waiting time (dynamic response measurement value acquisition) of each of a plurality of different dynamic response waiting times starting from the timing near the rising edge of the load signal from the load sensor 12. The dynamic response measurement value is obtained from the output response signal from the filter device 17 at the time).

<Description of static response measurement value acquisition means>
The static response measurement value acquisition means 21 is more static than the output response signal from the filter device 17 at the final time (static response measurement value acquisition time) of the static response waiting time after a plurality of different dynamic response waiting times. It has a function to acquire response measurement values.

<Description of storage means>
The storage unit 22 has a function of storing a predetermined program executed by the control device 8 and various data.
The storage means 22 is acquired by the dynamic weight measurement value acquisition means 19 and the dynamic weight measurement value acquisition means 19 acquired by the dynamic weight measurement value acquisition means 18 when the weighing is performed a plurality of times during the adjustment operation before the actual operation. Store static weight measurements.
The storage means 22 includes the dynamic response measurement value acquired by the dynamic response measurement value acquisition means 20 and the static response measurement value acquisition means 21 when the measurement is performed a plurality of times during the adjustment operation before the actual operation. The acquired static response measurement value is stored.

<Description of variation amount calculation means>
Based on the dynamic weight measurement value and the static weight measurement value stored in the storage means 22, the variation amount calculation means 23 is a dynamic corresponding to each of a plurality of different dynamic weight measurement value acquisition times. It has a function to calculate the amount of variation in the weight measurement value.
Further, the variation amount calculation unit 23 corresponds to each of a plurality of different dynamic response measurement value acquisition times based on the dynamic response measurement value and the static response measurement value stored in the storage unit 22. It has a function of calculating a variation amount of the dynamic response measurement value, a variation amount of the static response measurement value corresponding to the static response measurement value acquisition time, and the like.

<Description of Mean Deviation Calculation Means>
Based on the dynamic weight measurement value and the static weight measurement value stored in the storage means 22, the average deviation calculation means 24 is a dynamic corresponding to each of a plurality of different dynamic weight measurement value acquisition times. It has a function to calculate the average deviation of the weight measurement value.
Further, the average deviation calculation unit 24 corresponds to each of a plurality of different dynamic response measurement value acquisition times based on the dynamic response measurement value and the static response measurement value stored in the storage unit 22. It has a function of calculating the average deviation of the dynamic response measurement values, the average deviation of the static response measurement values corresponding to the static response measurement value acquisition time, and the like.

<Description of dynamic weight measurement value acquisition time determination means>
The dynamic weight measurement value acquisition time determination unit 25 sets the dynamic weight measurement value acquisition time when the variation amount of the dynamic weight measurement value calculated by the variation amount calculation unit 23 is equal to or less than a predetermined allowable value during the actual operation. It has a function of determining the dynamic weight measurement value acquisition time.

<Description of filter determining means>
The filter determination means 26 is a variable response amount of the dynamic response measurement value with the shortest response waiting time among the plurality of different filters 17a (filters A1 to Ag) set in advance. The filter has a function of determining a filter whose average deviation is smaller than a preset allowable value as a filter to be used in actual operation.
The filter determined by the filter determining means 26 is a filter candidate that can be used in the actual operation in the filter device 17 according to the measurement conditions such as the type of the object to be weighed, the supply amount, and the allowable measurement time. It is prescribed.

<Explanation of stabilization wait time timer>
The stability waiting time timer 27 starts from the time when the gate of the supply hopper 5 begins to open, and the weight from the load sensor 12 when an object to be weighed in the supply hopper 5 is dropped and supplied to the weighing hopper 6. The time until the transient response vibration signal generated in the signal converges enough to obtain an accurate weight measurement value is defined as a stable waiting time, and time is counted for each time interval Δt. The stability waiting time timer 27 set in this way is operated during both the adjustment operation and the actual operation.

<Explanation of response waiting time timer>
The response waiting time timer 28 uses the timing near the rising edge of the load signal from the load sensor 12 as the starting point of time measurement, the time until the dynamic response measurement value acquisition time is the dynamic response waiting time, and the static response measurement value acquisition time. The time is counted for each time interval Δt, using the time until the static response waiting time.
In the following, “dynamic response waiting time” and “static response waiting time” are collectively referred to as “response waiting time” unless otherwise specifically used.

<Description of display device>
The display device 9 displays the weighing accuracy related information including the dynamic weight measurement value acquisition time when the variation amount of the dynamic weight measurement value calculated by the variation amount calculation means 23 is equal to or less than a predetermined allowable value.
Further, the filter characteristic evaluation related information including the variation amount of the dynamic response measurement value, the variation amount of the static response measurement value, the average deviation of the response measurement value, and the like calculated by the variation amount calculation unit 23 is displayed.
Furthermore, the display device 9 displays filter candidates defined in the filter device 17.

<Description of operating device>
The operation device 10 has a function of performing various selection settings and the like based on the contents displayed on the display device 9.
For example, when information regarding candidate filters to be used during actual operation is displayed, a desired filter is selected and set by operating a key switch (not shown) of the operation device 10 based on the display content. .

<Explanation of supply operation of weighing object during actual operation>
During the actual operation, when the weighing hopper 6 is empty, an object to be weighed close to Wt / M (g) is dropped and supplied from the supply hopper 5 to the weighing hopper 6. However, the weight of the object to be weighed supplied to the weighing hopper 5 varies around Wt / M.
The load signal output from the load sensor 12 mounted on each weighing hopper 5 is introduced into the filter device 17 via the amplifier 15 and the A / D converter 16, and the vibration noise component is attenuated by the filter device 17. Smoothed to an output response signal suitable for obtaining response measurements.
The object to be weighed stays until a response measurement value which is an accurate dynamic weight measurement value is obtained from the output response signal output from the filter device 17, but when the dynamic weight measurement value is obtained, The gate of the weighing hopper 6 is opened and dropped and supplied to the memory hopper 7.
Even if the phase of the vibration signal varies back and forth due to some variation in the timing of supply of the object to be weighed to the weighing hopper 6 or the amplitude varies depending on the magnitude of the impact load, the stabilization waiting time is not necessary in most supply conditions. The filter characteristics are set so that the vibration signal converges at the completion timing and a dynamic weight measurement value with a predetermined weighing accuracy is obtained.

<Explanation of weighing and discharging operation during actual operation>
Performs a combination operation between the weighing object in the weighing hopper 6 for which the dynamic weight measurement value has been acquired and stored and the weighing object in the memory hopper 7 for which the dynamic weight measurement value has been stored. Then, the combination whose combined total value is closest to the target value within a certain allowable range is selected. The objects to be weighed in the weighing hopper 6 or the memory hopper 7 selected in combination are dropped into the collecting funnel 14 via the collecting chute 13, collected as commodities, and discharged to the outside.
A new object to be weighed is supplied from the supply hopper 5 to the weighing hopper 6 from which the object to be weighed is discharged by the combination selection calculation, and an object to be weighed is supplied from the weighing hopper 6 to the memory hopper 7 from which the object to be weighed is discharged. Is done. In addition, the weighing / combination selection calculation is continuously performed by supplying an object to be weighed from the linear feeder 4 to the supply hopper 5.
During the actual operation, the time point when the gate of the supply hopper 5 starts to open is the starting point of the time count of the stability waiting time timer, and the weight signal when the object in the supply hopper 5 is dropped and supplied to the weighing hopper 6 The time until the transient response vibration signal generated at the time of convergence enough to obtain an accurate weight measurement is counted as a stable waiting time for each time interval Δt.

  Next, a method for performing an adjustment operation for setting a filter to be used during the actual operation from among a plurality of different filters 17a (filters A1 to Ag) will be described.

<Explanation of operation of linear feeder during adjustment operation>
When an optimum filter is set from among a plurality of different filters 17a (filters A1 to Ag) for a certain type of object to be weighed, the specification of the combination product is set to the target weight Wt according to the conditions during the actual operation. When the target number of combinations is M, the linear feeder 4 is set so that the weight of the objects to be weighed and fed from the linear feeder 4 to the supply hopper 5 at a time becomes about Wt / M (g). Adjust the sending parameters of. That is, the supply weight of the object to be weighed from the linear feeder 4 during the adjustment operation is matched with that during the actual operation.
When setting a filter to be used during actual operation from among a plurality of different filters 17a (filters A1 to Ag), the state of the transient response of the weight signal in the weighing hopper 6 depends on the magnitude and properties of the weight to be weighed. Since it is different, it is appropriate to use the supply weight value that is applied during the actual operation during the adjustment operation.

<Description of conversion from load signal to response measurement value>
As shown in FIG. 2, the load signal “a ′” output from the load sensor 12 passes through the amplifier 15 and the A / D converter 16, respectively, and is a load that represents the weight of the digitized object to be weighed. After being converted into the signal measurement value “a”, it is sent to the filter 17a (filters A1 to Ag). When the load signal measurement value “a” is input to the filter 17a (filters A1 to Ag), the filter calculation unit 17b performs a filter calculation algorithm corresponding to the filter type, filter constant, and the like set by the operation of the operation device 10 And a response measurement value “b” is calculated for each response waiting time. Thus, the load signal “a ′” from the load sensor 12 is converted into a response measurement value “b”.

  FIG. 3 (a) shows a graph of a load signal when an object to be weighed is supplied to the weighing hopper. Moreover, the graph of the response measurement value after passing the filter after the load signal is converted into the load signal measurement value is shown in FIG.

<Explanation of response waiting time>
The starting point of the time measurement of the response waiting time as a time domain for evaluating the response characteristics of the filter 17a (filter A1 to filter Ag) is determined as follows.
That is, in the graph shown in FIG. 3A, the time (time t0 ′) when the load signal output from the load sensor 12 rises to a certain level Wh or more due to the load of the object to be measured is determined from the load signal measurement value. Then, this timing is used as the starting point (time t0 ′) of the response waiting time measurement.
Thus, by taking the timing in the vicinity of the rise of the load signal as the starting point of the response waiting time measurement, the gate of the supply hopper 5 opens, the object to be weighed begins to fall, and the dispersion time (until it reaches the weighing hopper 6) This time has nothing to do with the evaluation of the filter characteristic) so that it does not participate in the response characteristic evaluation of the filter 17a (filter A1 to filter Ag).
It should be noted that it is also possible to detect the appearance of the first maximum value after the load signal measurement value is greater than or equal to the above Wh, and to determine the time point as the starting point of the response waiting time measurement.
In short, the starting point of the time measurement of the response waiting time is determined at a point in the vicinity of when the load signal starts to change due to the load of the object to be weighed.

<Explanation of table data of load signal measurement values>
The objects to be weighed are supplied in parallel from the supply hopper 5 to the weighing hoppers 6 of the weighing hopper numbers 1 to k in the same operation as in the actual operation.
A weight signal measurement value “a”, which is a sampling value of the load signal “a ′” shown in FIG. 3A in each weighing hopper 6, from time t 0 ′ to time tn ′, and a weight signal for a predetermined period of time. Sampling is obtained for each interval Δt ′, and as shown in Table 1, it is stored in the storage means 22 for each weighing hopper 6 from weighing hopper numbers 1 to k in time series as table data of load signal measurement values.
Here, when the load signal measurement value is input to a filter having a response characteristic that is assumed to have the slowest response among a plurality of different filters 17a (filters A1 to Ag) set in advance, The time when the response measurement value of the calculation result by the filter calculation means 17b corresponding to the filter sufficiently approaches the final stable value (convergence value at time infinity) is set.

<Explanation of table data of load signal measurement values>
Load signal measurement values “a”, which are sampling values at times t 0 ′ to tn ′ with respect to the load signal “a ′” by the first test supply of each weighing hopper 6, are applied to the weighing hoppers 6 to 1. Each is stored in the storage means 22. More specifically, for each weighing hopper 6 of weighing hopper numbers 1 to k, at time t0 ′, w011, w012,..., W01k, and at time t1 ′, w111, w112,. .., Wn11, wn12,..., Wn1k are stored in the storage means 22 at time tn ′.
Note that the object to be weighed supplied to the weighing hopper 6 is stopped without being discharged until the output response signal of the filter device 17 responds to the final stable value, so that the operation cycle is slower than in the actual operation.

<Description of filter settings>
Each time the filter type, constant, order, etc. are different, the filter is estimated to be close to a constant value that is empirically optimal considering the weighing conditions such as the type and supply of the object to be weighed and the allowable measurement time. Set as filter A1, filter A2,..., Filter Ag.

<Explanation of response measurement table data>
Next, using the load signal measurement value table data shown in Table 1, for each of the preset filters 17a (filters A1 to Ag), the calculation of the filter calculation means 17b when the load signal measurement value is input. The response measurement values as results are sequentially output until time t0 ′, t1 ′, t2 ′,..., Tn ′, and the response measurement values at times t0 to tn according to the following definitions are extracted and filtered. Response measurement values for evaluation are stored in the storage means 22 as table data of response measurement values as shown in Table 2 at each time t0, t1, t2,. Let
In Table 2, table data of response measurement values stored for each weighing hopper, for each filter, and for each evaluation time are listed for all weighing hoppers.

<Explanation of definition of time to evaluate response measurement value>
With respect to the definition of the time t0, t1, t2,..., Tn at which the response measurement value is evaluated, that is, the final time of the response waiting time measurement, tn = tn ′ and the response measurement value every Δt from the time t0. Response measurement values of the filter 17a (filters A1 to Ag) are extracted by the filter calculation means 17b at times t1, t2, t3,..., Tn (= tn ′) at time intervals (see FIG. 3B). ).
Here, the above Δt is expressed by the following formula (1).
Δt = r · Δt ′ (1)
(R is an integer satisfying r ≧ 1.)

<Explanation of definition of time to evaluate response measurement value>
The timing of picking up the response measurement values for evaluating the response characteristics of the filter 17a (filters A1 to Ag) immediately after t0 ′, which is the rise time of the response signal, is naturally significant because the variation and deviation are large. Even when a certain amount of time has elapsed from the starting point (time t0 ′), that is, even when the slowest filter response value is applied in the filter 17a (filters A1 to Ag), the response to the step input corresponds to the final response stable value. A time that overlaps with the sampling timing for each Δt ′ at a time sufficient to reach the allowable range is set to t0, and after this time t0, each time of time t1 to tn (tn = tn ′) is set ( (Refer FIG.3 (b)).

<Explanation of response measurement calculation>
For example, calculation of the response measurement value of the filter A1 by the filter calculating means 17b for the weighing hopper 6 of the weighing hopper number 1 will be described.
From the time t0 ′, the load signal measured values w011, w111,..., Wn11 at t1 ′,..., Tn ′ every time interval Δt ′ are input, and the filter calculation algorithm corresponding to the filter A1 is executed. With the time t0 as the starting point of the filter characteristic evaluation, the outputs wa1011, wa1111,..., Wa1n11 of the filter calculating means 17b at t0, t1,.
Next, load signal measurement values w011, w111,..., Wn11 at times t0 ′, t1 ′,..., Tn ′ are input to the filter A2, and a filter calculation algorithm corresponding to the filter A2 is executed. , Response measured values wa20111, wa2111,..., Wa2n11 are obtained as outputs of the filter calculation means 17b at times t0, t1,.
The filter is sequentially changed to obtain response measurement values, and finally, the load signal measurement values w011, w111,..., Wn11 at times t0 ′, t1 ′,. , A filter calculation algorithm corresponding to the filter Ag is executed, and response measurement values wag011, wag111,..., Wgn11 are obtained as outputs of the filter calculation means 17b at times t0, t1,.
The same calculation is performed in parallel in each weighing hopper 6 of weighing hopper numbers 2 to k.

<Description of the first supply / discharge operation of the weighing hopper during adjustment operation>
In each weighing hopper 6 of weighing hopper numbers 1 to k, when response measurement values at times t0 to tn are calculated for each filter for the first supply of the objects to be weighed, the weighing objects in all the weighing hoppers 6 are measured. Things are discharged.
However, if there is a possibility that clogging may occur if all the weighing hoppers 6 are discharged to the collecting chute 13 at the same time, it is preferable that the weighing hoppers 6 are grouped into appropriate numbers and discharged with a time difference.

<Description of the second supply / discharge operation of the weighing hopper during adjustment operation>
Next, the second object to be weighed is supplied to the weighing hopper 6. In the weighing hoppers 6 of the weighing hopper numbers 1 to k as described above, when the response measurement values at the times t0 to tn are calculated for each filter for the second supply of the objects to be weighed, all the weighing hoppers 6 The object to be weighed is discharged.

<Explanation of m-th supply / discharge operation of weighing hopper during adjustment operation>
Then, the m-th weighing object is supplied to the weighing hopper 6, and in each weighing hopper 6 of the weighing hopper numbers 1 to k as described above, the m-th feeding of the weighing object is time t0 to tn for each filter. When the measured response value is calculated, all objects to be weighed in the weighing hopper 6 are discharged. After the discharge operation is completed, the adjustment operation is terminated. In this way, all response measurements shown in Table 2 can be obtained.
In addition, it is preferable not to employ | adopt as a measured value, when the response measured value of the time tn exceeds the upper / lower limit range predetermined from the value of Wt / M. If there are p such measurement values in the weighing hopper 6, the calculation of standard deviation and average deviation described below is targeted for (k−p).

<Explanation of standard deviation of response measurement value>
Next, based on the response measurement value table data shown in Table 2, the standard deviation indicating the variation amount of the response measurement value will be described.
First, at time t0 in the case of the filter A1, with respect to the weighing hoppers 6 of the weighing hopper numbers 1 to k, m · k response measurement values wa1011,..., Wa10m1, wa1012,. .., Wa10m2,..., Wa101k,.
Similarly, standard deviations σa11 ′ to σa1n ′ of response measurement values for each time from time t1 to tn are obtained.
Further, standard deviations σa20 ′ to σa2n ′ of response measurement values are obtained for each time from time t0 to time tn in the case of the filter A2.
Then, standard deviations σa30 ′ to σa3n ′,..., Σag0 ′ to σagn ′ of response measurement values are obtained for each time from time t0 to time tn in the case of filters A3 to Ag.

<Explanation of standard deviation of response measurement value by vibration signal>
Since the standard deviations σa10 ′ to σa1n ′,..., Σag0 ′ to σagn ′ of the response measurement values are different each time, the variation in the weight of the supplied object to be measured and the variation due to the vibration signal Is added.
However, since the vibration signal has converged at time tn, the standard deviation of the response measurement value at time tn is a value only due to variation due to supply weight. If there is a large difference in the supply weight, there is a correlation between the magnitude of the supply weight and the variation caused by the vibration signal, but the difference in the magnitude of the supply weight is small in each hopper 6 and the number of times. Factors are uncorrelated and independent.

<Explanation of standard deviation of response measurement value by vibration signal>
Therefore, for example, in the case of the filter A1, the standard deviation σa10 of the response measurement value by the vibration signal at time t0 can be calculated by the following equation (2).

σa10 = (σa10 ′ ² −σa1n ′ ² ) ^1/2 (2)

Further, for example, in the case of the filter A1, the standard deviation σa11 of the response measurement value by the vibration signal at time t1 can be calculated by the following equation (3).

σa11 = (σa11 ′ ² −σa1n ′ ² ) ^1/2 (3)

In this way, σa10 to σa1n in the case of the filter A1, σa20 to σa2n in the case of the filter A2,..., Σag0 to σagn in the case of the filter Ag can be calculated.
Note that σa1n = σa2n =... = Σagn = 0.

<Explanation of average deviation of response measurement value by vibration signal>
On the other hand, the deviation of the response measurement value by the vibration signal at each time with respect to the final stable value is, for example, the deviation ea1011 in the case of the response measurement value wa1011 of the first measurement count at time t0 when the filter A1 is obtained from the following equation (4). As is apparent, it is obtained as a deviation of the measured response value from the final stable value wa1n11 in the first measurement.

ea1011 = wa1011−wa1n11 (4)

Similarly, for each of the weighing hoppers, as shown in Table 3 from the response measurement value table data shown in Table 2, regarding the filters A1 to Ag, deviations ea1011,. Ask.

  Subsequently, as shown in Table 4 from the table of response measurement value deviations shown in Table 3, with respect to the filters A1 to Ag, the average values of response measurement values at all times, that is, average deviations ea10,. Ask for.

<Description of filter determination procedure>
Next, a procedure for determining a filter by the filter determination unit 26 will be described.
First, a reference allowable variation value V that represents an allowable value related to the variation amount of the response measurement value is set in advance, and a reference allowable average deviation value E that represents an allowable value related to the average deviation of the response measurement value is set in advance. Note that both the reference allowable variation value V and the reference allowable average deviation value E are arbitrarily set in design based on the specifications of the apparatus.
Next, the reference allowable values V and E are compared with the standard deviation (see Table 2) and the average deviation (see Table 4) of the response measurement values.

<Description of filter determination procedure>
That is, the time at which the variation of the vibration signal included in the response measurement value becomes small and approaches the final stable value is determined.
It is assumed that the standard deviation of the response measurement value at the arbitrary time tx1 from time t0 to tn of the filter A1 is σa1x1, the average deviation is ea1x1, and the following expressions (5) and (6) are simultaneously satisfied for the first time at time tx1.

σa1 × 1 ≦ V (5)
ea1x1 ≦ E (6)

Similarly, the filters A2 to Ag are examined, and for each filter, the time tx2, when the standard deviation of the response measurement value is equal to or less than the reference allowable variation value V and the average deviation of the response measurement value is equal to or less than the reference allowable average deviation value E. -Find txg.
Then, the optimum filter is any one of the filters A1 to Ag having a time that satisfies the reference allowable values V and E in the shortest time from the time t0.
By the way, when the filters A1 to Ag do not satisfy the above expressions (5) and (6), the filters A1 to Ag are excluded, and another filter is set in the vicinity of the filter characteristics of these filters A1 to Ag. You can fix it and test again.
It should be noted that either one of the variation of the vibration signal included in the response measurement value or the degree of approach to the final stable value, that is, the filter using the conditional expression (5) or (6) You may make it decide.

<Description of the effects of this embodiment>
According to the present embodiment, the timing near the rising edge of the load signal is used as a starting point of time measurement of a plurality of different response waiting times for evaluating the response measurement value. It is possible to eliminate variations in the time taken from the timing at which the load signal starts to rise from the timing at which the element considered as the response characteristic of the filter, that is, the supply timing of the object to be weighed to the weighing unit. Then, by evaluating the response measurement values at a plurality of different response waiting times, a filter to be used during the actual operation is selectively determined from among the plurality of different filters 17a (filters A1 to Ag).
Therefore, the filter characteristics can be properly evaluated without being affected by the supply timing of the object to be weighed, and the optimum filter, that is, the filter that converges to the final stable value earliest in this embodiment can be determined easily and accurately. can do. In addition, it is possible to easily determine a suitable filter from among many filter candidates.
The determined filter is defined as a filter candidate that can be used in the actual operation in the filter device 17 in accordance with the measurement conditions such as the type of the object to be weighed, the supply amount, and the measurement allowable time. A number of filter candidates are defined in accordance with the conditions, and these filter candidates are displayed on the display device 9 and then the operator operates the key switch of the operation device 10 during the actual operation to select among the filter candidates. The desired filter can be manually selected and set.
Thus, when supplying an object to be weighed to the weighing hopper 6, the load signal varies depending on the type and supply amount (including weight) of the object to be weighed, but there are many filters depending on the type and supply amount of the object to be weighed. The candidate with the most desirable characteristics can be easily determined.

<Description of the effects of this embodiment>
Also, during the adjustment operation, the operation is performed under the same conditions as in the actual operation, and the objects to be weighed are continuously supplied to the supply hopper 5 and the weighing hopper 6 and are automatically affected without being affected by the supply timing of the objects to be weighed. Since the response characteristics of the filter 17a (filters A1 to Ag) are evaluated based on the response measurement values of the filter 17a (filters A1 to Ag) by the filter calculation means 17b, it is easy to use a large amount of data. A highly reliable filter can be determined.

<Description of the effects of this embodiment>
Further, when evaluating the characteristics of the filter 17a (filter A1 to filter Ag), the damping property of the vibration amplitude due to the variation amount of the response measurement value and the final stable value based on the average deviation of the response measurement value, that is, the true weight value of the object to be weighed By evaluating the convergence characteristics at the same time or individually, the filter can be optimally set according to the type of the object to be weighed and the supply amount.

<Description of Modification of Filter Determination>
In consideration of the case where the plurality of filters 17a (filter A1 to filter Ag) satisfy the above condition at the same time, the response measurement values of the plurality of filters 17a (filter A1 to filter Ag) are preliminarily determined. It is preferable to determine a rule for the order of determination as appropriate, such as whether to preferentially select a filter with the smallest amount of variation or preferentially select a filter with the smallest average deviation of response measurement values.
If the measured response value does not converge to the final stable value and the average deviation value is large, even if the variation amount is small, even if the average deviation value is large, it is stored as the dynamic correction value C, and the output response There is also a method of correcting by adding the dynamic correction value C to the measured value.
Thus, if the average deviation of the response measurement values is handled, the filter 17a (filter A1 to filter Ag) may be determined based only on the magnitude of the variation. That is, only σa1 × 1 ≦ V in the above equation (5) is used as a criterion.

<Description of Modification of Filter Determination>
The filter 17a (filter A1 to filter Ag) is represented by one letter of A1, A2,... Ag, but is already prepared when the filter 17a is a notch filter and the constants of the notch filter are different, for example. When it is desired to determine whether or not to add a notch for the new noise frequency f3 on the notches for the noise frequencies f1 and f2, from the viewpoint of filter response characteristics and noise amplitude attenuation rate, A1 = (f1, f2, 0), A filter with A2 = (f1, f2, f3) as an argument is prepared, and two types of calculation are performed.

<Description of Modification of Filter Determination>
In addition, when the indispensable notch frequency is f0 and two or more appropriate notch frequencies need to be set in the vicinity of a plurality of frequencies f1 and f2 that are separated from each other, two types are necessary. If a set of notches is selected from the frequencies f12, f22, f32, and f42 in the vicinity of f1, the filter is given by A1 = (F0, f11, f12), A2 = (f0, f11, f22), A3 = (f0, f11, f32), A4 = (f0, f11, f41), A5 = (f0, f21, f12),.・ A16 = (f0, f41, f42) and 16 types of arguments are used for calculation.

<Description of Modification of Filter Determination>
Further, if the filter 17a (filters A1 to Ag) is a low-pass filter and has different time constants, for example, various magnitudes for the time constant T1 in G (s) = 1 / (T1 + 1), A1 = T11, A2 = T12, A3 = T13,...
Note that G (s) is G (s) = 1 / (T ₁ S ² + T ₂ S + 1) or G (s) = 1 / (T 1 + 1) ^2.
The order may be different as shown in FIG.
Further, the filters A1 to Ag may include different types of filters such as the above-described notch filter and low-pass filter.

<Description of Modification of Filter Determination>
In the present embodiment, the example in which the filter determination unit 26 automatically and selectively determines the filter from the response measurement value data stored in the storage unit 22 based on a predetermined determination criterion has been described. After displaying the variation amount and / or average deviation (see Tables 2 and 4) of the response measurement value in the response waiting time on the display device 9, the operator operates the key switch of the operation device 10 to select a desired filter. You may make it select and set manually.

<Description of application to other weighing devices>
In the present embodiment, an example in which the present invention is applied to a combination weigher has been described as an application example of the present invention to a weighing device, but the present invention can of course be applied to a quantitative balance.
Here, the quantitative balance is provided with a supply hopper for storing an object to be weighed, called a storage hopper, at the top, and is configured to supply an object to be weighed with a predetermined weight to the weighing hopper.
In order to determine an appropriate filter in the adjustment operation, the size of the opening degree Ga of the gate capable of supplying an object to be weighed with a predetermined weight, the opening time Ta, and the closing time Tb are set. After the opening time Ta is multiplied by the opening time Ta with respect to the gate of the hopper, the operation is given until the closing time is multiplied by the time Tb.
In the adjustment operation, this weighing operation is repeated several times. As in the case of the combination weigher, when there are a plurality of pairs of supply hoppers and weighing hoppers, it is efficient if they are implemented in parallel.
For the load signal generated from the load sensor, the timing in the vicinity of the rise of the load signal is detected in the same manner as described above, and is set as the starting point of the response waiting time.
Also in the weight sorter, there is a timing at which the presence of an article is detected by the article sensor immediately before the weighing object enters the weighing conveyor, and a timing at which the load signal rises when the weighing object is actually loaded on the weighing conveyor. In the meantime, even if the conveyor speed is constant, variations occur depending on the state of the object to be weighed every time.
Therefore, since the filter response characteristic cannot be accurately evaluated by the method using the article sensor, it is appropriate to take the starting point of the response waiting time for evaluating the filter response characteristic at a timing near the rise of the load signal.

<Description of another example of variation in response measurement value>
In the description of the above embodiment, an example in which the standard deviation of the response measurement value is used as an indication of the variation amount of the response measurement value is shown, but the present invention is not limited to this, and the deviation of the response measurement value is not limited thereto. There may also be an embodiment using.
That is, the absolute value of the deviation of the response measurement value is obtained (see the following formula (7)), and a value twice the standard deviation of the absolute value of this deviation may be the variation amount of the response measurement value.

| Ea1011 | = | wa1011-wa1n11 | (7)

<Explanation of terms>
The “variation amount of the response measurement value” in the present invention is a generic term for a standard deviation of the response measurement value and a value twice the standard deviation of the absolute value of the deviation of the response measurement value.
The response waiting time including the dynamic response waiting time and the static response waiting time corresponds to the “response waiting time” of the present invention.
The combination scale 1 corresponds to the “metering device” of the present invention.
The weighing hopper 6 corresponds to a “weighing unit” of the present invention.
The configuration including the dynamic response measurement value acquisition unit 20 and the static response measurement acquisition unit 21 corresponds to the “response measurement value acquisition unit” of the present invention.
The display device 9 corresponds to the “display unit” of the present invention.
The operating device 10 corresponds to the “filter setting means” of the present invention.

  Since the weighing device of the present invention has the characteristic that the optimum filter can be accurately determined by properly evaluating the filter characteristics without being affected by the supply timing of the object to be weighed, there are various It can be suitably used for various weighings for measuring various weights of powders having the following properties, roses and other articles.

DESCRIPTION OF SYMBOLS 1 Combination scale 2 Article supply apparatus 3 Dispersing feeder 4 Straight advance feeder 5 Supply hopper 6 Weighing hopper 7 Memory hopper 8 Control apparatus 9 Display apparatus (display means)
10 Operating device (filter setting means)
DESCRIPTION OF SYMBOLS 11 To-be-measured object receiving part 12 Load sensor 13 Collecting chute 14 Collecting funnel 15 Amplifier 16 A / D converter 17 Filter apparatus 17a Filter 17b Filter calculating means 18 Dynamic weight measurement value acquisition means 19 Static weight measurement value acquisition means 20 Movement Response measurement value acquisition means 21 Static response measurement value acquisition means 22 Storage means 23 Variation amount calculation means 24 Average deviation calculation means 25 Dynamic weight measurement value acquisition time determination means 26 Filter determination means 27 Stabilization wait time timer 28 Response wait time timer

Claims (5)

In a weighing device comprising a plurality of filters having different filter characteristics from each other for filtering a load signal output from a load sensor according to a load applied to a weighing unit of an object to be weighed,
A filter calculation means for calculating a response measurement value by executing a filter calculation algorithm according to the plurality of different filters;
Response measurement value acquisition means for acquiring response measurement values of the filter calculation means at a plurality of different response waiting times starting from the timing near the rising edge of the load signal;
Based on the response measurement value acquired by the response measurement value acquisition means when the measurement is performed a plurality of times, the response measurement of the response measurement value at the different response waiting time for each of the plurality of different response waiting times. An average deviation calculating means for obtaining an average deviation which is an average value of deviations from the final stable value of the value;
Filter determining means for determining a filter in which the average deviation is smaller than a preset allowable value at the shortest response waiting time among the plurality of different response waiting times as a filter to be used during the actual operation. A weighing device characterized by that. In a weighing device comprising a plurality of filters having different filter characteristics from each other for filtering a load signal output from a load sensor according to a load applied to a weighing unit of an object to be weighed,
A filter calculation means for calculating a response measurement value by executing a filter calculation algorithm according to the plurality of different filters;
Response measurement value acquisition means for acquiring response measurement values of the filter calculation means at a plurality of different response waiting times starting from the timing near the rising edge of the load signal;
Based on the response measurement value acquired by the response measurement value acquisition means when the measurement is performed a plurality of times, a variation amount of the response measurement value in the different response waiting time is obtained for each of the plurality of different response waiting times. A variation amount calculating means and an average deviation calculating means for calculating an average deviation of the response measurement values;
A filter in which the variation amount and the average deviation simultaneously become smaller than a preset allowable value at the shortest response waiting time among the plurality of different response waiting times is determined as a filter to be used in actual operation. And a filter determining means. The filter determined by the filter determining means is defined as a filter candidate that can be used during the actual operation according to the weighing condition, and the display means for displaying the filter candidate and the filter candidate displayed on the display means are actually operated. The weighing apparatus according to claim 1 or 2 , further comprising a filter setting unit that selectively sets the filter to be used during operation. The weighing device according to claim 1 , further comprising : a display unit that displays the average deviation; and a filter setting unit that selectively sets a filter to be used during the actual operation based on the display content of the display unit. 3. The weighing apparatus according to claim 2 , further comprising: a display unit that displays the variation amount and the average deviation; and a filter setting unit that selectively sets a filter to be used during the actual operation based on the display content of the display unit.

Images