JPS6037409B2 - Electronic weight sorter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic weight sorting machine that automatically sorts sequentially conveyed articles according to their weight.

As shown in FIG. 1, the conventional electronic weight sorter uses a position detector 11 such as a photo cell to detect when the sample has just arrived at the weighing position, and when the sample blocks the light beam of the position detector 11. The output of the bottle section 12 is sent to a comparator 13, which determines the magnitude of the sample weight with respect to a preset reference value, and outputs a sorting signal 14.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic weighing machine which obtains a weight sorting signal by detecting the maximum value of the output of an electronic scale, omitting a weighing position detection device.

The configuration of the present invention will be explained based on the block diagram shown in FIG.

The articles to be weighed are transferred by the transfer means 21 onto the weighing pan of the electronic scale 22 . The electronic scale 22 continuously measures the weight or mass of the article on the weighing pan. The digitally converted data of the output of the electronic scale 22 is processed by the sampling means 23.
Sampled at predetermined time intervals. The sampled data is stored in the sequential storage register 24 in order from the latest data. The calculation means 25 sequentially determines the magnitude relationship of each data in the storage register 24 and supplies the determination result to the maximum value detection means 26 . In the maximum value detection means 26, based on the magnitude relationship determination result from the calculation means 25, the difference SN obtained by subtracting the N previous data DN from the latest data Do is negative, and the data Do and the data DN are Data DN-
, ○2, D, respectively, when the differences SN-, . Maximum value detection means 26
The local maximum value detected by is sent to the comparator 27 as the weighing value of the article, where it is compared with a reference value, and the comparison result is output as a weight sorting signal. FIG. 3 is a block diagram of an embodiment of the invention.

The configuration of the present invention will be explained in more detail with reference to this drawing. This device includes a weight-voltage converter 32 that converts the weight 31 of an article into voltage and outputs the electronic scale 22, and the electronic scale 22.
a sequential storage register 38 that samples two outputs of digital conversion data at predetermined time intervals and stores the sampled data in order from the latest data; and an arithmetic unit 36 that determines the magnitude relationship between the two pieces of data; Program device 3 that controls the storage register and the arithmetic device
7, and a comparison number setter 39 which can be freely set from the outside to determine how many pieces of data are to be compared for the programming device to determine the maximum value, and the latest data D. Rhombus SN obtained by subtracting the N previous data DN from
, D, by subtracting the above DN from each other, SN-,,...
..., S2, S, are all negative, the data DN is determined to be the maximum value. Next, the principle of the maximum value detection means 23 in the present invention will be explained.

Load and vehicle values are sampled at regular short time intervals,
While sequentially storing the sampled values in the memory register 38, the absolute value IDOL of the newly input sampled value Do is changed to the absolute value IDN of the n previous sampled value DN taken in previously! The difference SN obtained by subtracting SN, that is, SN=ID.

! -IDNI...When m is positive or zero, it is determined that the maximum value has not yet been reached,
When the difference SN is negative, the sampling value DN-, which was input after the (n-1) previous sampling, is
..., D2, the absolute value of the sampling value DN n times before the absolute value of D! Difference SN-,,... after subtracting DNI
..., S2, S, that is, when all of are negative,
The n previous sampling value DN is determined to be the maximum value, and SN-,
, ..., S2, S, is positive or zero, it is determined that the maximum value has not yet been reached, and the determination process is continued. For example, when it is established that n=5, it is assumed that the load W changes as shown in FIG.

At time L', when the five previous sampling value D5 is subtracted from the latest sampling value Do, Do-D5 is positive, so the sampling value 5 is not determined to be the local maximum value. Next, at the time, the latest sampling value is ○. When the five previous sampling value D5 is subtracted from , Do-D5 becomes negative. Therefore, when calculating each subtraction shown in formula '21, since D4-D5, D3-D5, D2-D5, D, and -D5 are all positive, the five previous sampling value D5 is of course determined to be the maximum value. Not done. However, at time 1, the difference shown in equation m is negative, and S4, S3, S2, S, shown in equation
It is determined that the sampling value D5 five samples before this is the local maximum value. In addition, the latest data D.

The fact that the difference SN obtained by subtracting N data DN from DN is negative means that if the calculation is not specifically performed using this procedure, for example, whether the difference obtained by subtracting Do from DN is positive or not. It includes an arithmetic means for determining the same result even when the above-mentioned determination is made using a comparison circuit that compares the magnitude relationship without using an addition/subtraction circuit. Similarly, the difference SN-, . . . , S2, S, obtained by subtracting DN from DN-, . . . , D2, D, is also negative. Next, the operation and usage method of the embodiment of the present invention will be explained.

The transfer means 21 transfers the articles to be weighed onto the weighing pan of the electronic scale 22 . The weight 31 of the article is converted into voltage by the weight voltage converter 32, which becomes the output of the electronic scale 22, and is continuously input to the A/D converter 34.
The A/D converter 34 outputs a digital weight value at predetermined time intervals, for example, every 0.1 seconds. Furthermore, if the response output of the electronic scale 22 when the article is placed on the weighing plate includes a rapid fluctuation part, the low-pass filter 33 removes the fluctuation part. The digitally converted input data is sequentially temporarily stored in the storage register 38 through the control section 35. The storage register 38 has, for example, seven data areas Do, D1, ..., D6, and the newest data is stored in the memory area Do, and each time data is input, the data is changed from Do→D, →...→
D6 and the oldest data stored in memory area D6 are discarded. The control unit 35 executes the subtraction and positive/negative determination as described above in accordance with the program, and calculates n based on the set number N' of the comparison number setter 39.
Determine whether the previous data is a local maximum value for each data input. When the local maximum value is detected, the contents of the local maximum value detection are transferred from the control section 35 to the display device 40 and the sorting comparator 41. When the weight-sorted article passes through the weighing pan of the electronic scale 22 and the output becomes 0 or minute, the zero or minute amount detection section 42 outputs a reset signal to the control section 35 for the next sorting. Clear the above note and register 38. In this way, the display device 4
The weighed value W of the detected maximum value is displayed. Further, the control unit 35 compares the reference value A preset with the weighed value W, and the selection comparator 41 selects one of W>A, W=A, and W<A as a selection signal. 4
Output as 3. FIG. 5 is a diagram showing the output waveform of the electronic scale 22 in a continuous use embodiment of the present invention.

Line G and line Day indicate the upper and lower limits of passing, respectively, and the area between the two lines is the passing range. The maximum value of each article to be sorted is B,, B2, &, B4, where B, & are passed, B3 is "too heavy", and B4 is "too light".
Using the sorting signal, the articles can be sorted by, for example, a sorting gate (not shown) connected to the electronic scale 22. Since the time from the end of local maximum value detection to the transfer of the article is constant, the opening/closing timing of the sorting gate etc. can be determined based on this time. In the above embodiment, W>A, W=A, W<
This is an example of three-stage sorting in A, but by increasing the number of stages of comparators, it is possible to sort into many types.

As mentioned above, the low-pass filter used in the present invention has an effective effect, but when using an electronic scale in which the weight to be weighed can be directly obtained as a digital output, for example, an electronic scale that uses string vibration, Instead of the above low-pass filter function, a predetermined sampling number,
A similar effect can be obtained by averaging the data.

The input data of the control section 35 is supplied to a latch circuit (not shown).
If the numbers are displayed on the display device 40 via the display device 40, the numbers are retained until the next sorting, which is convenient for reading and confirmation.

A conveyor is normally used as the continuous transport method of the transport means 21, but any conveyor may be used as long as it does not interfere with the above-mentioned maximum value detection.

According to the present invention, a sensor for detecting a weighing position and an accompanying device are completely unnecessary, and an inexpensive weight sorting machine can be obtained.

Furthermore, since the maximum value is detected when the output of the electronic scale is sufficiently stable, a highly accurate electronic weight sorter can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a secondary electronic weight sorter, Fig. 2 is a schematic diagram of the configuration of the present invention, Fig. 3 is a block diagram of an embodiment of the present invention, and Fig. 4 is a diagram of the maximum value detection means. FIG. 5, which is a diagram for explaining the principle, is an output waveform diagram in the usage state of the embodiment of the present invention. 21... Transfer means, 22... Electronic scale,
32... Weight voltage converter, 34... A/D
Converter, 35...Control unit, 38...Register, 39...Comparison number setting device, 40...
. . . Display device, 41 . . . Sorting comparator, 43 . . . Sorting signal. Figure 5 Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 In a device that weighs articles to be weighted while moving them on a weighing pan, compares the weighed value with a preset reference value, and outputs a weight sorting signal, the weight or mass on the weighing pan is continuously measured. an electronic scale for measuring digitally, a means for sampling digitally converted data of the output of the electronic scale at predetermined time intervals, a sequential storage register for storing the sampled data in order from the latest data, and two data and the latest data D.
The difference S_N obtained by subtracting the N previous data D_N from _O is negative, and the intermediate data D_N_-_1, ..., D_2, D_1 to the above D_N
The difference S_N_-_1, ..., S_2,
A maximum value detecting means for determining the data D_N to be a maximum value when all of S_1 are negative, and the detected maximum value is used as a weighed value of the article for comparison with the reference value. Electronic weight sorting machine.