JPH0237970B2 - KEIRYOSOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a weighing device that can charge a predetermined weight of articles into a weighing container equipped with a load detector based on the output of the load detector.

Conventionally, as the above-mentioned measuring device, there is, for example, a Pakka scale shown in FIG. That is, in the same figure, 1 is a service hopper, inside which a large amount of goods, such as powder, is stored, and 2 at the bottom.
It has two gates 2 and 3. A weighing hopper 5 equipped with a load detector 4 such as a load cell is arranged below the service hopper 1. After the output of the load detector 4 is amplified by an amplifier 6,
The signal is converted into a digital signal by the A/D converter 7 and supplied to the arithmetic control section 8. When the push button switch 9 is pressed, the arithmetic control section 8 opens both the gates 2 and 3 to allow the article to be thrown from the service hopper 1 into the weighing hopper 5. When the output of the load detector 4 reaches W1, the arithmetic control unit 8 closes the gate 2 and reduces the input flow rate to a small flow rate. Then, when the output of the load detector 4 becomes a value (W2 - Wd) smaller than the predetermined weight W2 by the amount of head Wd, the arithmetic control unit 8
is closed, the drop Wd of the article falls into the weighing hopper 5, and finally an article of weight W2 is thrown into the weighing hopper 5. FIG. 2 shows the change in the output of the load detector 4 at this time. 10, 11, 12 are respectively
They are W1 setting device, W2 setting device, and Wd setting device. After this, the gate 13 of the weighing hopper 5 is opened and the article having a weight of W2 is put into another container (not shown).

Such weighing devices are generally required to have high accuracy and high-speed weighing (reducing the time required for weighing), but it has been difficult to satisfy both at the same time. In other words, the amount of input into the weighing hopper 5 varies depending on the disturbance of the scale and the properties of the article, and for production and quality control reasons, it is not always necessary to input the amount into the weighing hopper 5.
It is necessary to measure the final weight of the In order to measure this final weight with high precision, it must be measured after the time te shown in FIG. 2 has elapsed.
This is because if the measurement is performed at time ta, the output of the load detector 5 will not be stable and will contain errors. However, in order to perform high-speed weighing, the time required to measure the final weight must be shortened to, for example, the above-mentioned ta, and it has been difficult to achieve both high precision and high-speed weighing.

The object of the present invention is to provide a quantitative scale that can measure the final weight with high accuracy even after only the time ta shown in FIG. 2 has elapsed, in order to achieve both high accuracy and high-speed weighing. Therefore, in the present invention, the above-mentioned measurement is performed multiple times as a correction mode, and each time the deviation between the output of the load detector 4 at the elapse of time ta and the output of the load detector 4 at the elapse of time te is determined. is determined, the average value of these deviations is determined, and the above average value is subtracted from the output of the load detector 4 when time ta has elapsed in the normal mode, and the article is discharged from the weighing hopper 5 at this time. There is.

This will be explained with reference to the complaint correspondence diagram in FIG. detects that the timer has been stopped, generates a correction storage command signal 16a when time ta has elapsed, and
During the process, a correction subtraction and discharge command signal 16b is generated. Furthermore, when the mode switching means 14 is generating the normal mode signal 14b, the timing means 16 also determines the time ta based on the output of the load detector 4.
During the process, a normal subtraction and discharge command signal 16c is generated. The storage means 18 receives the correction storage command signal 16a.
load detector 4 at that time (when time ta has elapsed since the supply stop in correction mode)
The subtraction means 20 receives the correction subtraction and discharge command signal 16b, and stores the output of the load detector 4 and the output of the storage means 18 at that time (when time te has elapsed from the stop of feeding in the correction mode). Calculate the deviation from the stored value. A plurality of these deviations are detected and averaged by the averaging means 22. The subtraction means 24 receives the normal subtraction command signal 16c and subtracts the average value of the averaging means 22 from the output of the load detector 4 at that time (when time ta has elapsed since the stoppage of application in the normal mode). Further, in the normal mode, the gate 13 is opened by the normal subtraction and discharge command signal 16c.

Hereinafter, this invention will be explained in detail based on two embodiments shown in FIGS. 4 to 8. FIG. 4 shows a first embodiment. This embodiment is entirely composed of electronic circuits, and the same reference numerals are given to the parts corresponding to the respective constituent elements in the above-mentioned claim correspondence diagram. The mode changing means 14 generates a correction mode signal when the correction button 25 is pressed, and generates a normal mode signal at other times, and can be composed of a flip-flop, for example, and the timing means 16 includes: It is composed of a comparator 26, a subtracter 28, gates 30, 32, 34, 36, a pulse generator 38, and a timing pulse generator 40.
Although the timing pulse generator 40 is not shown in the figure, it can be constructed from, for example, two program counters. Storage means 18, subtraction means 20, 2
4 is composed of a memory and a subtracter, which are usually commercially available. The averaging means 22 is composed of an addition register 42, a counter 44, a divider 46, and an average value register 48, and both the addition register 42 and the average value register 48 can also store negative values.

Now, the mode changing means 14 outputs the correction mode signal 14.
Once a has been generated, these are supplied to gates 32 and 34. When the loading of articles into the weighing hopper 5 is started, the timing pulse generator 40 and the storage means 18 are both cleared, and the digitally converted value of the output of the load detector 4 is supplied to the comparator 26. When this digital conversion value becomes equal to the output (W2-Wd) of the subtracter 28, the comparator 26 calculates
That is, when both gates 2 and 3 are closed, an output is generated. Of course, before that, the gate 2 is closed by the comparator 51 when the digitally converted value of the output of the load detector 4 exceeds W1. The output of comparator 26 is applied to gate 30 to open it. This causes the timing pulse generator 40 to start counting the pulses of the pulse generator 38,
Output is generated when time ta has elapsed from this start. The gate 34 is opened by being supplied with the output from the timing pulse generator 40 and the correction mode signal 14a. By this, the storage means 18
The digitally converted value of the output of the load detector 4 at that time is stored. When a time te has elapsed since comparator circuit 26 generated an output, timing pulse generator 40 again generates an output. gate 32
is opened when this output and the correction mode signal are supplied, and the digital conversion value of the output of the load detector 4 at that time is supplied to the subtraction means 20. As a result, the subtraction means 20 subtracts the value stored in the storage means 18 from this digital conversion value, and the subtracted value is stored in the addition register 42. Further, the counter 44 counts the output generated by the timing pulse generator 40 when the time te has elapsed. In this state, the discharge gate 13 of the weighing hopper 5 is opened by the output of the timing pulse generator 40, and the article is discharged. Thereafter, when this is repeated n times, the cumulative value of each deviation is stored in the addition register 42, and n is stored in the counter 44. here,
When a offset command signal is supplied from the storage button 50 to the divider 46, the divider 46 calculates the average value of the deviations and stores it in the average value register 48.

Next, when the mode changing means 14 generates a normal mode signal instead of the correction mode signal, the gate 36
opens. In this state, input is started again, and when time ta has elapsed since the comparator 26 generated an output,
The output of the timing pulse generator 40 is subtracted by the subtraction means 2.
4, the subtracting means 24 subtracts the stored value of the average value register 48 from the digitally converted value of the output of the load detector 4 at that time, and this subtracted value is used as an output. At the same time, the discharge gate 13 is opened and the article is discharged from the weighing hopper 5.

The second embodiment uses a microcomputer 52 as shown in FIGS. 4 to 8. The microcomputer 52 has a central processing unit 54, a ROM 56, and a RAM 58.
The central processing unit 54 amplifies the output of the load detector 4 with the amplifier 6 and converts it into a digital value,
W1, W2, data from WD setting device 10, 11, 12, memory button 50, correction mode button 25, input button 9
In response to each command signal from the RAM 58, it controls the gates 2, 3, and 13 and displays the output while exchanging data with the RAM 58. This central processing unit 54
The program to operate as above is
It is stored in ROM56.

This program is explained as follows. First, as shown in FIG.
Set W1, W2, and Wd respectively. Next, in step 101, it is determined whether to use the correction mode or the normal mode. This decision is made depending on whether or not the correction mode button 25 is pressed. When the correction mode button 25 is not pressed, the correction mode flag is "0" and the normal mode is set. When the correction mode button 25 is pressed, the correction mode flag is "1". , it becomes correction mode. In step 102, the process waits until the input button 9 is pressed, and when it is pressed, the gates 2 and 3 are opened in step 103. As a result, the loading of articles into the weighing hopper 5 is started. Step 1
04 is the digital conversion value of the output of load detector 4
Wait until WI equals Wl. When they become equal, the gate 2 is closed in step 105 and the flow rate input to the metering hopper 5 is reduced. Next step 1
06, wait until WI becomes (W2-Wd) or more,
When the value exceeds (W2-Wd), the gate 3 is closed in step 107, and then in step 108 it is determined whether the mode is correction mode or normal mode. If it is the correction mode, the process moves to the correction mode routine shown in FIG.

In the correction mode routine, first step 109 is performed.
At step 110, the registers C and Wn are set to 0, and then, at step 110, the timer built in the central processing unit 54 is cleared, and the pulse generator, also built in the central processing unit 54, starts counting pulses.
Next, in step 111, the process waits until the count value T reaches ta, and when it reaches ta, the current WI is stored as Ml in step 112. Then step 1
At step 13, wait until T becomes te, and when it becomes te, at step 114, subtract Ml from WI at that time,
In step 115, the subtracted value Wa is added to Wn, and
At step 116, the value in the register C is incremented by one, and the gate 13 is opened to discharge the article from the weighing hopper 5. Then, in step 117, it is determined whether or not to cancel, and if not, step 1 in FIG.
The process returns to step 02, and the steps described above are executed up to step 116, and the process is repeated until it is determined that the process is to be stopped. Therefore, if it is repeated n times, Wn will be n
This is the total value of Wa, and C is n. Step 1
If it is determined in step 17 that the process is to be canceled, the process moves to step 118 and waits until the memory button 50 is pressed. When the memory button 50 is pressed, Wn is divided by C in step 119, the divided value is stored as M2, and the correction mode flag is set to "0" in step 120.
Return to step 102 in FIG.

Thereafter, steps 102 to 1 are performed in the same manner as described above.
The steps up to step 08 are executed, but since the correction mode flag in step 108 is set to "0" in step 120, the routine moves to the normal mode routine shown in FIG.

In the normal mode routine, step 121 clears the timer and starts counting pulses;
In step 122, the process waits until the timer count value reaches ta. When ta is reached, the gate 13 is opened in step 123 to discharge the article from the weighing hopper 5, and M2 is subtracted from WI at that time, the subtracted value is stored as WI', and in step 124, M2 is subtracted from WI.
Display/output WI′. Next, in step 125, it is determined whether or not to cancel, and if not, step 10 is executed.
Returning to step 2, the above-described operation is repeated, and if the operation is to be canceled, the process proceeds to step 126 shown in FIG. 6, where the operation is canceled.

In the weighing device according to the present invention, the gate 13 of the weighing hopper 5 is opened in the correction mode to compensate for the head difference.
WD has fallen and is still unstable load detector 4
Detect multiple deviations between the output of the load detector 4 and the stable output of the load detector 4, calculate the average value, and determine whether the gate 13 of the weighing hopper 5 opens in the normal mode and the head amount wd falls and is still stable. The average value of the above deviations is subtracted from the output of the load detector 4 which is not in use, and this subtracted value is displayed as the output, so this subtracted value is almost the same as the stable output of the load detector 4, and is highly accurate. Becomes the property of Furthermore, since this highly accurate output can be obtained before the output of the load detector 4 becomes stable, both high accuracy and high speed measurement can be achieved.

In the above embodiment, the present invention is applied to a hopper scale, but the present invention can also be applied to other scales such as a hopper scale. Further, in the above embodiment, the present invention is implemented in a so-called two-stage charging system, but it goes without saying that the invention can be implemented in a known three-stage charging system, a single-stage charging system, and the like.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a conventional weighing device, FIG. 2 is a diagram showing changes in the output of the load detector shown in FIG. 1, and FIG. 3 is a functional block diagram of a weighing device according to the present invention. 4 is a block diagram of the first embodiment of the same device, FIG. 5 is a block diagram of the second embodiment of the same device, and FIG. 6 is a flowchart showing the main routine of the program of the second embodiment. FIG. 7 is a flowchart of the correction mode routine of the program of the second embodiment, and FIG. 8 is a flowchart of the normal mode routine of the program of the second embodiment. DESCRIPTION OF SYMBOLS 1... Loading device, 4... Load detector, 5... Measuring container, 13... Discharging means, 14... Mode switching means, 16... Timing means, 18... Memory means, 20... First Subtraction means, 22...Average means, 24...Second subtraction means.

Claims (1)

[Claims] 1. Load an article into a weighing container equipped with a load detector from a loader installed above it, and when the output of the load detector becomes equal to a weight signal that is smaller than a predetermined weight signal by the difference in head, the load is carried out. In a weighing device that stops input from a weighing device, there is provided a mode switching means that always generates either a normal mode signal or a correction mode signal, and a mode switching means that always generates either a normal mode signal or a correction mode signal; When the stoppage of the supply is detected and a first time period which is not sufficient for the output of the load detector to become stable has elapsed from the time of this detection, a storage command signal is generated and the output of the load detector is changed from the time of the detection of the stoppage of the supply. A correction subtraction and discharge command signal is generated after a second time period sufficient for the output to stabilize, and when the normal mode signal is received, the normal mode signal is generated when the first time period has elapsed from the time when the supply stop was detected. timing means for generating a subtraction and discharge command signal; means for storing the output of the load detector at each time the storage command signal is generated; and means for storing the output of the load detector at each time the storage command signal is generated; subtracting means for subtracting the corresponding stored value in the storing means from the output of the load detector; means for averaging the output of the subtracting means for a predetermined number of measurements in the correction mode; and the normal subtraction and discharge means. means for subtracting the output of the averaging means from the output of the load detector each time a command signal is generated;
A weighing device comprising a discharge means provided in the weighing container and discharging the article from the weighing container in response to the corrected subtraction and discharge command signal or the normal subtraction and discharge command signal.