JP3857966B2 - Packer scale operation - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to automatic weighing of a packer scale that performs automatic weighing of powder or fluid.
[0002]
[Prior art]
The so-called packer scale three-stage or two-stage input method is a combination of large or medium input with a large flow rate to speed up the measurement time and small input with a small flow rate to improve measurement accuracy. Measure with.
In order to perform automatic weighing, initial weight setting values such as a weight setting value for switching from large charging or medium charging to small charging and a falling weight value (falling setting) of a drop difference after stopping small charging are required.
Even during driving, it may be necessary to modify the weight setting values.
The set value is corrected manually (manual work). Some automatically correct the set value.
[0003]
However, those having these correction functions also require a certain initial weight set value.
In addition, there is a disadvantage that the drop weight value (drop setting) of the drop difference after stopping the small injection is not known unless automatic weighing is performed.
[0004]
On the other hand, due to the difference in the particle size, specific gravity, etc. of the powder granules that are the objects to be weighed, the article (object to be weighed) supply device also has a different mechanical structure such as a vibration feeder type or a screw feeder type.
Therefore, the initial weight setting value also has various numerical values.
Specifically, an empirical value in consideration of the physical properties of the supply device and the article (object to be weighed) is input as a weight setting initial value by a manufacturer, or a weight setting value is determined based on a measurement result in a trial run.
[0005]
[Problems to be solved by the invention]
Conventional technologies such as those described above are specialized in how the packer scale works and the physical properties of an article (weighed object) when starting up a weighing device or when weighing an article (weighed object) for the first time. There was a problem of requiring knowledge.
As an improvement measure described above, an object of the present invention is to provide a packer scale operating method for automatically calculating a weight setting value by driving and stopping an actuator of a supply device before starting normal automatic weighing. .
Furthermore, an object of the present invention is to provide a packer scale operating method for performing a weighing operation for automatically acquiring a weight setting value so that automatic weighing can be started by setting only a target weighing value.
[0006]
[Means for Solving the Problems]
The present invention adopts the following configuration in order to solve the above points.
<Configuration 1>
Before starting automatic weighing, the weight setting value is automatically acquired. Before starting the packer scale, fully open the supply gate and increase the weight data within the range not exceeding the target weight value (quantitative setting). Immediately after confirmation, close the supply gate to a predetermined opening, obtain the weight deviation (increased weight) from the start of the supply gate closing operation until the end of overshoot, and calculate the weight set value Packer scale driving method characterized by
<Configuration 2>
Servo motor that opens and closes the supply gate, and before starting the packer scale, fully opens the supply gate, and immediately after confirming the increase in weight data within the range not exceeding the target weight value (quantitative setting), supply to the specified opening Means for controlling the gate to be closed, and means for obtaining a weight deviation (increased weight) from the start of the closing operation of the supply gate to the end of the overshoot and calculating a weight set value. Packer-scale driving device characterized.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an outline drawing of a prototype for testing the present invention.
The numbers in the circles are the part numbers shown in FIG. 2 and FIG.
FIG. 2 is a component diagram of the supply gate portion.
17: Servo motor to 21: lever, 12: connecting rod, 9: knuckle joint, 3: connected to supply gate.
When the servo motor rotates once, the supply gate is structured to be closed → open → closed.
In the implementation control, a region of 0 ° (fully closed) to 180 ° (fully opened) was used.
[0008]
FIG. 3 is a component diagram of the weighing tank section that generates a weighing signal.
44: From the measuring tank main body, 42: suspended metal fitting, 39: suspended intermediate length nut, 37: rod end, 32: connected to load cell.
When the supply gate is opened, the article (object to be weighed) falls into the weighing tank and a weight signal is generated from the load cell.
After the measurement, 55 and 56 are discharged downstream by a measurement tank lower lid and a high rotor 61 that drives the measurement tank.
[0009]
The above mechanism has the following characteristics.
A servo motor was used as the actuator for the supply gate.
The gate opening can be set freely by changing the electrical parameters.
The gate opening / closing speed can be set freely.
Also, repeatability is better than actuators such as air cylinders.
A servo motor is used to drive the supply gate, and this is realized by a two-stage injection system consisting of a large input and a small input.
In the three-stage injection method consisting of large injection, medium injection, and small injection with an actuator such as an air cylinder, the weight setting value and the drop amount setting value for switching from medium injection to small injection are automatically acquired.
[0010]
FIG. 4 is a schematic flowchart of this actuator control method, and FIG. 5 is a detailed flowchart of each part.
Description will be made in the order of (1), (2), (4), and (5) along the schematic flowchart of FIG.
Section (3) is a control that is not related to the automatic acquisition of the initial weight set value, and will not be described. For automatic acquisition of the weight setting value, it is necessary to control the actuator within a range not exceeding the target weight value (quantitative setting).
In the flow chart (1), the supply gate shown in FIG. 1- (3) is fully opened, and as soon as an increase in weight data is confirmed, the supply gate is closed to a small charging opening.
The small throwing opening is a servo motor opening (angle) at which the article flows only from the semicircular cut portion of the supply gate in FIG.
At the time of switching from large input to small input, an overshoot occurs in the weighing signal due to the impact caused by the flow rate difference.
The end of the overshoot is detected, and the head weight value at the large input is acquired. At the time of overshoot, the weight value decreases as can be seen from the graph 1 in FIG. Therefore, since the deviation becomes negative, this is detected.
The head weight at the large input represents a weight deviation (increase in weight) from the start of the supply gate closing operation to the end of the overshoot.
In normal weighing, it corresponds to W1r (g) in Graph 1.
[0011]
Graph 2 in FIG. 7 is a graph when the weight set value acquisition operation is performed.
The drop weight value in the large input obtained in the flowchart (1) corresponds to W1r (g) in the graph 2.
Since the weight value graph 2-W1r (g) here also includes the weight value resulting from the opening operation of the supply gate, the drop amount at a larger input than the normal weighing state (graph 1-W1r (g)) is A large number.
The drop weight at large input is larger than the appropriate value. This means safe weight setting data.
The meaning of safety will be described in the calculation of the initial weight set value described later.
[0012]
In part (2) of the flowchart, a weight increase value for 1.5 seconds in a stable small charging state is acquired.
The stable small throw-in state represents a portion that increases in a directly proportional state on the weight value Y-axis and the time lapse X-axis.
Obtain the weight value A (g) when stability is detected (constant deviation) in part A of graph 2 and the weight value B (g) after 1.5 seconds, and increase W2w (g) = B (g) -Calculate A (g).
The method of using the increased amount W2w (g) and the time data value of 1.5 seconds will be described later in the calculation of the initial weight setting value.
[0013]
In part (4) of the flowchart, after restarting the small charging operation, the charging is stopped at C (g) in the weight value graph 2 1000 g before the target weight value W2t (g), and the weight value D (( Get g).
A small input head amount W2r (g) = D (g) −C (g) is calculated.
The portion after the flowchart (5) is normal measurement after data acquisition.
If the small throwing operation is restarted and the throwing stop weight value W2s (g) = target weight value W2t (g)-small throwing drop value W2r (g), the weighing result weight value is equal to the target weight value ( (Assuming that the repeated weighing error is zero).
1000 g is a weight range value sufficiently larger (safe) than the weight range necessary for performing the flow chart (5).
[0014]
Large input or medium input is intended to supply at a large flow rate to speed up the weighing time, but if there is a large error in the weight value at the end of the large input overshoot, the error Will end up with a small input.
Accordingly, even when the charging is large or medium, good weighing cannot be performed unless the repetition error of weighing accuracy is constant to some extent.
It can be easily understood that the small charging stop weight value W2s (g) = target weight value W2t (g) −small charging drop value W2r (g) in the above-mentioned flowchart (5).
If the same reason as the small input stop weight value is applied to the large input stop, the large input stop weight value W1s (g) = the large input target weight value W1t (g) −the large input drop value W1r (g).
Since the head weight value W1r (g) at the large input is calculated in the flow chart (1), the large input stop weight value (switching from the large input to the small input is obtained if the large input target weight value W1t (g) is calculated. Weight setting value) can be calculated.
The large input target weight value is a portion obtained by removing the input weight by the appropriate small input from the target weight value.
If the physical properties such as the specific gravity of the object to be weighed differ, the weight value supplied by small input in a certain time also varies. Therefore, by setting the time as the set value, it was decided to calculate the input weight by small input.
This is the part for calculating the flow rate for 1.5 seconds of small input in the flow chart (2).
The large input target weight value W1t (g) is calculated by calculating W1t (g) = small input stop weight value W2s (g) −weight value W2w (g) for the small input 1.5 seconds.
[0015]
In the second automatic weighing, W1s (g) weight value is switched from large input to small input, and charging is stopped at W2s (g) weight value.
In this measurement, a large input (overshoot) end weight value Ww1 (g) and a measurement completion weight value Ww2 (g) are acquired (graph 3 in FIG. 8).
Compare the target weight value W2t (g) and the weighing completion weight value Ww2 (g), and correct the small input drop weight value W2r (g) with the weight value corresponding to the deviation.
The correction of the small input drop amount is performed by a conventional method of calculating an average value of the number of times or a correction method of multiplying the correction value by a coefficient (%).
Since the small input drop amount is calculated accurately in the first weighing (flow chart (4)), if the repeated weighing error is zero, the target weight value W2t (g) and the measured weight value Ww2 (g ) Deviation is zero, and there is no correction of the set value.
[0016]
For large inputs, the large input drop value W1r (g) obtained in part (1) of the flow chart includes the weight value resulting from the gate opening, so the W1s (g) set weight value reduces the value from large input to small. When switching to charging, only the falling weight due to large closing only increases.
Since the gate is switched earlier by the weight value resulting from the opening, the large input target weight value W1t (g)> the large input end weight value Ww1 (g).
W1s (g) that does not exceed the target value is a safe large input stop weight value.
[0017]
Even in the large input stop weight value W1s (g), the set value is corrected using the concept of a head.
Compare the large input target weight value W1t (g) with the large input end weight value Ww1 (g), and correct the large input drop weight value W1r (g) with the weight value corresponding to the deviation.
In order to avoid exceeding the target value, a correction value multiplied by a coefficient (50%) was used to bring it closer to the appropriate value by several measurements.
[0018]
After repeating the same large input stop weight value correction as the second automatic weighing several times, the large input stop weight value W1s (g) is locked.
A button for selecting whether or not to use this control operation (denoted as auto-tuning) was provided on the touch panel.
If the auto-tuning button is turned ON when the packer scale is activated, it operates without using the large input stop set value and the head set value.
[0019]
Even an operator with specialized knowledge can hardly determine the initial set value when the article to be weighed is the first one.
By referring to similar data, the large input stop weight setting value and the head setting value are determined.
For the time being, it is possible to obtain a weight set value by this auto-tuning control, and then perform fine adjustment manually, so that even a skilled operator can be a very useful control method.
[0020]
Specifically, it is as follows.
The quantification of the prototype is 10050g. That is, the supply device is charged until the object to be weighed reaches 10050 g.
In this case, a set value 3909 g for switching from large input to small input is obtained by calculation.
The drop of small input is 169g. This is automatically acquired.
With small inputs, the weight increases by about 5g in 10msec.
If the small injection is continued for 1.5 seconds, the weight increases by about 750g.
The target for large input (end value) can be calculated as [quantitative]-[head]-[small increase in input weight].
Therefore, the end value of the large input is 10050 g−169 g−750 g = 9131 g.
From the graph of FIG. 6, the overshoot end value is 5222 g.
The difference is obtained by subtracting the overshoot end value from the large input end value.
Difference = 9131g-5222g = 3909g.
That is, when the weighing signal reaches 3909 g, switching from large input to small input allows the input speed to be switched safely even if the overshoot is taken into account.
By the calculation as described above, a set value 3909g for switching from large input to small input is automatically calculated.
[0021]
【The invention's effect】
As described above, the weighing method of the present invention is the reverse idea of normal weighing in which an actuator is operated with a preset value.
Since it is a simple and clear idea that the weight set value can be calculated by operating the actuator first, it can be used as it is for a three-stage packer scale using a conventional air cylinder or the like.
In the case of three-stage charging, the weight setting value that switches from large charging to medium charging increases by one, so it is possible that the total weight setting value cannot be acquired by a single control within the target weight value range. Can be realized by dividing the process into two.
[Brief description of the drawings]
FIG. 1 is a front view of a prototype.
FIG. 2 is a part diagram of a prototype supplying unit.
FIG. 3 is a diagram of a measuring unit and parts of the prototype.
FIG. 4 is a schematic flowchart of the invented operating method.
FIG. 5 is a detailed flowchart of the invented operating method.
FIG. 6 is a graph showing an actuator opening degree and a weight change during a weight value decreasing operation during overshoot.
FIG. 7 is a graph showing an actuator opening degree and a weight change when a weight set value acquisition operation is performed.
FIG. 8 is a graph showing actuator opening and weight change when switching from large input to small input.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cut gate body 2 Gate shaft fixing bolt 3 Supply gate 4 Bush 5 Spacer 6 Gate shaft 7 Split pin 8 Knuckle joint pin 9 Knuckle joint 10 Flat washer 11 Nut 12 Connecting rod 13 Nut 14 Plate presser 15 Plate 16 Servo motor Mounting base 17 Servo motor 18 Proximity switch mounting base 19 Proximity switch 20 Nut 21 Lever 22 Rod end 31 Load cell cover 32 Load cell 33 Spring washer 34 Bolt 35 Load cell cover 36 Load cell mounting base 37 Rod end 38 Nut 39 Hanging intermediate length nut 40 Dust-proof cloth 41 Nut 42 Suspension fitting 43 Bush 44 Measuring tank body 45 High rotor mounting opening / closing arm 46 Bushing 47 Knuckle joint left screw 48 Nut 49 Turnbuckle 0 nut 51 split pin 52 flat washer 53 knuckle joint right screw 54 pin 55 Determination tank lower cover 1
56 Fixed tank lower lid 2
57 Bush 58 Fixed tank lower cover shaft 59 High rotor mounting base 60 High rotor cover 61 High rotor 62 Tapered pin

Claims (2)

Automatic weighing control device
An operation of fully opening the supply gate and starting large injection into the weighing tank;
Immediately after measuring the weight of the weighing tank and detecting a weight increase after starting large charging, the operation of closing the supply gate to a predetermined opening, stopping large charging and switching to small charging,
Detects the end of the overshoot after stopping the large injection, and calculates the weight of the weighing tank at the end of the overshoot as the large input drop weight ( W1r )
After stopping the large injection and switching to the small injection, the operation to stop the small injection after continuing the stable small injection state in which the weight increases in direct proportion,
Weight increase of the weighing tank in the stable small charging state ( W2w )
Opening the supply gate to the predetermined opening and resuming small injection;
An operation of stopping the small throw-in at a weight sufficiently before the target weight;
Subtract the weight (C) of the weighing tank when the small charging is stopped from the weight (D) when the weight is stable after the small charging is stopped. W2r )
Target weight ( W2t ) To increase the weight of the weighing tank ( W2w ) And the small drop drop weight ( W2r ) And the large input drop weight ( W1r ) And subtract the safe large input stop weight ( W2s ) In order, and a packer scale operation method. The method of claim 1, further comprising:
  Automatic weighing control device
The target weight ( W2t ) To the small drop head weight ( W2r ) Is subtracted to determine the weight to end small injection,
An action to resume small throwing,
An operation method of a packer scale, wherein an operation of stopping charging is executed in order when the weight for ending the small charging is reached.

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