JPH11183239A - Automatic weight sorting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make shorter the sorting time of an automatic weight sorting machine using an electromagnetic force balance-type electronic balance as a weight measuring section. SOLUTION: The automatic weight sorting machine is provided with a weight setting means 105 which sets a reference weight, a current supplying means (an arithmetic control section 102 and a current generating section 104) which forcibly sets an electronic balance 1 in an unbalanced state by making the electric current used for generating the electromagnetic force corresponding to the set reference weight to flow to a force coil 15, and an article detecting means 3 which detects that an article is loaded to the balance 1. In addition, the balance 1 is constituted so that the balance 1 may start balancing operations after an article detecting output is generated from the detecting means 3. Therefore, the time required for balancing a balance mechanism 10 can be shortened by reducing the variation of the current flowing to the coil 15 when the balance 1 is shifted from a no-load state to an article placing state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic weight sorter, and more particularly, to an automatic weight sorter using an electromagnetic force-balanced electronic balance.

[0002]

2. Description of the Related Art In an electromagnetic force balance type electronic balance, a force coil is arranged in a static magnetic field, and a balance mechanism is balanced by countering an electromagnetic force generated by flowing a current through the coil against a load to be measured. The load to be measured is determined from the magnitude of the current flowing through the force coil in the balanced state.

[0003] Such an electromagnetic force-balanced electronic balance is used as a weight measuring unit, and the measured result is compared with a preset sorting weight in a comparing unit, and the comparison result is displayed or printed, or the articles are sorted. Automatic weight sorter configured to generate an operation output of a mechanism for the purpose is known.

In this type of automatic weight sorter, conventionally, articles to be sorted are sequentially placed on a measuring dish of an electronic balance in an unloaded state, and an equilibrium state of a balance mechanism is obtained after placing each article. The balance output at the time is supplied to the comparison unit.

[0005]

By the way, the electronic balance of the electromagnetic force balance type can perform high-precision measurement by the measurement principle based on the null method, but the balance mechanism is equilibrated without load. The step response speed when the object to be measured is loaded from the state in which it is in the state cannot be arbitrarily increased, and is considered so as to stabilize as quickly as possible by performing PID (proportional / integral / differential) calculation. However, when used as a weight measuring unit of an automatic weight sorter, there is a problem that the time required to sort the weight of articles cannot be shortened to a certain extent or more.

The present invention has been made in view of the above-mentioned circumstances, and performs highly accurate weighing by using an electromagnetic force-balanced electronic balance as a weight measuring unit, and furthermore, reduces the time for sorting the weight of articles compared to the conventional one. The purpose is to provide an automatic weight sorter that can be shortened.

[0007]

A structure for achieving the above object will be described with reference to FIG. 1 showing an embodiment. An automatic weight sorter according to the present invention is an electromagnetic balance type electronic balance. A weight setting means 105 for setting a reference weight in an automatic weight sorter provided with a comparison means 2 for comparing the output from the electronic balance 1 with the weight to be sorted and outputting the result. A current supply means for supplying a current for generating an electromagnetic force corresponding to the set weight to the force coil 15 of the electronic balance 1 to force the electronic balance 1 into an unbalanced state (the operation unit control 102 and the current Generating unit 103) and an article detection unit 3 for detecting a load of an article on the electronic balance 1;
Is characterized in that it is configured to start a servo operation for maintaining a balance state after the detection output by the article detection means 3 is generated.

According to the present invention, an electromagnetic force close to an electromagnetic force required for balancing a balance mechanism of an electronic balance of an electromagnetic force type is generated in advance before an article is placed, that is, in an unloaded state. Accordingly, the step response amount of the servo mechanism when the article is loaded is reduced, and the time required for the balance mechanism to balance is shortened.

That is, when using, the weight setting means 1
When an arbitrary weight is set in step 05, a current for generating an electromagnetic force corresponding to the set weight is supplied to the force coil 15 of the electronic balance 1. As a result, the electronic balance 1 is forced into an unbalanced state. By setting the weight set by the weight setting means 105 to, for example, the weight to be sorted or the average weight of the article, when the article is placed on the electronic balance 1, the servo system sets the weight of the article to the set weight. By generating an electromagnetic force corresponding to the difference, the balance can be achieved, and the time required for the balance can be reduced.

Here, the balance mechanism 10 of the electronic balance 1 is used.
Is in an unbalanced state in a no-load state, and mechanically requires a longer time to balance as compared with a normal electronic balance. However, the natural frequency of this type of balance mechanism 10 is generally about 8 to 30 Hz,
The amount of time reduction by reducing the step response amount of the servo system is greater, and therefore, the overall required time of the electronic balance 1 is reduced by employing the present invention.

[0011]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

The electronic balance 1 of the electromagnetic force balanced type supports a plate 11 on which an article to be measured is placed by a well-known balance mechanism 10 including a roberval mechanism 12, a lever 13, and the like. The displacement is detected by the displacement sensor 14.

A force coil 15 is fixed to the lever 13, and the force coil 15 is disposed in a static magnetic field generated by a magnetic circuit. Accordingly, an electromagnetic force is generated by passing a current through the force coil 15.

The displacement detection output of the lever 15 by the displacement sensor 14 is digitized by the A / D converter 101 and then taken into the arithmetic and control unit 102. Arithmetic control unit 1
In the step 02, the PID calculation processing is performed on the displacement detection data of the lever 15, and the PID data as the processing result is supplied to the current generator 103. The current generator 103 generates a current corresponding to the size of the PID data from the arithmetic and control unit 102 and supplies the current to the force coil 15. The electromagnetic force generated by the current flowing through the force coil 15 acts to make the displacement of the lever 15 zero, and a digital servo system is constructed as a whole.

The PID data from the arithmetic control unit 102 is
At the same time, it is taken into the weighing value determining unit 104, converted into the weight value on the plate 11, and output to the comparing unit 2. However, the weight measurement data is output to the comparison unit 2 because P
This is the time when the ID data reaches the stable state, that is, the time when the balance mechanism 10 is in the balanced state.

The comparing unit 2 compares the weight value from the weighing value determining unit 104 with a preset sorting weight, for example, a weight range such as a lower limit value and an upper limit value, and determines and displays the result as a sorting result. At the same time as outputting to the section 106, it is supplied as an operation command to the sorting section 107 such as a sorting chute.

The arithmetic control unit 102 receives the weight data set by the weight setting unit 105 and the article detection output by the article detection sensor 3.

The weight setting unit 105 is for setting a weight which is a reference for the operation of the embodiment of the present invention described below.
A detection output is generated when it is detected that an article is placed on the device.

In a no-load state, that is, in a state where no output from the article detection sensor 3 arrives, the arithmetic control unit 102 applies a current for generating an electromagnetic force corresponding to the weight set by the weight setting unit 105 to a force. Coil 1
5, the balance operation of the balance mechanism 10 by the servo system described above is stopped, and when the output from the article detection sensor 3 arrives in this state, the balance operation is started.

The weight set value by the weight setting unit 105 is set to, for example, a median value in the vicinity of the sorted weight, when the weight range between the upper limit and the lower limit is the sorted weight as described above. Is preferred.

In a no-load state, a current that generates an electromagnetic force corresponding to the weight set by the weight setting unit 105 is applied to the force coil 15 of the electronic balance 1, and the balance is controlled by the servo system. Since the operation is stopped, the balance mechanism 10 is in an unbalanced state.

In this state, when the article is placed on the plate 11 and the article detection output arrives, the servo system starts the balance operation. At this time, the force coil 15 has a weight corresponding to the weight already set. Since a current that generates an electromagnetic force is applied, the amount of change in the current flowing through the force coil 15 is significantly smaller than the amount of change from a normal no-load state, and therefore, the balance mechanism 10 is not balanced. The time required to reach the state is reduced. As a result, the accurate weight measurement data of the article is promptly supplied to the comparison unit 3, and the article sorting speed as a whole is improved. In particular, when the weight variation of the article is small and the weight set by the weight setting unit 105 is near the median of the weight variation range, the effect of shortening the time is great.

In the above-described embodiment, an example is shown in which the weight of the article is compared with the range between the upper limit and the lower limit in the comparison section 2. However, the present invention is not limited to this. One weight is set, and the magnitude relation to the weight is selected. Or, a plurality of boundary weights are set, and any one of a plurality of weight ranges divided by the boundary weight is entered. It is also possible to use such as sorting out whether there is.

The reference weight set by the weight setting unit 105 is not particularly limited as long as it is in the vicinity of the above-described sorting weight. In short, the amount of change in the current flowing through the force coil 15 is limited. Setting as small as possible is useful in increasing the effect of the present invention.

Further, in the above-described embodiment, an example is shown in which the weight setting section 105 is provided so that the user of the apparatus can set and input a reference weight. However, the present invention is not limited to this. Instead, for example, when upper and lower limit weight values are set as weights to be sorted, a median value may be calculated and the value may be automatically set as a reference weight value.

The means for detecting that an article is placed on the plate 11 of the electronic balance 1 includes the article detection sensor 3 as in the above embodiment, and the output of the displacement sensor 14 of the electronic balance 1. It is needless to say that any means such as a combination of the above can be used.

[0027]

As described above, according to the present invention,
In an automatic weight sorter that uses an electromagnetic force-balanced electronic balance as a weight measuring unit for an article, a current that generates an electromagnetic force corresponding to the weight set by the weight setting unit is passed through a force coil in advance, and the article is Since the balance mechanism is started by the servo system from the point when the load is applied to the electronic balance to balance the balance mechanism, the current flowing through the force coil is lower than when an article is placed directly on a plate from no load. Is greatly reduced, the time required for the balance mechanism to be in a balanced state is reduced, and the sorting speed of articles is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic balance 10 Balance mechanism 11 Plate 12 Roberval mechanism 13 Lever 14 Displacement sensor 15 Force coil 101 A / D converter 102 Operation control unit 103 Current generation unit 104 Weighing value determination unit 105 Weight setting unit 106 Judgment display unit 107 Sorting unit

Claims (1)

[Claims] 1. An automatic weight sorter having an electromagnetic force-balanced electronic balance and a comparing means for comparing an output from the electronic balance with a weight to be sorted and outputting the result.
Weight setting means for setting a reference weight, and a current for generating an electromagnetic force corresponding to the set weight is supplied to a force coil of the electronic balance to forcibly bring the electronic balance into an unbalanced state. And an article detecting means for detecting a load of an article on the electronic balance. The electronic balance starts a servo operation for maintaining a balance state after the detection output by the article detecting means. An automatic weight sorter characterized by being constituted.