JPH0833322B2 - Electronic balance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an electronic balance, and more particularly to an electronic balance suitable for a quantitative weighing operation such as a dispensing operation.

<Prior Art> Generally, in an electronic balance, a measured value is determined by calculation using data from a load detection unit and displayed on a digital display. The metric value is determined from the average value of the individual data. The larger the number of data for this averaging, the more stable display can be performed against disturbances.

On the other hand, when a certain amount of a sample such as a drug is weighed using such an electronic balance, it is necessary to read the displayed value while sequentially adding the sample on the dish, and therefore, there are many measured values. Since it is determined by averaging the data of No. 3, the responsiveness of the display to the fluctuation of the load on the plate is deteriorated, and the workability is significantly reduced.

Therefore, conventionally, each time the data from the load detection unit is taken in, the variation amount of the latest predetermined number of data is obtained, and whether or not the variation amount falls within a preset stable width equivalent to a certain weight. By determining whether the data is in a stable state or in a fluctuating state, the weighing value is determined by a small number of data while the data is fluctuating to improve the responsiveness of the display and stabilize the data. If this is the case, a method is adopted in which the measured value is determined by averaging a large number of data to enhance the stability and reliability of the display.

<Problems to be Solved by the Invention> By the way, in the quantitative weighing operation of a sample such as a drug, an allowable range of the weighing error is set, but this allowable range is within a predetermined percentage with respect to the target value of the weighing. Is often set. Therefore, the allowable range of the weighing error, when converted into the weight value, depends on the size of the weighing target value.

This means that when performing weighing work using an electronic balance that adopts the above-mentioned conventional data stability determination method, the method of data stability determination and the method of determining the weighing value accompanying it are always optimal. It means that I cannot say. Specifically, for example, when the allowable range of the error is 1% with respect to the weighing target value, if the weighing target values are 100 g and 1 g, the weighing display value is determined when determining whether the weighing is completed or not. The minimum digits that require a guarantee are 1g and 0.01g, respectively. Therefore, if the stability width is set to 0.01 g, the optimum display will be displayed for a 1 g scale, but for a 100 g scale, wait until the data becomes more stable than necessary. This is the first time that the guaranteed measurement value is displayed, which is an obstacle to work efficiency.

An object of the present invention is to perform an appropriate data stability determination according to the size of the weighing target value, and thus always be able to perform optimum display regardless of the size of the target value, that is, the required accuracy. Is to provide an electronic balance capable of obtaining a guaranteed weighing value as soon as possible.

<Means for Solving Problems> A configuration for achieving the above object will be described with reference to the basic conceptual diagram shown in FIG. 1. The present invention is incorporated from the load detection unit a every moment. In order to input the target weight value W ₀ to be weighed in the balance displayed on the digital display c by determining the weighing value W by calculating the data D ₁ , D ₂ , ... D _i ... Input means d, a memory e for storing the input weight target value W _0, and the content W ₀ of the memory e of the weight conversion value w _i of the momentary data D _i from the load detection unit a
Load / target value ratio calculation means f for calculating the ratio R _i (= w _i / W ₀ ) and the latest predetermined number of calculated ratios R _i R ₁ , R ₂ ,
The data stability determining means g for determining whether the data D _i is stable or fluctuating according to whether the fluctuation width B _{R of} R _n is within a preset stability width B ₀ is provided. It is sometimes characterized by the fact that the metric value W is determined by the average of a larger number of data D _i than when the data changes.

<Operation> After converting the data D _i into the rate R _{i based} on the weight target value W ₀ to be weighed, whether or not the fluctuation width B _R of the latest predetermined number is within a constant stability width B ₀ Since the stability determination of the data D _i is performed with, the weight conversion value of the stability width B ₀ substantially changes automatically in accordance with the weight target value W ₀ , and the degree corresponding to the required accuracy is obtained. When the data is stable,
Immediately, the measured value that guarantees the accuracy will be displayed stably.

<Examples> Examples of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of the embodiment of the present invention.

The load detection unit 1 detects the load on the dish 1a, and the digital conversion data D _i thereof is taken into the control unit 2 every predetermined minute time.

The control unit 2 is composed of a microcomputer and is a CP that executes various calculations and programs and controls each peripheral device.
U21, ROM22 in which a program to be described later is written, RAM2 in which an area for storing the data D _i from the load detection unit 1 and an area for storing a target weight value W ₀ for weighing described later are set.
Has three.

In addition to the load detection unit 1, the control unit 2 is connected with a keyboard 3 for inputting a target weight value W ₀ for weighing, and a display unit 4 mainly using a numeric keypad, and a plate,
Input port 5 for inputting data from external equipment
And an output port 6 for transferring weighing data and the like to an external device.

The display unit 4 includes a weighing display unit 41 for digitally displaying the weighing value W of the load on the pan 1a and a target value display unit 42 for digitally displaying the weighing target weight value W ₀ input from the keyboard 3. , And an analog display 43 for analogically displaying the excess / deficiency ratio (r%) of the measured value W with respect to the target value W ₀ based on the load / target value ratio R, which will be described later. As shown in the external view of No. 4, they are arranged adjacent to each other. Of these, the analog display 43
For example, an excess / deficiency rate of ± 1% is set as “OK” display, and a plurality of display elements 43a, 43b, 43b, 43b, 43b, 43b, 43b, 43b, 43b It is configured by arranging 43c and 43d continuously, and the corresponding display element can be turned on by a command from the control unit 2.

FIG. 4 is a flow chart showing a program written in the ROM 22. The operation will be described with reference to this figure.

Before carrying out the weighing operation, first, the weighing target weight value W ₀ is input by the keyboard 3. As a result, the target value W ₀ is displayed on the target value display 42.

When the sample is placed on the dish 1a, the data D _i from the load detection unit 1 changes every moment, but this data D _i is sequentially stored in the RAM 23. The RAM 23 has an area for storing n pieces of data, and shifts the already stored data every time the latest data D _i is sampled, so that the latest n pieces of data D _{1 to} D _n are always stored. Is stored.

Each time data D ₁ is sampled, each data D _{1 to} D in RAM23
weight value w ₁ to w _n based on _n, the rate with respect to the target value W ₀ R ₁ ~R _n
(R _i = 100 × w _i / W ₀ ) is calculated, and the difference between the maximum value and the minimum value in the _n rates R _{1 to} R _n is obtained as the fluctuation width B _R.
This fluctuation range B _R is the stable range B
Compared with ₀ (%), if the fluctuation range B _R is not within the stable range B ₀ , the data is regarded as changing and the latest data
The weight value w ₁ based on D ₁ is displayed as the weight value W on the weighing display 41, and at the same time, the weight value w _1, that is, the target value of the weight value W.
Target value W ₀ obtained by subtracting the rate R ₁ for W ₀ from 100%
The excess / deficiency ratio r of the measured value W with respect to is displayed by turning on the corresponding elements other than the "OK" display element 43a of the analog display 43. In this state, the display of the weighing display 41 and the analog display 43 changes in quick response to the sample loading onto the dish 1a.

When the fluctuation width B _R fits stably width B in the _0, the data is considered to be in steady state, the average value of the weight values w ₁ to w _n based on n data D ₁ to D _n in the RAM23 metering Weighing indicator as value W
41, and at the same time, the above-mentioned excess / deficiency ratio r is R _{1 to} R _n.
The value obtained by subtracting the average value of 100% from the analog display 4
Displayed in 3. In this state, the stable weighing value W and the excess / deficiency ratio r which are stable even if there is some disturbance are displayed. In addition, each display value in this data stable state is the stable width.
It will be guaranteed within the weight conversion value of B ₀ (%).

Only when the data is in a stable state and the excess / deficiency ratio r is within ± 1%, the "OK" display element 43a is turned on or blinks to notify that the weighing is completed.

Here, the stability width B ₀ is set in the unit of%, and within this stability width B ₀ , the target value of the weight value w _i corresponding to the load on the plate 1a is set.
Since the stability of the data is determined by the deviation between the rates R _i relative to W ₀ , that is, whether the fluctuation range B _R is within the range, the weight conversion value of the stability range B ₀ depends on the set target value W _0. Change. For example, if the stability width B ₀ is 2%, the weight conversion value is 2 g if the target value W ₀ is 100 g and 0.2 g, 1 if the target value W ₀ is 10 g.
If g, it will be 0.02 g. This means that even if the data D _i fluctuates by an amount equivalent to 2 g at the maximum when weighing 100 g, the data D _i is 0.02 g at the maximum when weighing 1 g. It is judged that the data is stable only when it is contained in a considerable amount of variation, and the criterion for judging the stability of the data substantially changes to the size of the target value W ₀ for weighing.

The present invention is an analog display 43 is not necessarily required, but the data stability determination criterion as it is capable of achieving the targeted effects simply by substantially automatically changed as described above, the target value W ₀ By displaying the excess and deficiency with respect to the ratio in an analog manner, it is easy to detect the required amount of the sample to be input and the required amount to be removed of the sample in the weighing operation, and it is possible to significantly improve the efficiency. Further, it is also possible to display the rate digitally instead of the analog display.

Further, by providing an indicator lamp or the like for notifying that the data is in a stable state, the operator can easily recognize the fact, which leads to improvement in work efficiency.

Furthermore, the target weight W _{0 for} weighing is not limited to being input by the keyboard 3, but may be input from an external device such as a host computer via the input port 5.

Further, the stability width B ₀ (%) can be arbitrarily set by the keyboard 3 or the like, and can be appropriately changed according to the use environment of the balance or the weighing accuracy. Further, as the display mode by the analog display 43, not the excess / deficiency ratio r, but the ratio of the measured value W to the target value W ₀ , that is, the ratio R in the above-described embodiment.
It is also possible to display itself and display 100% of the display elements for "OK" display. In this case, even if all the elements lower than the element corresponding to R are turned on and a bar graph is displayed, Good.

In addition, if the minimum display unit of the analog display 43 is set to be smaller than the one-count equivalent amount of the measurement display 41, that is, the display resolution of the analog display 43 is changed to the measurement display 41.
If the lowest digit of the weighing display 41 changes due to external disturbance, etc., the analog display 43
However, since the analog display easily recognizes the median value of the fluctuation when the fluctuation occurs, it is possible to more quickly recognize the degree of excess or deficiency of the measured value with respect to the weighing target value. At the same time, the display of the least significant digit of the weighing display 41 is determined by rounding the least significant digit, but even if the displayed value of the least significant digit is the same, the analog display 43 further lowers the least significant digit. There is also an effect that it is possible to monitor how much a digit is.

<Effects of the Invention> As described above, according to the present invention, the weight value based on the data from the load detection unit is converted into a rate with respect to the input weighing weight target value, and the latest predetermined number of the rate is calculated. The stability of the data is determined by whether or not the fluctuation range is within the preset stability range, and when the data is stable, it is configured to display a stable weighing value by averaging a larger number of data than when it fluctuates. The absolute amount of the stability criterion for data changes substantially depending on the amount of weight to be taken.If the weighing amount is large, it is determined that the data is stable even if the absolute amount of data fluctuation is large. As described above, quick weighing can be performed without waiting for the data to stabilize. On the contrary, when the amount of weighing is small, it is determined that the data is stable after the absolute amount of the data fluctuation amount is sufficiently small, so that a highly reliable measurement value can be displayed without causing a lack of accuracy.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram showing the configuration of the present invention, FIG. 2 is a block diagram showing the configuration of the embodiment of the present invention, FIG. 3 is an external view of its display unit 4, and FIG. 4 is written in its ROM 22. 7 is a flowchart showing a program. 1 …… Load detection section 1a …… Plate 2 …… Control section 21 …… CPU 22 …… ROM 23 …… RAM 3 …… Keyboard 4 …… Display section 41 …… Weighing indicator 42 …… Target value display 43 …… Analog display 43a, 43b… 43b, 43c, 43d …… Display element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-27821 (JP, A) JP-A-56-108918 (JP, A) JP-A-63-78022 (JP, A)

Claims (3)

[Claims] 1. An input for inputting a target weight value to be weighed in a balance which determines a weighing value by calculating the data taken in momentarily from the load detection unit by an arithmetic unit and displays it on a digital display. Means, a memory for storing the input weight target value, and a load / target value ratio calculation means for calculating a ratio of the weight conversion value of the momentary data from the load detection unit to the contents of the memory, A data stability determination means for determining whether the data is stable or fluctuating depending on whether or not the fluctuation width of the latest predetermined number of the rates falls within a preset stability width,
An electronic balance, characterized in that when the data is stable, the above-mentioned weight value is determined by averaging a large number of data rather than when the data fluctuates. 2. A weighing ratio display means for displaying the ratio of the measured value to the target value in an analog manner on the basis of the value calculated by the load / target value ratio calculating means. An electronic balance according to the first section. 3. The electronic balance according to claim 2, wherein the minimum display unit by the weighing rate display means is smaller than the amount corresponding to one count of the digital display.