JPH0640019B2 - Electronic balance - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic balance, and more particularly to an electronic balance suitable for weighing animals.

(B) Conventional technology In general, in order to improve the measurement accuracy in an electronic balance, some weighing data are averaged, and the time required for this averaging is called the averaging time.

In animal weighing balances used to check the stability of chemicals, because the animals move around on the weighing dish, there are large variations in the data, and if you want to obtain accurate data, set the averaging time longer and vice versa. In addition, even if there is some measurement error, if you want to shorten the measurement time, it is considered that the weighing value is in a stable state.The stability tolerance range is expanded and the averaging time is shortened. It is necessary to set the width. In particular, since the administered drug may cause the animal to be excited and swirled around, it requires a high degree of skill to set the condition each time so as to adapt to the changing measurement situation, and it is a troublesome task.

(C) Object of the Invention An object of the present invention is to provide an electronic balance for animal weighing which does not require any specially advanced technique and can be simply, accurately and quickly weighed by anyone.

(D) Configuration of the invention The electronic balance of the present invention is a load detecting means for converting the load on the weighing pan into an electric signal every moment, a variation calculating means for calculating the magnitude of the variation of the electric signal, and the calculation thereof. Data processing condition determining means for determining the conditions required for data processing such as the average number of weighing data, averaging time, stability width, etc. according to the variation, and condition determination for instructing whether or not to execute the condition determination Only when there is an instruction means and there is an execution instruction by the condition determination instruction means, the calculation of the variation of the weighing data of the measured object placed on the weighing pan as a sample and the determination operation of the data processing condition based on it It is characterized in that it is configured to be executed and, thereafter, that the weighing data is processed according to the determined processing conditions.

FIG. 1 is a block diagram showing the configuration of the present invention. The load detecting means 1 outputs the weighing data every moment, the variation calculating means 2 calculates the variation of the weighing data, for example, the standard deviation, and the condition determining means 3 processes the data processing condition according to the variation of the weighing data. To decide. The condition determining means 3 and the variation calculating means 2 function only when there is an instruction to execute the condition determination from the condition determining instructing means 6, and when there is no instruction, the processing condition once determined is fixed. Data processing means 4 based on the processing conditions
Processes the weighing data and displays it or outputs it to a printer or the like.

Here, a plurality of types of programs are prepared as condition determining programs by the condition determining means 3, and when there is an instruction to execute condition determination, the program of the mode selected by the mode selection switch 5 is followed. It is preferable to determine the conditions.

(E) Embodiment FIG. 2 shows a block diagram of an apparatus for carrying out the present invention.

The load detection unit 1 converts the load W on the dish 1a into weighing data of digital electric signals. This weighing data is, for example, 0.2
It is converted every second. The microcomputer 7 is provided with a switch interface 8 in addition to a CPU, a RAM, and a ROM, and a tare subtraction switch SW ₁ , a mode selection switch SW ₂ , and a condition storage instruction switch SW ₃ are provided at locations that can be operated from the outside. The microcomputer includes a variation calculation means, a condition determination means, and a data processing means. The data processing result is displayed on the display 9.

FIG. 3 shows a flow chart of the program stored in the ROM of the microcomputer 7.

Prior to the measurement, first, one of the modes A, B, and C is selected by the mode selection switch SW ₂ , then the first animal is placed on the dish 1a as a sample, and the condition storage instruction switch SW ₃ is turned on. . In this state, the condition determining means 3
Is the average data number N or the averaging time and the stability width e is determined, and then the condition storage instruction switch SW ₃ is turned off, the measurement data processing thereafter is based on the determined average data number N and the stability width e. It is processed.

In step S-1, the first variation of the weighing data of the animal, for example, the standard deviation σ is calculated. When the allowable variation e with 95% probability is obtained, e = 2σ (1) If the variation of the average value of N pieces of weighing data is ε, Have a relationship. Therefore, the number N of weighing data required for animal measurement is Is calculated by Allowable variation according to equation (2) or equation (3) The calculated values of luck e are shown in the following table.

The A mode is programmed with a calculation method that we call the stability width priority method. This mode enables highly accurate measurement in a short time for animals with small variations, but has the disadvantage that the measurement time becomes long when the variations are large. Normally, the allowable variation of the weighing data is about ± 3 counts, so, for example, by substituting ε = 3 into the equation (3), The number N of weighing data is obtained by.

The B mode is programmed with a calculation method that we call the measurement time priority method. For example, the number of data N is obtained with ε = 3, but when N exceeds a certain value, for example 16, N = 1 without further increasing the number of data N.
Fix at 6.

That is, when e exceeds 12, N is fixed and ε is e /
Only compressed to 4. Therefore, when the variation of the weighing data becomes large, the measurement time has priority over the stability width, and the increase of the measurement time is suppressed.

In the C mode, the data N to be averaged and the allowable variation ε
Is a method in which the value becomes a value determined in advance according to the variation e of the input, and is an eclectic method of the A mode and the B mode. First, set ε = 3 as in A mode and B mode, and when e is 12 or less, The number of data N is determined by, but when e exceeds 12, the number of data N is determined according to the range of e, for example, as shown in the following table. As a result, the value of ε also increases from 3, but e /
Compressed much less than 4.

When 80 <e, a warning that measurement is impossible is issued.

Measurement conditions are set by each mode Then, the program proceeds from step S-2 to average the weighing data N times and stores it in the display register D.
D when numerical data is written in the display register D
Since ≠ 0, the print flag P is set in step S-3.
Set. Next, in order to check whether or not the averaged data is within the stable range, in step S-4, the difference between the latest average value and some average values before that is calculated for each. If all the differences are not within ± e, it is determined that it is not stable, and the determination step S-
5 proceeds to N (no), and the data processing is repeated. If all the differences are within ± e, it is judged that the data is stable and the judgment step S-5 advances to Y (yes). If the print flag is set to P = 1, the contents of the display register D are changed. Output to the printer (S-6), and then reset the print flag P to 0.

When the condition storage instruction switch SW ₃ is switched to OFF, the program without entering the branch through the variation calculation step S-1, performs data processing to the variation of the average value of N times the data will be within ± e .

Instead of the simple average calculation in step S-2, for example, a digital filter method can be used for the calculation. This is illustrated in FIG. Display data is Yn (or previous data is Y _n-1 , Y _n-2 , ...) and input data is X.
When n (or the one before it is X _n-1 , X _n-2 , ...) Yn = a (Y _n-1 -Y _n-2 ) + b (Xn + X _n-1 + X _n-2 ) ... ( 5) However, the display data is calculated by 2a + 3b = 1 (6). Here, as the coefficient a increases and the coefficient b decreases, the filter effect increases and the responsiveness deteriorates. Therefore, the present invention is implemented by automatically setting the coefficients a and b according to the variation e of the weighing data. can do. An example of the combination of the coefficients a and b is as follows.

Further, as another modified example of the present invention, instead of calculating the standard deviation σ in the variation calculating means, a variation width (RANGE) can be used.

Further, it is possible to omit the condition storage instruction switch SW ₃ and substitute it for the condition storage instruction when the tare weight subtraction switch SW ₁ is pressed for, for example, 3 seconds or more.

Furthermore, it goes without saying that the mode of the condition setting program is not limited to the above-mentioned A, B, and C, for example, C
It is also possible to implement the present invention with only a single mode of mode and omitting the mode changeover switch.

(F) Effect As described above, according to the present invention, by simply giving an instruction for condition determination in a state where the sample is placed on the weighing dish, data adapted to the magnitude of the variation in the weighing data in that state is given. The processing conditions are automatically determined, and after that, the conditions are fixed and the weighing data is processed.For example, when a large number of certain experimental animals are prepared and their weight is measured continuously, By simply selecting an appropriate animal and placing it on the weighing dish and instructing it to execute the condition determination, the optimum data processing conditions are automatically determined according to the rampage of the animal, and it is the same for the subsequent measurements. The data is processed under the conditions described above, and it is not necessary for the measurer to be familiar with setting the conditions.Moreover, when performing a series of measurements, measured values are obtained under the same data processing conditions, and the measured values may include individual differences. Absent. Further, unlike the conventional case, a stable width setting device, an averaging time setting device, etc. are not required, and the operation part is simplified.

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram showing an example of an apparatus for carrying out the present invention, and FIGS. 3 and 4 are flowcharts showing the contents of a program of the apparatus of FIG.

Claims (4)

[Claims] 1. A load detecting means for converting a load on a weighing pan into an electric signal every moment, a variation calculating means for calculating a magnitude of variation of the electric signal, and weighing data of the weighing data according to the calculated variation. Data processing condition determining means for determining conditions required for data processing such as average number, averaging time, and stability width, and condition determination instructing means for instructing whether or not to execute the condition determination are provided. Only when there is an execution instruction by the determination instruction means, the calculation of the variation of the weighing data of the measured object placed on the weighing pan as a sample and the determination operation of the data processing condition based on the calculation are performed, and thereafter the determination is performed. An electronic balance configured to process weighing data according to specified processing conditions. 2. The electronic balance according to claim 1, wherein a plurality of types of programs are provided in advance as the data processing condition determining means, and a switch for selecting one of the programs is provided. 3. The program according to claim 2, wherein the program of the data processing condition determining means includes a program for calculating the number of pieces of weighing data or averaging time required to reach a predetermined stability width. Electronic balance. 4. The electronic balance according to claim 2, wherein the program of the data processing condition determining means includes a program in which the upper limit of the number of weighing data or the averaging time is suppressed.