JPS6046428A - Zero-point correcting device of weighing instrument - Google Patents

Abstract

PURPOSE:To perform high-precision weighing through a weighing instrument which increases in sticking weight with a frequency of weighing by storing estimated values of the sticking weight previously, calculating the sticking weight when weighing is performed specific times, and correcting the zero point. CONSTITUTION:A memory 12 is stored with estimated values beta1-betam of sticking weight at respective sampling points of weighing frequency which are determined previously, and gradient coefficients alpha1-alpham between the estimated values at the respective sampling points. When a weighing signal is generated by the weighing instrument 10, a counter 14 counts the frequency of weighing. Its counted value is read by a read circuit 16 to read the estimated value and gradient coefficient corresponding to a sampling point frequency out of the memory 12, and those and the counted value from the sampling point are applied to a multiplier 18 and an adder 20 to calculate the sticking amount. This calculated value is subtracted out of the measured value to obtain the measured weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a zero point correction device for a measuring instrument, and in particular to a device for a measuring instrument in which the amount of deposits increases as the number of measurements increases.

In general, there are various types of measuring instruments. For example, if a measuring device with a load cell installed in the measuring tank repeatedly measures and discharges powder, etc., some of the powder, etc. will be discharged. Some of the particles also adhered to the measuring tank, and the amount of the adhered particles increased non-linearly as the number of measurements increased, as shown in FIG.

Conventionally, in such a measuring instrument, the zero point correction device used to accurately measure K.sub.t is used to stop the measurement of one quart after each measurement as shown in FIG. al, , β2...an) shown in FIG.
1. until the next time the stored value in memory 2 is updated.
The value stored in the memory 2 was subtracted by the subtractor 6 from the measurement signal of the measuring device 4. However, this has the problem that if the number of times of measurement is large before updating the value stored in the memory 2, the value stored in the memory 2 and the actual amount of adhesion will be too far apart, and the correction effect will be weakened. In order to prevent this, if the number of measurements taken until the value stored in the memory 2 is updated is reduced, the number of stops of the weighing device will increase, resulting in a decrease in measurement performance.

This invention was made to solve the above two problems at the same time.As shown in Fig. 1, when the amount of adhesion increases non-linearly as the number of measurements increases, is determined, and the predicted value b1. of the adhesion amount at each sample point is determined. ．． When b2...bn are known, the curve representing the adhesion amount can be approximated by a broken line (indicated by a dotted line in FIG. 1) connecting each predicted value.

Therefore, the present invention has a storage unit that stores the predicted value of the adhesion amount at each sample point, and also stores the gradient coefficient between each sample point, and the number of measurements between n and nth sample points. A counter for counting, a multiplier for multiplying the count value by a gradient coefficient between n and n sample points read from the storage unit, and a measuring device for measuring when the color/li is counting. The subtracter subtracts the multiplied value of the first multiplier and the predicted value of the n-th sample point read from the storage section from the signal.

With this configuration, as shown in Figure 3, if the predicted value at the n-th sampling point is βn, and the predicted value at the n-th sampling point is β(n+1), then the The gradient coefficient o<'n is expressed as (β(n+n1JA). However, d is the number of measurements between the n and (n+1)th sample points. During measurement between sample points, OCn and a are stored from the storage unit.
For example, the adhesion amount at the third measurement counting from the nth sample point is determined by 3D (n + βn, so multiply the count value 3 of the counter by n using a multiplier,
Multiply values 3cxn and an from the weighing signal at the third weighing
By subtracting and with a subtractor, we get the true is moth.

According to this, there is no need to take the trouble to stop the measurement and update the stored value in the memory.Since the adhesion amount is calculated using a polygonal line approximation, the accuracy is very high.

In the above invention, since the predicted value is used for an,
Its accuracy is somewhat low. Therefore, in another invention, only the gradient coefficient is stored in the storage section, and the actual adhesion amount at the n-th sample point is stored in another storage section, and the above multiplication value and n The actual adhesion amount at the second sample point is subtracted.

Hereinafter, these two inventions will be explained in detail based on three embodiments shown in FIGS. 4 to 6. FIG. 4 shows the first embodiment, in which numeral 10 is a measuring instrument.

12 is a memory that stores predicted values β1, β2...8m of the adhesion amount at each sample point N11N2...Nm, and gradient coefficients tel, α2...O+jm between the predicted values of each sample point. There is.

These predicted values and gradient coefficients are read out by the counter 14 and readout circuit I6. That is, the counter 14
counts the number of times of weighing based on the weighing signal generated by the weighing device 10. This count value CI is supplied to the continuation circuit I6, and the continuation circuit 16 reads XI and β1 until the count value reaches N1.
N2 and β2 are read until N2 is reached. Thereafter, in the same manner (Xm and βI' 111 are read out in order).

The thus read gradient coefficient is supplied to the multiplier I8, and the predicted value is supplied to the adder 20.

The multiplier 18 multiplies the count value C2 of the counter 22 by the gradient coefficient. The counter 22 also counts the number of times of weighing by the scale O1o based on the weighing signal, but is different from the counter 14 in that it is read out every time the count value CI of the counter 14 reaches Nl, N2...Nm. It is reset by the signal of the circuit 16. Therefore, the count value C2 of the counter 22 represents the number of times of measurement from one sample point to the next sample point. Therefore, as explained earlier, the count value C of this counter 22
The value obtained by adding the predicted value to the multiplied value of 2 and the gradient coefficient by the adder 2o represents an approximate value of the amount of I" at that time. Zero point correction is performed by subtracting this approximate value using a subtracter 24. Incidentally, it goes without saying that the Curtain Moon 4 is reset when the deposit is removed.

The second embodiment differs in that the first embodiment uses the predicted value of the amount of adhesion at each sample point, whereas the actual amount of adhesion at each sample point is used. That is, as shown in FIG.
6 stores only the gradient coefficients Nl to ocm, and the count value C! of the counter 14! The actual adhesion amount at that time is stored in the memory 28 by the output of the continuous circuit 16 when the value becomes Nm or Nm, and thereafter, the value stored in the memory 28 is subtracted from the measurement signal of the measuring instrument 10 by the subtractor 30. Then, the output of the multiplier 18 is subtracted by the subtracter 32 from the subtraction output of the subtracter 30. The accuracy will be higher if the actual adhesion amount is used instead of the predicted value.

In contrast to the first and second embodiments, in which the gradient coefficient is predetermined, the third embodiment determines the amount of adhesion upon completion of a predetermined number of measurements and the amount of adhesion before starting this predetermined number of measurements. The difference is that the next gradient coefficient is determined based on the amount of clothing.

That is, in FIG. 6, a counter 34 counts the number of measurements based on the measurement signal from the measuring instrument IO, and generates an output when the count value reaches a predetermined number. 36
is a memory that stores the actual amount of adhesion before the counter 34 starts counting anew. When the counter counts a predetermined number of times, the scale (meter) 0 generates a measurement signal representing the amount of adhesion at that time. This weighing signal and memory 36
The difference from the stored value is obtained by a subtracter 38, the difference is divided by the count value of color/di by a divider 40, and multiplied by an appropriate constant Kl by a multiplier 42 to obtain the next gradient coefficient. It will be done. When this is obtained, the output of the counter 34 delayed by the delay circuit 44 (the output generated by the counter 34 when the count value of the counter 34 exceeds the predetermined value VCfz) is supplied to the memory 36.46 and the counter 34, and the memory 36 The stored value is updated to the current amount of clothing, the memory 46 stores the newly calculated gradient coefficient, and the counter 34 is reset.

Thereafter, when weighing is restarted, the subtracter 48 subtracts the value stored in the memory 36 from the measurement signal of the scale, and the multiplier 59 multiplies the count value of the counter 34 and the value stored in the memory 46. . The multiplication value of the multiplier 50 is subtracted from the subtracted output of the subtracter 48 by the ° subtracter 52, and zero point correction is performed. Note that since the changeover switch 54 interposed between the memory 46 and the multiplier 50 cannot initially calculate the gradient coefficient, the constant 2 cannot be used as the gradient coefficient initially.

In each of the embodiments described above, the present invention is implemented in an ordinary measuring instrument, but it can also be implemented in a measuring instrument used in a combination scale.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between the number of times of measurement with a measuring instrument and the amount of adhesion on the measuring instrument, Fig. 2 is a block diagram of a conventional zero point correction device, and Fig. 3 is an explanation of the principle of the zero point correction device according to the present invention. 4 is a block diagram of the first embodiment of the zero point correction device, FIG. 5 is a block diagram of the second embodiment of the zero point correction device, and FIG. 6 is a block diagram of the second embodiment of the zero point correction device. FIG. 3 is a block diagram of the third embodiment. IO...Measuring device, 12...Storage unit, 18...Multiplier, 22...Counter, 24.32.52...Subtractor, 26.46...First storage unit, 2B, 36...
Second storage section. Patent applicant Yamato Seiko Co., Ltd. Representative Tetsu Shimizu and two others 1 figure 'Xzr; No. 154537 No. 2, Name of the invention Zero point correction device for measuring instruments 3, Relationship with the person making the amendment (2) In the first line of page 8 of the same page, the phrase “Actual deposition amount at that time” should be changed to “No amount at that time.” The actual adhesion amount is the value under load.''

Claims (1)

[Claims] +11 Even if the article to be weighed is discharged, a part of it remains as deposits, and the amount of deposits increases non-linearly as the number of measurements increases. a storage unit that stores a predicted value of the amount of deposits at a smaller number of sample points than the number of times of measurement at the time of measurement, and also stores a gradient coefficient between each sample point; Multiply the counter that counts the number of measurements between the Noyo sample point and the count value of the bottle by the gradient coefficient between the n-th sample point and the n+1-th sample point read from the storage unit. subtracting the multiplication value of the multiplier and the predicted value of the amount of the deposit at the n-th sample point read from the storage unit from the measurement signal of the measuring device when performing the counting; A zero point correction device for a measuring instrument consisting of a subtracter. (2) Even if the article to be weighed is discharged, some of it may be contaminated with foreign matter.
In a measuring instrument in which the amount of the deposit increases non-linearly as the number of measurements increases, the predicted value of the amount of the deposit at a smaller number of sample points than the number of measurements when measured multiple times. a first storage unit that stores the gradient coefficient between the nth and n+ points; a second storage unit that stores the actual amount of the deposit at each sample point;
a counter that counts the number of measurements at the first sample point; a multiplier that multiplies the count value by a gradient coefficient between the n-th and n+1-th sample points read from the first storage unit; , a subtracter that subtracts the multiplication value of the multiplier and the actual amount of deposits at the n-th sample point read from the second storage unit from the measurement signal of the measuring device when performing the counting; A measuring instrument zero point correction device consisting of: