JPH0718738B2 - Electronic balance - Google Patents

Description

The present invention relates to an electronic balance equipped with a built-in weight for sensitivity calibration.

<Prior art> Generally, in an electronic balance that has a built-in reference weight for sensitivity calibration, the data from the load detection unit when there is no load and the load when the built-in reference weight (hereinafter referred to as the built-in weight) is loaded. The sensitivity is calibrated from the data from the detector and the known mass of this built-in weight. The sensitivity is normally calibrated by updating a coefficient (hereinafter referred to as a sensitivity coefficient) for converting the data from the load detection unit into a mass value.

In performing the sensitivity calibration as described above, if the data from the load detection unit is not stable and varies due to the action of disturbance or the like in the usage environment, accurate sensitivity calibration cannot be performed. Therefore, in the conventional electronic balance of this type, when the load data is not stable, the calibration operation is not performed even if the sensitivity calibration command is given.

<Problems to be Solved by the Invention> By the way, for a side using a balance, it is not always necessary to completely guarantee the accuracy of the balance when using the balance. In other words, there is a case where the user wants to use it anyway because the accuracy may be a little poor. In order to realize such use, a method that enables execution of sensitivity calibration regardless of whether the data is stable or unstable can be considered. However, the expected problem in this case is that the sensitivity calibration is performed in the unstable state of the data, that is, it is used without knowing that it was an inaccurate sensitivity calibration, and it is adopted without knowing the incorrect measurement result. It means that there is a possibility of doing.

The present invention has been made in view of this point, and the sensitivity calibration can be performed in any state of the environment in which the balance is used, and the user can obtain information on whether the sensitivity calibration is accurate or inaccurate. The purpose is to extend the use conditions of the balance while eliminating the above-mentioned expected problems.

<Means for Solving the Problems> A configuration for achieving the above object will be described with reference to the basic conceptual diagram shown in FIG. 1. According to the present invention, the data from the load detector a and the storage means b The mass to be displayed as the measured value is determined by the calculation by the mass calculating means c using the sensitivity coefficient stored in 1., and the built-in weight d for sensitivity calibration and the weight d are loaded on the load detector a. A weight adjustment mechanism e, and a sensitivity calibration calculation means f for updating the contents of the storage means b by calculating the sensitivity coefficient from the data from the load detection part a before and after the loading of the built-in weight d and the known mass of the built-in weight d. The balance has a data stability determining means g for determining whether or not the data used for calculating the sensitivity coefficient is stable under preset conditions, and an informing means h for notifying the determination result. do it Characterized by being present.

<Operation> The user of the balance is informed by the notifying means h whether or not the sensitivity calibration was accurate, and even if the sensitivity calibration can be performed in any environment, the above-mentioned problems do not occur. .

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

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

The load detection unit 1 that engages with the dish 1a includes a load sensor such as a balanced electromagnetic force generation mechanism and an AD converter, and outputs data corresponding to the applied load.

The weight detecting unit 1 can be loaded with a built-in weight 3 of known mass by driving the weight removing / applying device 2. In the weight adding / removing mechanism 2, the lever 21 that supports the built-in weight 3 includes a cam 22 that determines the tilt angle of the lever 21, a motor 23 that rotates the cam 22, a driver 24 that drives the motor 23, and the like. Has been done.

The data from the load detection unit 1 is taken into the control unit 4 every moment. The control unit 4 is mainly composed of a microcomputer, and includes a CPU 41, a ROM 42, a RAM 43, a non-volatile RAM 44, an input / output interface 45 and the like.

The control unit 4 is connected with a display 5 for displaying a measured value, a key 6 for giving various commands such as a tare erase command and a sensitivity calibration command, and an alarm lamp 7 described later,
Further, the control signal to the driver 24 of the weight adding / removing device 2 described above is also supplied from the control unit 4.

In addition to the normal measurement program, the ROM42 has a sensitivity calibration program, which will be described later, written in it.
In 4 is written basic data for determining the sensitivity coefficient such as the mass of the built-in weight 3.

FIG. 3 is a flow chart showing the contents of the sensitivity calibration program written in the ROM 42. This program is automatically selected, for example, when the balance is turned on or when the ambient temperature changes.
It can be selected at any time by operating.

In this program, first, data D _{1 under} no load
And then data D ₂ when the built-in weight 3 is loaded. Then, the data D ₁ and D ₂ and the nonvolatile RAM 4
Calibrate the sensitivity from the weight mass M in 4.

Now, in collecting the data D ₁ in the no-load state, the disturbance flag is set to 0, the timer is initialized, and then the timer is started. Next, load data is taken every moment and RA
Although it is stored in M43, an area for storing n load data is set in the RAM 43, and data sampling is continued until the number of load data samples reaches n.

When the load data reaches n data, for example, the difference between the maximum value and the minimum value of the n data is calculated, and the data is determined by determining whether or not the value is within a preset range. The stability is determined. This discrimination standard is set within the range of the limit data dispersion for performing the sensitivity calibration that can guarantee the accuracy of this balance.

If the data is not stable, the sampling of the load data is continued until the time measurement data of the timer reaches a preset time T ₀ . In this case, each time the load data is newly sampled, the data already stored is shifted, and the oldest data is discarded. And
The stability determination of n pieces of data is similarly performed for each sampling of the load data.

When the data reaches a stable state by the time measured data of the timer reaches T ₀ , the n load data at that time are averaged to calculate data D ₁ in the no-load state and store it in the RAM 43. If the data does not reach a stable state even if T ₀ is exceeded, the disturbance flag is set to 1, and similarly n load data are averaged to calculate D ₁ .

Next, the data D ₂ in the loaded state of the built-in weight 3 is sampled. In this case, first, a command is supplied to the driver 4 to load the built-in weight 3, and then the load data is sampled in exactly the same procedure. Data stability is determined and data D ₂ is calculated and stored.

When the data D ₁ and D ₂ are obtained, the internal weight mass M in the nonvolatile RAM 44 is loaded into the RAM 43, and the M is (D ₂ −D ₁ )
The sensitivity coefficient K is calculated by dividing by. Here, the obtained coefficient K is used as a coefficient for calculating the mass from the load data until the next sensitivity calibration is executed.

At the same time that the coefficient K is calculated, the built-in weight 3 is removed, and it is determined whether the disturbance flag is 0 or 1, and if it is 1, the alarm lamp 7 is turned on. Here, the disturbance flag is 1 because the data D _{1 in the} no-load state is
This is the case when the load data was not stable to the extent that the accuracy can be guaranteed in either or both of the case of collecting the load condition data D ₂ and the case of the load condition data. It is a message that the accuracy of the balance is not completely guaranteed.

If the alarm lamp 7 is not turned on, this program is terminated and the normal measurement program is immediately returned to. Also,
When the alarm lamp 7 is turned on, it is determined whether the alarm is confirmed by the user, for example, by pressing the key 6, and after it is determined that the alarm is confirmed, the process returns to the normal measurement program. .

Therefore, even if the sensitivity calibration this time does not guarantee the accuracy of this balance, the user can use this balance after confirming that fact by pressing the key 6.

In the above embodiment, the stability of the latest n pieces of data is determined every time the load data is sampled.
Although a so-called moving average method is used, in which D ₁ or D ₂ is obtained by averaging the n pieces of data, stability determination and averaging may be performed using all data sampled within a certain fixed time.

In addition, a plurality of types of data stability determination criteria are set to determine the degree of data stability, and a plurality of alarm lamps are provided correspondingly to provide notification according to the degree of data stability. It can also be configured. In this case, the user knows the degree of inaccuracy of the sensitivity calibration, which is more effective.

Further, it goes without saying that the notification of the data stability determination result can be performed by an appropriate means such as displaying in the form of a message on the display 5 instead of using the alarm lamp.

<Effects of the Invention> As described above, according to the present invention, the stability of load data used for sensitivity calibration is determined, and the sensitivity calibration is performed regardless of whether the data is stable. Is notified based on the above stability judgment, it is possible to use the balance by performing sensitivity calibration under any disturbance conditions, and the user can Since it is used after knowing whether it is accurate or inaccurate, there is no problem such as employing an incorrect measurement result.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram showing the configuration of the present invention, FIG. 2 is a configuration diagram of an embodiment of the present invention, and FIG. 3 is a flow chart showing a sensitivity calibration program written in the ROM 42. 1 …… Load detection unit 2 …… Weight adjusting device 3 …… Built-in weight 4 …… Control unit 41 …… CPU 42 …… ROM 43 …… RAM 44 …… Nonvolatile RAM 45 …… Interface 7 …… Alarm lamp

Claims (1)

[Claims] 1. A mass calculation means using the data from the load detection part and the sensitivity coefficient stored in the storage means to determine the mass to be displayed as a measured value, and a built-in weight for sensitivity calibration. , A weight addition / removal mechanism for loading the weight on the load detection unit, the sensitivity coefficient is calculated from the data from the load detection unit before and after the built-in weight load and the known mass of the built-in weight, and the contents of the storage means In a balance equipped with a sensitivity calibration calculation means for updating, the data stability determination means for determining whether or not the data used to calculate the sensitivity coefficient is stable under preset conditions, and the determination An electronic balance having a notifying means for notifying a result.