JPH0618319A - Electronic balance - Google Patents

Abstract

PURPOSE:To calibrate the sensitivity of a balance in compliance with a user's purpose by detecting whether the output change of a load sensor generated when the sensitivity is calibrated, satisfies the set permissible range of the change. CONSTITUTION:A load sensor 2 in an electronic balance housing 1 measures the weight of an object 4, and is also capable of measuring the weight by placing the weight of a weight 5 housed in the housing 1 onto a load receiving part 3. The output of the sensor 2 is sent to a data processing part 20 every predetermined minute time interval. The processing part 20 not only averages the load data, but operates a calibration coefficient from the output data at the calibrating time and so on. On the other hand, simultaneously with the calculation of the sensitivity calibration coefficient, it is detected whether the changing width of a group of output data of the sensor 2 at the calibrating time of the sensitivity is within a set permissible range of the change width. If the change width is within the permissible range, the calibration program is terminated. However, if the change width exceeds the permissible range, a warning buzzer 13 is sounded and the fact is displayed at a display panel 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic balance having a sensitivity calibration function.

[0002]

2. Description of the Related Art Generally, an electronic balance has a function of performing sensitivity calibration by loading a load sensor with a reference weight having a known mass, and using the output of the load sensor and the mass of the weight in that state. There is.

In an electronic balance having such a sensitivity calibration function, generally, a weight for sensitivity calibration is built in the balance case, and a mechanism for loading / removing the built-in weight to a load detection mechanism is provided.

[0004]

The electronic balance is affected by wind and temperature changes even during sensitivity calibration.
The output of the load sensor may fluctuate slightly.

If such variations occur during sensitivity calibration,
When the fluctuation range is large, only a sensitivity calibration coefficient with poor accuracy can be obtained, and proper sensitivity calibration cannot be performed. Therefore, in the conventional balance, a constant reference value is set for the output fluctuation range of the load sensor during sensitivity calibration. When the allowable fluctuation range exceeds the reference value, it is determined that the sensitivity calibration cannot be performed satisfactorily, and a warning is issued to that effect, and the sensitivity calibration is urged again.

This reference value has conventionally been set to a value required for measurement with the highest measurement accuracy (when the reading limit is the smallest) defined in the performance specifications of the balance. For this reason, electronic balances with high maximum measurement accuracy require high-precision sensitivity calibration, and the allowable fluctuation range of the load sensor output during sensitivity calibration was set to be narrow.

Therefore, in the balance having the highest measurement accuracy, it is necessary to pay special attention to ambient vibration and temperature during the sensitivity calibration, and the sensitivity calibration has been performed with great care. However, no matter how meticulous the attention may be paid, fluctuations exceeding the permissible fluctuation range may occur depending on the measurement environment, which is not only inconvenient for the balance user, but also often requires that sensitivity calibration be repeated again. I spent time. Such highly accurate sensitivity calibration is sometimes necessary and unavoidable, but is not always necessary. That is, depending on the purpose of use of the balance, there is a case where it is desired to measure the object to be measured quickly because the object to be measured can be roughly measured. However, with conventional balances, it is always necessary to perform highly accurate sensitivity calibration regardless of the purpose of use, and it is necessary to perform such highly accurate sensitivity calibration even when performing only rough measurements, which is troublesome. It was inconvenient.

On the other hand, when performing a highly accurate measurement, the sensitivity calibration is carried out with great care before the measurement. However, as described above, when the measurement environment is bad, a fluctuation exceeding the allowable fluctuation range occurs, A warning was issued that the sensitivity could not be satisfactorily calibrated. In this case, in the conventional balance, it is inconvenient because there is no appropriate data that can be used to determine whether or not recalibration is necessary because it is not possible to grasp how much the output fluctuation range of the load sensor that occurred during sensitivity calibration was known. The present invention has been made to solve such inconveniences all at once.

[0009]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above-mentioned problems, is designed to drive a weight removing and adding mechanism in response to the generation of a calibration command to add and remove a built-in weight to a load receiving portion, and output a load sensor at this time. In the electronic balance that calculates the sensitivity calibration coefficient from the known weight of the built-in weight and the sensitivity calibration coefficient when measuring the weight of the DUT using this sensitivity calibration coefficient,
The allowable fluctuation range of the load sensor output that occurs during sensitivity calibration is set by the balance user arbitrarily or in accordance with the measurement accuracy required by the balance user. Set by the sensitivity calibration judging means for judging whether the output fluctuation of the load sensor that occurs in 1) satisfies the allowable fluctuation range set by the sensitivity calibration allowable fluctuation range setting means and the sensitivity calibration allowable fluctuation range setting means. And a warning display means for displaying a fluctuation range generated when such calibration is performed. .

[0010]

In the electronic balance of the present invention, the allowable fluctuation range of the load sensor output at the time of sensitivity calibration is set according to the purpose of use of the balance user. That is, when performing highly accurate measurement, it is necessary to increase the accuracy of sensitivity calibration, and therefore, the allowable fluctuation range of the output of the load sensor during sensitivity calibration is set to be narrow. on the other hand,
In rough measurement that does not require very high accuracy, high accuracy is not required even in sensitivity calibration, so that the allowable fluctuation range of the output of the load sensor can be set wide. In this way, it is possible to eliminate the need for highly accurate sensitivity calibration, which is unnecessary for measurement, and to easily perform sensitivity calibration particularly in rough measurement.

Further, in the case where sensitivity calibration with a narrow permissible fluctuation range of the load sensor output is performed in order to perform a highly accurate measurement,
When the measurement environment is bad and calibration exceeding the allowable fluctuation range is performed, how much the actual output fluctuation of the load sensor at this time can be displayed together with the warning.
This enables the balance user to recognize how much the fluctuation range of the load sensor output during sensitivity calibration was, and to decide whether to perform sensitivity calibration again or to use the calibration coefficient by this calibration if there is no problem in measurement. Can be

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a basic conceptual diagram showing one embodiment according to the present invention. The electronic balance of the present invention comprises a weight adjusting mechanism c for adding and removing the built-in weight b to the load receiving portion a, a load sensor d for detecting the weight of the load receiving portion a, an output of the load sensor d and a known built-in weight mass. Sensitivity calibration coefficient calculation means e for calculating the sensitivity calibration coefficient, sensitivity calibration means f for performing sensitivity calibration when measuring the weight of the object to be measured using this calibration coefficient, and allowance of the output of the load sensor generated during the sensitivity calibration. The fluctuation range is set by the sensitivity calibration allowable fluctuation range setting means g that sets the fluctuation range according to the measurement accuracy required by the balance user, and the output fluctuation of the load sensor that occurs during the sensitivity calibration is set by the sensitivity calibration allowable fluctuation range setting means. A sensitivity calibration judgment means h for judging whether the set allowable fluctuation range is satisfied, and a warning is issued when calibration is performed which does not satisfy the allowable fluctuation range set by the sensitivity calibration allowable fluctuation range setting means. Together constituted by a warning display means i for displaying the variation width resulting when the calibration has been performed.

In the sensitivity configuration allowable fluctuation range setting means g, the balance user manually inputs means j for arbitrarily inputting the allowable fluctuation range, and the balance user is allowed to operate in conjunction with the measurement accuracy input in advance. A measurement accuracy interlocking input means k for inputting the fluctuation range is provided.

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

Load sensor 2 in electronic balance housing 1
Is connected to the load receiving portion 3 and can measure the weight of the DUT 4 placed on the load receiving portion 3, and the weight of the built-in weight 5 provided in the electronic balance housing 1 can be changed by the built-in weight removing mechanism 6 It can be measured by driving it and placing it on the load receiver 3.

The output of the load sensor 2 is the A / D converter 10
After being digitized by, it is taken into the data processing unit 20 at every predetermined minute time. The data processing unit 20 is mainly composed of a microcomputer, and has a CPU 2
1, a ROM 22, a RAM 23, an input / output interface 24 and the like. Of these, in the ROM 22, programs necessary for various operations are written in addition to a sensitivity calibration program described later. Further, the RAM 23 is provided with a storage area for load data from the A / D converter 10 and a storage area for sensitivity calibration coefficients.

The data processing unit 20 has the above-mentioned A /
In addition to the D converter 10, a display unit 11 for displaying a measured value and a fluctuation range of the load sensor output when a warning is generated,
An input device 12, a warning buzzer 13, and a signal cable to the built-in weight adding / removing mechanism 6 for the balance user to directly input to the data processing unit are connected.

In the data processing unit 20, the A / D converter 10
In addition to averaging the load data sampled via, the built-in weight is used to determine whether sensitivity calibration has been performed properly, and the calibration coefficient is calculated from the output data during calibration. I also do it.

FIG. 3 is a flow chart showing a sensitivity calibration program written in the ROM 22, and the operation of the embodiment of the present invention will be described below with reference to this figure.

This sensitivity calibration program starts when a calibration command is issued.

Before performing the sensitivity calibration, the user inputs the measurement accuracy of the measurement to be performed in advance. Then ROM
The normal measurement program written in 22 sets a permissible fluctuation range at the time of measurement of the load sensor output necessary for performing weighing that satisfies this measurement accuracy. That is, when the user wants to perform a precise measurement, the allowable fluctuation range of the load sensor output at the time of measurement is set narrow in order to improve the measurement accuracy, and conversely, when the rough measurement is acceptable, the allowable fluctuation range is set wide.

When a calibration command is issued, first, the permissible fluctuation range of the load sensor output at the time of sensitivity calibration is automatically set in conjunction with the above-mentioned permissible fluctuation range of the load sensor output at the time of measurement, or the balance user Select whether to do it arbitrarily (st
1). When the one automatically set in conjunction with the allowable fluctuation range of the load sensor output at the time of measurement is selected, the allowable fluctuation range is directly input as the allowable fluctuation range at the time of sensitivity calibration (st2). Therefore, the permissible fluctuation range of the load sensor at the time of sensitivity calibration is set to be narrow at the time of precision measurement and wide at the time of rough measurement.

For example, as shown in FIG. 4, when the allowable fluctuation range at the time of measurement is switched in four steps of 1, 3, 5, 9 counts in accordance with the measurement accuracy input by the balance user, the sensitivity calibration The allowable fluctuation range is also linked with this, 1.
It automatically switches between 3, 5, and 9 counts, and this value is input.

When the balance user arbitrarily inputs the allowable fluctuation range of the load sensor output during sensitivity calibration, the input device 1 is used.
The permissible fluctuation range is manually input by step 2 (st3).
At this time, it can be set independently of the allowable fluctuation range of the load sensor output at the time of measurement. For example, in the example of FIG.
You can enter any value from 9 counts.

Subsequently, an operation command is given to the weight adding / removing mechanism 6,
The built-in weight 5 is loaded on the load sensor 2 (st4). In that state, the output data group D1 collected by the load sensor 2 at every minute time is read (st5). Next, an operation command is again given to the weight adding / removing mechanism 6 to remove the built-in weight 5 from the load sensor 2 (st6), and in that state, the output data group D2 sampled from the load sensor 2 every minute time is read (st).
7).

Next, the read data groups D1 and D2 are subjected to a predetermined calculation performed by an ordinary balance to obtain an average value <D1.
> And <D2>, the sensitivity calibration coefficient K is calculated from the known mass M of the built-in weight 5 by the equation (1) (s)
t8).

K = M / (<D1>-<D2>) (1) On the other hand, in parallel with the calculation of the sensitivity calibration coefficient, output data groups D1 and D2 of the load sensor 2 when this sensitivity calibration is performed.
It is determined whether or not the fluctuation range of is within the set allowable fluctuation range at the time of sensitivity calibration (st9). And the data group D1,
When the fluctuation range of D2 is within the allowable fluctuation range, the calibration program is terminated, but when it exceeds the set allowable fluctuation range, the warning buzzer 13 is sounded and the display unit 11 displays how much the fluctuation range is. (St10), the calibration program ends. Here, the balance user looks at the displayed fluctuation range and finds that this calibration is unsatisfactory,
It is determined whether to repeat the calibration again or use the calibration to start the weight measurement of the object to be measured.

After the calibration is completed, the weight of the object to be measured is measured according to a normal measurement program.

[0030]

As described above, according to the present invention,
It is possible to calibrate the sensitivity according to the purpose of use by the balance user. That is, when measuring with high accuracy, the allowable fluctuation range of the load sensor output during sensitivity calibration is set narrow, but when performing rough measurement, the allowable fluctuation range is widened to avoid unnecessary high-precision calibration. Can be done. As a result, the sensitivity can be easily calibrated without any careful attention at the time of the rough measurement, and the warning is less likely to be generated, which is easy to use.

Further, in the embodiment, the sensitivity calibration with a narrow allowable fluctuation range of the output of the load sensor was carried out in order to carry out the measurement with high accuracy, but the calibration exceeding the allowable fluctuation range was carried out due to the bad measurement environment. In this case, the actual fluctuation range of the load sensor at this time can be displayed at the same time as the warning display, so that the balance user can see how much the fluctuation range of the load sensor output was at the time of calibration. Can be always recognized, and the sensitivity calibration can be performed again, or if the measurement is not hindered, it can be easily determined whether to use the calibration coefficient by this calibration.

[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 a configuration of an embodiment of the present invention.

FIG. 3 is a flowchart of a sensitivity calibration program of the programs written in the ROM according to the embodiment of the present invention.

FIG. 4 is a diagram showing the relationship between the allowable fluctuation range of the load sensor output during measurement and the allowable fluctuation range of the load sensor output during sensitivity calibration according to the embodiment of the present invention.

[Explanation of symbols]

 1: Balance housing 2: Load sensor 3: Load receiving part 5: Built-in weight 6: Weight adjustment mechanism 10: A / D converter 11: Display device 12: Input device 20: Data processing part 21: CPU 22: ROM 23: RAM

Claims (1)

[Claims] 1. When a calibration command is generated, the weight adding / removing mechanism is driven to add / remove the built-in weight in the load receiving portion, and a sensitivity calibration coefficient is calculated from the output of the load sensor at this time and the known built-in weight mass, and this sensitivity is calculated. For electronic balances that perform sensitivity calibration when measuring the weight of an object to be measured using a calibration coefficient, the allowable range of fluctuations in the output of the load sensor that occurs during sensitivity calibration can be specified by the balance user or required by the balance user. The sensitivity fluctuation allowable fluctuation range setting means that can be set according to the measurement accuracy, and the output fluctuation of the load sensor that occurred during sensitivity calibration satisfy the allowable fluctuation range set by the sensitivity calibration allowable fluctuation range setting means. Sensitivity calibration determining means for determining whether or not there is a means for issuing a warning when calibration is performed that does not satisfy the allowable fluctuation range set by the sensitivity calibration allowable fluctuation range setting means, or An electronic balance comprising: a warning display unit for displaying a fluctuation range generated when such calibration is performed.