JPH0641880B2 - Electronic balance - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic balance that digitally displays a measured value.

<Prior Art> In an electronic balance that digitally displays a measured value, generally, for example, one digit lower than a display resolution by a display, so-called scale interval, is measured, and the resolution of the measurement is called an internal resolution. Then, the measured value based on this internal resolution is rounded and displayed on the display.

In a conventional electronic balance, this rounding is performed by rounding or rounding (for example, rounding).

<Problems to be Solved by the Invention> In a high-sensitivity electronic balance, a measured value based on the above-mentioned internal resolution changes due to a disturbance such as a slight vibration. When the measured value is rounded off by a rounding method to determine the display value like a conventional electronic balance, when the measured value is exactly on the boundary of the rounding, etc., the change in the actual measured value is sufficient for the display resolution. Although it is about one, there is a problem that the lowest digit of the displayed value fluctuates. In such a case, the operator cannot read the display value without anxiety, and since the display value changes more than the actual change in the measured value, the evaluation as a product will be degraded.

The purpose of the present invention is that, even if the measured value fluctuates in the internal resolution order on the rounded boundary due to the disturbance due to the minute vibration as described above, the displayed value does not change, and the disturbance is settled, the final The purpose is to provide an electronic balance capable of displaying the display value closest to the measured value.

<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 provides a higher resolution than the display resolution by the display a. A balance in which the measured value P is determined by the measured value determining unit b having the above-mentioned value based on the detected value from the load detecting unit c, and the measured value P is rounded by the display value determining unit d and digitally displayed on the display a. , Between the display values (D _i-1 and D _i , D _i and D _{i + 1} , ...), which are adjacent to each other, between the display values (for example, between D _i and D _{i + 1).} ), The three threshold values (L _i , M _i , H) including the threshold value (M _i ) matching the midpoint
_i ) is provided, and the measured value P with respect to the present display value D _i , three types of threshold values (L _i-1 , M _i-1 , H) sandwiching the display value D _i .
_i-1 and L _i , M _i , H _i ) the display value D _i is changed only when the farthest threshold range L _{i-1 to} H _i-1 is exceeded. When a preset condition is satisfied, the display value (D _i ) between the threshold values (for example, M _{i + 1} and M _i ) that sandwich the measured value P and that coincide with the midpoint is displayed. It is characterized by

When <Action> measurements P changes as shown in FIG. 6 (a) due to disturbance such as vibration, for example, as shown in FIG. (B), the measured value P is initially until exceeding H _i The display of the display value D _i is continued. Further, once the measured value P exceeds H _i and the display value is once changed to D _{i + 1} , this display continues until the measured value P becomes smaller than L _i , but
If a preset condition, for example, the condition that the time t has elapsed after the display value has changed, the display numerical value D _i
The display value is determined on the basis of the relationship between the measured value P and the threshold value M _i that coincides with the midpoint between D _{i +1} and D _{i + 1. In} this example, the display value is changed to D _i at that time. . As a result, the figure
Compared with the transition of the displayed value of the conventional electronic balance shown in (e),
The displayed value becomes more stable, and when the disturbance or the like is subsided, the displayed value becomes the closest value to the measured value P.

<Example> An example of the present invention will be described below with reference to the drawings.

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

The load detection unit 1 is composed of, for example, an electromagnetic force balance type balance mechanism, and outputs an electric signal corresponding to the load on the dish 1a. The output signal of the load detector 1 is digitized by the A / D converter 2, and is stored in the CPU 31, ROM 32, RA.
It is incorporated in the microcomputer 3 including the M33, the input / output port 34, and the like. To the input / output port 34 of the microcomputer 3, a display 4 for digitally displaying a weighing result based on a command from the CPU 31 and a tare erase switch 5 for instructing the CPU 31 to erase the tare amount are connected. .

FIG. 3 is a flow chart showing a data processing program written in the ROM 32, and the operation will be described below with reference to this figure.

The load detection signal output from the load detection unit 1 is digitized by the A / D converter 2 at every predetermined minute time,
The load data C is taken into the microcomputer 3 every moment (ST1). The loaded load data C is
The data is sequentially stored in the data storage area in the RAM 33, and the latest predetermined number of data are averaged and converted into the load value W by a known method such as multiplying by a span coefficient (ST
2). When the tare erase switch 5 is pressed, the load value W is stored in the RAM 33 as the tare amount T, and thereafter, the tare amount T is subtracted from the load value W to determine the measurement value P (ST3, ST4, ST4, ST4). ST5).

The resolution of the measured value P has a so-called internal resolution, and the measured value P is obtained by a numerical value of, for example, one digit to a lower digit than the display resolution of the display unit 4, a so-called scale interval.

Now, in the measured value P obtained as described above, when the scale interval is e, the current display value is D _i , and further, D _i-1 = D _i −e D _{i + 1} = D _i + e , ST6 to ST8, D _i-1 3/4 · e <P ≦ D _{i + 1 +} 3/4 · e ... (1) D _i + 3/4/4 · e <P ... (2) P ≦ D _i − 3/4 · e ... (3) is determined by whether or not one of the respective formulas is satisfied, the fourth
As indicated by a number line in the figure, it is determined which region the measured value P belongs to based on the current display value D _i . And
If the condition in ST13 described later is not satisfied,
Measured value P for the current display value _{D i, D i -3/4 · e} < range of P ≦ _D i +3/4 · e, i.e. the display value D when in a region I
The display of _i is continued (ST7, ST8, ST9). Further, when the measured value P is within the range of D _i-1 −3 / 4 · e <P ≦ D _i −3 / 4 · e, that is, within the area II, the display value is changed to D.
Change to _i-1 (ST6, ST7, ST8, ST10, S
T9), further, the measurement value P, _D i +3/4 · e <range of _{P ≦ D i + 1 +3/4 ·} e, that is, when in the region II 'may change the displayed value to the D _{i + 1} Yes (ST6, ST7, ST11, ST
9).

Further, in ST13, it is determined whether or not a preset time t has elapsed since the display value was changed, and when the condition that the time t has elapsed is satisfied, the measured value is The value Pr of the resolution e obtained by rounding off P is displayed (ST13, ST12, ST
9).

As described above by changing the viewpoint in FIG. 5 by a number line, three kinds of threshold values H = D + 3 / 4.e M = D + 1 are provided between the display numerical values D adjacent to each other due to the difference in the scale interval e. / 2 · e L = D + 1/4 · e is provided, and for example, when the current display value is D ₅ and the condition of ST13 is not satisfied, P is the farthest threshold value range sandwiching D ₅ , that is, The display value is changed only when L ₄ <P ≦ H ₅ is outside the range. Similarly, when the current display value is D ₆ , the display value is displayed only when P is outside the range of L ₅ <P ≦ H _6. And change ST
When the condition of 13 is satisfied, the threshold value M _{5 which is} the midpoint between the display numerical values D ₅ and D _{6 in which} the measured values P are adjacent to each other.
Depending on which side of D ₅ and D ₆ is closer to
This means that D ₅ or D ₆ is used as the display value.

In addition, when the measured value P is outside the range of the formula (1) or in the range of the regions III and III ', that is, when the measured value is largely deviated from the current display value, this is the case when loading and unloading the sample. Correspondingly, in this case, the process proceeds to ST12 and the value Pr of the resolution e obtained by rounding off the measured value P is displayed (ST6.
ST12, ST9). This allows the display value to follow a large change in the measured value in a short time, and the display responsiveness is not impaired.

In the above embodiment, instead of the determination condition in ST13, the determination as to whether or not the measured value P is stable can be adopted. That is, if it is determined that the measured value P is stable, the process proceeds from ST13 to ST12, and if it is not stable, the process proceeds to ST9. The stability determination method of the measured value P can be performed by a method of determining that the fluctuation range of P is stable when the variation width of P is within 1/4 · e for a time t. Further, the time t has passed since the last passing of the determination condition of ST13, ST10, ST11 or ST12, or finally ST1
It is possible to change whether or not the time t × n (n is a positive integer) has elapsed after passing 2. In this case, after the display value changes, the measurement value P is rounded off every time t and the value is displayed.

FIG. 6 is a diagram showing how the display value changes in response to the change in the measured value P when the load is stable. FIG. 6 (a) is a graph showing changes in the measured value P due to minute vibration, wind, etc. Here, although P is a digital value, it is represented in analog for convenience of explanation. FIG. 7B is a time chart showing the transition of the display value according to the first embodiment of the present invention, and FIGS. 7C and 7D are the display values according to the second and third embodiments of the present invention, respectively. It is a flowchart which shows the transition of. Further, FIG. 6E is a time chart showing the transition of the display value by the conventional electronic balance, and shows an example of the case where the display value is determined by rounding off.

As shown in FIG. 6 (b), in the first embodiment, the measured value P
There Viewing _{D i} is performed until the time A exceeds the _{H i,} since D
_{i + 1} is displayed, but at time B when time t has passed from time A, the display value is determined by rounding off the measurement value at that time, and as a result, the display value is changed to D _i and the measurement value is changed. The display value closest to P will be displayed. After the display value has been changed at time B, the display value is determined by rounding off the measured value P at time c when time t has further elapsed. In this example, P is the current display value D _i. Since it is closest to, the display is not changed.

As shown in FIG. 6 (c), in the second embodiment, the measured value P
Is detected and the rounded value of P is displayed as a display value at time D. That is, while the measured value P is fluctuating due to disturbance, the change in the displayed value is suppressed,
After stabilization, the displayed value closest to the measured value will be displayed by rounding off.

Further, as shown in FIG. 6 (d), in the third embodiment, after the display value is changed, the display value is determined by rounding off the measured value P at each elapse of time t, for example, the same figure ( As indicated by a broken line in a), even when the measured value P stabilizes and then changes again, the display value closest to the measured value P is displayed at time E, corresponding to the change.

Incidentally, in the conventional example shown in FIG. 6 (e), while the measured value P fluctuates, the display value frequently reciprocates between D _i and D _{i + 1} , which makes it difficult to read. .

The three threshold values H, M, and
Of L, H and L are 3/4 · e and 1/4 · e, respectively.
It is needless to say that it is not limited to e and can be set appropriately according to the characteristics of the balance.

<Effects of the Invention> As described above, according to the present invention, three kinds of thresholds including a threshold value which coincides with the midpoint between the displayed numerical values adjacent to each other due to the difference in the scale interval e. By setting a value, as a general rule, the displayed value is only when the measured value is outside the range of the farthest threshold among the three thresholds that sandwich the currently displayed value. In addition to changing the measurement value, when the preset conditions such as the stability of the measurement value are satisfied, the rounded value of the measurement value is displayed. Even if there is a fluctuation in the internal resolution order, the displayed value will not only be extremely stable, but eventually the displayed value closest to the measured value will be displayed, impairing the reliability of the display. There is no.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram showing the configuration of the present invention, FIG. 2 is a system block diagram showing the configuration of an embodiment of the present invention, FIG. 3 is a flow chart showing a data processing program written in the ROM 32, and FIG. FIGS. 6 and 5 are views for explaining a method of determining a display value according to the embodiment of the present invention, respectively.
The figure is an operation explanatory view showing the transition of the display value according to each embodiment of the present invention in comparison with the conventional example. 1 ... Load detection unit 2 ... AD converter 3 ... Microcomputer 4 ... Display

Claims (4)

[Claims] 1. A measured value determining means having a resolution higher than a display resolution of a display device determines a measured load value based on a detection signal from a load detecting section, and the measured value is rounded by the display determining means. In the balance which digitally displays on the display, the display determining means provides three kinds of threshold values including a threshold value corresponding to a midpoint between the respective display numerical values, between the display numerical values adjacent to each other,
The display value is changed only when the measured value exceeds the farthest threshold value range among the three types of threshold values sandwiching the display value with respect to the current display value, and An electronic balance, which is configured to display a displayed numerical value between threshold values that coincide with the midpoint when the preset condition is satisfied, and sandwich the measured value. 2. The electronic balance according to claim 1, wherein the preset condition is that a predetermined time has elapsed after the display value changed. 3. The electronic balance according to claim 1, wherein the preset condition is that the measured value is stable. 4. The electronic balance according to claim 1, wherein the preset condition is that a predetermined time elapses after the display value is changed.