JPH0627668B2 - Electronic scale with display illumination - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic scale with a display illuminating device, and more specifically, to an electronic scale including a non-emissive display such as a liquid crystal display. .

(B) Conventional Technology In general, a liquid crystal display has an advantage of extremely low power consumption, but on the other hand, it does not emit light by itself, so that it must be illuminated by a lamp or the like when the surroundings become dark. Electronic balances and electronic balances equipped with such a non-emissive display have conventionally been equipped with a lamp that can be manually turned on and off so that they can be used even in a dark place. However, if the lamp is constantly turned on while using the electronic scale, the advantage of the liquid crystal display, which consumes less power, cannot be fully utilized.
In addition, it is very troublesome for the user to operate the on / off switch each time it is used. Further, during the sensitivity calibration of the electronic balance, if the manual lamp lighting switch is accidentally or intentionally pressed because the displayed weight value is dark and difficult to read, there is a possibility that correct calibration may not be performed due to disturbance.

(C) Object of the invention The present invention has been made in view of the above, and even if the user does not press the lamp lighting switch, the illumination lamp of the display is automatically turned on when necessary, and the liquid crystal display is displayed. To provide an electronic scale that can take full advantage of the power-saving features of the instrument, and to eliminate the need to manually turn on the illumination lamp during certain operations such as tare erase and sensitivity (span) calibration. Is intended to provide.

(D) Configuration of the invention An electric balance with a display unit lighting device according to the first invention comprises a weight value detection unit, a display unit for displaying the weight value, a lamp for illuminating the display unit, and lighting of the lamp. It has a display control section for controlling the erasing and a judging means for judging whether or not the change amount of the weight value exceeds a predetermined value, and lights the lamp when the change amount of the weight value exceeds the predetermined value. It is characterized by being configured as follows.

A second aspect of the invention is configured to automatically turn on the lamp while a specific operation such as tare erase, span calibration, etc. is being performed and / or at least one of a predetermined time after the operation. It is characterized by that.

(E) Embodiment FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a flow chart of a program stored in the ROM 14 of FIG.

The weight measuring unit 1 converts the load into an electric quantity by using, for example, a strain gauge, and this data is stored in the amplifier 2, the A / D converter 3,
It is input to the CPU 13 via the I / O port 12 and data processing is performed here according to the program written in the ROM 14. The RAM 15 is a data buffer for data processing. The A / D converter 3 has a predetermined period, for example 0.2
Data is output every second, and the I / O port continues to output the previous data until the next data is output. Data that has been subjected to arithmetic processing such as arithmetic mean is displayed on the liquid crystal display 6 via the I / O port 12 and the display drive circuit 7. An illumination lamp 8 for illuminating the liquid crystal display 6 is turned on by a lamp drive circuit 9. A brightness detector 4 such as a CaS cell is disposed near the display 6, and the output of the detector 4 is input to the lamp lighting determination unit 11 via the amplifier 5. Further, an illumination switch 10 that can be operated from the outside is provided, and the lighting of the illumination lamp 8 can be controlled. The illumination switch 10 includes an automatic / manual changeover switch 10A and a lighting / extinction changeover switch 10B. The lamp lighting control unit 11 inputs a flag A, a flag B, a flag C, and a flag D having a logic "0" or a logic "1" and outputs a control signal X. The flag A is set by the brightness detection signal. When the setting environment of the balance, especially the brightness in the vicinity of the display is not sufficient, A = “1”, and when the brightness is sufficient and the lamp does not need to be lit. Is set to A = “0”.
The flag B is determined by the operation switch 10A, and the flag C is determined by the operation switch 10B. For example, BC = “11” when automatic lighting control is selected, BC = “01” when manual lighting is selected, and C = “0” when manual lighting is selected. The flag D is a lighting flag determined by the program. When configured in this way, the control signal X to the lamp drive circuit 9 is represented by X = ABCD + ▲ ▼. The lamp drive circuit 9 immediately turns on the lamp when the control signal X changes from “0” to “1”, and continues to turn on the lamp when the control signal X remains “1”.
When it goes from "1" to "0", the lamp stays on for a certain period of time, then turns off, and a signal to turn off the light manually,
That is, when C = “0” is input to the lamp drive circuit 9, it is turned off immediately.

Next, the operation will be described. When the switch 10A selects the manual control, the lighting of the lamp 8 is controlled by turning on / off the switch 10B. When the switch 10A selects the automatic control, the lighting of the lamp 8 is automatically controlled by a command from the CPU 13 according to a predetermined program. The program has various embodiments such as (a), (b) and (c) below.
In the embodiment (a), the change in the measurement data by the weight measuring unit 1 is monitored, the lamp is turned on when the change exceeds a predetermined amount, and the lamp is turned off when a predetermined time elapses after the change disappears. It is a thing. In the embodiment (b), as described above, when the measured data is changing and it is determined by the output of the brightness detector 4 that the ambient brightness is not sufficient, the lamp is turned on and the measured data changes. The lamp is extinguished when a predetermined time has passed after it was stopped. In the embodiment (c), a lamp is turned on when a specific routine program such as span calibration and tare deletion is being executed and the balance is in use for a predetermined time thereafter.

FIG. 2 is a flow chart showing a program in the above embodiments (b) and (c).

In the first step ST0, the balance is powered on.
If it is determined that the routine is in the normal weight value display routine, ST
Go to 3. As the data processing in ST3, usually, the weight measurement data that is input every moment is temporarily stored a predetermined number of times N times and the arithmetic mean value thereof is calculated to obtain the display weight value W ₂ . This value W ₂ is displayed on the display 6 and stored in the RAM 15 (ST4). Next CPU
Comparing the previous stored weight values _{W 1} and the current weight value _{W 2} is _(ST5), the lighting flag D at ST6 if W 1 = _{W 2} to "0", there in W ≠ _{W 2} For example, in ST7, the lighting flag D is set to "1". Next, in ST8, the signal of the lighting flag D is output to the lamp lighting determination unit 11. ST
In 9, the display weight value W _{2 is set} to “previous display weight value W ₁ ”. Unless the program branches from ST1 to ST10, the above-mentioned programs from ST1 to ST9 are repeatedly executed. Therefore, when an object is placed on the balance plate or lowered and the weight value changes, the lighting flag D becomes "1". Set.

In this embodiment, the lighting flag D is set to "1" when the displayed weight value changes even a little. As a modified example of this, when the weight value changes by a predetermined value ε or more,
That is, the flag D may be set to “1” when | W ₂ −W ₁ | ≧ ε. It is preferable that the predetermined value ε is selected so as not to be affected by the change in weight value due to disturbance such as vibration or wind.

The Yes branch of ST-1 in FIG. 2 represents the embodiment (c). That is, when the span calibration or tare erasing routine is selected in ST1, the lighting flag D is set to "1" in ST10, the lamp is lit during the span calibration or tare routine execution (ST12), and this routine ends. The lighting flag D is reset and turned off. After that, the process returns to step ST-1.

(F) Effect According to the first invention of the present invention, the illumination lamp is automatically turned on only when necessary, so that the user does not need to operate the switch each time, which is convenient. Since it is off, it consumes less power. Further, according to the second aspect of the present invention, when the tare key is pressed, it is lit for a while, so that it is easy to see whether the display is zero, or the lighting switch is operated during span calibration. It is possible to prevent the situation where the calibration is not performed correctly.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flow chart showing the contents of the program stored in the ROM 14 of FIG. 1 ... weight detection unit, 2 ... amplifier 3 ... A / D conversion, 4 ... brightness detector 6 ... liquid crystal display, 7 ... display drive circuit 8 ... illumination lamp, 9 ... lamp drive Circuit 10 …… Operation switch, 11 …… Lamp lighting judgment unit

Claims (3)

[Claims] 1. A weight value detector, an indicator for displaying the weight value, a lamp for illuminating the indicator, a display controller for controlling lighting and erasing of the lamp, and an amount of change in the weight value. Has a judgment means for judging whether or not the value exceeds a predetermined value,
An electronic scale with a display illumination device, configured to turn on the lamp when the amount of change in the weight value exceeds a predetermined value. 2. A brightness detector for detecting the brightness around the display is provided, wherein the change amount of the weight value exceeds a predetermined value and the output of the brightness detector is less than the predetermined brightness. An electronic scale with a display illumination device according to claim 1, wherein the electronic scale is configured to turn on the lamp when indicating. 3. A weight value detecting section, a display for displaying the weight value, a lamp for illuminating the display, a display control section for controlling lighting / erasing of the lamp, a tare erase, a span calibration and the like. It has a specific key to instruct, so that the above lamp is automatically turned on while the specific key operation such as tare erase, span calibration, etc. is being executed and / or at least one of the predetermined time after the operation. An electronic scale with a built-in display illumination device.