JPH0349378B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electronic scale, and more particularly to an electronic weighing scale using a battery as a power source.

[Prior art] Conventionally, in electronic scales that use batteries as a power source, especially weighing scales, in order to accurately measure weight when weighing, in an unloaded state, first manually turn on the main power switch and then turn the zero adjustment knob. It was necessary to perform the troublesome operations of rotating the device, adjusting the zero point, setting the zero point, and then applying a load and weighing.

Furthermore, there is a method of constantly energizing the entire device when not in use, and rememorizing the zero point when no load is applied at regular intervals for weighing, but since it uses a battery as a power source, the battery life is shortened, making it unusable.

Furthermore, attempts have been made to fix and store certain count data equivalent to the weight at no load inside the microcomputer, but this does not compensate for changes in the zero point at no load due to environmental changes such as temperature and humidity. It wasn't something I could get.

[Objective of the Invention] The present invention solves the problems of the prior art, such as the troublesome operation during weighing, short battery life, and changes in zero point due to temperature and humidity, using an extremely simple electronic circuit and switch. The purpose is to

[Means for Solving the Problems] In a scale composed of a scale body 1, a sensor section S, an amplification and A-D conversion section 4, a microcomputer 5, a display section 6, a power supply circuit section 7, etc., the scale body 1 has a An operating switch P _SW is provided that turns on when a load is applied, and when there is no load, the microcomputer 5, which can measure time, temporarily supplies power to the sensor section S, amplification and A-D conversion section 4 at regular intervals. Specifically, at the same time as applying electricity via the changeover switch 9, the amount of electricity detected by the sensor section S during this no-load state is applied at the predetermined time interval.
While the microcomputer 5 is provided with a means for updating the memory, when the load is applied, the operating switch P _SW provided on the scale body 1 is turned on by the load, and after the power is turned on to the entire device, the sensor section S detects when the load is applied. Means is provided for subtracting the amount of electricity for the load when no load is stored in the microcomputer 5 from the amount of electricity, converting the amount of electricity into weight, and displaying the weight value on the display section 6.

[Function] The sensor section S, amplification and A-D conversion section 4 are connected to the microcomputer to which power is always applied when no load is applied.
The power is temporarily turned on, and the sensor section S detects the amount of electricity at that point in time (under the temperature and humidity conditions of the environment) when there is no load, and this amount of electricity is stored in the microcomputer 5 as zero point data. On the other hand, when a load is applied, the operating switch P _SW is turned on according to this weight, and the power is turned on to the entire device, and the weight at this point is detected by the sensor section S as described above, and from the amount of electricity at this load. The amount of electricity (zero point data) at the time of no load is subtracted, this amount of electricity is converted into a weight value, and the weight value is displayed on the display section 6.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to drawings and flowcharts.

FIG. 1 shows a scale body 1 which is a flat weight scale.
This scale body 1 consists of a base 2 and a cover 3, and a scale mechanism is provided inside the base 2, and this scale mechanism has a sensor unit S, such as a capacitance Formula S1, load cell formula S
2. It is coupled to a sensor section S such as a dielectric type (not shown), and these sensor sections S include an amplifier section, an A-D converter section 4, and a clock for a watch, as shown in the block diagram of the electronic circuit in Fig. 3. It is connected to a low current consumption microcomputer 5 having an oscillator, and a display section 6 of a liquid crystal display.
A power supply circuit 7, which is the energy for driving these electronic circuits, is powered by a battery 8. and is connected to the A-D converter 4.

P _SW 11 is an operating switch. This operating switch P _SW is connected between the ground and the microcomputer 5 and is attached to one of the four corners of the base 2 .

As shown in FIGS. 2a and 2b, a switch button 11 is provided at one corner of the base 2 against a coil spring 10 and is movable up and down.
The switch base 13 with the contact 12 fixed thereon is passed between the supports 2a made of insulating material, and the switch base 13 and the top 11 of the switch button 11 are connected to each other.
A switch leaf spring 14 is disposed between a and a. Therefore, under normal conditions (when no load is applied to the scale body 1), the button portion 11b of the switch button 11 is moved against the base 2 by the repulsive force of the coil spring 10.
The switch plate 14 is pushed out slightly from the surface of the switch plate 14, and the switch plate 14 is also straightened and separated from the contact point 12 of the switch base 13, so that the operating switch P _SW is in the OFF state. Next, when a load is applied to the scale body 1, the switch button 11 is pushed against the coil spring 10, contrary to the above operation, and the switch plate spring 14 is slightly bent.
Contact 12 is contacted, and this operating switch P _SW is turned ON.
state.

The procedure programmed into the microcomputer 5 using the above configuration will be explained below.

In other words, when a load is applied to the scale body 1, the activation switch is activated.
The P _SW turns ON as described above and is input to the microcomputer 5. Microcomputer 5 is the sensor S section, amplification and A-
Turn on the power of the D converter 4, subtract the electrical quantity at zero point (zero point data) at no load, which will be explained later, from the electrical quantity detected by the sensor at this time, convert this electrical quantity to weight, and calculate the weight. is displayed digitally on the display section 6. (~).

When the load is removed and the operating switch P _SW is turned OFF (as explained above, when the load is removed, the operating switch P _SW is automatically turned OFF), the power to the sensor section S, amplification and A-D converter section 4 is turned off and the standby mode is set. Enter the mode. (~). If there is no load after a certain period of time (approximately 1 hour) has passed in this standby mode, that is, if the operating switch P _SW is OFF, the sensor section S, amplification and A-D conversion section 4 are powered to the output port of the microcomputer 5. It is automatically turned on via the changeover switch 9, and the amount of electricity at that time (when no load is applied) is stored in the microcomputer as zero point data (~), and when there is no load, it is automatically turned on at a fixed time interval (approximately 1 hour). The data at that point in time is repeatedly updated and stored in the microcomputer 5 as zero point data.

After that, when a load is applied, the process returns to the beginning, subtracts the most recently stored zero point data from the amount of electricity at the time of loading, converts the subtracted amount of electricity into weight, and displays the weight on the display section 6 (~).

[Effect] As mentioned above, when not in use (no load), the power is temporarily turned on to the sensor section S, amplification and A-D conversion section 4 at regular intervals via the changeover switch 9 under the control of the microcomputer 5. The amount of electricity under the conditions (temperature, humidity) at that point in time (temperature, humidity) when no load is stored is stored as zero point data, and this accurate zero point data is subtracted from the time when loaded to display the weight. Therefore, even if the zero point changes due to changes in temperature or humidity, the zero point data for that environmental condition is always stored, allowing accurate weight measurement. In addition, the battery power source is a microcontroller 5 with low current consumption.
Except for the sensor part S, the amplification and A-D converter part 4 are applied intermittently as necessary, and the battery life is extended significantly. After turning on the main switch, there is no need to further adjust the zero point, and the accurate weight can be displayed on the display simply by applying a load to the scale body 1, which is convenient.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the scale body 1, Fig. 2a is a sectional view of the operating switch _PSW 11, Fig. 2b is a bottom view, Fig. 3 is a block diagram of the electronic circuit, and Fig. 3b is a cross-sectional view of the operating switch PSW 11. Block diagram showing the sensor section (capacitance type), No. 4
The figure is a flow chart. 1... Scale body, 9... Selector switch, S... Sensor unit, P _SW 11... Operating switch, ZR... Zero point data, W... Weight value.

Claims (1)

[Claims] 1. A sensor that detects the load and converts it into an electrical quantity, an amplifier for the sensor output and its A/D converter, a power switch for these that is controlled by a microcomputer, a low-power microcomputer that can measure time, and displays the measured value. It has a display, a power supply circuit including a battery, and an activation switch that is connected by applying weight to the mounting table.When the measurement is completed and the activation switch is disconnected,
Turn off the power to everything other than the microcontroller, such as sensors, amplifiers, A/D converters, and displays, and set the timer.
When not used within the set period (the activation switch is not connected), power is temporarily supplied to the sensor, amplifier, and A/D converter, and the data at that time is taken as the zero point for the next measurement. An electronic scale characterized in that it repeats until used (until an activation switch is connected).