JPS61195311A - Electronic balance - Google Patents

Abstract

PURPOSE:To automatically turn off an electrical source when the balance is out of use for longer than a predetermined time period to reduce power consumption by using a constitution in which the power source is automatically turned off when the load detection data remains near zero for longer than a predetermined period and again turned on upon actuation of a tare deduction command key. CONSTITUTION:When a near-zero value is supplied after turning on of a power switch 7 to a control part 3 from a load sensor 1 through an AD converter 2, the control part 3 judges that the balance is in a non-use state and transmits a judgement result signal J to an FF 12b of a power source on/off control circuit 12. The FF sends a low level control signal C to a contactless AC relay 11 which is automatically turned off so that the power supply is terminates by a main current circuit 9. On the other hand, upon actuation of the tare command key 5, reset signals are sent to the FF 12b from the control circuit 3 so that the signal C goes to H level to turn on the relay 11 to again initiate power supply from the circuit 9.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to electronic balances.

<Prior art> Electronic balances generally include a load detection unit that outputs an electrical signal corresponding to the load, a calculation control unit that processes the output data from the load detection unit to determine a weight value, and a display unit that displays the weight value. It is composed of a display section and the like, and driving power for each section is supplied from a power supply circuit connected to an external power source such as a commercial power source.

Conventionally, turning on/off the power of such electronic balances was done by
This is done by operating a manual power switch provided in the power circuit section.

<Problems to be solved by the invention> In measurement work using an electronic balance, measurements may be carried out continuously, but for example, after one measurement, the next measurement may be carried out several tens of minutes to several hours later. In such cases, the power switch is often left in the ON position. Also, the power switch is usually
It is often located on the back or side of the electronic balance body, and you may forget to turn it off.

Electromagnetic balance type electronic balances generate electromagnetic force that brings the pan to a certain position, so even when there is no load, current flows through the coil for generating electromagnetic force, so it is difficult to turn on the power. Approximately 15W of power is consumed just by turning on the device.

The present invention has been made in view of the above, and it automatically turns off the power when the electronic balance is not used for a certain period of time or more.
The purpose of the present invention is to provide an electronic balance that can reduce power consumption as much as possible, and that can be turned on again with a simple operation.

Means for Solving the Problems> The configuration of the present invention will be explained based on the basic conceptual diagram shown in FIG.

The load detection section and calculation control section that make up the electronic balance.

Driving power for the display section and the like is supplied from a power supply circuit connected to an external power supply. The power supply circuit is provided with a switch element, and by opening and closing this switch element, the power supply circuit stops or starts the above-mentioned supply.

The operation of the switch element is controlled by a control circuit.

The determining means determines that the electronic balance is not in use when the load detection data of the load detecting section continues to have a value near O for a predetermined period of time or more, and supplies the result to the control circuit. Furthermore, when a tare weight subtraction command key is operated to instruct the arithmetic control section to perform tare weight subtraction processing, a signal indicating that the operation has been performed is sent to the control circuit.

When the control circuit receives a determination result indicating that it is not in use from the determination means, it drives the switch element to stop power supply to each part, and in the stopped state, if the tare command key is not operated. When this happens, the switch elements are activated to restore power supply to each part.

Function> Even without cutting off the connection between the power supply circuit and the external power supply, if the load detection data is close to 0 for a certain period of time, the power supply to each component will be automatically stopped, reducing wasted power. Consumption is reduced. When restoring the power supply, this is done by operating the tare command key, which is always attached to ordinary electronic balances and placed in an easy-to-operate position, without the need for a special operation switch. This is possible with simple operations.

<Example> Embodiments of the present invention will be described below based on the drawings.

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

The load detection unit 1 generates an electromagnetic force that balances the load on the plate,
The load on the pan is detected by measuring the current required to generate the electromagnetic force. The detection output is digitized by the A-D converter 2 and then taken into the control section 3.

Based on this digital data, the control unit 3 determines a metric display value by performing predetermined calculations, and displays the value on the display 4.

The control unit 3 is composed of a microcomputer, and includes a CPU 31. RO in which the measurement display value calculation program and non-use determination program described later are written.
M32. In addition to the RAM 33, which has an area for storing input data and calculation results from the A-D converter 2, there is also an input port 341 for inputting data from the A-D converter 2, and an input port 341 for inputting data to the display 4. display output port 35 for output;
An output boat 36° for a power OFF command and a tare command key 5 for outputting the determination result J by the non-use determination program to a power ON/OFF control circuit 12 to be described later.
The computer is connected to an interrupt signal generating device 37 for generating an interrupt signal to the CPU 31 in response to the operation of the key.

When an interrupt signal is generated by operating the tare subtraction command key 5, the CPU 31 stores the measured value at that time as the tare amount in the RAM 33, and thereafter displays a value obtained by subtracting that value from the detected value of the load on the pan. Display it on the container 4. This tare weight cancellation designation key 5 is the power ON/OFF control circuit 1.
It is also a component of 2.

A transformer 8 connected to a commercial power source (A, C, 100V) via a manual power switch 7 supplies A, C, voltages to a main power circuit 9 and a sub power circuit 10, respectively.

A non-contact AC relay 11 is interposed between the main power supply circuit 9 and the transformer 8, and this non-contact AC relay 11 is activated when the control signal C from the power ON/OFF control circuit 12 is at H level. It is turned ON when it is at L level, and it is turned OFF when it is at L level. The main power supply circuit 9 operates only when the non-contact AC relay 11 is ON, and the load detection unit 1. A-
D converter 2. Control unit 3. It is also possible to supply driving power to each component of the electronic balance, such as the display 4.

The sub power supply circuit 10 serves as a power source for a power ON/OFF control circuit 12.

The power ON/OFF control circuit 12 includes an OR element 1
The flip-flop 12b is provided with the output of the flip-flop 12b as a set input, and the determination result signal J from the power OFF command output port 36 of the control unit 3 as a reset input.
It is supplied to the non-contact AC relay 11 as follows. That is, when the power switch 7 is closed or the tare command key 5 is pressed, a set input is supplied to the flip-flop 12b, the control signal C becomes H level, and the non-contact AC relay 11 is turned on. , when the determination result signal J arrives from the control section 3, a reset input is supplied to the free-operated flop 12b, the control signal C becomes L level, and the non-contact AC relay 11 is turned off.

The non-use determination program in the control unit 3 samples the digital conversion data of the load detection value of the load detection unit 1 at predetermined time intervals, and keeps the value within a preset minute range near 0 for a predetermined time (for example, 15 The device is configured to determine that the device is not in use and output a determination result signal J when the device has counted for more than 1 minute.

According to the embodiment of the present invention described above, when the power switch 7 is turned on, power supply to each part is started, and if the no-load state continues for a predetermined time or more, the non-contact AC relay 11 is automatically turned off. The power supply by the main power supply circuit 9 is then stopped. If the tare command key 5 is pressed in this state, power supply to each part by the main power circuit 9 will be immediately restored.

Effects> As explained above, according to the present invention, even if the manual power switch 7 is left on, the main power circuit 9 automatically stops supplying power to each part if it is not used for a predetermined period of time, for example, 15 minutes or more. Since it is stopped, wasteful power consumption can be reduced. When the present invention is applied to an electromagnetic balance balance, the power consumption when not in use can be reduced from about 15W to IW.
was able to reduce it to When a battery is used as an external power source, its life can be extended. In addition, power supply can be restored by pressing the tare command key, which is usually located at an easily accessible location on the front panel of the electronic balance.
Not only is it easy to operate, but it is also economically effective since there is no need to provide a separate dedicated switch.

[Brief explanation of drawings]

FIG. 1 is a detailed explanatory diagram of the present invention, and FIG. 2 is a circuit configuration diagram of an embodiment of the present invention.

Claims (1)

[Claims] In a balance to which driving power for each component such as a load detection section, arithmetic control section, and a display section is supplied from a power supply circuit connected to an external power supply, a switch element that turns the power supply circuit ON/OFF, and the switch element. and a determining means for determining whether the balance is in use or not based on the load detection data from the load detection section, and when the load detection data continues to have a value close to 0 for a predetermined period of time or more, By automatically turning off the above power circuit and operating the tare command key of the balance,
An electronic balance characterized in that the power supply circuit is configured to be able to be turned on again.