JPH0572021A - Multi load cell type balance - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the number of circuit components, simplify the circuit configuration, and reduce costs. [Arrangement] The analog switch control means 30 causes the analog switch 25 to perform the time-division selection operation of the voltage signals from the load cells 21 to 24 when the weighing mode is selected, and designates the analog switch when the adjustment mode is selected. The selection operation of only the voltage signal from the selected load cell is performed. When the weighing mode is selected, the computing means 31 sequentially takes in digital data corresponding to each load cell from the A / D converter and calculates the weight value and displays it on the display 34, and when the adjustment mode is selected, the A
The digital data corresponding to the designated load cell is fetched from the / D converter and the digital data is directly displayed on the display. When selecting the adjustment mode, the zero point and the span coefficient can be input by the keyboard.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-load cell type balance.

[0002]

2. Description of the Related Art As a balance in which a plurality of load cells are arranged on a common base and measurement is performed by a voltage signal proportional to the load from each load cell, for example, JP-A-58-7672 is known.
What is seen in Japanese Patent Publication No. 8 is known. As shown in FIG. 4, this conventional device supplies voltage signals proportional to the weights from the four load cells 1 to 4 to operational amplifiers (operational amplifiers) 5 to 8 and amplifies them, respectively.
Is supplied to the adder 9 provided with a variable resistor for adjusting the output of each operational amplifier to perform addition processing, and the added voltage signal is supplied to the A / D converter 11 via the low-pass filter 10. is doing. Then, this A / D converter 11 converts it into digital count data according to the input voltage, and supplies the digital data to the control device 12. In this control device 12, the digital data is changed into a weight value in units of grams and displayed on the display unit 13. It should be noted that the keyboard 14 is adapted to be used for adjusting the zero point, taring, and the like.

[0003]

In such a conventional device, the operational amplifiers 5 to 9 corresponding to the load cells 1 to 4 and the adder 9 having a variable resistor for adjusting the output of each operational amplifier are provided. It is necessary to increase the number of circuit components to be used, which complicates the circuit configuration and has a poor economy.

Therefore, according to the present invention, common electric circuits can be used not only for processing the electric signal from each load cell at the time of weighing but also for adjusting the zero point and the span coefficient for each load cell at the time of adjustment. An object of the present invention is to provide a multi-load cell type balance in which the number of circuit components can be reduced to simplify the circuit configuration and reduce costs.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a plurality of load cells that output a voltage signal proportional to a load, and a common signal including an amplifier, an analog / digital converter, etc., by selecting the voltage signal from each load cell. An analog switch to be supplied to the electric circuit, a mode selecting means for selecting the measuring mode and the adjusting mode, and a metering mode selection operation by the mode selecting means, the analog switch is caused to perform a time division selection operation of the voltage signal from each load cell, When the adjustment mode is selected, the analog switch control means that causes the analog switch to select only the voltage signal from the specified load cell based on the specification of the load cell, and the digital data corresponding to each load cell from the electric circuit when the measurement mode is selected Is calculated sequentially and the weight value is calculated and displayed on the display. And arithmetic processing means for displaying directly the digital data corresponding to the constant by load cell uptake of the digital data to the display, the adjustment mode, is provided with a input means for inputting a zero and span coefficients.

[0006]

In the present invention having such a structure, when the weighing mode is selected, the voltage signal from each load cell is time-divisionally selected by the analog switch and is sequentially transferred to the arithmetic processing means as digital data through the common electric circuit. Get caught. Then, the weight value is calculated by this arithmetic processing means and displayed on the display.

When the adjustment mode is selected, only the voltage signal from the designated load cell is selected by the analog switch and taken into the arithmetic processing means as digital data through the electric circuit. The digital data is displayed on the display as it is from the arithmetic processing means. In this state, the input means inputs the zero point and the span coefficient to adjust the designated load cell.

[0008]

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

As shown in FIG. 1, four load cells 21,
22, 23, 24 are provided. A voltage signal proportional to the load from each of the load cells 21 to 24 can be selectively taken out via the analog switch 25.

An operational amplifier (operational amplifier) 26, a low-pass filter 27 and an A / D converter 2 which are electric circuits common to the voltage signal taken out through the analog switch 25.
It supplies to 8 in sequence.

The A / D converter 28 outputs digital count data corresponding to the input voltage, and this digital data is taken in by the microcomputer 29 constituting the control device. The microcomputer 29 is provided with an analog switch control means 30 for controlling the analog switch 25 and an arithmetic processing means 31.

The analog switch control means 30 is adapted to perform the processing shown in FIG. 2 in response to a mode selection signal from a mode selection switch 32 which constitutes a mode selection means. That is, when the mode selection signal from the mode selection switch 32 is the selection signal of the metering mode, the analog switch 25 is caused to perform the time division selection operation of the voltage signals from the load cells 21 to 24, and the selection signal of the adjustment mode is selected. At times, the analog switch 25 is made to perform a selecting operation of only the voltage signal from the designated load cell based on the designation of the load cell from the keyboard 33.

The arithmetic means 31 is adapted to perform the processing shown in FIG. 3 in response to a mode selection signal from the mode selection switch 32. That is, when the mode selection signal from the mode selection switch 32 is the selection signal of the weighing mode, the load cells 21 to 2 from the A / D converter 28 are selected.
The digital data corresponding to 4 is sequentially taken in, the weight value is calculated and displayed on the display 34, and when the adjustment mode selection signal is received, the digital data corresponding to the load cell designated by the A / D converter 28 is taken in and the digital data is displayed. The data is displayed directly on the display 34.
The keyboard 33 also constitutes input means for inputting the zero point and the span coefficient when the other adjustment mode is selected.

In the embodiment having such a configuration, when the adjustment mode is selected by the mode selection switch 32 and the load cell 21 is designated by the keyboard 33, the analog switch control means 30 informs the analog switch 25 of the voltage signal from the load cell 21. Causes the operation to select only.

Therefore, the voltage signal from the load cell 21 is supplied to the operational amplifier 26 via the analog switch 25 and amplified, and the amplified voltage signal is supplied to the A / D converter 28 via the low pass filter 27. .. Then, in the A / D converter 28, it is converted into count data corresponding to the input voltage, and the digital data is taken into the microcomputer 29. Microcomputer 2
In 9, the digital data taken in by the arithmetic processing means 31 is displayed on the display 34 as it is. That is, the display 34 displays the count data from the A / D converter 28. In this state, the zero point and the span coefficient can be adjusted for the load cell 21 by inputting the zero point and the span coefficient from the keyboard 33. Similarly, in this adjustment mode, the zero point adjustment and the span adjustment can be performed for the other load cells 22 to 24 by changing the designated load cell.

As described above, the zero point adjustment and the span adjustment for the load cells 21 to 24 can be performed using the common electric circuit including the operational amplifier 26, the low pass filter 27, and the A / D converter 28.

When the metering mode is selected by the mode selection switch 32, the analog switch control means 30 causes the analog switch 25 to perform an operation of sequentially selecting a voltage signal proportional to the load from each load cell 21 to 24 in a time division manner.

The voltage signals from the load cells 21 to 24 are sequentially supplied to the operational amplifier 26 via the analog switch 25 and amplified, and the amplified voltage signal is supplied to the A / D converter 28 via the low-pass filter 27. Is supplied to. Then, in the A / D converter 28, it is converted into count data corresponding to the input voltage, and the digital data is taken into the microcomputer 29. In this way, the microcomputer 29 sequentially receives the digital data corresponding to the load cells 21 to 24 in a time division manner. Then, in the microcomputer 29, the arithmetic processing means 31
A weight value in, for example, a gram unit is calculated on the basis of each digital data captured by, and the weight value is displayed.
Displayed in.

As described above, the processing of the voltage signals from the load cells 21 to 24 is performed by the operational amplifier 26 and the low pass filter 2.
7. A common electric circuit composed of the A / D converter 28 can be used.

As described above, zero point adjustment and span adjustment for each load cell 21-24 when the adjustment mode is selected and each load cell 21-24 when the measurement mode is selected.
Since a common electric circuit can be used to process the voltage signal from the circuit, the number of circuit components used can be reduced, and therefore the circuit configuration can be simplified and the cost can be reduced. In addition, although the said Example demonstrated the thing which used four load cells, it is needless to say that it is not necessarily limited to this.

[0021]

As described in detail above, according to the present invention, a common electric circuit is used not only for processing the electric signal from each load cell at the time of weighing but also for adjusting the zero point and the span coefficient for each load cell at the time of adjustment. It is possible to provide a multi-load cell type balance which can be used and by which the number of circuit components used can be reduced to simplify the circuit configuration and reduce the cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the processing of the analog switch control means in the embodiment.

FIG. 3 is a flowchart showing the processing of the arithmetic processing means in the embodiment.

FIG. 4 is a block diagram showing a conventional example.

[Explanation of symbols]

21-24 ... load cell, 25 ... analog switch, 2
6 ... Operational amplifier, 28 ... A / D converter, 29 ... Microcomputer, 30 ... Analog switch control means, 31
... arithmetic processing means, 32 ... mode selection switch, 33 ... keyboard, 34 ... indicator.

Claims (1)

[Claims] 1. A plurality of load cells that output a voltage signal proportional to a load, and an analog switch that selects the voltage signal from each load cell and supplies it to a common electric circuit including an amplifier, an analog / digital converter, and the like. A mode selecting means for selecting a measuring mode and an adjusting mode; and a selecting mode for the measuring mode by the mode selecting means, which causes the analog switch to perform a time-division selecting operation of the voltage signal from each load cell. Analog switch control means that causes the analog switch to select only the voltage signal from the designated load cell based on the designation of the load cell, and digital data corresponding to each load cell is sequentially taken from the electric circuit when the weighing mode is selected. Calculate the value and display it on the display, and specify it from the electric circuit in the adjustment mode. Multi-load cell characterized by including arithmetic processing means for taking digital data corresponding to the loaded load cell and displaying the digital data directly on the display, and input means for inputting a zero point and a span coefficient in the adjustment mode. Formula scale.