JPH0277624A - Data processing method of load cell-type balance - Google Patents

Abstract

PURPOSE:To make a data processing program common by a method wherein the count value taken in from an A/D converter at the time of a large range is converted so as to become the same characteristics as the relation between load within a small range and the count value. CONSTITUTION:A microprocessor 4 reads a count value from an A/D converter 3 to store the same in an RAM 6 and judges a count value from the taken-in count value to check whether said count value is equal to or more than about 5kg being a weighed value preset in order to change over a small range to a large range. When the count value is 5kg or more, an analogue switch 5 is closed by a change-over control circuit 7 to change over the small range to the large rang and, when the count value is 5kg or less, the switch 5 is opened by the circuit 7 to change over the large range to the small range. The amplification in an amplifying part 2 within the small range becomes two-stage amplification due to amplifiers 21, 22 and, within the large range, amplification is performed only by the amplifier 21.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a load cell type weighing machine capable of changing ranges.
As seen in Publication No. 54618, after the output of the load cell is amplified by an amplifier, the range is switched to large or small depending on whether or not it passes through an attenuator, and the output is further converted to a digital count value by an analog/digital converter. There is a known method for incorporating the weight into a weight display device.

[Problem to be solved by the invention] However, in a device that performs range switching in this way, there are a total of four types of data: zero point data and maximum weighing data in the small range, and zero point data and maximum weighing data in the large range. data must be set and the data processing program must be changed between the small range and the large range, resulting in the problems that the required program becomes complex and the memory capacity for storing the program becomes large.

Therefore, even if the relationship between the count value and the load changes due to switching between large and small ranges, the present invention makes it possible to share the data processing program when creating weight data from the count value, simplifying the necessary program, and The present invention aims to provide a data processing method for a large load cell that can reduce the memory capacity for storing data.

[Means for Solving the Problems] The present invention converts a voltage signal from a load cell that outputs a voltage signal in response to a load into a digital count value using an analog/digital converter, and calculates weight data from the count value. Create and display the load cell that changes the count value from the analog/digital converter that corresponds to the load to switch between the small range and the large range.In the large range load cell, the count value from the analog/digital converter is taken in when the large range is selected. The purpose is to convert the count value so that it has the same characteristics as the relationship between load and count value in the small range, and to create weight data by performing the same data processing in the large range as in the small range. .

[Function] In the present invention having such a configuration, the count value taken in from the analog/digital converter during the large range is
Since the conversion is performed to have the same characteristics as the relationship between load and count value in the small range, the data processing when creating weight data from the count value in the large range is the same as the data processing in the small range. This can be done by processing.

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

In FIG. 1, 1 is a load cell that outputs a voltage signal according to the load, 2 is an amplifier that amplifies this load cell output, 3 is inputted with the voltage signal output from this amplifier 2,
Analog/digital (converts to digital count value)
Hereinafter, it will be referred to as A/D. ) The converter 4 is a microprocessor which processes the data taken in by interrupting the count value from the A/D converter 3 at a predetermined cycle.

The amplifying section 2 includes a two-stage amplifier 2. ．． 22, and an analog switch 5 is connected between the input terminal and output terminal of the amplifier 22 at the subsequent stage.

The microprocessor 4 receives the count value from the A/D converter 3 and stores the count value in the RAM 6. Then, determine the weighing value from the captured count value,
It is checked whether the weighed value is 5 kg or more, which is the weighed value set in advance for changing the range from the small range to the large range.

When the measured value is 5 or more, the switching control circuit 7 closes the analog switch 5 and switches to the large range,
Further, when the measured value is less than 5 centimeters, the analog switch 5 is opened by the switching control circuit 7 to switch to the small range.

However, in a small range, the amplification in the amplifier section 2 is performed by the amplifiers 2, .
22 results in a two-stage amplification, and in a large range, the amplification in the amplification section 2 is amplified only by the amplifier 21. As shown in Figure 2, 5υ is 125,000 counts in the small range, while it is 25,000 counts in the large range, and the count value for the load is 115 in the large range compared to the small range. There is.

The microprocessor 4 is programmed to perform the data processing shown in FIG. 3 upon receiving the count value from the A/D converter 3. That is, when a count value is taken in, it is determined whether it is in a large range or a small range, and if it is a large range, the count value at that time is converted into data when it is in a small range. This data conversion is performed using (5x-α).

The reason for performing such data conversion is as follows. That is, in FIG. 4, if graph a is a characteristic graph of a small range and graph b is a characteristic graph of a large range, simply multiplying graph b by five results in a characteristic graph of graph C, which does not match graph a. In the figure, SA indicates the maximum weighing count value in the small range, and SB indicates the maximum weighing count value in the large range.

If you look at this near the zero point, it will be as shown in Figure 5. If the count value of the zero point of graph a (small range) is ZA, and the count value f of the zero point of graph b (large range) is ZB, then ZBX5-ZA=α, and a deviation of α occurs. Therefore, if the count value from the A/D converter 3 when a load is applied in the large range is x'h, it can be converted to data in the small range by setting it to (5X-α).

In this way, when the range is large, the count value X (
5x-α), and when the range is small, the count value is left unchanged.

Based on the count value thus obtained, data processing is performed in a small range to create weight data.

Then, the obtained ff1Et data is set.

From this set weight data, determine whether the range is large or small. If it is 2, set the next data large range input. Also, if it is a small range, the next data is also set as a small range input.

The microprocessor 4 then displays the weight data thus obtained on the display 9 via the round keyboard/display controller 8 for display. This display roundness is, for example, 0.2 g at 1st stitch minus 5 counts when in the small range, and 109 at 1st stitch minus 50 counts when in the large range. Further, a keyboard 10 is connected to the keyboard/display controller 8, and key signals from the keyboard 10 are received.

In this embodiment having such a configuration, when a load is applied to the load cell 1, a count value corresponding to the load is taken into the microprocessor 4 from the A/D converter 3. At this time, if the load is less than 5 mm, the analog switch 5 is closed by the switching control circuit 7, and the amplifier section 2 is connected to the two amplifiers 2. ．． 22 is in a state where two-stage amplification is performed.

In other words, it becomes a small range.

At this time, the microprocessor 4 processes the captured count value as it is to create weight data, and further rounds it up for display and displays it on the display 9.

Also, if the load applied to load cell 1 exceeds 5 kg,
The microprocessor 4C1 controls the switching control circuit 7 to open the analog switch 5. Thus, the amplifying section 2 is in a state where only the amplifier 21 performs amplification. In other words, it is a large range.

At this time, the microprocessor 4 converts the loaded count value It is rounded up for display and displayed on the display 9.

In this way, data processing for creating weight data can be performed using the same program when using a large range as when using a small range, so the program used can be simplified. Furthermore, the amount of programs can be reduced accordingly, and the memory capacity for storing the necessary programs can also be reduced. Furthermore, by simplifying the program, the maintainability of the program also improves.

In the above embodiment, the count value for the load in the small range is set to five times that in the large range, but it is needless to say that the count value is not limited to this.

[Effects of the Invention] As detailed above, according to the present invention, even if the relationship between the count value and the load changes due to switching between large and small ranges,
It is possible to provide a data processing method for a large load cell that can standardize the data processing program when creating weight data from count values, simplify the necessary programs, and reduce the memory capacity for storing the program. be.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention. Fig. 1 is a block diagram, Fig. 2 is a graph showing the relationship between load and count value in small range and large range, and Fig. 3 shows data processing by a microprocessor. The flowcharts shown in FIGS. 4 and 5 are graphs for explaining the conversion principle when converting a large range count value into a small range count value. DESCRIPTION OF SYMBOLS 1... Load cell, 2... Amplification part, 3... Analog/digital (A/D) converter, 4... Microprocessor, 5... Analog switch, 7... Switching control circuit, 9...Display device. Applicant's agent Patent attorney Takehiko Suzue (G-c', '5-L4) Loco (91-)

Claims (1)

[Claims] A voltage signal from a load cell that outputs a voltage signal in response to a load is converted to a digital count value by an analog/digital converter, and weight data is created and displayed from the count value, and the analog signal corresponding to the load is converted to a digital count value. /In a load cell scale that switches between a small range and a large range by changing the count value from a digital converter, the count value taken from the analog/digital converter when in the large range is used as the load and count in the small range. A data processing method for a load cell type scale, characterized in that weight data is created by converting values so that they have the same characteristics as the relationship between values, and performing the same data processing for a large range as for a small range.