JPH0226733B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a weight measuring method applied to, for example, electronic toll scales.

In conventional electronic toll scales, data from a weight detection unit that outputs the weight of the object to be weighed as a digital quantity is sequentially stored in a register, and the latest plural pieces of data, for example, over ₈ , stored in this register are stored in the register. ₈
Count the number of data n ₁ , n ₂ , n ₃ that match data M ₁ , M ₂ , M ₃ respectively among these numbers, and select the one with the largest number among these counted values, for example, if n ₁ is the largest number. Then, when n ₁ ≧ 5, the display is updated with the data M ₁ of n ₁ as new measurement data, while when n ₁ < 5, the difference between data M ₁ and the previous measurement data M is changed to a certain set value. If it is within the set value, the previous measurement data M is left as is, and if it is larger than a certain set value, the display is updated using data _M1 as new measurement data.

However, in this method, (i) when the largest number among n ₁ , n ₂ , and n ₃ satisfies the condition of 5 or more, it is regarded as a stable state, and the data with the largest number is displayed; (ii) When the largest number among n ₁ , n ₂ , and n ₃ is less than 5, and the difference between that data and the previous measurement data M is within a certain set value, it is considered to be a flickering state due to vibration, etc. The previous measurement data M is displayed as is, and (iii) the largest number among n ₁ , n ₂ , n ₃ is less than 5, and that data and the previous measurement data M
When the difference between the weight and the weight exceeds a certain set value, it is regarded as a weight fluctuation state and the data with the largest number is displayed, which causes the following difficulties.

First, the display changes significantly depending on the condition (iii) from when the object to be weighed is placed on the weighing pan until it reaches a stable state, making it extremely difficult to read and tiring. Second, if there are large variations in the data output from the weight detection section due to factors such as installation conditions, a situation may occur where the condition (i) above cannot be obtained at all. Then, for example, when an object to be weighed is placed on the weighing pan, the weighing data increases sequentially according to the state (iii) above, and then the state enters the state (ii) above based on the weighing data of the final stage. , there is a drawback that measurement errors occur. Thirdly, when the object to be weighed is taken down from the weighing pan, there is a problem similar to the first point due to the condition (iii) above, and, for example, in a weighing instrument that lights up a lamp according to the weight category. In particular, the disadvantage was that it took a long time to display zero.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a weight measuring method that solves the above-mentioned drawbacks.

An electronic toll scale will be described below as an embodiment of the present invention. Figure 1 shows the overall circuit configuration of the electronic toll scale. In the figure, reference numeral 1 denotes a weight detection unit that detects the weight of the object to be weighed as an analog quantity and then converts it into a digital quantity, which includes a weight sensor 2, a differential amplifier 3, a low-pass filter 4, and an A-D converter 5.
It consists of As the weight sensor 2, for example, an electrical resistance wire type load cell is used which detects, as an analog voltage signal, mechanical strain generated in proportion to the weight of an object to be weighed when it is placed on a weighing pan. The differential amplifier 3 amplifies the analog voltage signal detected by the weight sensor 2 and supplies it to the low-pass filter 4 . The low-pass filter 4 filters out relatively high-frequency vibrations and noise from the applied signal and supplies it to the A-D converter 5 . The A-D converter 5 samples the analog voltage signal that has passed through the low-pass filter 4 at approximately regular intervals, converts the analog signal into a digital signal, and then supplies the digital signal to the data processing section 7 through the I/O port 6.

The data processing unit 7 includes a central processing unit (CPU) 8,
It consists of a read only memory (ROM) 9 and a random access memory (RAM) 10. The CPU 8 performs flicker prevention processing on the weight data provided from the weight detection section 1 according to the processing procedure described below, and then sends the weight data to a keyboard 12 connected via a keyboard/display controller 11.
It performs arithmetic processing based on the data input from the computer, and digitally displays the data on the display 13. Further, the ROM 9 stores a program for controlling the above-described operations of the CPU 8. Furthermore, as shown in FIG. 2, the RAM 10 includes registers REG ₀₀ to REG ₀₅ and REG ₁₀ to
REG ₁₄ , REG ₂₀ , counters C ₁ to C ₅ and flag F are assigned to predetermined addresses.

Here, the input data inputted from the weight detection section 1 is inputted to the registers REG ₀₀ to REG ₀₅ , and _the input data inputted from the weight detection section 1 is inputted to the registers REG ₁₀ to _{REG 14} .
Selected data selected under the conditions described below from among the data transferred to REG ₀₅ is transferred to the register.
REG ₂₀ stores measurements after flicker prevention processing, which will be described later. Further, the counter _C1 stores the number of data that matches the data in the register REG ₀₀ among the data transferred to the registers REG ₀₀ to REG ₀₅ , and the counter _C2 stores the number of data that matches the data in the register REG _00.
~Register in the data transferred to REG ₀₅
The number of data that matches the data in REG ₀₁ is stored in the counter _C3 , and the number of data that matches the selection data in register REG ₁₀ among the selected data transferred to the registers REG ₁₀ to REG ₁₄ is stored in the counter _C4 . 4, the processing circuit passed through in the flowchart of FIG. 4 stores the number of decreases when the input data is decreasing in the counter _C5 . Furthermore, in the flicker prevention processing described below, the flag F is set to "0" when the result of subtracting the selection data of register REG ₁₀ from the data of register REG ₂₀ is positive or zero, and is set to "1" when it is negative. .

Next, the data processing of this apparatus will be explained with reference to the flowchart shown in FIG. First, when the power is turned on, the CPU 8 defaults to RAM 10, for example.
After clearing the I/O port 6, etc., the input data from the weight detection section 1 is received, and flicker prevention processing (flow chart in FIG. 4) is performed. The flicker prevention process will be explained in detail later. Next, key input is checked, and if any key is pressed, a flag (not shown) corresponding to the pressed key is set to "1", and then arithmetic processing is performed based on the set flag. For example, if the corresponding flag is set by operating a unit price key, the unit price data per unit weight input before that unit price key and the weighing data after flicker prevention processing, that is, the data in register REG ₂₀ , are The price is calculated by the calculation. After the calculation process is completed, the unit price, weight, and price are digitally displayed on the display 13, and the loop of returning to data input is repeated.

Here, the flicker prevention process will be explained in detail along the flowchart of FIG. 4.

First, data in registers REG ₀₀ to REG ₀₅ is shifted in order. That is, the data in register REG ₀₀ is transferred to register REG ₀₁ , the data in register REG ₀₁ is transferred to register REG ₀₂ , and so on in this order. At this time, the data in register REG ₀₅ is discarded.

Next, the latest data given from the weight detection section 1 is transferred to the register REG ₀₀ .

Next, the data (selected data) in registers REG ₁₀ to REG ₁₄ are shifted in order. i.e. register
Selection data of REG ₁₀ to register REG ₁₁ , selection data of register REG ₁₁ to register REG ₁₂ ,
...Transfer in order. At this time, register REG ₁₄
selection data is discarded.

Next, it is checked whether there is any data that matches the data in register REG ₀₀ among the data in registers REG ₀₀ to _{REG 05} , and if there is data that matches, the number of data is set in counter _C1 .

Next, it is checked whether there is any data that matches the data in register REG ₀₁ among the data in registers REG ₀₀ to REG ₀₅ , and if there is data that matches, the number of data is set in counter _C2 .

Next, the number of data in the counter _{C2 is subtracted from the number of data in the counter C1 ,} and it is determined whether the result is greater than or equal to zero.

If the above subtraction result is zero or positive, that is, if the number of data that matches the data in register REG ₀₀ is the same as or greater than the number of data that matches the data in register REG ₀₁ , the register
Transfer the data in REG ₀₀ to register REG ₁₀ as selection data.

Additionally, if the above subtraction result is negative, that is, if the number of data that matches the data in register REG ₀₁ is greater than the number of data that matches the data in register REG ₀₀ , the data in register REG ₀₁ is transferred to register REG ₁₀ as selected data. Transfer as.

Then, after processing the above or the register
Registers in the selection data of REG ₁₀ to REG ₁₄
It is checked whether there is data that matches the selected data of REG ₁₀ , and if there is matching data, the number of data is set in counter _C3 .

Next, the number of data in counter C ₃ is “3”
Determine whether or not the above is true. In this judgment, if the number of data is not "3" or more, that is, if the number of selected data that matches the selected data of register REG ₁₀ is two or less, the process jumps to the flowchart of FIG. 3. Therefore, the above-described process is repeated until this condition is satisfied. In this case, the data in register REG ₂₀ does not change, so the display remains in its previous display state.

In the above judgment, if the number of data in counter C ₃ is "3" or more, that is, if there are 3 or more selected data that match the selected data in register ₁₀ , the register is read from the data in register REG ₂₀ .
Subtract the data of REG ₁₀ and find the difference S.

Next, the difference S obtained by the above subtraction
Determine whether or not is greater than or equal to zero.

In the above judgment, if the difference S is zero or positive, that is, if there is no weight change or if the weight is decreasing, the flag F is set to "0".

Further, in the above judgment, if the difference S is negative, that is, if the weight fluctuation is in the increasing direction, the flag F is set to "1".

Next, after the processing of or, it is determined whether the absolute value |S| of the difference S obtained by the subtraction described above is equal to or greater than "5" count.
Note that here, the minimum measurement unit is 8 counts per 1 g, for example.

In the above judgment, if the absolute value |S| is more than "5" count, the register
The data in REG ₁₀ is transferred to register REG ₂₀ , that is, the data in register REG ₁₀ is used as the measurement data after flicker prevention processing.

Next, after clearing the processing circuit of the counter _C4 to "0", the process returns to the flowchart of FIG. 3 and arithmetic processing and display are performed. Therefore, in this case, the data after flicker prevention processing is stored in the register.
Since the data has been updated to the data in register REG ₁₀ , arithmetic processing is performed and displayed using the data in register REG ₁₀ .

In addition, in the above judgment, the absolute value |S|
If the count is less than “5”, the counter
It is determined whether the processing circuit of _C4 has reached "5". Here, if the processing circuit has reached "5", the process proceeds to the above processing.

Further, in the above judgment, if the number of processing times has not reached "5", it is judged whether or not the difference S obtained by the above subtraction is zero.

Next, in the above judgment, if the difference S is not zero, that is, if the weight fluctuation is in the increasing or decreasing direction, it is judged whether the flag F is "0" or not.

In the above judgment, if the flag F is not "0", that is, if the weight fluctuation is in the increasing direction, the decrement circuit of the counter _C5 is cleared to "0".

〓〓 Next, "1" is added to the processing circuit of the counter _C4 , and after setting the result to the counter _C4 again, the process jumps to the flowchart of FIG. In this case, the display on the display 13 does not change because the data in the register REG ₂₀ has not been updated.

〓〓 Also, in the above judgment, if the flag F is "0", that is, if the weight fluctuation is in the increasing direction, "1" is added to the number of decreases in the counter _C5 , and the result is sent to the counter _C5 again. Set.

〓〓 Next, the number of times the counter C ₅ decreases is “3”
Determine whether it has been reached. Here, if the number of decreases has not reached "3", the above
Proceed to processing.

〓〓 Further, in the above judgment 〓〓, if the number of decreases has reached "3", the processing number of the counter _C5 is cleared to "0" and then the process proceeds to the above processing. In this case, the number of processing times of the counter _C5 is cleared to "0" by the process 〓〓 described above when the weight fluctuation is increasing, or by the process 〓〓 described later when there is no weight fluctuation. This is executed only when the absolute value |S| continues to decrease three times in a state where the absolute value |S| is less than "5" count.

〓〓 In addition, in the above judgment, if the difference S obtained by the above subtraction is zero, that is, if there is no weight fluctuation, it is determined whether the number of processings of the counter _C4 is "3" or less. to decide. Here, if the number of times of processing is "3" or less, the process proceeds to the process of 〓〓.

〓〓 In the above judgment 〓〓, if the number of processing is 4 or more, the number of decreases in the counter _C5 is cleared to "0".

〓〓 Next, after clearing the processing number of counter _C4 , the process jumps to the flowchart of FIG. Therefore, when the difference S becomes zero when the number of processings of the counter _C4 is 4 or more, the counters _C4 and _C5 are cleared to "0" and the above 〓〓
Because the selection data of register REG ₁₀ is not transferred to register REG ₂₀ under the conditions of , flickering due to vibrations etc. can be prevented.

Although the flicker prevention processing according to this embodiment has been described above, the present invention is not limited thereto.

According to the present invention, the weight data detected by the detection means is sampled approximately periodically and sequentially stored in the first data storage means, and for each sampling, a plurality of weight data stored in the first data storage means are stored in the first data storage means. The number of data that matches the latest data and at least one or more data before the latest data is counted, and the data with the largest counted value is selected as the second selected data.
Since the process of storing the data in the data storage means is repeated, even if the data from the detection means is relatively scattered, the condition for proceeding to the next process, that is, the second
The condition that the number of pieces of data that match the latest selected data among the selected data stored in the data storage means reaches a predetermined number is satisfied, and when this condition is met, the previous weighing data is Determine whether the difference with the latest selected data is within the set value, and update the latest selected data as measurement data when the difference exceeds the set value or if it is within the set value for a specified number of consecutive times. This makes it possible to measure weight more accurately, and also provides an easy-to-read display because the value when the weight changes when the object to be weighed is placed or taken down is not displayed.
In addition, when repeating the condition that the difference between the previous weighing data and the latest selected data is within the set value for the first prescribed number of times, the latest selected data is updated as new weighing data, and the difference is in the direction of weight reduction and Since the latest selected data is updated as new weighing data when the second specified number of times is repeated less than the first specified number of times, for example, the final display after unloading the weighing object from the weighing pan can be displayed quickly.

[Brief explanation of drawings]

The figures show an example in which the present invention is applied to an electronic toll scale. Fig. 1 is a block diagram showing the overall circuit configuration, Fig. 2 is an explanatory diagram showing the contents of the RAM, and Fig. 3 is the overall structure. FIG. 4 is a flowchart showing flicker prevention processing. REG ₀₀ to REG ₀₅ ...first data storage means,
REG ₁₀ ~ REG ₁₄ ... second data storage means,
REG ₂₀ ...A register that stores the weighing data after flicker prevention processing.

Claims (1)

[Scope of Claims] 1. The weight data of the object to be measured is detected as a digital quantity by a detection means, and the data detected by this detection means is sampled approximately periodically and sequentially 1
data storage means, and each sampling corresponds to the latest data among the plurality of data stored in the first data storage means and at least one or more data before the latest data. After counting the number of data to
The process of storing the data with the largest count value as selection data in the second data storage means is repeated, and the number of data that matches the latest selection data among the selection data stored in the second data storage means reaches a predetermined number, it is determined whether the difference between the previous weighing data and the latest selected data is within the set value, and when the difference exceeds the set value or for a specified number of consecutive times, the difference is within the set value. A method for measuring weight, comprising updating the latest selected data as the weighing data when . 2 The weight data of the object to be weighed is detected as a digital quantity by a detection means, and the data detected by this detection means is sampled approximately periodically and sequentially 1
data storage means, and each sampling corresponds to the latest data among the plurality of data stored in the first data storage means and at least one or more data before the latest data. After counting the number of data to
The process of storing the data with the largest count value as selection data in the second data storage means is repeated, and the number of data that matches the latest selection data among the selection data stored in the second data storage means reaches a predetermined number, it is determined whether the difference between the previous weighing data and the latest selected data is within a set value, and when the difference exceeds the set value, the first
When the specified number of consecutive times is within the set value, and when the second specified number of times is consecutively within the set value in the weight decreasing direction with respect to the weighing data and is smaller than the first specified number of times, the latest selected data is A weight measurement method characterized by updating as weighing data.