JPH0225147Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a center zero detection device mounted on an electronic scale employing a digital span.

Figure 1 shows the configuration of a digital span electronic scale. The analog signal output from the load cell 1 is converted into digital data by the A/D converter 3 via the amplifier 2, and the weight raw data output from the A/D converter 3 is scaled to 1/N by the span adjustment section 4 and then further scaled. Adjust the minimum scale to a predetermined value in section 5 and turn it on to the weight display 6.
It is output as weighing data. Reference numeral 7 indicates a center zero detection unit that determines whether or not the weight raw data is within a preset center zero width range; 8 indicates a center zero that lights up when the center zero detection unit 7 detects center zero; It is an indicator.

Conventionally, the center zero width in the center zero detection section 7 of such electronic scales is a predetermined fixed value regardless of the span value or scaling value, so in high-resolution scales, when disturbance etc. are applied, the weight display changes. Currently, the center zero indicator 8 blinks even though the vibration is a zero point shift within the 1/2 degree range, making it impossible to stably display the center zero.

An object of the present invention is to provide a center zero detection device that can stabilize center zero display.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. Components having the same functions as those in FIG. 1 are given the same reference numerals and their explanations will be omitted.

9 is a microcomputer that executes the processing of the span adjustment section 4 and scaling adjustment section 5 and the processing corresponding to the center zero detection section 7; The center zero width determination means 12 determines the center zero detection width according to the scaling setting value B, and the center zero detection width determined by the weighed raw data of the A/D converter 3 output and the center zero detection width determined by the center zero width determination means 12 is calculated. It has a determining means 13 that compares and determines whether or not it is center zero and controls the center zero indicator 8.

Note that when the scaling adjustment unit 5 sets the scaling setting unit 11 to “1”, the minimum scale is aligned to “1”, and the scale is set to “2”, “5”, “10”, “20”,
When set to "50", the minimum scale is arranged to be "2", "5", "10", "20", and "50", respectively. Specifically, an A/D converter 3 whose weight raw data is 0 to 10,000 digits is used, A=0.4, B=1, and the weight display 6 displays 0.
~1000, the weighing raw data 0 to 10000 is converted to 0 to 4000 and input to the scaling adjustment unit 5, and since B=1 here, the scaling adjustment unit 5 divides it by (÷4). . Expressing this in a formula is 10000×0.4÷4=1000...The first display is (10000/1000)=10 digits. Also, this resolution is (1/
1000).

If you change B=2, the first formula becomes (10000×0.4÷4)×2=2000... and the first expression is {10000/(2000÷2)}
= 10 digits, and the resolution is also the same as when B = 1 (1/1000).

When changing B to 10, the first formula becomes {(10000×0.4÷4)÷10}×10=1000... and the first expression is {10000/(1000÷10)}
= 100 digits, and the resolution is lower than in the case of B = 1, 2. In addition, here B=5,
Although 20 and 50 are not explained, B=5 has the same resolution as B=1 and 2, and B=20 and 50 have the same resolution as B=10.
It has the same resolution as

FIG. 3 shows a flowchart of the center zero width determining means 13 and the determining means 14. C=20, 10, 5, 3, and 1 are respectively set for blocks [] to [] in FIG. 3 according to the resolution so that the resolution is 1/2 or less. Therefore, in the above specific example where A=0.4 and B=1, first, A, B at [a-1]
is read, B=1 is determined in [a-2], and the process moves to center zero width determination routine [J-1] for scaling B=1, 2, and 5. [J-1] adopts C=5 digit that has passed through [a-3] and [a-4], a match is detected in [a-5], and is set to [], and then [ a-6], the weighing raw data and C=5 are compared. Note that C=5 means -2, -1, 0, + at the A/D converter 3 output.
1, +2, and [a-6] checks whether the weight raw data is within the range of ±2. If it is within the range, it is determined that center zero has been detected, and [a-7] displays the center zero. If it is outside the range at [a-6], it is determined that the center zero is not present, and the center zero display 8 is turned off at [a-8]. This C=5 is 1/2th or less,
It also complies with OIML standards.

[J-2] in Figure 3 is the center zero width determination routine when B = 10, 20, 50, and a setting section for C is provided like [] to [] in [J-1]. , for example, C=50 is set for the portion corresponding to [].

In this way, C is determined according to A and B to determine the center zero, so for example, A=0.4, B=1
The center zero is determined at C=5, and in the case of lower resolution A=0.4 and B=10, the center zero is determined at C=50, which stabilizes the center zero display on low-resolution scales. It is.

In the above embodiment, C is changed into five stages when B = 1, 2, 5 and when B = 10, 20, 50, but this division stage can be made coarser or finer. You can also.

As explained above, according to the present invention, the center zero width is configured to change according to the resolution of the scale, so the center zero can be displayed with a tolerance commensurate with the resolution. Compared to a system that detects the center zero using the center zero width, it is possible to obtain a stable center display on a scale with low resolution.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an electronic scale, Figure 2 is a configuration diagram of an embodiment of an electronic scale equipped with the center zero detection device of the present invention, and Figure 3 is a flowchart of the main parts of Figure 2. be. 3... A/D converter, 9... Microcomputer, 10... Span setting section, 11... Scaling setting section, 12... Center zero width determining means,
13... Judgment means.

Claims (1)

[Scope of utility model registration request] In electronic scales that process the raw weighing data output from the A/D converter according to the digital span setting value and scaling setting value to produce weighing data, center zero is set according to the setting value that determines the resolution of the electronic scale. A center zero value determining means for determining a detection width, and a determining means for determining whether or not the weighed raw data is included within the center zero width determined by the center zero width determining means. A center zero detection device configured to display a center zero judgment based on an output signal of a judgment means.