JPH0131575B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a weighing signal processing method in an electronic weighing machine, and its purpose is to improve the responsiveness of a scale in an unstable state when the output signal is stabilized by taking a moving average of data. It is in. A conventional electronic weighing machine is constructed as shown in FIG. 1 is a load cell that converts the load G into an analog signal, 2 is an amplifier, 3 is an analog-to-digital converter, 4 is a memory for storing zero tracking values, etc., and 5 is raw weighing data W of the output of the analog-to-digital converter 3. A first arithmetic unit 6 takes the minuend and the content of the memory 4 as the subtrahend, and 6 reduces the resolution by reducing the resolution by 1/5 of the output data W′ corrected through the first arithmetic unit 5 to increase stability. A second calculation unit 7 is a third calculation unit that multiplies the output of the second calculation unit 6 by a (where a is a positive integer) to align the minimum scale of the weight value display;
8 is a weight display section that digitally displays the weighed value. Further, a hysteresis circuit 6' may be interposed between the first arithmetic section 5 and the second arithmetic section 6. In this way, flickering of the weight value digitally displayed on the weight display section 8 has conventionally been prevented by interposing the second calculation section 6 and the hysteresis circuit 6', but this processing method In order to further suppress the flickering of the weight value display without lowering the resolution, it is necessary to use a higher resolution analog-to-digital converter 3, and this processing method has its limits. be. As a means to avoid such problems, it is conceivable to take a moving average of the weighed raw data W and use it as an output signal. FIG. 2a shows changes in the weight raw data W, and FIG. 2b shows changes in the moving average value of five weight raw data W. As can be seen by comparing Figure 2 a and b, although the weight value display no longer flickers in the stable state [times _t1 to _t11 , _t19 to], on the other hand, in the unstable state [time _t12] ~t ₁₈ ] is poor, and there is a delay in the transition of the weight value display from an unstable state to a stable state, which has the drawback that the weight value cannot be read quickly. The present invention monitors the latest value of weight raw data obtained by digitally converting the weight value signal at regular intervals, determines whether the change in the weight value signal is stable or unstable, and when the change in the weight value signal continues to be stable, updates the The weighted raw data of is stored in the moving average calculation register, the moving average value is calculated from this latest weighted raw data and the past weighted raw data previously stored in the moving average calculation register, and this is output as a signal. When transitioning from unstable to stable, all the contents of the moving average calculation register are updated to the latest weighted raw data, and the calculated moving average is used as the data for the output signal. It is characterized by outputting the latest weighing raw data as data, by adopting a moving average value only in stable conditions, and by switching to successive conversion display of weighing raw data as weighing value display data in unstable conditions. This improves the responsiveness in an unstable state when a moving average is used. The specific processing method of the present invention is shown in Figs. 3 to 6 below.
This will be explained based on the diagram. Components similar to those in FIGS. 1 and 2 are given the same reference numerals and their explanations will be omitted. Reference numeral 9 denotes _a processing device for the weighed raw data _W , and as shown in FIG. Registers _R1 to _R5
writing and reading data to and from the first flag bit 10 according to the state of the flag bit 10.
The central processing unit 11 determines data for output signals to the arithmetic unit 5, and the central processing unit 11 is programmed as shown in the flowchart of FIG. First, the central processing unit 11 inputs recent weighing raw data W(t) and one of the analog-to-digital converters 3.
Compare the weighing raw data W(t-1) from the previous conversion [a-1] and find |W(t-1)-W(t)|≦N, where N is a positive number, is not detected. It is determined that the state is unstable and the flag bit 10 is set [a-
2], and when [a-2] is completed, the first calculation unit 5
The latest weighing raw data Wt is outputted to [a-3] and returned to [a-1]. If it is determined that the state is stable in [a-1] above, then flag bit 10 is set.
Check [a-4] and if the flag is set, the previous W(t-1) is unstable and W(t)
It was determined that it was stable, and then [a-
5] is executed. In [a-5], register R ₁
The contents of ~ _R5 are all updated to the latest weighing raw data W(t). Then, the flag bit 10 is reset [a-6], and at the same time, [a-7] is executed. [a-7] Based on the contents of registers R ₁ to R ₅ (R ₁ to _{R 5} ), (R ₁ ) + (R ₂ ) + (R ₃ ) + (R ₄ ) + (R ₅ )/5 is executed, and when [a-5] is executed, 5·W(t)/5 is output to the first arithmetic unit 5. Also, if it is determined in [a-4] above that the flag is not set, the previous W
Since (t-1) is also in a stable state and continues to be stable, [a-8] is executed next. [a
-8], the content of one of the registers R ₁ to R ₅ is rewritten to W(t) every time the signal passes through [a-8]. After completing [a-8], [a-7]
Execute and return to [a-1]. With this configuration, when the weighing raw data _{W changes as shown in FIG .} Then, in [a-3], W ₁₂ to _{W 18} are output to the first arithmetic unit 5 each time, and a sequential change display is executed. At time _t19 , if [a-1] determines that it is stable and [a-4] determines that the flag is not set, registers _R1 to _R5 are set at [a-5]. Contents (R ₁ ~
R ₅ ) are all updated to W ₁₉ and the moving average value is output. At time _t20 , _t21 , ... _t25 , at time _t20 , _t21 , .

【table】

[Table] The solid line A in FIG. 6 shows the output signal data of the processing device 13 when the weighing raw data W changes as shown in FIG. 2a, and the broken line B shows the characteristics shown in FIG. 2b. shows the interval of unstable state. That is, the time
Even if it moves from an unstable state to a stable state at t ₁₉ ,
In the case shown by the broken line B, the first calculation unit 5 at time _t19
The output data W _B is the weighted raw data _{W 18 , W 17} , _{W 16 , W 15 during the} transition period _.
comes in, so W _B < W ₁₉ , whereas
In the case shown by the solid line A, the first calculation unit 5 at time _t19
The response of the output data W _A to W _B = W ₁₉ is improved. As explained above, according to the weighing signal processing method of the present invention, flickering is reduced by taking the moving average of raw weighing data, and at the transition point from unstable to stable state, all the data for calculating the moving average is updated to the latest data. Since the weighing raw data is rewritten, responsiveness can be greatly improved compared to conventional methods, and weighing values can be read quickly.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional electronic weighing machine, Figures 2a and b are raw weighing data before simple moving average processing and output signal data after processing, and Figure 3 is a diagram showing how to implement the present invention. 4 and 5 are the main part configuration diagram of FIG. 3 and its flowchart, and FIG. 6 is a characteristic diagram showing changes in output signal data after processing according to the present invention. be. 1...Load cell, 3...Analog-digital converter, 8...Weight display section, 9...Processing device, 1
0...Flag bit, 11...Central processing unit,
_R1 to _R5 ...Registers.

Claims (1)

[Claims] 1 Monitor the latest value of raw weighing data obtained by digitally converting the weighing value signal at regular intervals,
It is determined whether the change in the weighing value signal is stable or unstable, and if stability continues, the latest weighing raw data is stored in the moving average calculation register, and this latest weighing raw data is stored in advance in the moving average calculating register. The moving average value is calculated from the past weighing raw data, and this is used as the data for the output signal. When transitioning from unstable to stable, all the contents of the moving average calculation register are updated to the latest weighing raw data. The calculated moving average is used as the output signal data, and when it is unstable,
A weighing signal processing method that outputs the latest weighing raw data as output signal data.