JPH0259408B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic scale, and more particularly to an electronic scale suitable for determining the deviation amount or deviation ratio of the weight of a comparative sample from a reference weight.

When using conventional electronic scales to perform weight deviation tests in pharmaceutical quality control or to measure the deviation amount and deviation ratio of sample weights from standard weights during product weight management, the standard weight Place the sample on the weighing pan, confirm that the indicated value is stable, press the tare key to set it to 0g or 0%, remove the reference weight from the weighing pan, and sample the sample to be measured from the production lot. At that time, place the sample to be measured on the weighing pan, check that the indicated value is stable while looking at the numerical value on the display, read and record the displayed deviation amount or deviation ratio. Alternatively, the displayed value could be output and recorded on a printer or the like by key operation.
Measurement using this conventional electronic scale allows the subjectivity of the operator to enter into the measurement when confirming the stability of the indicated value, and is not suitable for measuring and recording a large number of samples.

The purpose of the present invention is to measure the amount of deviation or deviation ratio as described above by simply placing the sample on and unloading the weighing pan after setting the reference weight, and automatically determining the amount of deviation or deviation when the indicated value becomes stable. An object of the present invention is to provide an electronic scale capable of transmitting ratio data to the outside.

The present invention is characterized by a means for determining whether the detected data of the load on the weighing pan is changing or in a stable state, and a means for determining whether the detected data of the load on the weighing pan is being lowered from the weighing pan. A means for detecting that a sample has been placed is provided, and only when it is determined that the load detection data is in a stable state, the load on the weighing pan is stored as a reference weight by key operation, and the reference weight is set on the scale. For the samples that are sequentially placed on the weighing pan after being lowered from the pan, when the load detection data becomes stable, it is configured to calculate and output the deviation amount or deviation ratio of the sample weight with respect to the reference weight. be.

Embodiments of the present invention will be described below based on the drawings.

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

The load detection unit 1 detects the load on the weighing pan 1a, and converts the digitally converted data for a predetermined period of time, for example.
It is output every 0.2 seconds and supplied to the control unit 2. The control unit 2 includes a central processing unit CPU that executes various calculations and programs and controls each peripheral device, a read-only memory ROM in which data processing programs, etc. are written, digital conversion data from the load detection unit 1, and various other information. It is composed of a random access memory RAM and the like having areas for storing calculation results and the like and serving as various registers, and these are connected to each other by bus lines. Control part 2
is connected to a keyboard 3 equipped with operation keys such as a reference weight key and a clear key, which will be described later, and a numeric keypad for setting initial conditions, etc., and a display 4 that displays numerical values based on commands from the control unit 2. Furthermore, an output port 5 is provided for transferring the calculation result data of the control section 2 to an external computer or the like.

Next, the operation of the embodiment of the present invention will be explained along with its usage method.

FIG. 2 is a flowchart showing a data processing program according to an embodiment of the present invention.

When a load is placed on the weighing pan 1a, for a predetermined time,
For example, the load data on the weighing pan 1a output from the load detection unit 1 every 0.2 seconds is taken into the random access memory RAM of the control unit 2, and the random access memory RAM has an area for storing up to m+1 pieces of data. The oldest data dm is discarded every time the latest data _d0 arrives (ST1, ST2). When the latest data d ₀ arrives, the average value W 0 is calculated from the latest i (for example, 3) data d ₁ ... d _i from among the data stored up to that time, and the average value W ₀ is _calculated . A value W is calculated by subtracting the value of a reference weight memory T, which will be described later, from the value W (ST3).
Then, the newly collected data for the above average value W ₀
Until the deviation of d ₀ (d ₀ - W ₀ ) satisfies the following formula (1), the data is judged to be changing, and the value W obtained in ST3 is displayed every moment (ST4, ST5, ST6) .

d ₀ −W ₀ ≦R√ ...(1) In equation (1), R is the precision of the scale. For example, if m is ₂₀ for an electronic scale with a precision of 1 mg, then As long as the deviation of the newly collected data d ₀ is not within about 4.5 mg, it is determined that the data is fluctuating. After a load is placed on the weighing pan 1a, the step response waveform of the load detection unit 1 attenuates over time and satisfies equation (1). Sequentially increasing from i, i+n data d ₁ ,
... An average value W ₀ ' is calculated by d _i+o , and W' is calculated by subtracting the value in the reference weight memory T from W ₀ ' (ST4, ST9). Note that the number of data is increased until the maximum data storage capacity of the random access memory RAM is reached (ST7, ST8). Then, _the deviation (d _{0 −}
Until W ₀ ′) satisfies the following equation (2), it is determined that the data is not completely stable, and the value of W determined in ST3 is displayed moment by moment (ST10, ST5, ST6).

d ₀ −W ₀ ′≦R√+ …(2) In equation (2), for example, if the precision R of the electronic scale is 1 mg, and the number of data for calculating the average value W ₀ ′ is i+n
Assuming that there are 8 pieces of data, it is not determined that the data is in a completely stable state until the deviation of the newly collected data d ₀ from the average value W ₀ ' is within about 2.8 mg. Note that W determined in ST3 and W' determined in ST9 are T = 0 until the reference weight described later is set, so their values are the values of the average value W ₀ and the average value W ₀ ', respectively. be equivalent to. Next, when the step response waveform further attenuates and the deviation of the newly collected data d ₀ from the average value W ₀ ' satisfies equation (2), it is determined that the data is in a completely stable state, and ST9 Display W' obtained in step 4 on the display 4 (ST10, ST11, ST12). If the reference weight key provided on the keyboard 3 is pressed in this data stable state, the load W ₀ ' on the weighing pan 1a at that time is stored in the reference weight memory T as the reference weight, and the reference weight key ON flag is set. Along with
Once again, W′ is calculated by subtracting T from the average value W ₀ ′, and the value W′ is displayed (ST17, ST18, ST19,
ST11, ST12). At this point, W ₀ '=T, so the value of W' determined in ST19 is 0. After the reference weight is set in this way, until the load that has become the reference weight is lowered from the weighing pan,
When the value of W' is displayed as 0 and the load is removed and the detected data becomes stable, the value of W' calculated in ST9 will be -T, but it is important to note that W' has become close to -T. is detected and it is determined that the load has been lowered from the top of the weighing pan 1a (ST13, ST14,
ST15), and set the load removal flag (ST16).
In this state, the sample is placed on the weighing pan 1a, and when the data becomes stable, the value of W' is not in the vicinity of -T, and this is detected and the load is placed on the weighing pan 1a. Judgment (ST14, ST17,
ST20), sets the transfer command flag and transfers the data from output port 5 using the value of W' as the deviation amount, and resets the load removal flag (ST21,
ST22, ST23). When the data of the deviation amount is transferred for the sample, the transfer command flag is reset, and the data is not transferred until the sample is replaced (ST24). Next, when the sample is unloaded and the data enters a stable state, it advances from ST14 to ST15 and detects that it has been unloaded.When the next sample is placed and the data enters a stable state, it advances from ST14 to ST25.
Detects that the sample has been placed and calculates the deviation amount.
Data transfer W′.

As described above, when you press the reference weight key when the data is stable, the load on the weighing pan at that time is memorized as the reference weight, and then you can load and unload the samples by changing the samples one after another. When it is automatically detected and it is determined that the sample load data has entered a stable state, the deviation amount of the sample weight from the reference weight is automatically transferred one after another. In addition, when changing the reference weight, the above-mentioned procedure may be executed after pressing the clear key provided on the keyboard 3 to set T=0. In addition, if you want to find the deviation ratio instead of the deviation amount, please refer to the flowchart in Figure 2.
If the reference weight T≠0 at ST3, ST9, and ST19,
From the average value W ₀ or W ₀ ′ and the reference weight T, the following (3)
Calculate the deviation ratio Q using the formula, transfer the Q to the display register in ST5 and ST11, and
It is sufficient to transfer data of Q in ST23.

{Q=W ₀ −T/T×100 or Q′=W ₀ ′−T/T×100} (3) The flowchart shown in FIG. 3 is a data processing program according to another embodiment of the present invention. It shows.
In this example, the average value W ₀ of i data
After calculating (ST30), the value of W ₀ is the reference weight T
When the value is more than K% away from the value, it is determined that the load has been removed from the weighing pan 1a, and a less than K% flag is set (ST32, ST33). In this state, the next sample is placed on the balance pan 1a, and the data becomes stable, and the average value of i+n pieces of data is
When W ₀ ' reaches a value within K% from the reference weight T, it is determined that the sample has been placed, and the deviation amount W' is transferred from the output port 5, and the less than K% flag is reset. Wait for the sample to be unloaded (ST34, ST35, ST31). When detecting the loading and unloading of a sample using this embodiment, the deviation ratio from the standard weight of the sample whose deviation amount is to be determined is usually ±10.
It takes advantage of the fact that it is within ~20%. In other words, if the reference weight is, for example, 500g, the sample weight for which the deviation amount is to be measured is usually 450g~
It is considered to be 550g or within the range of 400g to 600g, so by setting the above K% to 40%, 500g x 40% = 200g
If the weight on the scale pan 1a deviates from the reference weight, it is determined that the load has been removed, and if the weight on the scale pan 1a falls within the range of 500g±200g again, it is determined that the load has been placed. If this loading/unloading detection method is adopted, it will be detected that the sample has been unloaded without waiting for the data to become completely stable, so the next sample can be loaded immediately, improving work efficiency. will improve.

The flowchart shown in FIG. 4 shows a program for calculating the deviation ratio using the detection method of the embodiment shown in FIG. In this example, the deviation ratio Q is calculated from the average value W ₀ and T only when the reference weight is set and T≠0 (ST40,
ST41), if the value of Q is outside the predetermined K% range, it is determined that the load has been lowered from the weighing pan 1a, and a less than K% flag is set (ST42, ST43);
In this state, the sample is placed on the weighing pan 1a and the deviation ratio Q' (ST44,
If ST45) is within the range of K%, it is determined that the sample has been loaded, the deviation ratio Q' is transferred from the output port, the less than K% flag is reset, and the sample is waited for to be unloaded. (ST46,
ST47, ST48). In addition, the display on the display 4 will display Q or Q' if the reference weight has been set and the deviation ratio Q or Q' has been calculated, and if T=0, the average value W ₀ or W Display ₀ ′ (ST49,
ST50, ST51, ST52, ST53). In this way, the loading and unloading of the load on the weighing pan 1a is detected by detecting whether the value of the deviation ratio is within or outside the predetermined range. The following samples can be placed.

As explained above, according to the present invention, by simply placing the sample to be measured on the weighing pan one after another, it automatically detects that the indicated value is stable and calculates the deviation amount or deviation ratio to accurately measure the sample. Since the value is transferred from the output port, there is no need to visually check the stability of the displayed value, unlike when measuring with a conventional electronic scale.
There is no room for the worker's subjectivity to enter into the judgment. Additionally, there is no need to perform key operations each time a sample is replaced, and by connecting a data processing device such as a personal computer to the output port, large amounts of data can be quickly measured and processed, dramatically improving work efficiency. . Furthermore, when disturbances such as wind or minute vibrations act, it is not determined that the data is in a completely stable state, and therefore data transfer such as deviation amount is stopped, making it possible to obtain accurate data.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flowchart showing its program, and FIGS. 3 and 4 are flowcharts showing programs of other embodiments of the invention, respectively. . 1... Load detection section, 1a... Scale plate, 2...
Control unit, 3... Keyboard, 4... Display, 5...
...output port.

Claims (1)

[Claims] 1. A load detection section for detecting the weight of a sample on a weighing pan, and means for determining whether the load detection data from the load detection section is changing or in a stable state;
means for storing the load on the weighing pan as a reference weight by key operation only when the above data is determined to be in a stable state; means for detecting that the sample has been lowered from the weighing pan; A means for detecting that a sample is placed on the weighing pan, and a means for detecting the load detected as the load stored as the reference weight mentioned above for the sample placed on the weighing pan after being lowered from the weighing pan. An electronic balance comprising means for calculating and outputting the deviation amount or deviation ratio of the sample weight from the reference weight when it is determined that the sample weight has reached the standard weight. 2. The means for detecting that the sample has been lowered from the weighing pan is means for detecting that the value obtained by subtracting the reference weight from the weight on the weighing pan is close to the negative value of the reference weight, and , the means for detecting that the sample is placed on the weighing pan is a means for detecting that the reduced value is again no longer in the vicinity of the negative value of the reference weight. Electronic scales as described in Scope 1. 3. The means for detecting that the sample has been lowered from the weighing pan is a means for detecting that the weight on the weighing pan is outside the predetermined ratio range with respect to the reference weight, and the sample is being lowered from the weighing pan. Claim 1, wherein the means for detecting that the scale is placed is a means for detecting that the weight on the weighing pan has again fallen within a predetermined ratio range with respect to the reference weight. Electronic scale.