JPH0259938B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic balance, and more particularly to an electronic balance suitable for weighing a sample of powder, liquid, etc. to a predetermined weight using a tare container or the like.

Generally, the method of weighing powder etc. to a predetermined weight is as follows:
After placing the tare container on the balance tray and performing the tare subtraction process, the sample is placed into the tare container relatively roughly until it reaches a predetermined weight, and then is vibrated using a spoon or the like until it reaches the target weight. A method is adopted in which a small amount of sample is continuously added until the sample weight exceeds the target weight, and if the sample weight exceeds the target weight, the sample is scooped out from the tare container and the sample is added again. However, there are cases where the user forgets to record the sample weight value, which has been measured with such painstaking effort, by writing a memo or by operating the print key, and performs the next process.
In such a case, the above-mentioned efforts will be in vain. In order to solve this problem, even if we apply a so-called auto print function that detects the stable load on the tray and automatically transfers the value, due to the nature of the weighing work, it is not always the stable load, that is, the weighed weight. It is unsuitable.

The present invention has been made in view of the above, and is an electronic device capable of automatically transmitting the data of the weighed weight when the sample is removed from the receiving pan together with the tare container after weighing is completed, and when the weighed value becomes stable. The purpose is to provide balances.

The electronic balance of the present invention includes a means for sampling and storing digitally converted data from a load detection unit that detects the load on a tray at predetermined time intervals, and a means for determining whether the sampled data is changing or in a stable state. means, means for taring the load value on the tray based on the sampling data, and when the sampling data is in a stable state;
Means for sequentially storing load values after tare weight subtraction, and determining that the sample is being weighed when the stored load value after tare weight removal is a positive value including 0, and the sampling data is in a stable state. can be,
It is also equipped with a means for determining that sample weighing is complete when the tare load value takes a negative value, and when it is determined that sample weighing is complete, the stored tare load value just before the tare load value changes to a negative value is externally stored. The feature is that it is configured so that data can be automatically transferred to.

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.

Load detection unit 1 that detects the load on the tray 1a
converts the detected value into digital data at predetermined minute intervals, for example every 0.2 seconds, and outputs the digitally converted data, and the digitally converted data is sampled by the control unit 2. The control unit 2 includes a central processing unit 21 that executes various calculations and programs and controls each peripheral device, a read-only memory 22 in which programs are written, and various registers that store the above-mentioned sampling data and various calculation results. It is composed of a random access memory 23 and the like having an area of 1, and is connected to each other by a bus line. The control unit 2 includes a keyboard 3 equipped with a numeric keypad for setting various cut-off values, a tare key for storing the tare amount for tare weight subtraction processing, and other operation keys, and command signals from the control unit 2. A display 4 for displaying numerical values based on , etc., and an output port 5 for transmitting data to the outside based on commands from the control unit 2 are connected.

Next, the function of the embodiment of the present invention will be described together with the method of use.

FIG. 2 shows a read-only memory 2 according to an embodiment of the present invention.
2 is a flowchart showing a data processing program written in FIG.

The digital conversion data from the load detection section 1 is taken into the random access memory 23 of the control section 2, but the random access memory 23 has a maximum of m+
It has an area for storing one piece of data, and the oldest data dm is discarded every time the latest data _d0 arrives (ST1, ST2). Now, before weighing the sample, place the empty tare container 1b on the receiving tray 1a, press the tare key on the keyboard 3 after the load detection data becomes stable as described later, and the load will be randomly accessed. The tare weight is stored in the tare memory t in the memory 23, and immediately tare subtraction processing is performed using that value, that is, 0 is calculated and displayed on the display 4 (ST15, ST16, ST1
2, ST13, ST14). Next, in this state, the measurement sample is relatively roughly put into the tare container 1b.
Then, the average value W
is calculated (ST3), and from the deviation (d ₀ −W) of the newly sampled data d ₀ from the average value W, it is determined whether the sampling data is changing or transitioning to a stable state. In other words, while the deviation (d ₀ - W) does not satisfy the following equation (1), it is determined that the data is changing, and when it satisfies equation (1), the data is determined to be in a stable state. It is judged (ST5).

|d ₀ −W|≦R√ ...(1) In equation (1), R is the precision unique to this electronic balance and is a value input in advance. For example, in an electronic balance where R is 0.1 mg and m is 25, it is determined that the balance is changing if the deviation (d ₀ -W) is 0.5 mg or more. When it is determined that the data is changing, the value in the tare memory t is subtracted from the average value W to perform tare subtraction processing, and then the value is displayed momentarily on the display 4 (ST6, ST7, ST14).
If the sample input is interrupted or changed to a small sample input, and the deviation (d ₀ - W) above satisfies equation (1), it is determined that the data is transitioning to a stable state, and the number of data is reduced to i for each data sampling. The average value increases sequentially from
W' is calculated (ST9, ST10). The number of data (i+n) for calculating the average value W' is:
The number of data stored in the random access memory 23 is increased until it reaches the maximum number m (ST8). and (i
As long as the deviation (d ₀ - W') of the newly collected data d ₀ from the average value W' of +n) data does not satisfy the following equation (2), it is determined that the data is not completely stable, If formula (2) is satisfied, it is determined that the data is in a completely stable state (ST11).

|d ₀ −W′|≦R√+ ...(2) In equation (2), R is the precision of this electronic balance as mentioned above, and if its value is 0.1 mg and (i+n) is 13, then The right side of equation (2) is 0.36 mg. If it is determined that the data is not completely stable, the average value W' is tared and the value is displayed momentarily on the display 4 (ST12, ST13,
ST14). When it is determined that the data is in a completely stable state, the contents of the register W ₀ ' provided in the random access memory 23 are transferred to the register W ₁ ',
The average value W' after tare subtraction is newly stored in the register W ₀ ' (ST17, ST18). From ST19 onwards, it is determined under what conditions this stable state is a stable state during the weighing work. This judgment will be explained below using a specific example of a weighing operation.

FIG. 3 is a graph showing the relationship between the time course of the weighing operation and the response of the balance. Now, the target weight for weighing is 10g, and the weight of tare container 1b is
23.6248g. As mentioned above, when the tare container 1b is placed on the receiving tray 1a and the tare key is pressed after waiting for the data to become stable, its weight of 23.6248g is stored in the tare memory t, and the tare weight subtraction process is immediately performed and the display is
It becomes 0.0000g (A in the figure). At this point, W ₀ ′=
0, W ₁ '=0. Next, when an appropriate amount of the sample is put into the tare container 1b and the data reaches a stable state, if the value of W' after tare weight is 9.2081 g, immediately after reaching the stable state (B in the figure) So,
W ₀ ′=9.2081g, W ₁ ′=0g, and the process proceeds from ST19 to ST22 and ST23, and the value of 9.2081g is displayed on the display 4. If you leave it in that state
W ₀ ′=9.2081g, W ₁ ′=9.2081g, ST19
Proceed from ST21 and similarly ST22 and below 9.2081
g continues to be displayed. Since the input is insufficient for the target weight, when the slight input is started, the data changes and the value of W or W' is displayed every moment. When the operator looks at the display and determines that the weight has almost reached the target weight, he stops adding a small amount.
Eventually, the data reaches a completely stable state (C in the figure), and the value of W' after tare subtraction, 10.0868g, is stored in register _W0 ', and register _W1 ' becomes 9.2081g. ₁ ′ is also 10.0868g, but even in this state, the value of W ₀ ′ from ST21 to ST22 or less is 10.0868g
is displayed on the display 4. The operator judges that the sample has been overloaded and scoops out the sample with a spoon. At that time, the operator hooks the spoon onto the tare container 1b and
Even if a shock is given by temporarily crossing 0g, or by pressing the tare container 1b, these will be judged as data changing, so ST19
It does not affect the decision process below. After the sample is scooped out, the data reaches a steady state and
If the value of W′ after taring is 10.0013g (E in the figure), register W ₀ ′=10.0013g, register W ₁ ′=
The result is 10.0868g, and 10.0013g below ST22 is displayed on the display 4, which is near the target weight, so the author determines that the weighing is complete, and unloads the sample along with the tare container 1b from the tray 1a, and the data changes in the negative direction. Eventually, the data becomes stable and after tare subtraction.
The value of W' becomes -23.8246g and is stored in the register _W0 ', and the value of the register _W1 ' (F in the figure) becomes 10.0013g. At this time, the process advances from ST21 to ST24, and the contents of the register W ₁ ', 10.0013g, are displayed together with an auxiliary display symbol indicating that the weighing weight is displayed, as shown on the display 4 in Figure 4, and the counter P is displayed. The value is set to 5 (ST25, ST26, ST
27). At the same time, the value of W ₁ ', 10.0013g, is transferred from output port 5 (ST28). Then, for each subsequent data sampling, count down the value of counter P by 1 until P becomes 0.
In other words, 0.2 x 5 = weight weighed in 1 second 10.0013
g and the auxiliary display symbol continue to be displayed (ST4,
ST24, ST29). After the continuous display ends, W ₀ ′=
23.8246g, W ₁ ′=-23.8246g, in this case
Proceeding from ST20 to ST22 and below, the value of W ₀ ′ -
23.8246g is displayed. Then, the next sample is weighed, but the empty tare container 1b and the receiving tray 1a are
When the data is stabilized, W ₀ ′=0g, W ₁ ′=
23.8246g, and the value 0g of W ₀ ' below ST20 and ST22 is displayed, and the next weighing is waited.

As mentioned above, until the data becomes completely stable, the measured weight after taring is displayed moment by moment.
When the data is completely stable and the weight after tare is a positive value including 0, it is determined that weighing is continuing and that value is displayed. When the after weight takes a negative value, it is determined that the weighing has ended, and the tare weight immediately before it changes to a negative value is transferred as data as the net weighing weight, and is continuously displayed for a certain period of time.

In the above-described embodiment, the keyboard 3 is provided with a print key, for example, so that in addition to the function of automatically transferring data of the net weighed weight as described above, data can also be transferred by pressing the print key. You may.

As explained above, according to the present invention, the data of the net weighing weight is automatically transferred by simply lowering the sample along with the tare container from the receiving tray after the weighing is completed, so it is easy to forget to record the net weighing weight. You can work with peace of mind without worrying about things like this. Furthermore, the transferred data has been confirmed to be stable in the load on the tray, so it is always an accurate value, and it can be used to judge whether the sample has been unloaded with the tare container. If the sampling data from the load detection section simply becomes a negative value or near zero, it will not be possible to determine whether it was caused by a spoon, etc. touching it or by a shock, or if the tare container was actually unloaded. Although there is a risk of data transfer, the present invention can also prevent such erroneous data transfer.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of an embodiment of the present invention, Fig. 2 is a flowchart showing the data processing program, and Fig. 3 is a graph showing the relationship between the time course of the weighing operation and the response of the balance. example,
FIG. 4 is a front view of the display device which is displaying the net weighed weight according to the embodiment of the present invention. 1... Load detection section, 1a... Receiver, 1b...
Tare container, 2...Control unit, 3...Keyboard, 4
... Display unit, 5 ... Output port, 21 ... Central processing unit, 22 ... Read only memory, 23 ...
random access memory.

Claims (1)

[Scope of Claims] 1. Means for sampling and storing digitally converted data from a load detection unit that detects the load on the tray at predetermined time intervals, and determining whether the sampling data is changing or in a stable state. means for determining, means for taring the load value on the tray based on the sampling data, means for sequentially storing the load value after tare subtraction when the sampling data is in a stable state; When the load value after tare subtraction is a positive value including 0, it is judged that the sample is being weighed, and when the above sampling data is in a stable state and the load value after tare subtraction takes a negative value. , is provided with a means for determining that sample weighing has ended, and is configured to automatically transfer data of the stored tare weight value immediately before changing to the negative value to the outside when it is determined that sample weighing has ended. electronic balance. 2. The electronic balance according to claim 1, wherein when it is determined that the weighing is completed, the weighed weight is continuously displayed for a certain period of time.