JPH0224329B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electronic balance that automatically calibrates span using a reference weight.

<Conventional technology> Since electronic balances are devices that measure mass,
Due to differences in the acceleration of gravity "g" due to differences in the installation location, errors may occur even if accurate adjustment is made during manufacturing, or the span may change due to changes in the temperature of the usage environment.

Therefore, it is necessary for electronic balances to be calibrated from time to time in response to such span changes.

In conventional electronic balances, this type of calibration is performed by adjusting a screwdriver, etc., or it is also called an automatic calibration method, which automatically calculates the span from the measured value of a reference weight by operating a push button, etc. There is also something to calibrate.

<Problems to be Solved by the Invention> By the way, among conventional electronic balances, those that perform span calibration by adjusting a screwdriver etc. are inconvenient to adjust, and automatic calibration types have
Normal operation of the balance may be affected due to a sudden change in the span that exceeds the operating tolerance due to sudden changes in the balance's moving parts due to rapid temperature changes or dew point phenomena, or due to foreign objects getting into the moving parts. Even if the balance runs out, there is a risk that the operator may unknowingly perform automatic configuration and end up using the balance.

The present invention has been made in view of the above-mentioned problems, and is designed to notify the measurer when the balance becomes abnormal in its automatic calibration type electronic balance, thereby reducing the risk of incorrect use. The aim is to provide a small number of electronic balances.

<Means for Solving the Problems> In order to achieve the above object, the present invention includes a first determination means for determining whether the measured value of a reference weight exceeds a preset tolerance range, and a calibration method. a second determination means for determining whether or not the operation of the automatic calibration pushbutton has been within a predetermined time since the previous operation; If the reference weight is operated within a predetermined time from the time when the reference weight is operated, and the measured value of the reference weight at that time exceeds the allowable range, a notification means is provided to notify that fact.

<Function> If the weighing value exceeds the allowable range even though the automatic calibration pushbutton was pressed within a predetermined time since the last time, the balance may be affected by the dew point phenomenon or foreign matter as described above. It is presumed that this is caused by an abnormality in the mechanism of the balance. Therefore, by notifying the user in such a case, it is possible to prevent the wrong balance from being used.

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

The output from the load detection section 1, which generates data corresponding to the load on the plate, is input to the control section 3.

The calibration push button 21 is connected to the control device 2, and when the calibration push button 21 is operated, the control device 2 transmits a notification to that effect to the control unit 3. By operating this calibration push button 21,
The control section 3 gives a command to the control device 2 to transmit a reset/start signal SP to the counter 5 if the conditions described later are satisfied.

The counter 5 counts pulses P of a constant period synchronized with the data collection period from the load detection section 1.
Every time the signal PS is transmitted, the previous count value is reset and a new pulse P is sent.
Start counting. And this counter 5
is controlled by generating an OK signal if the count value is greater than a predetermined value when the signal PS arrives, in other words, if more than a set time has elapsed from the arrival of the previous signal PS to the arrival of the current signal PS. 3.

The control unit 3 is actually composed of a microcomputer, but functionally it determines that a calibration operation is being performed by transmitting an operation signal of the calibration push button 21 from the control device 5. A determiner A31 that determines whether the data from the load detection unit 1 is calibration data or normal weight data; a correction amount storage register 32 that stores a correction value to be described later using a reference weight; an arithmetic device 33 that performs various operations such as converting into a value;
A reference weight amount register 34 that stores the mass value of the reference weight, a coefficient amount register 35 that stores a preset allowable range of the measurement value of the reference weight, and an arithmetic unit 33.
A comparator 36 that compares the reference weight measurement value from the reference weight and the contents of the coefficient amount register 35, and a determiner B that determines whether or not the above-mentioned OK signal is supplied from the counter 5.
37, and a program device 38 in which a program defining the overall operation of the control section 3 is written.

Connected to the control unit 3 are a display device 4 that displays the measured value calculated by the arithmetic device 33, and a notification device 6 that operates according to a command.

FIG. 2 is a flowchart showing the contents of the program written in the program device 38, as follows.
The operation of the embodiment of the present invention will be described with reference to this figure.

First, when the electronic balance is installed, the mass value W of the reference weight is initially set in order to eliminate errors caused by differences in the installation location (steps 100/102). This initial setting is a known adjustment performed, for example, by adjusting an adjustment resistor, but can be omitted if the difference in gravitational acceleration from the previous adjustment location is small. Also, if this adjustment is incomplete, the step
Adjust again by 103. The set reference weight mass value W is stored in the reference weight amount register 34.

Now, when such initial settings are completed, collection of data W _x from the load detection section 1 is started (step 104).

The sampling data _W
Calculation W _x using the contents of 2 w ₁ and the reference weight mass value W
(1+w ₁ /W), data W _x is corrected to the correct mass value and transferred to the display device 4 (step
301, 302).

When it is determined that the sampling data W _x is the calibration data W _i , the difference w ₂ (=W _i - W) from the content W of the reference weight amount register 34 is calculated, and this difference
A total correction value w ₁ +w ₂ is calculated by adding W ₂ and the content w ₁ of the correction storage register 32. (Step 106,
107). Then, this total correction value w ₁ +w ₂ is compared with the content w ₀ of the coefficient amount register 35, and the following operations are performed based on the result.

Here, the contents of the coefficient amount register 35 are the allowable value of the mass change of the reference weight, as described above.

If w ₁ + w ₂ ≦ w ₀ holds, w ₁ + w ₂ is stored as a new correction amount w ₁ in the correction amount storage register 32,
In addition to providing correction for subsequent measurements,
At the same time, a signal PS is sent to the counter 5 to reset its contents (steps 108, 110-113).

If w ₁ + w ₂ > w ₀ holds, it is determined whether the OK signal is output from the counter 5 in the determiner B, that is, the elapsed time from the previous operation of the calibration push button 21 or the time when the power was turned on is greater than or equal to the predetermined time. It is determined whether or not the period has passed (step 109), and depending on the determination result, the following:
We parted ways.

When it is determined in step 109 that the above elapsed time has passed the predetermined time, w ₁
+w ₂ is stored as the correction amount w ₁ at that point in the correction amount storage register 32, and is used for correction in subsequent measurements.
A signal PS is sent to reset the contents (steps 110 to 113).

If it is determined in step 109 that the above elapsed time has not exceeded the predetermined time, a sudden change in span has occurred, that is, an abnormality has occurred, and a command is sent to the notification device 6 to issue an alarm (step 109).
201). In this case, the correction amount is not updated and remains at _w1 , and the counter 5 is not reset.

As described above, when the calibration push button 21 is operated before a certain period of time has elapsed since the previous operation, if the measurement result of the reference weight at that time exceeds the preset tolerance range, then For example, a warning is issued by the notification device 6. Here, the span of the balance gradually changes over time, as shown in Figure 3, due to, for example, an increase in the temperature of the device due to power on (in this figure, the weighing value is a digital value). If the device is normal, there will be no sudden changes. Therefore, when this alarm occurs, the measurer can know that something has happened to the balance mechanism, etc. In this case, the measurer can check the balance and make appropriate adjustments to meet the conditions. All you have to do is

Now, after that alarm has been raised, the steps
When the calibration push button 21 is pressed twice in step 202, w ₁ +w ₂ is stored in the correction amount storage register 32 as a new correction amount by line 204, and the same operation as in the case of step 202 is performed. This is effective when the person using the balance knows this and uses the balance for some reason.

As another embodiment of the present invention, in a balance with an automatic weight addition/removal mechanism, by utilizing this function, the calibration operation, including the loading and unloading of the reference weight, can be fully automated.

<Effects of the Invention> As explained above, according to the present invention, in a balance having an automatic calibration calculation function and equipped with a calibration push button, the measured value of a reference weight falls within the allowable range within a short period of time within a predetermined period of time. If the change exceeds the limit, a notification will be sent to notify the operator of the occurrence of an abnormality, so there is no risk of erroneous use, such as calibrating without noticing an abnormality such as foreign matter contamination, as in the past. Measurers can always use the balance with peace of mind.

[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 the contents of a program written in the program device 38, and FIG. 3 is an explanatory diagram of the operation of the embodiment of the present invention. 1... Load detection section, 2... Control device, 21
...Calibration push button, 3...Control unit, 4...Display device,
5...Counter, 6...Notification device.

Claims (1)

[Claims] 1. In a balance whose measured value is calibrated by operating an automatic calibration push button using a calibration value from a reference weight, a first step is performed to determine whether the measured value of the reference weight exceeds a preset tolerance range. a determination means, a second determination means for determining whether or not the operation of the calibration push button has been within a predetermined time since the previous operation, and based on the determination results by the first and second determination means, The above-mentioned automatic calibration pushbutton is operated within a predetermined time from the previous operation, and when the measured value of the reference weight at that time exceeds the above-mentioned allowable range, a notification means is provided to notify that fact. An electronic balance featuring