JPH04134222A - Electronic balance - Google Patents

Abstract

PURPOSE:To improve the probability of a normal calibration condition at the beginning of measuring by automatically executing sensitivity calibration again after a given time when data, used in calibration at the time of the operation of an automatic sensitivity calibration function, have dispersion to the extent of the unsatisfactriness of a balance specification. CONSTITUTION:Automatic sensitivity calibration is made by loading an internal weight 2 onto a balancing mechanism 1b with a weight loading mechanism 3 driven, and renewing a calibration factor from the then output variation of an A-D converter 5 and the previously memorized mass value of the internal weight 2. When the calibration routine finishes, whether the degree of the dispersion of momentarily load data, obtained in the process of the sensitivity calibration from the A-D converter 5, is in a range, satisfying a previously set balance specification, or not is judged. Then when the degree of the dispersion is judged beyond the range, a warning lamp 8 is lit and concurrently a timer is set to N, and hereafter the timer value N is subtracted by one count at a time in turn until the value of N becomes zero. When the timer value becomes zero, the automatic sensitivity calibration is executed again.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electronic balance equipped with an automatic sensitivity calibration function.

<Prior Art> Generally, in an electronic balance, digital data from a load detection section is converted into a mass value using a calibration coefficient to determine the measured value to be displayed.

In such electronic balances, when a preset time elapses or a temperature change occurs, the built-in weight of the balance is automatically loaded onto the load detection section, and the load data in that state and the reference mass are used. There are some that have a function to update the calibration coefficient, so-called automatic sensitivity calibration function.

By the way, when performing sensitivity calibration, the surrounding environment in which the balance is installed greatly affects the accuracy of the calibration coefficients obtained, and if calibration is performed in a poor environment, the balance's specifications may not be met. be. When the automatic sensitivity calibration function operates and the calibration coefficients are automatically updated, if the new calibration coefficients do not meet the specifications, the balance user may take measurements without knowing this. be.

Therefore, with conventional electronic balances that have an automatic sensitivity calibration function, it is determined whether the environment at the time of sensitivity calibration is sufficient to satisfy the specifications based on the variation in load data during sensitivity calibration, and if it is not satisfied, We have taken measures such as displaying a warning to that effect and notifying balance users.

<Problems to be Solved by the Invention> When the automatic sensitivity calibration function is activated when the electric balance is powered on and not in use in the conventional electronic balance having the automatic sensitivity calibration function as described above, the specifications may be changed due to a disturbance, etc. If calibration is performed that does not meet the requirements, a warning will be displayed to that effect, but this will remain as is until use is started.

Assuming that the environment in which the balance is normally installed is a good environment with no external disturbances, for the balance user, if such a warning message appears when trying to use the balance, it may indicate that some kind of trouble has occurred with the balance. There is a fear that they might think that it was the case.

In addition, even though the automatic sensitivity calibration function has been used to calibrate the sensitivity, if the balance does not meet the specifications, the balance cannot be used even though it has the automatic sensitivity calibration function. There is also the problem that the sensitivity must be manually calibrated again before the calibration.

<Means for Solving the Problems> The electronic balance of the present invention has a calibration method that determines whether or not the environmental condition at the time of calibration is within a preset allowable limit from the output data of the load detection section at the time of sensitivity calibration. In addition to an environment determination means and a display means for displaying a warning to that effect if the environmental condition at the time of calibration is outside the permissible limit based on the determination result, the environmental condition at the time of calibration is determined based on the above determination result. If the calibration is outside the allowable limits and the condition continues for a preset period of time after the calibration was performed, the automatic sensitivity calibration function is reactivated at that point. We have measures in place.

Function> If automatic sensitivity calibration is performed that does not meet the balance specifications, this will be displayed, and if the condition continues after a certain period of time, the automatic sensitivity calibration function will be reactivated. If a sudden disturbance caused a calibration that did not meet the specifications during the initial automatic sensitivity calibration, there is a high possibility that sensitivity calibration that satisfies the specifications will be performed by restarting the automatic sensitivity calibration, and the warning display disappeared before use. It becomes a state.

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

The load detection unit 1 includes a balance mechanism 1b that engages with the plate 1a, and a balance sensor 1 that detects the balanced state of the balance mechanism 1b.
c and the detection results by its balance sensor 1c are always “
It is composed of an electromagnetic force generating section 1d that is feedback-controlled to generate an electromagnetic force that maintains an "equilibrium state,"
The electromagnetic force generating section 1d outputs an electric signal proportional to the generated force.

A built-in weight 2 whose mass has been measured in advance, and a weight addition/removal mechanism 3 for loading or unloading the built-in weight 2 with respect to the balance mechanism 1b are disposed within the load detection section 1.

The output signal of the electromagnetic force generating section 1d is introduced into the A-D converter 5 via the low-pass filter 4, where it is digitized and then input into the control section 6.

The control unit 6 is mainly composed of a microcomputer, and has a CPU 6a, a ROM 6b, a RAM 6c, an input/output interface 6d, etc., and a program to be described later is written in the ROM 6b.

In addition to the A-D converter 5, the control unit 6 includes a display 7 for displaying measured values, a warning lamp 8 that lights up if the environmental condition is bad during automatic sensitivity calibration, and the above-mentioned weight. An addition/extraction mechanism 3 is connected.

Figure 2 shows the programs written in ROM6b.
1 is a flowchart showing an excerpt of the characteristic parts of the present invention, and the operation of the embodiment of the present invention will be described below with reference to this figure.

5 in a normal measurement routine with power on.
If a preset time has elapsed since the last calibration, or if there has been a certain temperature change since the last calibration, the automatic sensitivity calibration function will work unless measurement is in progress at that time.

This automatic sensitivity calibration is performed by driving the weight addition/removal mechanism 3 to load the built-in weight 2 onto the balance mechanism 1b, and then calculating the change in the output of the A-D converter 5 and the mass value of the built-in weight 2 stored in advance. This is done by updating the calibration coefficients.

When such an automatic sensitivity calibration routine ends (A),
It is determined whether the degree of variation in the momentary load data from the A-D converter 5 taken in the process of sensitivity calibration is within the range that satisfies the preset balance specifications (B), If satisfied, the routine returns to the normal measurement routine without turning on the warning lamp 8 (C, D).

If it is determined in step B that the degree of variation in the load data is outside the above range, the warning lamp 8 is turned on (E) and at the same time, the timer is set to N (F) until the value becomes 0. Sequentially subtract one count from the timer value N (G, H).

If the timer value becomes 0, in other words, after a certain period of time has elapsed after automatic sensitivity calibration that did not satisfy the specifications, automatic sensitivity calibration will be performed again. Execute step B and subsequent steps as before.

As mentioned above, if it is determined that there are inconsistencies in the data obtained when the automatic sensitivity calibration function is activated that does not meet the balance specifications, the automatic sensitivity calibration is automatically performed again after a certain period of time has elapsed. This operation is repeated until the balance specifications are met.

Here, the time set by the timer is significantly shorter than the time during which the normal automatic sensitivity calibration function operates, and is preferably about several minutes, for example.

<Effects of the Invention> As explained above, according to the present invention, when the automatic sensitivity calibration function is activated, if the data used for the calibration varies to such an extent that the balance specifications cannot be satisfied, Sensitivity calibration is automatically performed again afterwards, so even if a sensitivity calibration that does not meet the specifications is performed due to a sudden disturbance, etc., there is a possibility that this recalibration will result in a calibration that satisfies the specifications. For example, when attempting to perform a measurement after being left unused for a long time, there is a high possibility that calibration has always been performed that satisfies the specifications.

As a result, the automatic sensitivity calibration function eliminates the fear that balance users may have run into trouble as in the past, and increases the probability that the calibration will be in a normal state at the beginning of the measurement. The original significance of something is brought to light.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a flowchart showing the main part of the program written in the ROM 6b. 1...Load detection section 1a...Dish 1b...Balance mechanism 1c...Balance sensor 1d...Electromagnetic force generation section 2...Built-in weight 3...Weight Addition/subtraction mechanism 4...Low pass filter 5...A-D converter 6...Control unit 6a...CPU 6b...ROM 6c...RAM 6d...Input Output interface 7... Display unit 8... Warning lamp

Claims (1)

[Claims] A calculation unit that determines the weighing value by calculation using a calibration coefficient from the output data of the load detection unit in the measurement state, and a calculation unit that automatically sends the calibration mass to the load detection unit when preset conditions are met. In a balance equipped with an automatic sensitivity calibration means that calculates and updates the above calibration coefficient from the output data of the load detection section under load, the environment at the time of calibration is calculated from the output data of the load detection section during sensitivity calibration. A calibration environment determination means for determining whether the condition is within a preset tolerance limit, and a warning display to that effect if the environmental condition at the time of calibration is outside the tolerance limit based on the determination result. If the environmental condition at the time of calibration is outside the permissible limit based on the display means and the above-mentioned determination result, and the condition continues after a preset time has elapsed from the time the calibration was performed, An electronic balance comprising means for reactivating the automatic sensitivity calibration means.