JPS6026967B2 - Automatic zero setting system for scales - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention consists of an electrical metering bridge, necessary amplifiers, voltage/frequency converters, and a presettable counter that is preset so that the scale reading is as close to zero as possible at the tare weight of the bridge mechanism. The present invention relates to an automatic zero-setting system for scales with a digital display consisting of:

Automatic zeroing is especially necessary in digital scales where weight is displayed numerically.

With such digital scales, if the food tray is empty, the weight will be 0.0.
Even a slight deviation from the reading of 00k9 is an inconvenience. Causes of temporary or permanent deviations in readings include the posture of the scale, vibrations, air currents, hysteresis after weighing particularly heavy objects, weighing residue left on the weighing pan,
There are the effects of temperature that is thought to be exerted on electronic components, residual deviation due to aging of components after a long period of time (several years), etc.

The purpose of the present invention is that when the scale is empty, the reading is 0.0.
To provide an automatic zero setting system capable of eliminating all reading errors due to the above-mentioned causes so as to prevent errors in measurement results due to the above-mentioned disturbance factors. It is in.

The present invention achieves the above object by having the configuration described in the claims.

The structure of the present invention will be explained below based on the embodiments shown in the drawings. Blocks 1, la of FIGS. 2 and 4 represent the article 1 of FIGS. 1 a and 1b, the metering bridge and the weight data amplifier.

As the measuring bridge la, for example, a strain gauge measuring bridge, which is known per se, can be used. The weight data is led to an amplifier in block 2 and is fed from a reduction filter to a voltage/frequency converter 3. Voltage/frequency converter 3
A pulsed voltage as shown at the top of FIG. 3 is obtained. As the weight increases, the number of weight pulses per unit time increases. That is, the density of the pulse sequence increases. Conversely, as the weight decreases, the pulse sequence density decreases. In the example presented here, one weight pulse corresponds to 0.5 hours. This weight pulse sequence passes through a two-part device (designated 13 in FIG. 4), and the pulse sequence exiting this two-part device is:
It has a frequency 1'2 smaller. That is, in the case of this embodiment, one sequence corresponds to one saw. This sequence of weight pulses is sent to a presettable BCD counter 4, which is shown in FIG. 3 as "Measuring Frequency to BCD Counter". The output of the voltage/frequency converter 3 is further sent to a weight change comparison section 6 and a function timing section 12. The basis for automatic zeroing is the tare weight of the bridge mechanism, the value of which can be "stored" in the presettable BCD counter 4.

For example, if the tare weight of the bridge mechanism is waza x 2 yen, then the preset value of 10,000 tars, 5 mils, 2 yen = 46 tare weights will be entered in the BCD counter 4. If the food tray is empty, the weighing result or count value is 46 balls, 10 wipes, 2 balls = [1
) 0000 yen, and since the output and display are only 4 digits, a display of 0.000 kg is obtained. For example, if a display is required in steps of every 2 ta, it will change continuously between 9.996 and 0.004k9 due to the disturbance factors mentioned above, and over a longer period of time, The total deviation in either direction becomes even larger.

The automatic zero setting method of the present invention described below is as follows:
This was done to eliminate these drawbacks.

In the embodiment shown in FIGS. 2 and 3, for example, a correction voltage step corresponding to about 0.5 volts in each case is taken from the correction voltage device 5 and applied to the summing amplifier 2. I can do it. In this embodiment, the zero setting coverage range is ±16 days. This range may be expanded as necessary.

The correction voltage step is, for example, 8 steps corresponding to 0.5 steps and 8 steps of 4 steps each (=8 x 0.5 steps)
It can be formed using a parallel resistance circuit consisting of:

The correction voltage is governed by the following criteria: '1} When the scale is turned on, a starting search period device 1-1 is initiated, for example of duration 11 every 2 seconds, which causes the automatic mechanism to search for the point at which the weight measurement is [1]0000k9.
This means that the correction voltage 5 is the lowest value (that is, the reading is [1]00
From 00-16=9 (4), the weight count gradually changes to larger values in steps equivalent to 0.5, and the weight count becomes [1] 0.
000 is reached. The period between correction steps is equal to 44 S (measurement period). The only limiting factor in this startup search procedure is that the product pan must be empty during the startup search period. If you plan to use a scale, 1 day a day.
It is by no means an unreasonable condition to allow two minutes of ``warming-up'' time per session. '21 count [1
] When it reaches 0000, the automatic zero setting function will
The information provided by the differentiator 7 as shown below (second
The operation starts based on the automatic zero setting data shown in the figure.

[a- The count of the measurement period is 9999.0 and [1] 0
000.5, the correction data processing device 8 supplies the correction command and the direction command “up” to the correction voltage device 5. {b) Furthermore, when the count falls between [1]0001.0 and [1]0002.0, a correction command accompanied by a direction command "down" is issued in response.

The resolving power of the count is 0.5 digits (1/2 digit).

The correction period or the interval between correction instructions is relatively long (440
However, since the measurement period is relatively long, the movement of the empty article due to disturbance factors (air current, vibration, etc.) may be incorrect, except for a maximum of one command per direction. It is extremely rare for an amendment order to be issued by
For the one instruction above, a correction in the opposite direction has already been obtained (result is 0).

In this way, the automatic function reduces the empty bridge count to [1
]0000.5 force) and [1]0001.0.

The above interval is 0 for count result [1] 0000.0
．． It was chosen to obtain a distance of 5.5 yen.

This reading serves as a display blanking limit, whereby a small result will blank the display and a larger reading will cause the display to illuminate.

For example, when the distance is 0.5 yen from the erasure reading, the automatic function
This is to prevent the display from being erased frequently as in the case where the interval from 1]0000.0 to [1]0000.5 is targeted. Since the readings are displayed in steps of two taps, the reading of 0.0001k9 will never appear in any case.

In the example described here, based on selected limit values or so-called "normal" criteria, the
Counts below 999.0 are not corrected by automatic functions; such counts result, for example, from manual lifting of the article plate.

This represents the actual metrological event [1]0002.
The same can be said for count results exceeding 0. [1]00
It is clear that results between 00.5 and [1]0001.0 are also not corrected. '3} Pulse and display erase data 10 from the weight change comparison unit 6 (activated when the rate of change exceeds 1.5 [9/220 ms)
occurs at the same time, for example, a residual weight search period 9 of 6.9 sand is started.

This actually results in the bridge mechanism overswinging in the "negative direction" after removing the article. During the static weight search period 9, the correction voltage 5 is adjusted to compensate for weighing residuals or hysteresis after weighing a particularly heavy object.
It has enough time to discount 14 increments of 0.5 evenings each, or a total of 7 evenings of residual leaves.

The static weight search criteria (and the same for the starting search criteria) is 9999.
The so-called “
overridden by the "Normal" criteria.

If another measurement is taken before the end of the search time, the stationary search period is immediately interrupted.

This interruption is effected by a pulse from the weight change comparator that occurs independently, without display erase data.

In this embodiment, when the static weight becomes 8 ta or more, the static weight search is not started at all, and the static weight remains as it is on the display as a measurement result. This only occurs if the total metering balance is too large and needs to be removed. Next, the embodiment shown in FIGS. 4 and 5 will be described. B
The manual preset switch 4a of the CD counter 4 is set to a value smaller than the preset value calculated according to the principle described above, for example, 45 points.

Between the preset switch 4a and the presettable BCD counter 4, there is a correction voltage device 5 for correcting the preset value.
is inserted, but this can be configured with a presettable BCD counter. The automatic zero setting process consists of continuous observation of the counts given by the BCD counter 4 and correction of the preset value voltage counterfeit 5.
The preset value correction device operates to change the preset value to a value that yields a reading of 0.000k9. According to the setting 45 of the preset switch 4a, if such a negative value is displayed, the empty scale will read 9900 evenings.

Next, a quick search approach from the value 9900 to count [1]0000 will be described. The counts of the BCD counter 4 (the third digit from the highest order) are continuously observed by a differentiator 11a which observes counts between spots 00 and 999 (N).

Here, (N) represents any number from 0 to 9.
When the scale is switched on, the count of the BCD force counter 4 will remain within the aforementioned limits even if, after the presetting of the switch 4a, a change equivalent to 100 mm occurs as a result of various disturbance factors. . Differentiator 11a is BCD
When detecting that the count of the counter 4 is within its differential range, the differentiator 11a activates the quick search device 11b.
At the same time, the preset value correction device 5' is controlled so that one correction pulse is obtained during each measurement period determined by the timer 12. In this embodiment, one correction pulse of the quick search increases the preset value of the preset value correction device 5' by one river, which in this case corresponds to 10 evenings. When the preset value increases to such an extent that a count of 999 (N) is obtained from the BCD counter, the limit of the differentiator 11a is reached and the quick search is stopped. At the same time, a zero search is started, which will be explained below.

The count of the BCD counter is monitored by the differentiator 7', and in this embodiment, the count from 999 (N) to 00
A differential range of 00.5 and 0000.5 to 00 female 0 is selected.

At the same time, the differentiator 7' observes the value 0000.5, on the basis of which direction or counting is carried out.

Therefore, after the quick search is stopped, the differentiator 7' supplies a correction pulse to the preset value correction diamond 5 via the correction data processing device 8, and the "up" correction direction is interrupted. and is in a valid state. The course of the correction pulse is indicated by an arrow 8a, and the course of the correction direction is indicated by 8b.

Only one correction pulse is provided for each of the two measurement periods determined by the timer 12.

The correction data processing device 8 divides the first weight pulse supplied from the voltage/frequency converter 3 so as to shorten the path through the divider 13 during the measurement period in which the correction pulse is generated. control device 13. During each second measurement period, no correction pulse is generated, allowing the first weight pulse to pass. In this way, a correction function is created which proceeds in steps of 0.8 strokes of measurement, for example 0.5 steps. This makes it possible to perform the correction operation with the same precision as the differential precision. The 0.5 unit differential accuracy of the measurement is based on the fact that a pulse corresponding to one measurement unit would otherwise be approximately 50 percent of its duration. It will be clear that in this way, for example, even if the preset value is increased by a step corresponding to 1, the correction proceeds as if it were carried out in steps corresponding to 0.5. Eventually, the count reaches the value 0000.5 and continues to oscillate to either side of it. The correction direction changes alternately to "upj" and "down".

Alternatively, it is also possible to provide the differentiator 7' with a range within which no corrective action occurs at a certain count within that range. It is also possible to select the upper limit of the differentiator 7' according to the minimum weight one wishes to weigh.

For example, in a store scale, it is not actually necessary to determine a weight of 10 ta or less, so in this embodiment, the upper limit of the differentiator is selected to be 00 points BO. Therefore, if the count of the balance deviates above a value which would result in a zero reading due to the above-mentioned disturbance factors, in particular weighing residuals, the differentiator 7' will, via the correction data processing device 8, set the preset value. A correction pulse and a correction direction of "down" are supplied to the correction device 5 of. Also in this case,
Only one correction pulse is supplied for two measurement periods. During the measurement period when no correction pulse occurs,
The passage of the first weight pulse through the divider 13 during that period is interrupted, so that even if the preset value is not corrected, the 0.0. Job 4 fixed unit ``do''
wn” correction is performed. 1st in the next measurement period
If the pulse path is not closed, even if the preset value is corrected in the "down" direction by one measurement unit, it will still be 0.0% with respect to the previous correction. Correction is performed in the "down" direction only in Fujiq-constant units.

After correction, it oscillates to both sides of the value of [1]0000.5 in steps of 0.5. In order to prevent unnecessary correction from occurring in the normal weighing process, the weight change comparator 6 uses correction data to prevent correction from occurring if the weight change does not exceed a predetermined G rate. It is configured to control the processing device 8 .

For a normal store scale, an S of 1.5/220, for example, is appropriate as a rate of change. The count of the presettable BCD counter 4 is fed to a memory 14 and from there to a calculator 17 and via a display device 18 to a display 19 .

When the keyboard 16 supplies price data from 16a to the calculator 17, the controller 15 outputs the weight data from the memo IJ-14 until an output command is given to send the weight data from the memory 14 to the calculator 17. Make sure not to. In the calculator 17, the product of unit price and weight is formed and the final price is displayed on the display.

However, these operations do not form part of the automatic zero setting of the present invention. The automatic zero setting of the invention can be applied to all types of scales that have a digital display. The automatic zero correction of the present invention has the character of tare adjustment.

In other words, the weight corresponding to the correction amount is added or subtracted from the total weight. Therefore, errors caused by residual deviation can be completely eliminated. Amplification errors can also be corrected by the tare/gross weight ratio.

[Brief explanation of the drawing]

Figures 1A and 1B are perspective views from opposite directions of a digital store scale requiring the automatic zero setting system of the present invention, and Figure 2 is a block diagram of the automatic zero setting system of the present invention. , FIG. 3 is a diagram showing voltage waveforms and data of the automatic zero setting system of the present invention, FIG. 4 is a block diagram of another embodiment of the automatic zero setting system of the present invention, and FIG.
The figure is a diagram showing voltage waveforms used in the embodiment of FIG. 4. 2... Weight data amplifier, 3... Voltage/frequency converter, 4... Counter, 4a...
- Setting switch, 5, 5'... Correction voltage device, 6. …．・Weight change comparison section, 7, 7'...
...First differentiator, 8...Correction data processing device, 9...Static weight search period, 10...Display erase data, 11...Start search period control device, 11a ...Second differentiator, 11b...
...Quick search weighted correction pulse, 13...
・・2 dividing device, 14・・・・Memory, 16・・
...Keyboard, 17...Calculator, 18.
...Display device, 19...Display. Figure la Figure lb Figure 2 Figure 4 Boat map

Claims (1)

[Scope of Claims] 1. An electrical measuring bridge and a weight data amplifier, a voltage/frequency converter and a presettable counter that is preset so that the scale reading is as close to zero as possible in the tare weight of the bridge mechanism. In an automatic zero-setting system for scales with a digital display consisting of a digital display, a correction voltage device is placed in the information path to the counter, so that the count given by the counter is one or the other from the count value giving a zero indication. observed using a differentiator configured to detect deviations of a given magnitude in the direction, on the basis of which the differentiator is adapted to supply a correction command and a correction direction to the corrector. Features an automatic zero setting system for the scale. 2. Automatic zero-setting system for a balance according to claim 1, characterized in that the amount of one correction step consists of 0.5 digits, preferably such that 1 digit corresponds to 1 g. 3. The period between correction steps, which is the same as the measurement period, is 0.
The automatic zero setting system for a scale according to claim 1 or 2, characterized in that the zero setting value is between 1 and 1.0. 4. There is a range within the count values giving a zero indication, and the deviation of the counts within a given limit above or below from this range controls the correction device; Automatic zeroing of a scale according to claim 1, characterized in that the correction device is adapted to be supplied with a correction command and an upward or downward correction direction until the range is achieved. Taing system. 5. Any one of claims 1 to 4, characterized in that a correction voltage that changes by a predetermined step at a predetermined interval is supplied, and the correction voltage is added to the weight data voltage by a correction voltage device. Automatic zero setting system for the scale described in item 1. 6. Claim 5, characterized in that the entire target range of the correction voltage supplied by the correction voltage device is a multiple of the differential range between the upper and lower limits of the differentiator. Automatic zero-setting system for the scales described. 7 Electrical measurement bridge and weight data amplifier and voltage/
In an automatic zeroing system of a scale with a digital display consisting of a frequency converter and a presettable counter which is preset so that the scale reading is as close to zero as possible at the tare weight of the bridge mechanism, information to the counter is provided. A correction voltage device is disposed in the path, and a differentiator configured to detect a deviation of a given magnitude in one or the other direction from the count value in which the count given by the counter gives a zero indication. Based on this, the differentiator supplies a correction command and a correction direction to the correction device, and after the scale is turned on, the start search period control device changes the correction voltage to the correction voltage. An automatic zero-setting system for a scale, characterized in that the compensation voltage device is controlled to increase by steps corresponding to upwards from the lowest value of the range. 8 Electrical measuring bridges and weight data amplifiers, voltage/frequency converters and bridge mechanisms, and voltage/frequency converters and bridge mechanisms whose tare weights are preset so that the scale reading is as close to zero as possible. In an automatic zero setting system for scales with a digital display consisting of a counter,
A correction voltage device is placed in the information path to the counter so that the count given by the counter gives a zero indication and the count gives a zero indication of a given magnitude in one or other direction from the count value. observed using a differentiator configured to detect the deviation, based on which the differentiator supplies correction commands and correction directions to the corrector, pulses from the weight change comparator and display erasure. The simultaneous presence of the data initiates a resting weight search period during which the resting weight resulting from weighing residue or hesteresis is discounted by the compensation voltage device if the resting weight is less than or equal to a given value. The scale's automatic zero setting system is characterized by: 9. Balances with digital display consisting of an electrical measuring bridge and weight data amplifier and a voltage/frequency converter and a presettable counter which is preset so that the scale reading is as close to zero as possible in the tare weight of the bridge mechanism. In automatic zerosetting systems, a correction voltage device is placed in the information path to the counter so that the count given by the counter is a given magnitude in one or the other direction from the count value giving a zero indication. Based on this, the differentiator supplies a correction command and a correction direction to the correction device, and the weight change comparator processes the correction data. 1. An automatic zero-setting system for a scale, characterized in that the processing device controls the device so as not to issue a correction command when the weight change rate exceeds a predetermined value. 10 A preset value correction device is provided between the presettable counter and its setting switch, and a differentiator that monitors the value given by the counter supplies a correction pulse and a correction direction to said correction device. Claim 1 is characterized in that:
An automatic zero setting system for a scale according to item 9 or item 9. 11. The automatic zero setting system for a scale according to claim 10, wherein both the counter and the preset value correction device are comprised of presettable BCD counters. 12. A scale with a digital display consisting of an electrical measuring bridge and a weight data amplifier and a voltage/frequency converter and a presettable counter which is preset so that the scale reading is as close to zero as possible in the tare weight of the bridge mechanism. In an automatic zero setting system, a correction voltage device is placed in the information path to the counter so that the counter provided by the counter has a given magnitude in one or the other direction from the counter value giving a zero indication. a first differentiating device configured to detect a deviation in weight, based on which the differentiating device supplies a correction command and a correction direction to the correcting device; controls the correction data processing device so that the processing device does not issue a correction command if the weight change rate exceeds a given value, and performs correction of the preset value between the presettable counter and its setting switch. A device is provided, wherein said differentiator for monitoring the value provided by the counter supplies a correction pulse and a correction direction to said correction device, said counter and preset value correction device both It consists of a presettable BCD counter, and the
The number given by the CD counter is monitored by a second differentiator which detects a significant deviation below the count value giving a zero indication, and on the basis of said deviation said second differentiator: The balance is characterized in that the weighted correction pulse of the quick search is supplied to the preset value correction device until the differential range of the first differentiator is entered, so that the count value approaches the count value giving a zero indication in fairly large steps. automatic zero setting system. 13. Scales with digital display consisting of an electrical measuring bridge and weight data amplifier and a voltage/frequency converter and a presettable counter which is preset so that the scale reading is as close to zero as possible in the tare weight of the bridge mechanism. In automatic zerosetting systems, a correction voltage device is placed in the information path to the counter so that the count given by the counter is changed by a predetermined magnitude in one or the other direction from the count value giving a zero indication. A first differentiator is configured to detect the deviation of the first differentiator, and based on this, the differentiator supplies a correction command and a correction direction to the corrector. A preset value correction device is provided between the presetting switch and the differentiator, which monitors the value given by the counter, supplies a correction pulse and a correction direction to the correction device; The first differentiator supplies only one correction pulse every two measurement periods, and the correction data processing device determines that the correction pulse is generated and the direction is "up".
When the direction is ``down'', the path of the first weight pulse reaching the 2-splitting device through the 2-splitting device is blocked, and when the direction is ``down'', no correction pulse is generated.A weight pulse corresponding to every two measurement periods. 1. An automatic zero-setting system for a scale, characterized in that the automatic zero-setting system for a scale is adapted to brake a two-part device placed in the path of a weight pulse so as to inhibit the weight pulse. 14. According to claim 9 or any one of claims 12 to 13, characterized in that the correction pulse and the weight pulse entering the BCD counter have equal values corresponding to the weight. Automatic zero-setting system for the scales described.