JP4125431B2 - Moisture meter device with calibration function and calibration method in moisture meter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a moisture meter device for measuring the moisture content of the aggregate in the manufacture of ready-mixed concrete, in particular, calibration function that can measure initialization and moisture content to calibrate a predetermined timing device with high precision The present invention relates to a moisture meter device and a calibration method in a moisture meter device .
[0002]
[Prior art]
For ready-mixed concrete, the composition of cement, water, aggregate, etc. is adjusted according to the workability at the time of placing concrete and the strength of the concrete required for the structure. The strength and workability of concrete are governed by the slump value. When producing ready-mixed concrete in a ready-mixed concrete batcher plant, it is necessary to provide ready-made concrete having predetermined workability while ensuring the strength of the specified ready-made concrete.
[0003]
Factors affecting the slump value include surface water ratio (moisture value) of aggregates such as coarse aggregate and fine aggregate, particle size and temperature, water quality of kneaded water, accuracy of dynamic load measurement, type of cement, etc. It is done. Among them, the fluctuation of the moisture value of the aggregate is a major factor. Especially in concrete materials, the moisture content of aggregates is likely to change. Even if the amount of other materials is accurately controlled, the moisture content of aggregates, especially fine aggregates such as sand, etc. The slump value fluctuates due to fluctuations.
[0004]
Therefore, conventionally, the moisture content of the aggregate is measured by a moisture meter, and the amount of water to be supplied is corrected based on the measured value.
The moisture value of the aggregate can be detected by, for example, a kneading system disclosed in Japanese Patent Application Laid-Open No. 8-90549, and optimum strength and workability can be obtained based on the detected moisture value. It has become.
[0005]
This system is configured to provide a moisture meter that detects the moisture level using microwaves on the natural fall path of the aggregate. Based on the moisture value of the aggregate obtained with this moisture meter, It corrects the amount of water to be supplied among the three ratios.
[0006]
[Problems to be solved by the invention]
The moisture value obtained by the above system is important for the initial setting for accurately detecting the moisture of the aggregate used for manufacturing and improving the measurement accuracy. However, it is difficult and unrealistic to collect ideal data of this aggregate, and it does not lead to calibration curve registration. Therefore, the moisture content measurement could not be made sufficiently accurate.
[0007]
Specifically, it is difficult to obtain aggregated data used for manufacturing having different moisture content (at least 1% or more), and even if an ideal calibration curve is registered, bone used for manufacturing When the material changed, it was necessary to grasp and manage the correlation after registering another calibration curve. Therefore, even if the moisture meter is used, if this ideal data is registered and subsequent setting management is not sufficiently performed, the moisture measurement of the aggregate cannot be made highly accurate. FIG. 9 shows (a) an ideal calibration curve and (b) an actual calibration curve.
[0008]
Problem 1 ... It is difficult to collect data with sufficient dispersion for aggregates used for manufacturing in order to obtain a calibration curve (regression line). As a result, the direction of the calibration curve is reversed and the sensitivity is abnormal (excessive or insufficient).
Problem 2 ... Resetting (calibration) is required due to changes in the aggregate used for manufacturing and changes in the environment (such as ambient temperature).
[0009]
The present invention has been made to solve the above-described problems, and can measure moisture content with high accuracy using a calibration curve that is optimal for the aggregate to be measured. It is an object of the present invention to provide a moisture meter device with a calibration function that can be updated and maintain measurement accuracy, and a calibration method in the moisture meter device .
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a moisture meter sensor that measures the moisture content contained in the aggregate and outputs an output electrical property value corresponding to the measured moisture content, and an output electrical property of the moisture meter sensor A calibration curve indicating the relationship between the value and the moisture content corresponding to this value is stored in advance and the output electrical characteristic value output from the moisture meter sensor is referred to the calibration curve registered in the memory. The difference between the moisture content measurement value calculation means for obtaining the measured moisture content of the aggregate, and the estimated slump value of the ready-mixed concrete manufactured using the preset moisture content of the aggregate and the target value of the slump value From the theoretical formula model means to calculate the true moisture content of the aggregate from the difference between the unit water volume corresponding to the estimated value and the unit water volume corresponding to the target value The true moisture content obtained from the means, Monitors the correlation state with the measured moisture content obtained from the fraction measurement value calculation means, and shifts the corresponding moisture content part on the set calibration curve to the corresponding value when there is a difference of more than the correlation state There is provided a moisture meter device with a calibration function provided with an updating means.
[0011]
According to the above configuration , the calibration curve is automatically updated when data with high or low measured moisture content is continuously generated with respect to the estimated surface moisture content. The calibration curve can be updated to a suitable one, and the moisture content can always be measured with high accuracy in continuous use of the apparatus .
[0012]
The measured moisture content obtained based on the output electrical characteristic value output from the moisture meter sensor when the aggregate is not measured is set as the first point of the calibration curve, and the aggregate is actually subjected to a moisture value test in accordance with the prescribed regulations. It is preferable to further include initial setting means for setting the obtained measured moisture content as the second point of the calibration curve and initially setting the calibration curve obtained based on these two points in the storage unit .
[0013]
According to the above configuration, a calibration curve necessary for measuring the moisture value at the start of operation of the apparatus can be obtained easily and accurately based on the output electrical characteristic value of the moisture meter sensor, and the moisture content measurement accuracy can be improved. I can .
[0014]
According to the present invention, in the calibration method in the moisture meter device that converts the output electrical characteristic value output from the moisture meter sensor into a moisture content based on a preset calibration curve, the moisture content set beforehand in the aggregate The difference between the estimated slump value and the target value of the slump value of the ready- mixed concrete that is blended using the rate is obtained as the difference between the unit water amount corresponding to the estimated value and the unit water amount corresponding to the target value. Calculate the true moisture content of the aggregate from the difference in the calculated unit water amount, monitor the correlation state between the calculated true moisture content and the converted measured moisture content, and the correlation state is more than a predetermined difference There is provided a calibration method in a moisture meter device that shifts a corresponding moisture content portion on a set calibration curve to a corresponding value when there is a calibration curve.
[0015]
According to the above configuration, the correlation between the surface moisture content and the measured moisture content is monitored, and when the correlation is lost, the calibration process corresponding to the measured moisture content is updated so that it is always used. It becomes possible to update to a calibration curve suitable for the aggregate .
[0016]
The measured moisture content obtained based on the output electrical characteristic value output from the moisture meter sensor when the aggregate is not measured is set as the first point of the calibration curve, and the aggregate is actually subjected to a moisture value test in accordance with the prescribed regulations. It is preferable to set the obtained moisture content as the second point of the calibration curve and to initially set the calibration curve obtained based on these two points .
[0017]
According to the above configuration, the calibration curve necessary for measuring the moisture value can be created by obtaining data of a minimum of two points, one of which is based on the output electrical characteristic value of the moisture meter. An accurate calibration curve can be initially set simply by measuring the water content of the sample .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is characterized by the following two points.
1. Use the characteristics of the moisture sensor to make initial settings easily.
2. A true surface water estimation model is constructed from the sand surface water estimation data output by the theoretical model of the slump controller, and the device automatically updates the calibration data.
[0019]
FIG. 1 is a configuration diagram showing a moisture meter device with a calibration function of the present invention. The apparatus generally includes a moisture meter sensor 1, an I / F box 2, a slump control device 3, and a plant operation panel 4. This moisture meter automatic calibration apparatus can be applied to a kneading system or the like for producing the above-mentioned ready-mixed concrete. At this time, as shown in the figure, a plurality of moisture meter sensors 1 can be provided corresponding to the number of storage bins for each aggregate.
[0020]
As the moisture meter sensor 1, for example, a microwave high-precision moisture meter is used. This moisture meter irradiates the aggregate with microwaves, and measures and outputs a moisture value (%) based on the amount of energy absorption. The moisture sensor 1 is housed in a sturdy stainless steel box to which a ceramic plate 1a is attached. And this moisture meter sensor 1 is provided in the natural fall path between the aggregate storage bin and the lower weighing hopper, the ceramic plate 1a portion is arranged facing this natural fall path, and the micrometer is passed through the plate 1a. Wave energy is released and aggregates flow over it to measure the moisture value.
[0021]
The I / F box 2 supplies a predetermined voltage for operating the moisture meter sensor 1 and converts the measurement output (voltage value) of the moisture meter sensor 1 into data and outputs it to the slump control device 3.
[0022]
The slump control device 3 manages the moisture value (surface water content) of the aggregate based on the voltage value input via the I / F box 2. The slump control device 3 has a moisture content measurement function, a slump estimation function, and a slump control function, and manages the moisture value of the aggregate. As will be described in detail later, a theoretical model of the slump controller is provided, and a true surface water estimation model is constructed from sand surface water estimation data output by the theoretical model. Then, the theoretical model executes the initial setting and automatic updating (calibration) for increasing the moisture value of the aggregate to be used.
[0023]
The slump control device 3 is a general-purpose computer device, and includes a processing means 3a that includes a CPU, a ROM, a RAM, and the like, and that executes a software program that realizes the management processing function. A display unit 3c such as a CRT that displays operation contents and management process contents (calibration setting screen) and the like and a printing unit 3d such as a printer that prints out the management process contents and the like are roughly configured.
[0024]
Next, the initial setting in the above configuration will be described.
In the initial setting required when the apparatus is introduced, a calibration curve for obtaining at least two measurement outputs outputted from the moisture meter sensor 1 and obtaining the surface water content of the aggregate is generated. FIG. 2 is a diagram showing the initial setting, and FIG. 2A shows a calibration curve at the time of initial setting.
[0025]
About the first point: When the moisture meter sensor 1 supplies a predetermined voltage (± 15 V) for operating the moisture meter sensor 1 from the I / F box 2 in the non-measurement state (sand empty state) of the aggregate, the moisture meter sensor 1 is predetermined. The voltage (11-12V) is output. As shown in the data table of FIG. 2B, the I / F box 2 converts the input voltage into, for example, 0 to 5 V (0 to 20 mA) and outputs the data. At this time, the moisture meter sensor 1 outputs 5V data from the I / F box 2 when the surface water content is close to 0%. In the present invention, this data (5 V) is used as data for the absolutely dry state of the aggregate (surface water ratio 0%), and is registered as one point for generating a calibration curve.
[0026]
The above-mentioned absolutely dry state refers to a state in which the aggregate is dried by heating to a constant weight with a dryer at 100 to 110 ° C., and all the water contained in the voids in the aggregate grain is removed. Say. That is, the moisture value is 0%.
Note that the moisture content of the aggregate increases in the order of air-dried state, surface-dried state, and wet state.
[0027]
Regarding the second point: At least two points are required to generate a calibration curve, and the second point is obtained by registering the surface water content of the collected aggregate by a test. For example, as shown in FIG. 2B, when the surface water percentage of the collected aggregate is 4.5%, the output voltage value 2 of the moisture meter sensor 1 (I / F box 2) corresponding to this surface water percentage. .Register 2V. In this way, a calibration curve is generated by performing a surface water ratio test of at least one point.
[0028]
FIG. 3 is a flowchart showing the initial setting process of the moisture meter. This initial setting will be described. First, moisture meter sensor output electrical characteristics (voltage, electrical resistance, current, etc.) at a moisture value of 0% (absolute dry state of fine aggregate) are set as one point of calibration data (S1). Next, the fine aggregate at the time of measurement is sampled (S2).
[0029]
Next, a surface water ratio test of the fine aggregate based on the JIS standard is performed (S3).
There are two test methods, a mass method and a volume method. Then, the volume C (ml) of the sample is obtained by the sample mass A / surface specific gravity B. From the container + water mass = D (g) and the container + water + sample volume = E (g), A + DE = replaced water amount F (g) is obtained. Thereby, (F−C) / (A−F) × 100 = surface water ratio G (%) is obtained. The deviation I (%) with respect to the average value H (%) needs to be 0.3% or less.
[0030]
Next, the surface water ratio test result obtained above and the output electric characteristic value of the moisture meter sensor 1 at the time of measurement (for example, the voltage value is set in the slump control device 3 as calibration data (S4). The moisture meter sensor 1 output electrical characteristic value to be set may be an electrical resistance value, a current value, or the like.
[0031]
And it is performed until the sampling frequency of the sample reaches N times (arbitrary number of 1 or more), and when it reaches N times (S5-Yes), the initial setting is finished.
The calibration data obtained from the surface water content test result may be set by obtaining an average value of sampling data.
[0032]
FIG. 4 is a diagram showing a setting screen at the time of the initial setting.
As shown in the figure, an initial setting screen is displayed on the display means 3c, and the numerical setting items for the two points are displayed on the left side of the screen, and a calibration curve is displayed on the right side corresponding to the set numerical values. Is displayed. Also, a plurality of calibration curves for each aggregate (sand) can be set and registered so as to be displayed at the top of the screen.
[0033]
Next, automatic calibration will be described.
The function of managing the slump of the apparatus included in the slump control apparatus 3 is described in Japanese Patent Application Laid-Open No. 8-335101 (name; intelligent process management apparatus and intelligent process management method) filed by the same applicant as the present application.
[0034]
An outline of this apparatus will be described. It is not easy to manage raw concrete and slump using the slump value as a management index, and the slump value varies depending on the blending ratio of water, the particle size distribution and shape of the aggregate, mixing time, temperature conditions, and the like. The weighing of various materials for producing ready-mixed concrete is automated at the above-mentioned plant and has a predetermined accuracy, but the amount of moisture contained in aggregates, particularly fine aggregates (sand), which has a great influence on the determination of the total amount of moisture. Fluctuations could not be suppressed, which was a problem with slump management.
[0035]
In the blending calculation to determine the blending ratio of ready-mixed concrete, it is necessary to calculate the amount of water brought into the aggregate by assuming the surface water ratio (surface water ratio) for each aggregate and multiplying it by the amount of aggregate used. Determine the water measurement by subtracting from the total amount of water. This surface water ratio must be finely adjusted based on the JIS standard (JIS A1101), in addition to regular inspections at the time of sampling when using materials, as well as by adjusting the dynamics for the purpose of correcting the composition at the time of use. There is. In particular, the amount of water brought in per unit weight is large due to the size of the specific surface area, and it is not easy to grasp the dynamics of the surface water of fine aggregates, which has a decisive factor in slump management. It is necessary to carry out accurate slump management in association with subtle changes in particle size distribution, particle shape, etc.), temperature, and the like. The surface water content of aggregates is measured in accordance with JIS regulations (JIS A1125). In addition to fixed point observation, which is usually twice a day, noise associated with sample sampling can be completely eliminated from the target aggregate. The current situation is that it is difficult and remains at the stage of material acceptance inspection.
[0036]
In order to cope with this, the apparatus disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-335101 is configured to output a guidance value for plant operation based on the operation status, operation history, dynamic tendency, and the like of the plant. The device is a theoretical model that theoretically determines the average guidance value for setting the surface water ratio, a neural network model that uses the learning formula to determine the average guidance value for the surface water ratio, and an inference formula for the guidance value for setting the surface water ratio. Fuzzy control model to judge in the meantime, the judgment result of the theoretical formula model and the neuro model is averaged, the integration result of the integrated module is verified with the judgment result of the fuzzy control model, and the integrated module etc. is configured to correct the guidance value ing.
[0037]
And in this invention, the theoretical formula model of the said apparatus is provided.
About the function of the theoretical model ... The cause of the slump difference obtained by subtracting the target slump value from the estimated slump value is based on the true value of the surface water ratio estimate of the fine aggregate that is the basis of the blending correction when measuring the kneaded material It is assumed that this is due to the divergence. Therefore, at the time of moisture content measurement processing by the plant (current batch), the true fine aggregate surface water rate is estimated on the basis of the set fine surface oil rate.
In the theoretical model, from the input slump data, it is assumed that the slump difference between the estimated slump value and the target slump value is due to the excessive amount of water obtained from the latest measurement results. Then, the surface water ratio to be operated in the next calculation is calculated, and an operation for obtaining and stabilizing the change amount with the currently set value is executed. The amount of change is called a guidance value.
[0038]
The configuration of automatic update (calibration), which is the second feature point of the present invention, will be described below. The measurement of the moisture value of the aggregate and the slump value management processing by the apparatus of the present invention are performed using the calibration curve set as described above. However, due to the use of the apparatus over time, it becomes increasingly difficult to use this calibration curve. That is, when the aggregate is changed from the initially set aggregate to another aggregate, or when the density of the aggregate is changed, a highly accurate moisture content measurement cannot be performed with the registered calibration curve. For this reason, it is necessary to update the calibration curve. The update (calibration) function in the apparatus of the present invention allows both automatic update automatically executed by the apparatus in addition to manual update based on the operator's judgment as in the existing apparatus.
[0039]
The automatic update process consists of three steps: (1) estimating the surface water content of the aggregate, (2) grasping the correlation between the estimated surface water content and the measured water content, and (3) calibrating the calibration curve. To do.
[0040]
(1) About estimation of surface water ratio of aggregate ... The theoretical model of the device is calculated by replacing the slump difference with the amount of water. FIG. 5 is a curve diagram showing the relationship between these slumps and unit water volume. Then, using the slump estimation function in the theoretical formula model, the surface water percentage of the sand calculated based on the data obtained from the basic composition of the plant is estimated. Then, a unit water amount difference (amount of water change) corresponding to the slump difference between the target slump and the estimated slump is obtained.
[0041]
(2) At this time, a correlation between the estimated surface moisture content and the measured moisture content is taken. As shown in FIG. 6, since the measured moisture content is shifted to be lower or higher than the estimated surface moisture content, this correlation is grasped (a correlation coefficient is obtained).
[0042]
(3) Then, calibration is performed and the calibration curve is updated. Based on the correlation coefficient between the estimated surface water content and the measured water content, the calibration is updated when a large number of data having a high (or low) measured water content is continuously generated with respect to the estimated surface water content. FIG. 7 is a diagram showing the calibration update. When a large number of data having a high (or low) measured moisture content with respect to the estimated surface moisture content is continuously generated with respect to the initially set calibration curve, Update the calibration curve.
[0043]
FIG. 8 is a flowchart showing the calibration procedure.
In the calibration, it is determined whether or not to perform the calibration after a predetermined period of time during which the apparatus has been used or when the aggregate is changed.
First, the correlation between the estimated surface water content and the measured water content obtained from the moisture sensor 1 is grasped (T1). In the state where the correlation is established, calibration is not necessary. Calibration is performed when the reliability of the measured moisture content value decreases. This execution can be selected from manual update (T2-manual) based on the operator's judgment and automatic device update (T2-automatic).
[0044]
Hereinafter, each procedure of automatic update will be described. First, it is determined whether the measured surface water ratio is within the set range (± X.X%) or out of the estimated surface water ratio (T3). As a result, if it is within the range (T3-within range), it is assumed that it is normal and automatic updating is not performed.
[0045]
On the other hand, when the measured surface water ratio is a large value exceeding the set range (± X.X%) with respect to the estimated surface water ratio (T3−higher than the range), it is temporarily determined to be abnormal. Then, this abnormal occurrence count is incremented (T4). Until this count reaches the predetermined number N set in advance, the process proceeds to T3 and the comparison process based on the new measurement value is re-executed. However, when the occurrence of the temporary abnormality reaches the predetermined number N (T5-equal). ), Calibration is executed (T6).
[0046]
Further, even when the measured surface water ratio is a small value less than or equal to the set range (± X.X%) with respect to the estimated surface water ratio (T3−lower than the range), it is temporarily determined to be abnormal. Then, this abnormal occurrence count is incremented (T7). Until this count reaches the predetermined number M set in advance, the process proceeds to T3 and the comparison process based on the new measurement value is re-executed. However, when the occurrence of the temporary abnormality reaches the predetermined number M (T8-equal) ), Calibration is executed (T6).
[0047]
The calibration process uses the true surface water ratio output by the theoretical model, obtains the output electric characteristic value (for example, the voltage value) of the moisture meter sensor 1 corresponding to the true surface water ratio, and calculates the calibration curve. Update. In updating the calibration curve, the second data at the time of the initial setting is updated. For example, as shown in FIG. 7, the measured moisture content is higher than the estimated surface moisture content with respect to the initially set calibration curve ( On the basis of the continuous generation of data (or low), based on the surface water ratio obtained from the theoretical model, the calibration curve at the location corresponding to this second surface water ratio is shifted up and down. Here, the initial value of the first point (water content 0%, at 5 V) is not changed. As a result of this shift, the first curve is the same as the initially set calibration curve, but the second curve is different up and down, so that the slope is varied and updated and stored.
[0048]
With this automatic update, even if the device continues to be used for a long period of time, it can be updated to adapt to the aggregate that uses the calibration curve itself, and the moisture value of the aggregate is always maintained with high accuracy. Will be able to continue.
[0049]
In the initial setting and the automatic update described in the above embodiment, regarding the aggregate to be used, if a large number of effective data placed on the calibration curve can be collected, the accuracy of the calibration curve can be further improved, Compared to generating a calibration curve with only two points, it enables more accurate moisture measurement. Therefore, the apparatus is not limited to the second point, and if data after the third point (data having different surface water ratios) can be obtained, this can be input and a calibration curve can be created and updated. ing.
[0050]
By the way, although the said embodiment demonstrated the structure using a microwave as an example as the moisture meter sensor 1, it is not restricted to this. The moisture meter sensor 1 may be a dielectric type that detects electromagnetic permitting to detect a dielectric constant and converts the moisture content into a moisture content, a radioisotope type that measures a hydrogen concentration by irradiating weak radiation, Even with an infrared sensor that projects light of an absorption wavelength and a comparison wavelength and measures the reflected energy, the moisture content can be measured with high accuracy by the above calibration as well. .
[0051]
【The invention's effect】
According to the present invention, there is an effect that the human work burden for maintaining accuracy in the operation of the moisture meter can be greatly reduced. In addition, since the calibration data can be automatically updated based on the latest moisture characteristics of the aggregate from the daily operation data of the plant, the moisture meter accuracy can be constantly maintained.
Accordingly, the surface water management of the fine aggregate can be performed with high accuracy in the production of ready-mixed concrete, and the concrete excellent in desired slump, strength, fluidity, durability, and workability can be manufactured.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of a moisture meter device with a calibration function of the present invention.
FIG. 2 is a diagram illustrating an initial setting procedure.
FIG. 3 is a flowchart showing a procedure of initial setting processing;
FIG. 4 is a diagram showing an initial setting screen.
FIG. 5 is a diagram showing the relationship between slump and unit water amount during calibration.
FIG. 6 is a diagram showing a correlation between an estimated surface water content and a measured water content during calibration.
FIG. 7 is a diagram illustrating updating of a calibration curve at the time of calibration.
FIG. 8 is a flowchart showing a calibration procedure.
FIG. 9 is a diagram showing an ideal calibration curve and an actual calibration curve.
[Explanation of symbols]
1 Moisture meter sensor 2 I / F box 3 Slump control device 4 Control panel

Claims (4)

A moisture meter sensor that measures the moisture content contained in the aggregate and outputs an output electrical characteristic value corresponding to the measured moisture content;
A storage unit in which a calibration curve indicating the relationship between the output electric characteristic value of the moisture meter sensor and the moisture content corresponding thereto is preset and registered,
Moisture content measurement value calculation means for obtaining the measured moisture content of the aggregate with reference to the calibration curve registered in the storage unit from the output electrical characteristic value output from the moisture meter sensor;
From the difference between the estimated slump value of the ready- mixed concrete manufactured using the preset moisture content of the aggregate and the target value of the slump value, the unit water amount corresponding to the estimated value and the target A theoretical model means for obtaining a difference from the unit water amount corresponding to the value, and calculating a true moisture content of the aggregate from the obtained unit water amount difference ;
The correlation state between the true moisture content obtained from the theoretical model means and the measured moisture content obtained from the moisture content measurement value calculation means is monitored, and when there is a difference of a predetermined value or more in the correlation state, Updating means for shifting the corresponding moisture content portion on the set calibration curve to a corresponding value;
A moisture meter device with a calibration function, comprising:   The measured moisture content obtained based on the output electrical characteristic value output from the moisture meter sensor when the aggregate is not measured is set as the first point of the calibration curve, and the aggregate is actually subjected to a moisture value test in accordance with a predetermined rule. The measurement moisture content obtained as described above is set as the second point of the calibration curve, and further includes an initial setting means for initially setting the calibration curve obtained based on these two points in the storage unit. The moisture meter device with a calibration function according to claim 1. In the calibration method in the moisture meter device that converts the output electrical characteristic value output from the moisture meter sensor into a moisture content based on a preset calibration curve,
From the difference between the value of the slump value of the ready- mixed concrete produced by using the preset moisture content of the aggregate and the target value of the slump value, the unit water amount corresponding to the estimated value and the target value To calculate the true moisture content of the aggregate from the difference in unit water amount obtained ,
The correlation state between the calculated true moisture content and the converted moisture content measured is monitored, and when there is a predetermined difference or more in the correlation state, the corresponding moisture content on the set calibration curve A calibration method in a moisture meter device, wherein the portion is shifted to a corresponding value.   The measured moisture content obtained based on the output electrical characteristic value output from the moisture meter sensor when the aggregate is not measured is set as the first point of the calibration curve, and the aggregate is actually subjected to a moisture value test in accordance with a predetermined rule. 4. The moisture meter device calibration according to claim 3, wherein the measured moisture content is set as a second point of the calibration curve, and a calibration curve obtained based on these two points is initially set. Method.

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