KR101519356B1 - Calibration Device Of The Sensor - Google Patents

Calibration Device Of The Sensor Download PDF

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Publication number
KR101519356B1
KR101519356B1 KR1020140138068A KR20140138068A KR101519356B1 KR 101519356 B1 KR101519356 B1 KR 101519356B1 KR 1020140138068 A KR1020140138068 A KR 1020140138068A KR 20140138068 A KR20140138068 A KR 20140138068A KR 101519356 B1 KR101519356 B1 KR 101519356B1
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South Korea
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calibration
sensor
meter
μs
value
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KR1020140138068A
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Korean (ko)
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길주형
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길주형
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D11/00Component parts of measuring arrangements not specially adapted for a specific variable
    • G01D11/24Housings ; Casings for instruments
    • G01D11/245Housings for sensors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D18/00Testing or calibrating of apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
    • G01D18/002Automatic recalibration
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means
    • G01N27/02Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means by investigating the impedance of the material
    • G01N27/04Investigating or analysing materials by the use of electric, electro-chemical, or magnetic means by investigating the impedance of the material by investigating resistance

Abstract

The present invention relates to a calibration apparatus for a sensor capable of easily performing a slope calibration operation of a sensor and an abnormality using a resistor having a resistance value corresponding to a measurement range of a standard solution without using a standard solution which is expensive and has a significant change in physical properties More specifically, a resistor having a resistance value corresponding to the measurement range value of the standard solution or having a resistance value of a cell constant is connected to the first and second electrodes of the sensor, and the error rate of the resistance value of the resistance value By repeating the calibration process on the meter, a calibration device is constructed to calibrate the sensor and meter for zero calibration and slope (span) calibration; By using a resistor instead of the standard solution, it is easy to carry and handle, and it has the effect of maintaining measurement accuracy and reliability even if it is used repeatedly for a long time.

Description

Calibration Device of the Sensor [0002]

The present invention relates to a calibration apparatus for a sensor, and more particularly, to a calibration apparatus for a sensor, which uses a variety of resistors having an inherent resistance value when calibrating a slope (span) by repeated measurement so as to minimize an error rate generated by a meter or a sensor by connecting the calibrated meter And more particularly, to a sensor calibration apparatus capable of determining a calibration operation of a sensor and an abnormality thereof and applicable to various sensors.

A water quality sensor for measuring salinity, total dissolved solids (TDS), resistivity and various ions among various characteristics of water quality by using resistivity variation of water quality is disclosed.

Particularly, there are DO, COD, pH and electrical conductivity, which is a measure of the degree of water pollution, including electrical conductivity, which includes the inclusion of ionic pollutants in water And is used as a measure of representative water pollution degree in that it provides direct information on the degree of water pollution.

This electrical conductivity is the degree to which a solution can carry a current and is an item that can quickly evaluate the ionic strength in a solution. It is represented by the reciprocal of the electric resistance, ohm-1 or mho, Units are commonly used.

The measurement principle is based on the fact that a constant voltage is applied to two electrodes in a solution, and the applied voltage causes the current to flow. The magnitude of the current flowing depends on the conductivity of the solution. As shown in FIG.

R (?) = (? · L) / A

(Ρ: resistance (Ω · cm), ℓ: distance between two electrodes (cm), and A: sectional area (cm 2)

The electrical conductivity L can be expressed by the following equation.

L = 1 / R = (A / l) K

(Where K (= 1 / ρ) is the specific conductivity (mho.cm), and the standard of the cell is constant when using the same measuring system.

Therefore, the measurement result is expressed as the electrical conductivity value (μmhos / cm) of the sample by multiplying the electrical conductivity value (mho) of the measured sample by the cell constant (cm-1). Currently, however, the international system of units, mS / m (millisimens / meter), also shows the measurement results in μS / cm (microsimens / centimeter), where mS / m = 10 μS / cm (or 10 μmhos / cm). Also, since the electrical conductivity is influenced by the temperature difference (about 2% / ℃), the value is converted into the value at 25 ℃

The cell constant is measured and the cell is cleaned. The cell is washed 2-3 times with water, and the cell is shaked 2 to 3 times with the potassium chloride solution (0.0001 M when the conductivity of the sample is low and 0.01 M when the conductivity of the sample is low) And the electric conductivity is measured with the temperature set at 25 ± 0.5 ° C. Subsequently, while changing the potassium chloride solution, repeated measurements are taken until the deviation between the measured values becomes equal to or less than 3% at the same temperature, and the average value is taken to calculate the cell constant.

C = (LKCl + LH2O) / Lx

(ΜS / cm) of the used potassium chloride standard solution, LH2O: conductivity value (μS / cm) of water used in preparing the potassium chloride solution)

In this case, the normal cell is suitable for most of the sample measurement using the cell constant 1 to 2, but in the case of the specific sample, refer to Table 1 showing the cell constant and the measuring range below, and the electric conductivity 1 = 1,000,000 Ω cm 25 ° C. .

Cell number (cm -1) Measurement range (μS / cm) 0.01 20 or less 0.1 1 to 20 One 10 ~ 2,000 10 100 ~ 20,000 50 1,000 to 200,000

In order to measure the electric conductivity as described above, a meter for measuring the measured value of the conductivity sensor and a sensor for measuring the conductivity of the water quality are required. The meter uses a standard source input device and a resistance box as an example. And the slope (span) correction is carried out using the test apparatus of FIG.

As shown in FIG. 1, for example, in the slope calibration process of the meter 200, six resistive switches 302 for selecting a resistance value for each position are formed so that a resistance value can be generated up to 100,000 OMEGA After the resistor terminals 301 of the resistor box 300 are connected to the first and second meter terminals 201 and 202 of the meter 200 and the resistor switches 302 of the resistor box 300 are all set to ' (Zero: 0) after the meter 200 is set to zero, and the zero value of the meter 200 is displayed so that the zero calibration is performed.

Then, when the cell constant K = 1 and the measurement range is, for example, 0 μS to 20000 μS, using the resistance switch 302 of the resistance box 300, the measurement range is 0 μS, 50 μS, 200 μS, 500 μS, 1000 μS, The resistance value of the resistance switch 302 in the resistance box 300 is set to 0 S, 50 S, 200 S, 500 S, 1000,, 2000,, 10000, and 20000 S, The resistance switch 302 is adjusted so as to be 20 KΩ, 5 KΩ, 2 KΩ, 1 KΩ, 500 QΩ, 100 QΩ, and 50 QΩ to randomly and repeatedly perform span calibration for calibrating the meter 200 regardless of the order of measurement ranges.

As shown in FIG. 2, the calibration of the meter 200 indicates the relationship between the selection resistance of the resistance box 300 and the measured value displayed in the meter 200, as shown in the graph.

The horizontal direction of the graph indicates the resistance value of the resistance box 300 and the vertical direction indicates 0 μS, 50 μS, 200 μS, 500 μS, 1000 μS, 2000 μS, 10000 μS and 20000 μS when the measurement range is 0 μS to 20000 μS. Each indicating value according to the selected resistance value of the resistance box 300 for the resistance box 300 for the meter 200 according to the measurement range (μS) 0 μS, 50 μS, 200 μS, 500 μS, 1000 μS, 20 μΩ, 5 KΩ, 2 KΩ, 1 KΩ, 500 KΩ, 2000 μS, 10000 μS, and 20000 μS, respectively.

That is, in the resistance box 300, a resistance value corresponding to a measurement range of 0 μS, 50 μS, 200 μS, 500 μS, 1000 μS, 2000 μS, 10000 μS, and 20000 μS is controlled through the resistance switch 302 of the resistance switch 302, 50 S, 200,, 500 S, 1000,, 2000 S, 10000, and 20000 S corresponding to the resistance value is displayed on the meter 200 after selecting 20,, 5 Ω, 2 Ω, 1 Ω, 500,, 100,, .

If the indication value differs from the measurement range value on the basis of the calibration result 0 μS, the measurement point where the resistance value and the measurement range meet is connected through the iterative process that matches the measurement range value through the span setting of the meter 200 The slope calibration of the meter 200 is completed so as to form a complete calibration line according to the magnitude of the resistance value and the measurement range based on 0 μS.

Thereafter, the electric conductivity sensor measures the value corresponding to the '0' indicating value, the repetitive zero calibration and the numerical value corresponding to the specific indicating value by using a separate standard precision measuring device, and repeatedly The signal line for connection to the meter with the in-span calibration completed is, for example, an anode lead, a cathode lead (K), and two temperature sensor (T) terminals for temperature compensation of the temperature sensor , And ground (E) terminal, connect it properly to the meter.

At this time, even if the slope calibration of the meter is completed and the sensor is also connected to the signal line for the water quality measurement in the state that the calibration is completed, the error value of the meter or the sensor is added to increase the error value. In order to solve this problem, the slope calibration of the meter and the sensor is performed by using a plurality of standard solutions having different conductivity values.

That is, the slope calibration of the meter and the sensor is performed according to the correlation between the conductivity value corresponding to the cell constant value and the measurement range (unit: μS / cm) corresponding to the conductivity value .

Thus, when the slope calibration of the meter is completed, the sensor for measuring the water quality characteristics using the change of the resistivity must undergo calibration for accurate measurement. Until recently, a standard solution The calibration method was as follows.

As shown in FIG. 3, the table shows the relationship between the cell constant and the measurement range. As shown in FIG. 4, the graph includes a resistance value corresponding to a cell constant value, (Range: (μS)) of the measured conductivity.

In this way, even if the meter and the sensor are individually calibrated, the error range due to the tolerance error may be increased. To further reduce the error, in order to calibrate the meter and the sensor, For example, when the cell constant K = 1, the measurement range is usually from 0 to 20000 μS, and the measured resistance value in the cell constant K = 1 according to the measurement range is a theoretical value.

In order to calibrate the slope of the meter and the sensor, in order to display a value of zero as shown in the graph, for example, a signal line connecting the zero sensor or the meter and the sensor may be short-circuited, or the sensor may be exposed in the air to zero- And the conductivity standard solution was measured with a cell constant of K = 1 as an example. The measurement range is 1 μS, 10 μS, 20 μS, 50 μS, 100 μS, 200 μS, 500 μS, 1000 μS, 2000 μS, 5000 μS, 10000 μS, The resistance values according to the cell constant values are shown in the table as 1MΩ, 100KΩ, 50KΩ, 20KΩ, 10KΩ, 5KΩ, 2KΩ, 1KΩ, 500Ω, 200Ω, 100Ω and 50Ω respectively.

The cell constant value and the measurement range are theoretical values. For the slope calibration of the meter and the sensor, for example, the horizontal direction of the graph is a cell constant corresponding to 4K, 2K, 1.333K, And the vertical direction indicates the measurement range corresponding to each cell constant value as 250 μS, 500 μS, 750 μS, and 1000 μS based on the value of 0, respectively.

If there is a standard solution with 250 μS, 500 μS, 750 μS, 1000 μS measurement range when calibrating the meter and sensor under the same condition as the above graph, if the sensor is measured in the state of being immersed in each standard solution, The indicated values are indicated as 250 μS, 500 μS, 750 μS, and 1000 μS, respectively.

If the standard solution is 248μS, 568μS, 746μS, or 998μS, for example, when the standard solution is measured by the sensor, the standard solution of 250μS, 500μS, 750μS, The zero calibration was repeated to expose the sensor to the air or to short the meter and the signal line to 0 μS. The error rate was reduced according to the μS value of the standard solution and the measurement interval Calibration Calibrate to achieve a straight line.

However, the method of calibrating the sensor using the standard solution according to the prior art is such that when the standard solution is transferred to another container for calibrating the sensor in the state where the solution is expensive and sold, the foreign substances in the container or various components in the air are dissolved So that there is a problem that the reliability of the measurement accuracy for calibration is reduced because the characteristic measurement range value of the standard solution is changed.

In addition, a method of calibrating a sensor using a liquid standard solution according to the related art has a troublesome problem in that the sensor must be cleaned thoroughly with distilled water or the like and then completely dried.

In addition, the method of calibrating the sensor using the liquid standard solution according to the related art has a problem in that it is impossible to set the measurement range and the accurate measurement range for the initial slope calibration.

In addition, since the standard solution has various types indicating the manufacturer or the measurement range value, it is inconvenient for the user to carry the standard solution at all times due to various types and large volumes for calibrating the sensor and meter, There is no way to calibrate the meter and the sensor.

This makes it possible to maintain the calibration performance constantly over a long period of use without affecting the measured value since it is easy to handle and maintain, easy to calibrate, unaffected by external influences, Is required.

1. Registration number 10-1164442 (Registration date July 04, 2012) 2. Registration number 10-1325994 (Registration date October 31, 2013)

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems of the prior art, and it is an object of the present invention to provide a calibration device of a sensor capable of calibrating a meter and a sensor by replacing a standard solution with a standard precision resistor used for calibration of a meter and a sensor The purpose is to provide.

It is another object of the present invention to provide a method of measuring a resistance value of a sensor by connecting a resistance terminal to a first electrode and a second electrode of a sensor having various shapes and characteristics to determine whether a measurement range corresponding to a resistance value of the theoretical cell constant is indicated, It is used to determine the slope calibration and the abnormality of the sensor or meter through the setting.

It is a further object of the present invention to shield the orthodontic appliance so as not to affect the resistance by blocking the influence on the surrounding electric field or magnetic field.

It is another object of the present invention to provide a method for repeatedly performing selective slope correction using a plurality of resistors having various resistance values.

It is a further object of the present invention to improve the accuracy of measurement values by using a resistance that replaces a standard solution which is expensive and changes in properties due to exposure to air during measurement, .

In order to achieve the above object, the present invention provides a method for measuring a salinity of a solution, a total dissolved solid (TDS), a resistivity, a conductivity, and various ions by using a resistivity change in a sensor body having a signal line connected to a meter An apparatus for calibrating a sensor in which a first electrode and a second electrode are formed, the method comprising: connecting a first electrode and a second electrode of the sensor to a sensor, And the error rate of the resistance value of the resistance and the resistance is calibrated by zero point adjustment and span adjustment in the meter to form a calibration device that calibrates the zero point and the slope (span) of the sensor and the meter period, The first and second calibration terminals are connected to the first and second terminals of the calibration resistor, respectively. When a plurality of the calibration resistances are constituted by the first calibration resistor to the nth calibration resistor, Through the hip and provides a calibration of the sensor device, characterized in that one of the first calibration resistor ~ n the calibration resistor is configured such that the contact selected to be the resistance value measurement in the sensor.

As described above, the present invention has the effect of improving the accuracy of the measured value by using a resistor having a resistance value of a standard solution in which the value is expensive and the property changes due to exposure to air during measurement, and is cheap and can be repeatedly used for a long period of time.

In addition, it is possible to connect different resistances to the first and second electrodes of the sensor having various shapes and characteristics, to calibrate the setting of the meter using the measured values of the resistance values, and to perform the slope calibration of the sensor and the meter. There is an effect that it is possible to easily judge whether the sensor and the meter are correct or not.

In addition, the calibration device is shielded to block the influence on the surrounding electric field or the magnetic field, so that the resistance is not changed, and the accuracy of calibration can be secured.

Another object of the present invention is to increase the reliability of calibration by repeatedly performing a selective calibration operation using a plurality of resistors having various resistance values.

Fig. 1 is a diagram showing a configuration in which a meter is slope-corrected using a resistance box,
FIG. 2 is a graph showing an example by slope calibration of a meter,
3 is a table showing the relationship between the cell constant and the measurement range,
FIG. 4 is a slope calibration graph of a sensor and a meter showing a slope of a conductivity measurement value according to a cell constant value and a measurement range using a standard solution,
5 is a photograph of an example of a commercially available standard solution,
6 is a schematic diagram for calibrating a slope calibration of a sensor and meter according to the present invention,
FIG. 7 is a cross-sectional view of a first calibration terminal and a calibration resistor according to the present invention,
8 is a sectional view of a measurement example of a state where first and second calibration terminals according to the present invention and a case surrounding a calibration resistor are formed;
FIG. 9 is a conceptual diagram of a calibration apparatus in which a selection control unit is formed,
FIG. 10 is a conceptual diagram of a state in which a selection controller of a calibration apparatus according to the present invention is operated;
11 is a conceptual diagram for calibrating a meter using a calibration apparatus according to the present invention,
12 is a slope calibration graph of a sensor and a meter showing a slope of a conductivity measurement value according to a cell constant value and a measurement range using a calibration apparatus according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

6 to 11, the calibration apparatus of the present invention includes a sensor body 12 provided with a signal line 11 connected to a meter 200, a salinity of a solution, a total dissolved solid matter (TDS The present invention relates to an apparatus for calibrating a sensor 10 in which first and second electrodes 13 and 14 for measuring resistivity, conductivity, and various ions are measured by using a change in resistivity of a solution, The calibration resistor 40 is repeatedly connected to the first and second electrodes 13 and 14 so that the resistance value of the calibration resistor 40 is measured by the sensor 10, And adjusts the slope between the sensor (10) and the meter (200) through the span adjustment.

Here, the sensor 10 includes a salinity meter for measuring salinity, a TDS sensor for measuring solid matter, a resistivity sensor for indicating the reciprocal of the conductivity, a conductivity sensor for measuring the degree of conduction of the solution, An ion measurement sensor may be constructed as an example.

The sensor 10 is generally configured to measure various characteristics of water quality and includes a first electrode 13 and a second electrode 13 on a sensor body 12 having a signal line 11 connected to the meter 200 14 will be described as an example.

At this time, a measurement range value of a standard solution used for calibration is substituted into the first and second electrodes 13 and 14 of the sensor 10, and a resistance having a resistance value obtained through calculation is connected to the sensor 10 The error rate between the indication value measured by the sensor 10 and the measurement range according to each resistance value in the table shown in FIG. 3 is spanned by the meter 200 to repeat the process of setting the sensor 10 and the meter 200 Thereby constituting a calibration apparatus 100 for correcting a slope (span).

That is, the calibration apparatus 100 includes first and second calibration terminals 20 and 30, which contact the first and second electrodes 13 and 14, respectively, with a calibration value having a resistance value corresponding to the resistance value of the standard solution. And to the first and second terminals 41 and 42 of the resistor 40, respectively.

The first and second calibration terminals 20 and 30 connected to the first and second terminals 41 and 42 and the first and second terminals 41 and 42 of the calibration resistor 40 are connected to a sensor 10) and the terminal contact point is difficult, the connection line formed with the contact point clamp may be connected.

If the terminal of the sensor 10 is not protruded, it is bumped by the contact clips and the convenience of the measurement is improved. It may be configured to be increased.

In this case, the calibration resistors 40 may be composed of a plurality of different resistances, and each of the resistances may be different from each other. For example, the calibration resistors 40 may include standard precision resistors, standard precision metal resistors , A standard precision carbon resistor, and the like.

The calibration device 100 may be configured such that the calibration resistors 40 are coated with an insulator 50 so as to be shielded by the remaining portions except for a portion of the first and second calibration terminals 20 and 30 The insulator 50 may be made of other insulating material such as Teflon, polytetrafluoroethylene (PTFE), PP or PVC, and the like.

That is, in the calibration apparatus 100, only a part of the first and second calibration terminals 20 and 30 are exposed so that the first and second calibration terminals 20 and 30 can contact and contact the first and second electrodes 13 and 14 The first and second calibration terminals 20 and 30 and the calibration resistor 40 can be easily assembled to the sensor body 12 of the sensor 10 during calibration. A separate case 70 may be made of a material different from that of the insulator 50 and having a shielding performance.

At this time, the case 70 may be formed of a cap type that can be fitted to the sensor 10, which may be configured by a fitting method or a spiral fitting method with the sensor body 12.

The first and second calibration terminals 20 and 30 may be made of a noble metal such as gold, silver, or platinum, or a non-ferrous metal or graphite that does not cause corrosion.

The calibration resistors 40 of the calibration apparatus 100 may be constituted by one or more resistors having different resistances. The calibration resistors 40 may be formed of a first calibration resistors 40a to an nth calibration In the case of the resistor 40n, one of the first to n-th calibration resistors 40a to 40n is selected through the selection control unit 60 as a contact.

The first calibration resistor 40a, the second calibration resistor 40b, the third calibration resistor 40c and the nth calibration resistor 40n of the calibration resistor 40 may be an insulator 50 or a case One of the first and second terminals 41 and 42 of the first to nth calibration resistors 40a to 40n is connected to the first and second electrodes 40a to 40n, One of the first and second terminals 41 and 42 which is always connected to one of the first and second calibration terminals 20 and 30 and is not connected to any one of the first and second calibration terminals 20 and 30, The first and second electrodes 13 and 14 are selectively connected to one of the first and second calibration terminals 20 and 30 by selecting one of the first and second calibration terminals 20 and 30.

That is, the selection control unit 60 may be configured to be selected in the form of a dial on the lower side of the insulator 50 or the case 70, for example.

The first terminal 41 of the first calibration resistor 40a, the second calibration resistor 40b, the third calibration resistor 40c and the nth calibration resistor 40n of the calibration resistor 40 is connected to the first A second calibration resistor 40b, a third calibration resistor 40c, an n-th calibration resistor 40a, a second calibration resistor 40b, and a third calibration resistor 40c, which are selectively connected to the first electrode 13 using a calibration terminal 20, 40n are always connected to the second electrode 14 by using the second calibration terminal 30.

More specifically, when the selection switch 61 is rotated while the first calibration terminal 20 and the first terminal 41 are kept apart from each other, the selection switch 60 A first calibration resistor 40a which is connected to the first calibration terminal 20 and the first terminal 41 so as to be connected to the second electrode 14 at all times while the movable terminal 62 connected to the first calibration terminal 20 rotates together, The second calibration resistor 40b and the third calibration resistor 40c and the second terminal 42 of the nth calibration resistor 40n are connected to the second electrode 14 via the second calibration terminal 30, .

The first and second terminals 41 and 42 of the calibration resistor 40 can be fastened to the first and second calibration terminals 20 and 30 in a pin- The insulator 50 and the case 70 can be detachably coupled to each other by using an insert injection method and can be easily replaced when an error occurs in the calibration resistor 40 .

The first and second calibration terminals 20 and 30 of the calibration apparatus 100 are directly connected to the first and second meter terminals 201 and 202 of the meter 200, The display state of the measurement instruction value of the resistor 40 is grasped and the abnormality of the meter 200 is determined.

When the first and second calibration terminals 20 and 30 are brought into contact with the first and second electrodes 13 and 14 in the case 70, It can be configured to be easily grasped visually and audibly.

The operation and effect of the present invention constructed as described above will be described below.

As shown in FIGS. 6 to 12, the present invention will be described by taking as an example a conductivity sensor for measuring the conductivity of water among various sensors 10 in order to explain an embodiment using the calibration apparatus 100.

The conductivity sensor is formed by a pair of first and second electrodes 13 and 14 and is connected to the first and second electrodes 13 and 14. The sensor body 12 has a meter Cathode (K) lead 11b connected to the first electrode 13 for connection to the first electrode 14 and the anode 20, an anode lead 11a connected to the second electrode 14, (T), ground (E) or shield (S) terminals for temperature compensation of the temperature sensor.

The conductivity sensor of the sensor 10 includes a sensor body 12 provided with a signal line 11 connected to the meter 200 and a first and a second electrodes 12 and 13 made of a material such as a noble metal, The two electrodes 13 and 14 may be formed. The outer shape may be variously formed by two electrodes, three electrodes, four electrodes, and the like.

Next, in order to calibrate the conductivity sensor using the calibration apparatus 100, the meter 200 is first span calibrated and then the sensor 100 and the meter 200 are connected to each other to measure the conductivity of the sensor 100 and the meter 200 The span calibration process is as follows.

First, the calibration of the meter 200 will be described by connecting a standard source input device or a pair of resistance lines 301 of the resistance box 300 to the first and second meter terminals 201 and 202 of the meter 200 Next, the resistance value is set by adjusting each of the resistance switches 302, and after confirming whether the meter 200 indicates the measurement range (μS) indicating value for the resistance value (Ω) set in the resistance box 300, And the zero point adjustment is performed by setting the set resistance value of the resistance box 300 to zero to calibrate the meter 200 and the meter 200 and the resistance box 300 Short-circuit.

That is, for the calibration of the meter 200, for example, when the measurement range is divided into 0 μS, 50 μS, 200 μS, 500 μS, 1000 μS, 2000 μS, 10000 μS and 20000 μS, the resistance switch 302 of the resistance box 300 is controlled The resistance values (Ω) corresponding to the measurement ranges 0 μS, 50 μS, 200 μS, 500 μS, 1000 μS, 2000 μS, 10000 μS and 20000 μS are selected as 0Ω, 20KΩ, 5KΩ, 2KΩ, 1KΩ, 500Ω, 100Ω and 50Ω respectively.

Thereafter, the resistance values (Ω) of the resistance box 300 are measured in the respective measuring ranges 0 μS, 50 μS, 200 μS, 500 μS, 1000 μS, 2000 μS, 10000 μS, and 20 μΩ corresponding to 20Ω, 5Ω, 2Ω, 1Ω, 20000 μS is displayed on the meter 200, and each measurement point is displayed on the basis of 0 μS.

If the line connecting the measurement points does not form a straight line, the measurement range (μS) corresponding to the resistance value (Ω) and the meter (200) based on the repetitive measurement and the span setting of the meter (200) And the slope correction of the meter 200 is completed (see FIGS. 1 and 2). [0053] In the present embodiment, the resistance value of the resistor box 300 is measured repeatedly,

The span calibration process of the sensor 10 and the meter 200 will be described with reference to the first and second meter terminals 201 and 202 of the meter 200 having completed the span calibration, 11, the positive electrode lead 11a and the negative electrode lead 11b are connected.

The first and second calibration terminals 20 and 30 are connected to the first and second electrodes 13 and 14 of the calibration apparatus 100 so that the resistance of the calibration resistor 40 And the measurement value of the sensor 10 is measured by the meter 200 in accordance with the measurement range μS according to the resistance value Ω of the calibration resistor 40 and the error The span of the meter 200 is set.

In this case, there are two methods of calculating the resistance value in order to fabricate the calibration resistor 40. One is a resistance value corresponding to the cell constants K = 0.01, 0.1, 1, and 10 , And the other one can be calculated using a calculation formula using the measurement range value of the standard solution.

Here, for the cell constant, various cell constants exist. However, in order to facilitate understanding of the present invention, it is assumed that the cell constant K = 0.01, 0.1, 1, 10, .

If the cell constant is used, the calibration resistor 40 may be manufactured according to the resistance value of the table of FIG. 3. Alternatively, if only the indication of the measurement range of the standard solution sold or used in the market is known, The process of calculating the resistance value for the fabrication of the resistor is as follows.

3 and 12, the measured value (indicated value) and the cell constant (measured value) measured by the sensor 10 through the slope calibration of the meter 200 and the sensor 10, Can be calculated by the following equation.

(At this time, the condition for calculating the resistance value is assumed to be discarded below the decimal point, assuming that the cell constant K = 1, temperature compensation is 25 ° C, and all environments are normal conditions.)

3 is a table showing the relationship between the cell constant and the measurement range. The horizontal direction of the graph shown in FIG. 12 is the resistance value of the various kinds of the calibration resistors 40, (Unit: μS) measured by the measuring instrument (10).

For example, if the standard solution for slope calibration of meter 200 and sensor 10 is 4 standard solutions having a measurement range of 570 μS, 1000 μS, 1413 μS, 2000 μS, each standard solution Is calculated as follows using the following equation.

Resistance value = 1,000,000 ÷ measured value (knowledge value) × cell constant K (cell constant)

(Here, 1,000,000: Electrical Conductivity 1 at 25 캜 is a value expressed in Ω cm, measured values: 570 μS, 1000 μS, 1413 μS, 2000 μS, and cell constant K: 1.)

Assuming that the measurement values of 570 μS, 1000 μS, 1413 μS, and 2000 μS are displayed on the meter 200, the resistance values according to the respective measured values are It can be expressed by four equations.

1. Resistance value = 1,000,000 ÷ 570 × 1 = 1754.38 Ω

That is, the resistance value is about 1754 ?. In the present invention, the calibration resistor 40 is manufactured to have a resistance value of 1754? At the time of fabrication, and can replace the standard solution having a conductivity value of 570? S.

2. Resistance value = 1,000,000 ÷ 1000 × 1 = 1000 Ω

That is, the resistance value is 1000 OMEGA. In the present invention, the calibration resistor 40 is fabricated to have a resistance value of 1000 OMEGA at the time of fabrication and can replace the standard solution having a conductivity value of 1000 OMEGA.

3. Resistance value = 1,000,000 ÷ 1413 × 1 = 707.71 Ω

That is, the resistance value is about 707 ?. In the present invention, the calibration resistor 40 is manufactured to have a resistance value of 707? At the time of fabrication and can replace the standard solution having a conductivity value of 1413? S.

4. Resistance value = 1,000,000 ÷ 2000 × 1 = 500 Ω

That is, the resistance value of each standard solution is calculated as 1754?, 1000?, 707?, And 500?, And in the present invention, four resistors having resistance values of 1754?, 1000 ?, 707 ?, and 500? The slope correction of the sensor 10 can be performed using the calibration resistor 40 in the absence of a solution.

Next, a calibration resistor 40 is connected to a sensor (not shown) for slope calibration of the meter 200 and the sensor 10 using a calibration resistor 40 having resistances of 1754?, 1000?, 707 ?, and 500? 14, 14, 13, and 570 μS are displayed on the meter 200 corresponding to the resistance values, respectively.

If the value displayed on the meter 200 indicates 1998 μS, 997 μS, 1411 μS, and about 569 μS as measured by the sensor 10, 2000 μS, 1000 μS, 1413 μS, and about 570 μS are represented through the span calibration of the meter 200 After this calibration, it is repeatedly measured and calibrated in this manner to calibrate a complete calibration line according to the measurement range and the inherent μS value of the standard solution on the basis of 0 μS.

At this time, when the sensor 10 is taken out of the standard solution in the span calibration process and exposed to the atmosphere or the signal line is short-circuited to the meter 200, if the meter 200 does not indicate '0', the zero point adjustment is repeatedly performed .

On the other hand, when the calibration value is measured by connecting the calibration device 100 to the sensor 10, if the indication value displayed on the meter 200 indicates an error rate which is too large as the measurement range value of the calibration resistor 40 or is not displayed, After disconnecting the sensor 10 from the meter 200, the first and second calibration terminals 20 and 30 of the calibration apparatus 100 are connected to the first and second meter terminals 201 The meter 200 detects the display state of the measurement range value of the calibration resistor 40 and if the measurement range value of the calibration resistor 40 appears in the meter 200, And there is a characteristic that the sensor 10 can easily confirm that there is an abnormality.

When the case 70 is manufactured to fit the sensor body 10 in accordance with the morphological characteristic of the sensor 10, the calibration apparatus 100 may be configured such that the first and second electrodes 13 and 14 And the first and second calibration terminals 20 and 30 connected to the first and second terminals 41 and 42 of the calibration resistor 40 are contacted with each other to improve the convenience of the calibration work have.

The first and second calibration terminals 20 and 30 of the calibration apparatus 100 and the calibration resistor 40 are surrounded by the insulator 50 and are not affected by an external electric field or a magnetic field. There is a characteristic that measurement error due to the measurement is not generated.

Further, when the first and second calibration terminals 20 and 30 are in contact with the first and second electrodes 13 and 14, the contact state can be easily grasped by an indicator lamp or a buzzer.

The selection controller 60 of the calibration apparatus 100 may be used to select one of the first to third calibration resistors 40a to 40n of the calibration resistor 40 having a plurality of resistance values, It is possible to improve the reliability of the calibration and to compare the measurement range values of the respective calibration resistors 40 even if an abnormality occurs in one of the first to third calibration resistors 40a to 40n So that it is possible to easily ascertain whether the calibration resistor 40 is abnormal or not.

Table 2 and Table 3 below show the comparison of the features and the shortcomings of the standard solution used for the slope calibration of the sensor 10 and the meter 200 and the calibration device 100 of the present invention.

Classification by type and function Standard solution Correcting device compare



Form and Portability
Liquid
Uncomfortable to carry.
Solid: Electronic components Conventional liquid standard solutions are bulky, uncomfortable to handle and impossible to calibrate if not prepared in advance;
The calibration apparatus (100) of the present invention is characterized by being easy to handle by downsizing.




Writing
It can be manufactured to have a limited measurement range value, and it is difficult to produce an accurate measurement range value. Can be manufactured to have any resistance value. Conventional standard solutions are difficult to produce with varying or precise measurement range values;
The calibration resistor (40) of the calibration apparatus (100) of the present invention is capable of mass production so as to exhibit various resistance values.







Deterioration and preservation
The standard solution is contaminated by the degree of contamination in the air, the container and the sensor, and it is difficult to store it for a long time after opening the container. It is not influenced by air, external force, magnetic field or electric field. Conventional standard solutions are contaminated due to exposure to air from the moment when the initial container is opened, are contaminated correspondingly by the contamination degree of the containers and sensors, and are difficult to be stored for a long time.
The calibration apparatus 100 of the present invention is characterized in that the calibration resistor 40 is shielded by the insulator 50 and is not affected by external forces such as contamination or magnetic field or electric field.

Classification by type and function Standard solution Correcting device compare




Property change
Sudden changes in physical properties occur even in the air. No physical property change occurs in the air. In the conventional standard solution, the ions existing in the air are dissolved from the moment of exposure to the air due to the characteristics of the solution, and physical properties are changed;
The present invention is characterized in that no change in physical properties occurs under any circumstances or conditions.






Accuracy by repeated use
Problems such as changes in physical properties and contamination due to contamination of air, containers and sensors occur rapidly. The characteristic of the calibration resistor 40 and the change in the accuracy due to no change in physical properties due to the shielding by the insulator 50 are eliminated. Conventional standard solutions can not reliably measure the reliability of the measurement indication and the measurement through the sensor due to changes in the measurement range value due to the fact that the contamination phenomenon or physical property change easily occurs;
The present invention is characterized in that the reliability of the measurement is kept constant because the change of physical properties and the contamination phenomenon do not occur.




price
Separately produced to represent various measurement values according to each measuring range. It can be mass-produced with small size. Conventional standard solutions do not have many manufacturing companies, and the types of solutions to be produced are limited and expensive.
The present invention is characterized in that it can be mass-produced at a low production cost.

As a result, the method of calibrating the sensor using the standard solution used until recently shows the measurement value of the standard solution measured by the sensor through the meter connected to the sensor while the sensor is immersed in the standard solution showing a certain inherent measurement value When an error rate is generated in the intrinsic measurement range value of the standard solution and the indication value of the sensor, the existing calibration method of calibrating the meter is used.

However, if the standard solution used in the existing calibration method is expensive and the standard solution is transferred to another container for calibration of the sensor while being sold, the foreign substances in the container or various components in the air are dissolved, The present invention has a problem in that the manufacturing cost is low by using the calibration resistor 40 and that the insulator 50 is used to prevent the influence of the magnetic field or the electric field generated in the periphery The resistance value is not changed and the reliability is excellent.

In addition, the standard solution used in the existing calibration method has a cumbersome problem that the sensor should be cleaned thoroughly with distilled water or the like after the complete drying in order to calibrate the sensor. Also, when the standard solution is used for the calibration of the sensor once, The standard solution is contaminated and the measurement value is not accurately measured upon reuse for calibration. On the other hand, the present invention is advantageous in that the calibration resistance is not changed due to contamination of the air or the sensor 10, There is a simple feature that can be measured accurately regardless.

In addition, although the standard solution used in the conventional calibration method has a problem of causing contamination and physical property change due to continuous contact with air even after the initial container is opened after the purchase and the stored state is maintained at the best, the calibration resistor 40 ) Can be used for the calibration work of the sensor 10 continuously and repeatedly for a long period of time without changing the physical properties, thereby minimizing the management aspect and the maintenance cost.

In addition, when the conventional standard solution is used, it is bulky and has a variety of types, which makes it inconvenient to carry or handle at all times. If the standard solution is not provided at the measurement site of the water quality in a state in which the standard solution is not prepared in advance, The calibration apparatus 100 according to the present invention is small in size and light in weight and easy to carry and handle so that the calibration apparatus 100 can be carried at any time and the sensor 100 and the meter 200 The slope correction operation can be performed without limitations.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Various changes and modifications may be made by those skilled in the art.

10: sensor 11: signal line
11a: positive electrode lead 11b: negative electrode lead
12: sensor body 13: first electrode
14: second electrode 20: first calibration terminal
30: Second calibration terminal 40: Calibration resistor
40a to 40n: first calibration resistor to nth calibration resistor
41: first terminal 42: second terminal
50: insulator 60:
61: selection switch 62: movable terminal
70: Case 100: Calibration device
200: Meter 201: First meter terminal
202: second meter terminal 300: resistance box
301: resistance terminal 302: resistance switch
T: Temperature terminal E: Ground terminal

Claims (8)

  1. A sensor body 12 provided with a signal line 11 connected to the meter 200 measures the salinity of the solution, the total dissolved solid matter (TDS), the resistivity, the conductivity, (13) and (14), wherein the sensor (10)
    A resistor having a resistance value corresponding to the measurement range value of the standard solution or having a cell constant value is connected to the sensor 10 on the first and second electrodes 13 and 14 of the sensor 10, The error rate between the indication value and the resistance value of the resistance is calibrated by the zero point adjustment and the span adjustment in the meter 200 so that the zero point calibration and the slope (span) correction between the sensor 10 and the meter 200 are repeated. Forming device 100,
    The calibration apparatus 100 includes first and second calibration terminals 20 and 30 which are in contact with the first and second electrodes 13 and 14, 42, respectively,
    When a plurality of the calibration resistors 40 are composed of the first calibration resistors 40a to the nth calibration resistors 40n, the first calibration resistors 40a to the nth calibration resistors 40a 40n are contact-selected so that a resistance value is measured on the sensor (10).
  2. delete
  3. The apparatus according to claim 1, wherein the calibration device (100) is configured such that the calibration resistors (40) are coated with an insulator (50) so as to be shielded by the rest of the first and second calibration terminals (20, 30) And a sensor for detecting the position of the sensor.
  4. The calibration device of claim 1, wherein the calibration resistors (40) of the calibration device (100) are configured with one or more resistors having different resistance values.
  5. The calibration device of claim 3, wherein the first and second calibration terminals (20, 30) are made of noble metals such as gold, silver and platinum, non-ferrous metals free from corrosion, and graphite.
  6. delete
  7. The method of claim 1, wherein one of the first and second terminals (41) and (42) of the first to fourth calibration resistors (40a to 40n) One of the first and second terminals 41 and 42 is selectively connected to one of the first and second calibration terminals 20 and 30 by the selection of the selection controller 60, And the sensor is configured to be connected.
  8. The apparatus of claim 1, wherein the first and second calibration terminals (20) and (30) of the calibration apparatus (100) are directly connected to the first and second meter terminals (201, 202) 200) detects the abnormality of the meter (200) by grasping the display state of the resistance value of the calibration resistor (40).
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105823504A (en) * 2016-04-13 2016-08-03 北京航天发射技术研究所 Zero-point-crossing processing method of encoder
KR101755223B1 (en) 2016-12-12 2017-07-07 길주형 pH measurement system with automatic calibration function
US10209210B2 (en) 2015-10-14 2019-02-19 HM Digital Ltd. Measuring device using electrical conductivity and having function of informing electrode contamination

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0518845A (en) * 1991-07-09 1993-01-26 Copal Electron Co Ltd Method for calibrating pressure sensor
JP2005114575A (en) * 2003-10-08 2005-04-28 Asahi Breweries Ltd Calibration method of conductivity meter
JP2006113036A (en) * 2004-10-13 2006-04-27 Ryuichi Yokota Measuring instrument and calibration method for sensor
JP2012184925A (en) * 2011-03-03 2012-09-27 Dkk Toa Corp Electroconductivity meter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0518845A (en) * 1991-07-09 1993-01-26 Copal Electron Co Ltd Method for calibrating pressure sensor
JP2005114575A (en) * 2003-10-08 2005-04-28 Asahi Breweries Ltd Calibration method of conductivity meter
JP2006113036A (en) * 2004-10-13 2006-04-27 Ryuichi Yokota Measuring instrument and calibration method for sensor
JP2012184925A (en) * 2011-03-03 2012-09-27 Dkk Toa Corp Electroconductivity meter

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10209210B2 (en) 2015-10-14 2019-02-19 HM Digital Ltd. Measuring device using electrical conductivity and having function of informing electrode contamination
CN105823504A (en) * 2016-04-13 2016-08-03 北京航天发射技术研究所 Zero-point-crossing processing method of encoder
CN105823504B (en) * 2016-04-13 2018-05-22 北京航天发射技术研究所 A kind of more zero point processing method of encoder
KR101755223B1 (en) 2016-12-12 2017-07-07 길주형 pH measurement system with automatic calibration function
WO2018110806A1 (en) * 2016-12-12 2018-06-21 길주형 Hydrogen ion concentration measurement system having automatic calibration function

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