JPH04147051A - Apparatus for measuring salinity - Google Patents

Abstract

PURPOSE:To make correct and highly reliable measurement by adopting a optimum value comparing the difference between the maximum and minimum values measured of each electrode by a sensor with the allowable value previously set up. CONSTITUTION:An apparatus body 2 connected with a sensor 1 having plural electrodes 1e1 to 1e3 detects the salt concentration and makes a prescribed operation process. A voltage of a sweep waveform is applied to each electrode 1e1 to 1e3 by D/A converter 6, each peak current is detected by an A/D converter 7 and whether it is error data or not is judged 9A by these data compared each other in a body 2 at this time. The peak current values through this judging measure 9A are converted into salt concentrations and a average of these value is computed together with it by the first operating measure 9B and stored to memories 10 and 11. Further, the said process is repeated according to the exchange of the sensor 1 by a repetitive command 9C, an average value of those values is computed by the second operating measure 9D, and this average value and the average salt concentration every time of the measurement are displayed by a display measure 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device for measuring salt concentration, and more particularly to a salt measuring device optimal for measuring the salt content in fresh concrete.

[Conventional technology] Due to the decrease in river sand, sea sand is increasingly used in concrete structures these days, and as a result, concrete contains salt, but salt in concrete has a large effect on the strength and life of concrete. In order to give concrete construction, the fresh concrete (hereinafter referred to as "
It is required that the salt content in fresh concrete (referred to as "ready-mixed concrete") be below a certain value.

Currently, when measuring the salt content in ready-mixed concrete, it is required by law to measure the sample three times in order to ensure the reliability of the measurement results, and the average value of these three measurements is used as the measurement target. The salinity concentration of ready-mixed concrete is

Conventional methods for measuring salinity include a chemical method using a reagent and an electrical method that measures the potential generated by the chlorination reaction at the electrode, but the chemical method lacks accuracy and takes time to measure. There is a disadvantageous force S.

Recently, a small portable salinity meter for ready-mixed concrete that uses an electrical method has been provided. The unit is connected by a cord, and the salt content can be digitally displayed on the display unit of the meter and can also be printed out.It also has an alarm function that issues an alarm when the salinity concentration exceeds a predetermined value. ing.

[Problems to be Solved by the Invention] However, in the above-mentioned salinity meter for ready-mixed concrete, the main body of the meter and the sensor section are connected by a cord. It is used as an integrated unit, and it requires a lot of effort to clean and dry the electrodes inside the sensor every time a measurement is made, making the operation complicated and time consuming. ≦Yes. In addition, the sensor section is larger by +1, making it inconvenient to carry and making it expensive to prepare a spare sensor in case of failure.

This salinity meter performs each measurement three times and calculates the average value (force), force S requires careful sample collection, and variation force S when sampling visually. However, this results in an error in the calculated average value of the force S, which has drawbacks such as a lack of reliability and the need to repeat the force S measurement.

The purpose of the present invention is to eliminate the drawbacks of the conventional salinity meter as described above, and to make it small and lightweight, making it convenient to carry.Of course, the sensor and the measuring device can be separated, making it easy to operate. The object of the present invention is to provide a salinity measuring device which has less errors due to scratches on the sample and has high reliability of measured values.

[Means for Solving the Problems] In order to achieve the above object, the salinity measuring device of the present invention has the following features:
It consists of a sensor for detecting salinity having a plurality of electrodes, and a main body of the measuring device that detects the salt concentration by connecting the sensors and performs predetermined arithmetic processing. An application means for applying a voltage with a sweep waveform to each electrode, a detection means for detecting each peak current flowing through each electrode, and a plurality of peak currents detected by the detection means are compared with each other to detect each peak current. a determining means for determining whether the data is error data; a first calculating means for converting the peak current passing through the determining means into a salinity concentration and calculating an average value thereof; and an average salinity calculated by the first calculating means. a memory for storing the concentration; a repetition command means for instructing the process from the applying means to the memory to be repeated multiple times according to sensor replacement; a second calculation means for calculating the average value from the average salinity of 1 degree, and a display means for digitally displaying the average value and the average salinity concentration for each measurement degree;
is provided, and the display means is configured so that the average value and the average salinity concentration for the number of new measurements due to sensor replacement can be continuously confirmed.

Furthermore, as a sensor, a sensor proposed separately by us in Japanese Patent Application No. 2-76790 can be used, and this sensor is constructed as a disposable type, and is attached to the sensor after spreading the electrode arrangement part into the sample. By loading the connector terminal into the connection part of the main body of the measuring device, the two are electrically connected and the salt concentration is measured.

The structure of the sensor is such that each electrode is arranged symmetrically on the electrode 41 portion located at the tip end of a substantially rectangular card-shaped substrate, and a sample solution is introduced into each electrode through a filter and a sample introduction hole. Each electrode and the connector on the rear end side are connected by independent wiring patterns for applying a sweep voltage to each electrode.

[Function] When a sample is supplied to the electrode portion of the sensor, a reaction occurs at the electrode due to the salt (CJ2 ions) contained in the sample, and a potential corresponding to the salt concentration is generated. The measuring device measures the potential at each of the electrodes of the sensor. If the difference between the maximum and minimum measured values is within a preset tolerance value, these values are adopted as appropriate values, and the average value of the adopted values is calculated. Store and display as measured values. Further, these measurements are performed a legal number of times, and the average value of each measurement value is calculated to obtain the final measurement value.

In this case, the sensor is formed into a substantially rectangular card shape and is disposable, and after the electrode placement part on the tip side is spread into the sample, the connector on the rear end side is loaded into the connection part of the main body of the measuring device.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

The first section is a flowchart corresponding to the configuration of the present invention, and the second section (A
), (B) is the above-mentioned patent application No. 2-767 related to our proposal.
The outline of the disposable salinity measurement sensor No. 90 is shown, and the second
Figure (C) shows its usage state. Also, Figure 2 (D
) shows a state in which the salt content is measured using this salinity measuring sensor and the salinity measuring device main body.

Note that the device according to the present invention does not require the use of this disposable salinity measuring sensor, and can be used with sensors of other configurations as long as they have a plurality of electrodes. An example of using a disposable sensor will be explained below.

First of all, in FIG. 2(A), ■ is a disposable sensor in the shape of a strip card, and the tip of the sensor has a plurality of (implemented) sensors on the back side of the substrate 1, as shown in FIG. 2(B). In the example, three electrodes (for example, silver electrodes) 1e+le2.
An electrode arrangement part 1a is provided by symmetrically arranging the electrode arrangement parts 1es, and a filter 1f such as filter paper or nonwoven fabric is arranged on the surface side of the electrode arrangement part 1a. Collected sample introduction hole 1d
to electrodes 1e+ to lea. A connector IC is provided on the rear end side of the sensor 1, and the connector 1c and each of the electrodes 1e+ to les are connected by independent wiring patterns 1p, and the connector 1c is provided on the rear end side. It is exposed when the cover 1b, which is provided so as to be openable and closable, is opened. In addition, in FIG. 2(B), 11 is a reference pole.

When measuring the salinity of fresh concrete, as shown in FIG. 2(C), first a sample is extracted from a portion of the ready-mixed concrete, and the sample is stored in a specific container. When the center of the ready-mixed concrete C stored in the container is recessed into a substantially conical shape, the solution (breezinda solution) L in the ready-mixed concrete C oozes into this recess and accumulates therein. During this solution, the electrode arrangement part 1 of the salinity measuring sensor 1
a to sufficiently infiltrate the electrode placement portion 1a with the solution.

Note that in the case of fresh concrete with a low water content, it takes some time for the solution to infiltrate, but the electrode arrangement part 1a of the sensor may be inserted directly into the ready-mixed concrete.

With the electrode part fully soaked with solution, lift up the sensor 1, open the cover 1b to expose the connector 1c, and connect the connector lc to the connection part of the salinity measuring device main body 2, as shown in FIG. 2(D). 2a, connect both electrically, and measure the salinity.

First, the configuration of the salinity measuring device will be explained using FIG. 3.

In the figure, 3a, 3b, 3c are amplifiers (hereinafter referred to as "channel amplifiers") respectively connected to the three electrodes 1e1, 1eanles in the sensor 1 connected to the measuring device main body 2, 4 is a switch, 5a, 5b , 5c is an amplifier (hereinafter referred to as a "range amplifier") that amplifies the current output from the channel amplifiers 3a to 3c via the switch 4. Basically, even one range amplifier can be configured as a device. However, by using three as shown in the figure, for example, the range amplifier 5a can be multiplied by 10, the range amplifier 5b can be multiplied by three,
5c is amplified by a factor of 1.5 to increase the sensitivity of the device.

Reference numeral 6 denotes an A/D as an application means for applying a sweep waveform voltage to each electrode (le, lea, leg) of the sensor.
Converter, 7 is an A/D converter as a detection means for detecting each peak current flowing through each of the electrodes, 8 is an I10 port connected to each of these converters, 9 is a central processor that controls the entire measuring device In the apparatus, 10 is a read-only memory (ROM) that stores data such as the relationship between peak current and salt concentration, 11 is a writable memory (RAM) that stores measured values, etc., and 12 is a timer.

In addition, a display device 2b and an input device 2c are connected to the central processing unit 9 via another I10 boat 13, and a printer 15 is connected via another I10 boat 14. Note that reference numeral 15a is a processing device for operating the printer, and 15b is a processing device for operating the printer 1 according to instructions from this processing device.
This is a driver for directly operating the 5.

Next, the operating state of this device will be explained.

Connect the sensor l for salinity measurement to the connector 2a of the measuring device main body 2.
When the device is turned on, a predetermined voltage is applied to the three electrodes 1e+ to les of the sensor
is applied to each of the Each electrode generates a potential corresponding to the salt concentration in the ready-mixed concrete to be measured. The channel amplifiers 38 to 3C are each connected to a specific electrode among these three electrodes, and the switch 4 switches these channel amplifiers 38 to 3C several times per second, and outputs from each channel amplifier 38 to 3c. The resulting voltage is supplied to range amplifiers 5a to 5c. Each range amplifier 58 to 5C performs different amplification as described above,
The A/D converter 7 converts the current into a current and outputs it to the central processing unit 9. The central processing unit 9 scans the output from each range amplifier 58 to 5c and monitors changes therein.

Here, the voltage applied to each electrode of the sensor 1 is the sixth
As shown in the figure, the voltage is a sweep voltage that increases over time. As a result, the sensor current obtained from the electrodes of each sensor also increases as the voltage increases, but since the electrode reaction depends on the salt concentration, at a certain point the current stops increasing, and after that it begins to decrease. The maximum value (peak value) of this current corresponds to the salinity concentration.

Based on the above points, the electrodes 1e1 to 1 in the sensor
Obtain each peak current P1 to P3 of e3. The range of values taken by each of these peak currents P1 to P3 is compared with a reference value stored in the ROMII, and if the range of the three values is within the reference value, all of these values are adopted. In addition, if one value deviates from this range, the deviating value is considered to be defective, such as an abnormality in the electrode or insufficient contact between the measurement target and the electrode, and is therefore rejected as error data. , adopt the remaining two values.

The adopted peak current value is converted into a C1-concentration based on the data (see FIG. 7) showing the relationship between the peak current value and Cl-41 degrees stored in the ROPJLI 1. Furthermore, by obtaining the average value of C1-concentration corresponding to the adopted peak current value, it is taken as a measurement value of one sensor,
- Finish the batch salinity measurement. By repeating this method, salinity measurements are carried out three times, the legal number of times, and the final measurement result is obtained by obtaining the average value of the three measurements.

Next, an outline of a method for measuring salinity using the above-mentioned device will be explained along with a method for handling the device.

In each step in FIG. 4, an internal calibration 53 in the measuring device main body 2 is first performed prior to the start of the measuring work. This internal calibration is performed to erase the data, such as when a salinity measurement was previously performed at another site, or to store the data in the memory mechanism in order to prepare for a new measurement. be. After performing this calibration, the device is set up to support the current salinity measurement.

First, the number of measurements is confirmed 54. Since the number of measurements stipulated by law is three, a case will be described below using an example in which measurements are performed three times.

The measuring device is preprogrammed to store each of the three measurement results and calculate the average value of these measurement results as the final salinity measurement result. Therefore, the measurer first inputs the number of measurements to be performed. That is, if the measurement is to be performed for the first time on the target ready-mixed concrete, input "once". From now on, by replacing the sensor, the number of measurements will be automatically counted, and there is no need to input the number of measurements each time.

Subsequently, the unit water amount is confirmed 55.

The unit amount of water refers to the amount of water in a specific volume (1 volume in this case) of ready-mixed concrete.

If the number of measurements is entered as 1 in confirmation of the number of measurements (54), that is, if it is the first measurement, an instruction to confirm the amount of water such as "Water volume = OOOkg/I" will be displayed on the measuring device main body 2. Part 2
b, and the digits in the numerical value display column flash in sequence.

When the amount of water is input using the key 2c according to the above instruction, the input value is displayed as shown below, for example. In addition,
From the second time onward, processing is performed based on this set amount of water.

"Suirigou = 185 kg/resistant" This amount of water is used when converting the total amount of salt after measuring the salinity.

The above is the procedure for setting up the salinity measuring device prior to measuring salinity.

Next, the actual salinity measurement mode will be explained.

First, the sensor 1 whose electrode placement portion 1a is sufficiently soaked with a solution is electrically connected to the measuring device main body 2 (sensor attachment 56).

A plurality of electrodes are formed for this sensor 1, and each of the electrodes generates a potential due to reaction with salt. The measuring device main body 2 sequentially measures the potentials at the plurality of electrodes (57), calculates the average value of these measured values, and displays the results of one measurement using this sensor (58). The results are stored 59 (details of the batchwise salinity measurement method will be described later with reference to FIG. 5).

As a result, a new sensor is installed, and the process returns to sensor installation 56 to perform the next salinity measurement in the same manner as described above.

The salinity measurement results of each time are stored 59, and the average value of the measurement values of each time is calculated to obtain a final measurement result 60. At this time, if it is desired to know the converted value of the total amount of chlorides, the stored unit water amount is used to perform, for example, the following (total amount display (display 61 of contained salt amount)).

Souryo=○OOkg/a These measurement results and the total amount of salt can also be printed out on paper P using the printer 15.

FIG. 5 shows the operating state of the salinity measuring device in the salinity measurement state, that is, the details of the flow shown in FIG. 4, particularly the portion corresponding to measurement 57. Dress up using this diagram! The operating state of will be explained in more detail.

First, a measuring person attaches a sensor in which a plurality of electrodes are infiltrated with a solution, which is a measurement sample, to the main body of the measuring device according to the indication on the display section.

In addition, during measurement work, only one type of measurement target (
Since the legal number of measurements for fresh concrete is three, it is convenient to have three sensors as one bag and use these sensors one after another.

By connecting the sensor 1, the measuring device main body 2 automatically starts measurement, and first performs a system check 20 to check the system of the device. This system check is performed by calibration and self-diagnosis, such as checking whether the salinity measuring circuit of the apparatus is working properly by applying a dummy peak current. After the system check 20 is completed, density value initialization 21 is performed next. Initializing the concentration value means determining whether or not to use the past measured value stored in the memory circuit of the measuring device. In other words, if you have completed three measurements, which is the legal number, and are going to take a new salinity measurement, you do not need the data from the previous final measurement, but for example, if you have completed two of the three measurements,
If the remaining measurement has not been completed yet, it is necessary to store and save the previous measurement value. Therefore, by density value initialization 21, it is determined whether to retain or erase the previous measured value.

Next, voltage is applied to each electrode of the sensor via the D/A converter 7, and A/D input of current from each electrode is performed (D
/A output, A/D input 22). At this time, a sensor check 23 is performed prior to converting the input current into salinity concentration. This check is performed by confirming that when the voltage is applied from 0, the initial value of the current to be measured is 0. In other words, when a voltage is applied from O as described above, the initial value of the current to be measured must naturally start from O, but if this initial value is not 0, the sensor has already been used or the electrode is In other words, the sensor is unreliable and cannot be used, such as when the sensor is defective, so if the initial value does not become 0, replace it with another sensor.

When the sensor check 23 is completed, the sensor current is measured and the result is stored 24. Furthermore, confirm the peak of the current 25. In this way, the peak current of each of the three electrodes of the sensor is determined 26, and the width of the variation in the values of these peak currents is checked 27. If the variation width is within the memorized range, then calculates 28 an average peak current from these plural peak currents. In this case, the relationship between peak current and salinity concentration changes depending on the ambient temperature, so the temperature near the sensor is measured and the average peak current is temperature-corrected29, but the measurement result is used as the correction value when converting the concentration. shall be. Further, in this case, if the electrode is defective, the timer 12 may not show a peak current within the count. Therefore, the current peak is checked again (30), and if the peak does not appear, the processing step is returned to the system check step (20) and the measurement is performed again.

On the other hand, if a current peak is confirmed, the peak current is converted 31 into salinity concentration based on the data shown in FIG. In this way, an average value is calculated 32 from each of the salinity concentrations corresponding to each peak current, the result is stored 33, and the result is further displayed 34 on a display device such as an LCD, so that one salinity value can be calculated. Finish measuring the salt concentration using the sensor. If the legal number of measurements has not yet been completed, a new salinity sensor is connected and measurements are performed sequentially from the system check 20 stage, and the average value of each measurement value is calculated. This is the measurement result of salinity 33.

FIG. 8 is a flow diagram showing another method for measuring salinity using this device.

The measurement starts 47a by attaching the sensor 1 46 .

First, the potential at the first electrode among the electrodes of this sensor is measured (first electrode i++ constant 47b), and this measurement result is stored 47c. Subsequently, a second electrode measurement 47d is performed in the same manner, the result is stored 47e, and a third electrode measurement 47d is performed.
Perform 7f and store the result 47g. Note that the processing time during this period is about 20 to 30 seconds.

Next, the measurement results of the three electrodes stored in the memory 47c, 47e, and 47g are compared, and it is determined whether the difference between the maximum value and the minimum value is within a tolerance value (47h). If this difference is greater than the allowable value, there may be problems such as insufficient contact of the solution with a part of the electrode of the sensor or a defect in the sensor itself, as in the case described above. In this method, if the difference is greater than the allowable value, a cancellation display 47i is displayed, instructing that the sensor itself be rejected, replaced with another sensor, and measured again. In addition to this method, the sensor itself is not rejected, but just one value out of the three values that deviates from two values is deleted as rejected, as in the case of the previous example. , the average value of the remaining two values may be obtained for economy.

On the other hand, if this difference is within the allowable value, calculate the average value of the memorized measured values for each electrode (average value calculation 47j
), the result is displayed 48 using this average value as a single measurement value, and the measurement value in parentheses is stored 49.

In this way, measurements are carried out three times, and the average value of these three measurements is further determined to determine the measured value based on the legal number of times.

In addition, it is also possible to display the data of the measurements performed so far in the middle of the measurement performed three times. For example, when the third measurement is completed and you want to know the results of the next measurement, for example, the following displays (1) to (6) may be shown in sequence.

"Souryo = 0.125kg/rrrJ...
(1) “Heikin = 0.74%” (2)
"Tsukuti 1 = 0.75%" ... (3) "Tsukuti 2 = 0.73%" ... (4) "Tsukuti 3 = No data" ... (5) "Main Return to menu j ...... (6) Of these, (1) displays the average value of the total salt content in the first and second measurements, and (2) displays the average value of the total salt content in the first and second measurements. (3) indicates the first measurement value, (4) indicates the second measurement value, and (5) indicates the third measurement has not yet been completed. Of course, it is also possible to print out the progress of these processes.

Although the device according to the present invention has been described above using a disposable sensor as an example, it is of course possible to use a sensor other than a disposable sensor as long as it has a plurality of electrodes.

[Effects of the Invention] According to the salinity measuring device of the present invention, there is provided a salinity detection sensor having a plurality of electrodes, and a measuring device body that detects salinity concentration by connecting the sensor and performs predetermined arithmetic processing, etc. applying a voltage with a sweep waveform to each electrode of the sensor by the measuring device main body, detecting each peak current flowing through each electrode, and comparing the detected plurality of peak currents with each other; It is determined whether each peak current is error data or not, and the peak current that has passed through the determination means is converted into salinity concentration, the average value is calculated, and this average salinity concentration is stored in memory, and further according to the repeat command. , by repeating the process from the applying means to the memory multiple times depending on the sensor replacement, an average value is calculated from the average salinity concentration stored in the memory and the average salinity concentration for each measurement number, Since the average value and the average salinity concentration for each measurement level are digitally displayed, accurate salinity measurement can be performed by sequentially measuring a predetermined number of times according to the message displayed on the display. Since it is possible to continuously check the average value and the average salinity concentration for the number of new measurements due to sensor replacement, there are fewer errors due to sample variations (highly reliable measurement results can be obtained).

In addition, by using a disposable type sensor, there is no need to clean the sensor, and since the sensor and the measuring device body can be separated, the sensor can be spread directly into the ready-mixed concrete and then removed from the measuring device body. Measurements can be made by loading the device into a device, making it extremely easy to handle and measure, and convenient to carry.

Furthermore, the sensor configuration includes a plurality of electrodes arranged symmetrically in the electrode placement section, and the sample solution is introduced into the electrodes through the filter and sample guide hole, reducing errors in the data obtained from each electrode. It is possible to obtain highly accurate data.

[Brief explanation of drawings]

The drawing shows a salt measurement bag according to the present invention! An example of the first
The figure shows a configuration flow diagram, Figure 2 (A) is a partially exploded perspective view of a disposable sensor, Figure 2 (B) is a back view of the board, and Figure 2 (C) shows an example of how the disposable sensor is used. Perspective view,
Fig. 2 (D) is a perspective view showing the disposable sensor and the main body of the salinity measuring device, Fig. 3 is a diagram showing the overall configuration of the salinity measuring device, and Fig. 4 is an overall view of the salinity measuring method using the salinity measuring device. Figure 5 is a flow diagram showing details of the salinity measurement method, Figure 6 is a diagram showing changes in sensor current in response to changes in voltage, Figure 7 is C1-concentration and electrode peak current. FIG. 8 is a flowchart showing another salinity measurement method. 1: Disposable sensor 1a: Electrode arrangement part, lc: Connector ld: Sample introduction hole, le+ -1ex: Electrode lf: Filter, 1k=Substrate, lp: Pattern 2: Measuring device main body 2a: Connection part, 2b: Display part 3a to 3C: Channel amplifier 4: Switches 58 to 5c: Range amplifier 6: D/A converter 7 as means for applying sweep voltage: A/D converter 9 as means for detecting peak current: Central processing unit 9A: Determining means , 9B: First calculating means 9C: Repetition command means, 9D = Second calculating means 10: Memory (ROM) 11: Memory (RAM) 12: Timer C: Ready-mixed concrete to be measured L: Sample solution Patent applicant's agent Patent attorney Isamu Kakiuchi Figure 1 Figure 2 (D)

Claims (1)

[Claims] 1. A salt detection sensor (1) having a plurality of electrodes;
It consists of a measuring device body (2) that detects the salt concentration by connecting the sensors and performs predetermined arithmetic processing, etc., and the measuring device body (2) is connected to each electrode (1e) of the sensor.
_1, 1e_2, 1e_3); an application means (6) for applying a voltage with a sweep waveform; a detection means (7) for detecting each peak current flowing through each of the electrodes; and a plurality of peaks detected by the detection means. Judgment means (9A) that compares currents and judges whether each peak current is error data or not
, a first calculation means (9B) that converts the peak current passing through the determination means into a salinity concentration and calculates the average value thereof, and a memory (10B) that stores the average salinity concentration calculated by the first calculation means. or 11), a repetition command means (9C) for instructing to repeat the process from the application means to the memory a plurality of times in response to sensor replacement; a second calculating means (9D) for calculating the average value from the average salinity concentration; and a display means (2b) for digitally displaying the average value and the average salinity concentration for each measurement degree, the display means A salinity measuring device characterized in that it is configured such that the average value and the average salinity concentration for the number of new measurements due to sensor replacement can be continuously checked. 2. The sensor (1) is constructed as a disposable type, and after spreading the electrode placement part (1a) into the sample, connect the connector terminal (1c) provided on the sensor (1) to the connection part (2) of the measuring device main body (2).
2. The salinity measuring device according to claim 1, wherein the salinity measuring device is configured to measure the salinity concentration by electrically connecting the two by loading the salinity measuring device. 3. The sensor (1) is a board (1k) that is approximately in the shape of a strip card.
Each electrode (1
e_1, 1e_2, 1e_3) are arranged symmetrically, and each electrode has a filter (1f) and a sample introduction hole (1d).
The sample solution is introduced through the connector, and each electrode and the connector (1c) on the rear end side are connected with independent wiring patterns to apply a sweep voltage to each electrode. The salinity measuring device according to claim 1 or 2, characterized in that: