JPWO2015137333A1 - Measurement system, electrode evaluation method and program - Google Patents

Abstract

Provided are a measurement system, an electrode evaluation method, and a program capable of accurately evaluating electrode responsiveness regardless of the degree of automation of the apparatus. After the sample in contact with the electrode is exchanged from the first sample to the second sample, the change rate per unit time of the detection value of the electrode becomes a predetermined first change rate, and a predetermined time T1 The time ΔS between the second change rate and the second time T2 is set as the evaluation time, and responsiveness information indicating the responsiveness of the electrode is generated based on the evaluation time ΔS.

Description

The present invention relates to a measurement system, an electrode evaluation method, and a program.
This invention claims priority based on Japanese Patent Application No. 2014-046810 for which it applied to Japan on March 10, 2014, and uses the content here.

Conventionally, a technique for evaluating the responsiveness of an electrode in a measuring apparatus using an electrode such as a pH electrode or an ion electrode is known. For example, in the ion concentration analyzer described in Patent Document 1, a standard solution having the same concentration as the signal value obtained after the first predetermined elapsed time after the electrode is immersed in a standard solution containing test ions having a known concentration. The difference between the signal value obtained after the second predetermined elapsed time after immersion and the allowable value stored in advance are compared, and a warning signal is issued when an allowable value is not obtained. ing.
For example, in the pH meter described in Patent Document 2, it is described that the state of the electrode is evaluated based on the response time at the time of calibration of the standard solution of the pH sensor and the life prediction is performed.

Japanese Patent Laid-Open No. 54-44593 Japanese Patent Laid-Open No. 4-132948

The signal value when the electrode is immersed in the standard solution fluctuates violently immediately after the immersion, and becomes stable as time elapses. Therefore, in order to evaluate the responsiveness by the method described in Patent Document 1, the time when the electrode is immersed in the standard solution is clearly specified, and the first predetermined elapsed time and the second predetermined elapsed time are accurately determined. It is necessary to keep time.
For example, when the time when the electrode is immersed in the standard solution is caught earlier than the actual time, a time shorter than the first predetermined elapsed time is mistaken as the first predetermined elapsed time, and the time is shorter than the second predetermined elapsed time. A short time is mistaken as the second predetermined elapsed time. As a result, the difference between the signal values after the first predetermined elapsed time and the second predetermined elapsed time is overestimated.
In addition, when the time when the electrode is immersed in the standard solution is caught later than the actual time, a time longer than the first predetermined elapsed time is mistaken as the first predetermined elapsed time, and the time exceeds the second predetermined elapsed time. A long time is mistaken as the second predetermined elapsed time. As a result, the difference between the signal values after the first predetermined elapsed time and the second predetermined elapsed time is underestimated.

In the apparatus of Patent Document 1, after giving a measurement start command, the apparatus automatically feeds the standard solution into the container containing the electrodes. Therefore, the time when the electrode is immersed in the standard solution can be clearly specified based on a previously programmed sequence, and the first predetermined elapsed time and the second predetermined elapsed time can be measured without any problem.
However, when the device is not an automated device such as the device of Patent Document 1, the time when the electrode is immersed in the standard solution must be set by a user pressing a button or the like. In that case, the set time tends to deviate from the time when the measurement of the standard solution or the like is actually started.
Therefore, if the evaluation technique described in Patent Document 1 is not an automated apparatus, it is difficult to accurately evaluate the electrode response.

On the other hand, Patent Document 2 does not describe automation of the work of immersing the electrode in the standard solution. That is, the pH meter assumed in Patent Document 2 is considered to be a normal pH meter in which a user immerses an electrode in a standard solution. However, Patent Document 2 does not explain at all how to specifically measure the response time at the time of calibration of the standard solution and how to specify the time when the electrode is immersed in the standard solution. Therefore, from the description of Patent Document 2, it is impossible to grasp a technique that enables accurate electrode response evaluation.
Furthermore, the responsiveness of the electrode is affected by the cleaning history of the standard solution and the like before the start of measurement. In the case of a non-automated pH meter as in Patent Document 2, cleaning performed before the electrode is immersed in a standard solution is also entrusted to human hands. For this reason, an evaluation error due to an operation history before being immersed in the standard solution is likely to occur.

  The present invention has been made in view of the above points, and provides a measurement system, an electrode evaluation method, and a program capable of accurately evaluating electrode responsiveness regardless of the degree of automation of the apparatus. Is an issue.

In order to achieve the above object, the present invention employs the following configuration.
[1] An electrode for obtaining a detection value corresponding to the property of the sample in contact and an arithmetic control device to which the detection value obtained by the electrode is input. The arithmetic control device includes a timer unit and the timer unit. A calculation unit that associates and acquires the time measured and the detected value at the time, and the calculation unit exchanges the sample that contacts the electrode from the first sample to the second sample; Thereafter, a first time at which a change rate per unit time of the detection value becomes a predetermined first change rate, and a change rate per unit time of the detection value after the first time is the first change rate. A responsiveness information indicating the responsiveness of the electrode is generated based on a time between the second time when the second change rate is smaller than a predetermined second change rate.

[2] An electrode for obtaining a detection value corresponding to the property of the sample to be contacted, and an arithmetic and control unit to which the detection value obtained by the electrode is input. The arithmetic and control unit includes a timing unit and the timing unit. A calculation unit that associates and acquires the time measured and the detected value at the time, and the calculation unit exchanges the sample that contacts the electrode from the first sample to the second sample; Then, after the change rate per unit time of the detection value becomes a predetermined final change rate, the detection value is set as the final detection value, and the sample that contacts the electrode is replaced with the second sample. The detected value is smaller than the first allowable range from the final detected value after the first time when the detected value becomes a value within a predetermined first allowable range from the final detected value, and after the first time. Based on the time between the second time and the value within the predetermined second tolerance, Generating a response information indicating the responsiveness of the electrode, and wherein the measurement system.

[3] The measurement system according to [1] or [2], further including an output device that outputs the responsiveness information.
[4] The measurement system according to any one of [1] to [3], wherein the electrode is a pH electrode.
[5] The measurement system according to any one of [1] to [4], wherein the second sample is a standard sample having a known property.

[6] An electrode evaluation method for evaluating the responsiveness of an electrode that obtains a detection value corresponding to the property of the sample in contact, after the sample that contacts the electrode is exchanged from the first sample to the second sample The time at which the rate of change of the detected value per unit time becomes a predetermined first rate of change is defined as the first time, and after the first time, the rate of change of the detected value per unit time is the first time. A time at which a predetermined second change rate smaller than one change rate is set as a second time, a time between the first time and the second time is obtained as an evaluation time, and based on the evaluation time, A method for evaluating the responsiveness of an electrode.

[7] An electrode evaluation method for evaluating the responsiveness of an electrode that obtains a detection value corresponding to the property of the sample in contact, after the sample that contacts the electrode is exchanged from the first sample to the second sample The detection value when the change rate per unit time of the detection value becomes a predetermined final change rate is the final detection value, and after the sample that contacts the electrode is replaced with the second sample, A time at which the detected value falls within a predetermined first allowable range from the final detected value is defined as a first time, and after the first time, the detected value is changed from the final detected value to the first allowable value. A time within a predetermined second allowable width smaller than a width is set as a second time, a time between the first time and the second time is obtained as an evaluation time, and based on the evaluation time, A method for evaluating the responsiveness of an electrode.

[8] Responsiveness information indicating the responsiveness of the electrode is provided in a measurement system including an electrode that obtains a detection value according to the property of the contacting sample and an arithmetic control device that receives the detection value obtained by the electrode. A program for generating, after the sample in contact with the electrode is exchanged from the first sample to the second sample, the change rate per unit time of the detected value is a predetermined first change rate. The first time is defined as the first time. After the first time, the second time is the time when the rate of change of the detected value per unit time becomes a predetermined second rate of change that is smaller than the first rate of change. And calculating the time between the first time and the second time as an evaluation time, and generating responsiveness information indicating the responsiveness of the electrode based on the evaluation time. A program to be executed.

[9] Responsiveness information indicating the responsiveness of the electrode is provided in a measurement system including an electrode that obtains a detection value according to the property of the sample in contact and an arithmetic control device that receives the detection value obtained by the electrode. A program for generating a sample, wherein a change rate per unit time of the detection value becomes a predetermined final change rate after the sample contacting the electrode is exchanged from the first sample to the second sample. The detected value is a final detected value, and after the sample in contact with the electrode is replaced with the second sample, the detected value is a value within a predetermined first allowable range from the final detected value. The first time is defined as the first time, and after the first time, the second time is defined as the time when the detected value is within a predetermined second allowable range smaller than the first allowable range from the final detected value. And the time between the first time and the second time is the evaluation time. Te calculated, on the basis of the evaluation time, generating a response information indicating the responsiveness of the electrode, a program to be executed by the arithmetic and control unit.

  According to the measurement system, the electrode evaluation method, and the program of the present invention, it is possible to accurately evaluate the electrode response regardless of the degree of automation of the apparatus.

1 is an overall configuration diagram of a measurement system according to an embodiment of the present invention. It is a block diagram which shows the detail of the arithmetic control apparatus part of the measurement system in embodiment of this invention. It is a flowchart of the electrode evaluation method which the measurement system of the embodiment of the present invention performs. It is the figure which showed typically the response curve of a pH electrode with favorable responsiveness. It is the figure which showed typically the response curve of the pH electrode which is not excellent in responsiveness. It is a flowchart of the electrode evaluation method which the measurement system of other embodiments of the present invention performs.

<First Embodiment>
[Device configuration]
A measurement system according to the first embodiment of the present invention will be described. As shown in FIG. 1, the measurement system of the present embodiment includes a pH electrode 1 and a device main body 10, and the pH electrode 1 and the device main body 10 are connected by a lead wire 9.
The pH electrode 1 is immersed in a sample solution 51 placed in a container 50 so as to obtain a potential (detection value) corresponding to the pH of the sample solution 51 (the property of the sample in contact). The pH electrode 1 has a built-in temperature sensor so that temperature information of the sample solution 51 can be obtained. The pH electrode 1 continuously obtains potential and temperature information regardless of whether in the measurement mode or the maintenance mode.

  The apparatus main body 10 includes an arithmetic control device 20 shown in FIG. Further, the operation unit 30 and the display device 11 are provided on the front surface, and the input / output terminal 12 is provided on the inner or outer surface. An analog signal or a digital signal can be output from the input / output terminal 12. In the present embodiment, an example in which an external computer 40 is connected through the input / output terminal 12 is shown.

The display device 11 displays the potential obtained by the pH electrode 1 and the pH corresponding to the potential. The display device 11 can display various types of information that should be recognized by the user, such as responsiveness information generated by the arithmetic and control unit 20.
The input / output terminal 12 and the computer 40 may be directly connected by a cable or may be connected using a communication system.

The arithmetic control device 20 includes a conversion unit 21, a time measurement unit 22, a storage unit 23, and a calculation unit 24. The conversion unit 21 performs impedance conversion and A / D conversion on the potential input from the pH electrode 1 and outputs the result to the calculation unit 24.
The timer unit 22 generates time information and outputs it to the calculator 24. In the present invention, the time simply means a moment in time. However, in order to specify the time, the time from the positive child that is the starting point of the day may be used as the time. The time measuring unit 22 continuously generates time information regardless of the measurement mode or the maintenance mode.

  The storage unit 23 stores an arithmetic expression for converting the potential input from the pH electrode 1 into pH and necessary information (for example, an electromotive force characteristic of the electrode obtained by calibration). Yes. The storage unit 23 can store numerical values (predetermined numerical values such as the first change rate, detection values, etc.) used when the calculation unit 24 performs various calculations.

The calculation unit 24 continuously acquires the time and the potential (detection value) at that time in association with each other in either the measurement mode or the maintenance mode.
Moreover, the calculating part 24 produces | generates the responsiveness information which shows the responsiveness of the pH electrode 1 by performing the below-mentioned step in maintenance mode.

  The operation unit 30 has operation keys 31, 32, 33, and 34. The operation key 31 is a power switch. The operation key 32 is a key for switching between the measurement mode and the maintenance mode, and each time the operation key 32 is pressed, either the measurement mode or the maintenance mode can be selected. The operation key 33 is a key for performing calibration using the first standard solution in the maintenance mode, and the operation key 34 is a key for performing calibration using the second standard solution in the maintenance mode.

[Measurement mode]
The user selects a measurement mode with the operation key 32 when performing pH measurement using a sample to be measured (clean water, drainage, process water, etc.) as the sample liquid 51.
In the measurement system of the present embodiment, while the measurement mode is selected, the calculation unit 24 converts the continuously acquired potential into a pH measurement value that is temperature-compensated based on the temperature information acquired simultaneously. To do. Then, the obtained pH measurement value and temperature are sequentially displayed on the display device 11 and output from the input / output terminal 12 to the computer 40. The computer 40 may also output the time measured by the timer unit 22 when the pH measurement value is acquired.

[Maintenance mode]
When the user performs cleaning or calibration of the pH electrode 1, the user selects the maintenance mode with the operation key 32 before taking out the pH electrode 1 from the sample to be measured.
In the measurement system of the present embodiment, even when the maintenance mode is selected, the calculation unit 24 converts the continuously acquired potential into a pH measurement value that is temperature-compensated based on the temperature information acquired at the same time. .
However, the display device 11 does not display the pH measurement value and the temperature obtained during that time, but displays the “maintenance mode” or the pH measurement value or temperature obtained at the end of the measurement mode. Display dummy information. The computer 40 also outputs a signal indicating the maintenance mode and a signal based on dummy information. Further, the time measured by the time measuring unit 22 when the operation key 32 is pressed may be output together.

  The user can perform standard solution calibration described below with the maintenance mode selected. In addition to the standard solution calibration, the pH electrode 1 can be taken out from the sample to be measured, such as cleaning or replacement of the pH electrode 1.

[Standard solution calibration]
When the user calibrates the pH electrode 1, after selecting the maintenance mode with the operation key 32, the user takes out the pH electrode 1 from the sample to be measured, cleans it with a cleaning solution such as water, and then first selects the first standard. The pH electrode 1 is immersed in the sample solution 51 using the solution as the sample solution 51. As the first standard solution, for example, a pH 7 standard solution having a pH of around 7 is selected.
In addition, the pH electrode 1 is immersed in the sample solution 51 that is the first standard solution, and the operation key 33 is pressed to instruct the arithmetic and control unit 20 to perform a calibration operation using the first standard solution.
When the potential continuously acquired after the operation key 33 is pressed is stabilized, the calculation unit 24 associates the potential with the temperature information acquired at the same time and the pH of the first standard solution at that temperature. To be stored in the storage unit 23.

Next, the user takes out the pH electrode 1 from the first standard solution, cleans it with a cleaning solution such as water, and then immerses the pH electrode 1 in the sample solution 51 using the second standard solution as the sample solution 51. As the second standard solution, for example, a pH 4 standard solution having a pH of around 4 or a pH 9 standard solution having a pH of around 9 is selected.
Further, the pH electrode 1 is immersed in the sample solution 51 which is the second standard solution, and the operation key 34 is pressed to instruct the arithmetic and control unit 20 to perform calibration work using the second standard solution.
When the potential continuously acquired after the operation key 34 is pressed is stabilized, the calculation unit 24 associates the potential with the temperature information acquired simultaneously and the pH of the second standard solution at the temperature. To be stored in the storage unit 23.

In standard solution calibration, the pH of the first standard solution and the second standard solution at that temperature can be obtained from the temperature characteristic table of each standard solution stored in the storage unit 23.
In the standard solution calibration, a known stability determination method can be adopted as appropriate to determine whether or not the acquired potential is stable.

For example, the rate of change of potential per unit time can be used as an index. Specifically, if the difference ΔE between the potential E1 at the time t1 and the potential E2 at the time t2 when the determination time ta has elapsed from the time t1 is within the predetermined allowable range Ea, it is determined to be stable. Without it, it can be determined that it is not stable.
It can also be considered that the potential is stable when the rate of change of the potential per unit time becomes a second rate of change described later.

Further, the fluctuation range per unit time of the potential can be used as an index. Specifically, n potentials E1 to En are acquired from time t3 to time t4 when the determination time tb has elapsed, and the difference ΔE ′ between the maximum potential Emax and the minimum potential Emin is a predetermined value. If it is within the allowable range Eb, it can be determined that it is stable, and if it is not, it can be determined that it is not stable.
Note that whether or not the potential is stable may be determined by using a change rate or a fluctuation range of the pH measurement value converted from the potential at that time as an index.

  The electromotive force characteristics of the electrode can be obtained by determining the correspondence between the pH and potential of the first standard solution and the correspondence between the pH and potential of the second standard solution. In the storage unit 23, the electromotive force characteristics of the obtained electrode or the correspondence between the pH and the potential of the first standard solution that can derive the electromotive force characteristics of the electrode, the correspondence between the pH and the potential of the second standard solution These two points and the temperature information are stored.

[Electrode evaluation]
When the user presses the operation key 33 or presses the operation key 34 after selecting the maintenance mode with the operation key 32, the calculation unit 24 performs the calibration operation using the first standard solution or the second standard solution. In parallel with this, the following steps are sequentially executed to perform electrode evaluation (electrode evaluation method of the present invention).
In the following description of the steps, “calibration key” means either the operation key 33 or the operation key 34. The “standard solution” means either the first standard solution or the second standard solution. Further, the “detected value” in the present embodiment is a potential obtained by the pH electrode 1 or a pH measured value converted from the potential.

Step A1: After the sample solution 51 in contact with the pH electrode 1 is exchanged from a cleaning solution (first sample) such as water to a standard solution (second sample), the rate of change per unit time of the detected value is The time when the predetermined first rate of change is reached is set as the first time.
Step A2: After the first time, a time at which the rate of change per unit time of the detected value becomes a predetermined second rate of change smaller than the first rate of change is defined as a second time.
Step A3: A time between the first time and the second time is obtained as an evaluation time.
Step A4: Responsive information indicating the responsiveness of the electrode is generated based on the evaluation time.
Hereinafter, each step will be described in detail with reference to FIG.

Step A1 is started by pressing the calibration key. First, the rate of change per unit time of the detected value (hereinafter sometimes simply referred to as “change rate”) is calculated based on the continuously acquired detected value and the time counted by the time measuring unit 22. Start (step A1-0).
The rate of change is obtained by dividing the difference ΔD between the detected value Dx at the time tx and the detected value Dy at the time ty after the determination time td from the time tx by td. The rate of change is obtained each time the determination time td elapses.

  It is determined whether or not the rate of change obtained every time the determination time td has elapsed is the first rate of change (step A1-1). When it is not the first rate of change, after confirming that the elapsed time from the start is not longer than the predetermined time (step A1-2), the determination of step A1-1 is repeated. When the determination of step A1-1 is repeated and the obtained change rate becomes the first change rate, the time at that time is stored as the first time T1 in the storage unit 23 (step A1-3).

  Next, it is determined whether or not the change rate obtained every time the determination time td elapses has become the second change rate (step A2-1). When it is not the second rate of change, after confirming that the elapsed time from the start is not longer than the predetermined time (step A2-2), the determination of step A2-1 is repeated. When the determination in step A2-1 is repeated and the obtained change rate becomes the second change rate, the time at that time is stored as the second time T2 in the storage unit 23 (step A2-3) and the change rate is calculated. Is terminated (step A2-4).

Next, the time from the first time T1 to the second time T2 stored in the storage unit 23 is obtained, and this is used as the evaluation time (step A3).
Then, after confirming that the evaluation time is not longer than the predetermined time (step A4-1), normal range responsiveness information is generated (step A4-2), and the electrode evaluation is completed.
When it is not less than the predetermined time in any of Step A1-2, Step A2-2, and Step A4-1, the response information of the abnormal range is generated (Step A4-3), and the electrode evaluation is finished.

For example, when the unit time is 1 second and the determination time td is 3 seconds, the change rate is obtained by obtaining the difference between the detected value acquired every 3 seconds and the detected value acquired 3 seconds before that. It can be obtained by dividing the difference between the detected values by 3.
Usually, since the rate of change decreases with time, the second rate of change is set to a value smaller than the first rate of change. The values of the first rate of change and the second rate of change are not limited, but the second rate of change is preferably a sufficiently small value so that the detected value can be regarded as being almost stable. The first rate of change is preferably set to a value different from the second rate of change to an extent necessary and sufficient to ensure a measurable evaluation time. For example, the first change rate can be set to 0.01 pH / second, and the second change rate can be set to 0.001 pH / second.
The first change rate and the second change rate may be stored in the storage unit 23 in advance, or may be newly set by key input or the like each time.

The first time obtained in step A1 is theoretically the time between the time when the change rate becomes less than the first change rate for the first time and the time before the determination time td (for example, 3 seconds). Similarly, the second time obtained in step A2 is theoretically the time between the time when the change rate becomes less than the second change rate for the first time and the time before the determination time td (for example, 3 seconds). is there.
However, in step A3, since the time between the two times is set as the evaluation time, for the sake of convenience, the time when the change rate becomes less than the first change rate for the first time is regarded as the first time, and the change rate is less than the second change rate for the first time. The time when becomes may be regarded as the second time. Further, in order to avoid the influence of the fluctuation of the detection value based on noise or the like, the time when the change rate is less than the first change rate can be confirmed several times (for example, 3 times) is regarded as the first time, and the change A time at which it has been confirmed several times (for example, three times) that the rate is less than the second change rate may be regarded as the second time. In that case, the number of times that the rate of change is confirmed to be less than the first rate of change and the number of times that the rate of change is confirmed to be less than the second rate of change are aligned.

In order to generate the responsiveness information from the evaluation time, it is preferable that the responsiveness information is classified into a plurality of evaluation categories according to the evaluation time by comparing with one or more predetermined threshold values. For example, a first threshold value to a fourth threshold value are set, and if the evaluation time is less than the first threshold value, state A, if the evaluation time is greater than or equal to the first threshold value and less than the second threshold value, state B, greater than or equal to the second threshold value, and the third threshold value. If it is less than the threshold value, it can be classified as state C, if it is greater than or equal to the third threshold value and less than the fourth threshold value, state D, and if it is greater than or equal to the fourth threshold value, it can be classified.
That is, in the normal range, it is possible to obtain responsiveness information divided into four from the good state A to the state D for which maintenance is recommended (step A4-2). Moreover, if it cannot be said that it is operating normally, the responsiveness information classified into the state E, that is, responsiveness information indicating an abnormal state can be obtained (step A4-3).

Although the specific threshold value is not limited, for example, the first threshold value can be set to 15 seconds, the second threshold value can be set to 30 seconds, the third threshold value can be set to 60 seconds, and the fourth threshold value can be set to 180 seconds.
Further, the responsiveness information is not limited to the classified information. For example, a numerical value obtained by multiplying the evaluation time by a predetermined coefficient (including 1) can be used as the responsiveness information.
The threshold value and the like necessary for generating the responsiveness information may be stored in advance in the storage unit 23, or may be newly set by key input or the like each time.

  In step A1-2 and step A2-2, also when the elapsed time from the start becomes a predetermined time or more, responsiveness information indicating an abnormal state is obtained (step A4-3). Thereby, even when the responsiveness of the detection value is extremely deteriorated, the electrode evaluation can be completed without continuing.

  The generated responsiveness information is displayed on the display device 11. Further, it outputs from the input / output terminal 12 and provides responsiveness information to the external computer 40 or the like. The user can perform maintenance work such as electrode replacement and cleaning according to the generated responsiveness information. In addition, it is possible to predict the life of the electrode and prepare a replacement electrode. When maintenance work such as electrode cleaning is automated, the frequency of maintenance work can be changed according to the responsiveness information.

[Function and effect]
FIG. 4 is a diagram schematically showing a response curve G1 of a pH electrode with good responsiveness, and FIG. 5 is a diagram schematically showing a response curve G2 of a pH electrode with poor responsiveness. In either case, the X axis represents the elapsed time after the pH electrode is immersed in the standard solution, and the Y axis represents the detected value (potential or pH measured value).

In the response curve G1 of FIG. 4, the elapsed time S1 until the first time T1 at which the change rate of the detected value becomes the first change rate is short, whereas in the response curve G2 of FIG. The elapsed time S1 ′ until the first time T1 ′ at which the rate of change is 1 is long.
In the response curve G1, the elapsed time S2 until the second time T2 at which the change rate of the detected value becomes the second change rate is short, whereas in the response curve G2, the change rate of the detected value becomes the second change rate. The elapsed time S2 ′ until the second time T2 ′ is long.

Therefore, if the elapsed time after immersing the pH electrode 1 in the standard solution can be accurately measured, the responsiveness of the pH electrode 1 can be evaluated by the elapsed time S1 (S1 ′) or the elapsed time S2 (S2 ′). it can.
However, if the time (X = 0) when the pH electrode 1 is immersed in the standard solution cannot be specified, the elapsed time S1 (S1 ′) or the elapsed time that is the elapsed time after the pH electrode 1 is immersed in the standard solution S2 (S2 ') cannot be measured accurately.

In the present embodiment, as shown in FIGS. 4 and 5, attention is paid to the fact that the evaluation time ΔS ′ is long in the response curve G2 while the evaluation time ΔS ′ is long in the response curve G2.
The evaluation time ΔS (ΔS ′), which is the elapsed time from the first time T1 (T1 ′) to the second time T2 (T2 ′), is the time (X = 0) when the pH electrode 1 is immersed in the standard solution. Even if it cannot be specified, it can be accurately timed. Therefore, even when the standard solution calibration is performed manually, the electrode response can be accurately evaluated.
In the present embodiment, each step from step A1 to step A4 has been described to be executed sequentially. However, if responsiveness information can be generated based on the above evaluation time, each step is not necessarily executed separately. There is no need to

Second Embodiment
The measurement system according to the second embodiment of the present invention has the same apparatus configuration as the measurement system according to the first embodiment. The operation is also the same as that of the measurement system according to the first embodiment except that the electrode evaluation method is different.
Hereinafter, an electrode evaluation method performed by the measurement system according to the second embodiment will be described.

[Electrode evaluation]
When the user presses the operation key 33 or presses the operation key 34 after selecting the maintenance mode with the operation key 32, the calculation unit 24 performs the calibration operation using the first standard solution or the second standard solution. In parallel with this, the following steps are sequentially executed to perform electrode evaluation (electrode evaluation method of the present invention).
In the following description of steps, the “calibration key” means either the operation key 33 or the operation key 34. The “standard solution” means either the first standard solution or the second standard solution. The “detected value” in the present embodiment is also a potential obtained by the pH electrode 1 or a pH measured value converted from the potential.

Step B1: After the sample solution 51 in contact with the pH electrode 1 is changed from a cleaning solution such as water (first sample) to a standard solution (second sample), the rate of change per unit time of the detected value is The detected value when the predetermined final change rate is reached is set as the final detected value.
Step B2: After the sample solution 51 in contact with the pH electrode 1 is exchanged from a cleaning solution such as water (first sample) to a standard solution (second sample), the detected value is a predetermined value from the final detected value. The time when the value falls within the first tolerance is defined as the first time.
Step B3: After the first time, a time when the detected value becomes a value within a predetermined second allowable range smaller than the first allowable range from the final detected value is set as a second time.
Step B4: A time between the first time and the second time is obtained as an evaluation time.
Step B5: Responsive information indicating the responsiveness of the electrode is generated based on the evaluation time.
Hereinafter, each step will be described in detail with reference to FIG.

Step B1 is started by pressing the calibration key. First, the rate of change per unit time of the detected value (hereinafter sometimes simply referred to as “change rate”) is calculated based on the continuously acquired detected value and the time counted by the time measuring unit 22. Start (step B1-0).
Moreover, it starts to store the detected value continuously acquired in the storage unit 23 in association with the time measured by the time measuring unit 22.

It is determined whether or not the change rate obtained every time the determination time td has passed is the final change rate (step B1-1). When it is not the final change rate, after confirming that the elapsed time from the start is not longer than the predetermined time (step B1-2), the determination of step B1-1 is repeated. When the determination in step B1-1 is repeated and the obtained rate of change becomes the final rate of change, the detected value at that time is stored as the final detected value in the storage unit 23 (step B1-3).
Then, the calculation of the change rate and the operation of storing the detected value in the storage unit 23 in association with the time are finished (step B1-4).
The final change rate may be stored in the storage unit 23 in advance, or may be newly set by key input or the like each time.

Next, a range of detection values within a predetermined first allowable range is calculated from the final detection value (step B2-1). The first allowable width may be stored in the storage unit 23 in advance, or may be newly set by key input or the like each time.
And the time which became the range of the detected value within the said 1st tolerance | permissible_range among the detected values memorize | stored in the memory | storage part 23 is read as 1st time T3 (step B2-2).

Next, a range of detection values within a predetermined second allowable range is calculated from the final detection value (step B3-1). The second allowable width is a value smaller than the first allowable width. The second allowable width may be stored in advance in the storage unit 23, or may be newly set by key input or the like each time.
And the time which became the range of the detected value within the said 2nd tolerance | permissible_range among the detected values memorize | stored in the memory | storage part 23 is read as 2nd time T4 (step B3-2).

Next, the time from the first time T3 to the second time T4 is obtained, and this is used as the evaluation time (step B4).
Then, after confirming that the evaluation time is not longer than the predetermined time (step B5-1), normal range responsiveness information is generated (step B5-2), and the electrode evaluation is terminated.
When it is not less than the predetermined time in either step B1-2 or step B5-1, the response information of the abnormal range is generated (step B5-3), and the electrode evaluation is terminated.

The method of obtaining the change rate is the same as in the first embodiment.
There is no limitation on the value of the final change rate, but it is preferably a sufficiently small value so that the detected value can be regarded as being almost stable. The final change rate can be set to 0.001 pH / second, for example.
Since the fluctuation range of the detected value usually decreases with time, the second time (time when the value is within the second allowable range) is the first time (time when the value is within the first allowable range). ) Later. There is no limitation on the values of the first tolerance width and the second tolerance width, but it is preferable to make the values different from each other to an extent necessary and sufficient to ensure a measurable evaluation time.
The second allowable width may be zero. In that case, the second time T4 is equal to the time when the final change rate is reached.

  The first time T3 obtained in step B2 is theoretically the time when the difference between the detected value and the final detected value becomes a value less than the predetermined first allowable range for the first time, and the determination time td (for example, 3 seconds). ) Time between previous time. Similarly, theoretically, the second time T4 obtained in step B3 is the time when the difference between the detected value and the final detected value becomes less than a predetermined second allowable range for the first time, and the determination time td ( It is a time between the previous time (for example, 3 seconds).

  However, in step B4, the time between the two times is set as the evaluation time. For convenience, the time when the difference between the detected value and the final detected value becomes a value less than the predetermined first allowable range for the first time is set as the first time. It may be regarded as T3, and the time when the difference between the detected value and the final detected value becomes a value less than the predetermined second allowable range for the first time may be regarded as the second time T4. Further, in order to avoid the influence of the fluctuation of the detection value based on noise or the like, the time at which the difference from the final detection value has been confirmed several times (for example, three times) can be confirmed as the first time. It may be regarded as T3, and the time at which the difference from the final detection value is less than the second allowable range can be confirmed several times (for example, three times) as the second time T4. In this case, the number of times that the difference between the final detection value and the final detection value is confirmed to be less than the first allowable width and the number of times that the difference between the final detection value and the final detection value are less than the second allowable width are aligned.

  A mode of generating the responsiveness information from the evaluation time can be the same as in the first embodiment. Further, in step B1-2, responsiveness information indicating an abnormal state is also obtained when the elapsed time from the start becomes a predetermined time or more (step B5-3). Thereby, even when the responsiveness of the detection value is extremely deteriorated, the electrode evaluation can be completed without continuing.

[Function and effect]
The effect of this embodiment is that the first time T1 (T1 ′) and the second time T2 (T2 ′) in FIGS. 4 and 5 are the first time T3 (T3 ′) and the second time T4 (T4 ′). It can be explained by replacing with
Also in this embodiment, attention is paid to the fact that the evaluation time ΔS ′ is short in the response curve G1, whereas the evaluation time ΔS ′ is long in the response curve G2.
The evaluation time ΔS (ΔS ′), which is the elapsed time from the first time T3 (T3 ′) to the second time T4 (T4 ′), is the time (X = 0) when the pH electrode 1 is immersed in the standard solution. Even if it cannot be specified, it can be accurately timed. Therefore, even when the standard solution calibration is performed manually, the electrode response can be accurately evaluated.
In the present embodiment, each step from Step B1 to Step B5 has been described to be executed sequentially. However, if responsiveness information can be generated based on the above-described evaluation time, each step is not necessarily executed separately. There is no need to

<Other embodiments>
In each of the above-described embodiments, an example in which the entire arithmetic and control unit is built in the apparatus main body has been shown. However, a part or all of the arithmetic and control apparatus in the measurement system of the present invention uses a communication system directly or in the apparatus main body. It may be an external computer connected. In that case, a program for causing an external computer to function as part or all of the arithmetic and control unit of the present invention is required.

The program may be recorded in advance on a computer, or may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer.
Further, a program recorded in advance in a computer and a program recorded in a computer-readable recording medium and read into the computer may be combined.

However, in order for an external computer to function as part or all of the arithmetic and control unit according to the present invention, it is necessary to input a detection value subjected to impedance conversion and A / D conversion in advance to the computer. Therefore, it is necessary to leave the conversion part in the said embodiment in an apparatus main body, or to make an electrode have a conversion part.
In addition, the conversion unit in each of the above embodiments may not be a part of the arithmetic control device, and the electrode may be provided with the conversion unit.

  In each of the above-described embodiments, an example in which the display device 11 is provided as an output device has been described. However, the output device is not limited to the display device, and may be a printer, a device that outputs sound, a buzzer, or the like. Further, the output device does not need to be integrated with the device main body, and may be an external output device connected directly or using a communication system.

In the above embodiments, the electrode evaluation is performed both when the operation key 33 is pressed and when the operation key 34 is pressed. However, when the operation key 33 is pressed and the operation key 34 is pressed. It may be performed only on one side.
In each of the above embodiments, the electrode evaluation step is started simultaneously with the pressing of the calibration key. For example, after the maintenance mode is selected with the operation key 32, the sample that contacts the electrode is set to the first one. The change from the sample to the second sample may be recognized by a significant instruction fluctuation of the detected value, and the process may be started when such a significant instruction fluctuation has subsided.

  Further, in each of the above embodiments, the example in which the property of the contacting sample is pH and the electrode that obtains the detection value (potential) according to the property of the contacting sample is a pH electrode. Examples of other electrodes for obtaining detected values include redox electrodes, ion electrodes, and gas electrodes. The detected value is not limited to a potential or a value obtained by converting the potential (pH measurement value in the case of a pH electrode), and may be, for example, a current or a resistance value.

In each of the above embodiments, the second sample is a standard sample having a known property. However, the second sample is not limited to the standard sample. Further, the first sample is not limited to a cleaning liquid such as water. That is, there is no particular limitation on the mode in which the contacting sample is switched.
For example, the first sample may be a sample to be measured (clean water, drainage, process water, etc.), and the second sample may be a cleaning liquid such as acid or alkali. Further, the first sample may be a cleaning solution such as acid or alkali, and the second sample may be a cleaning solution such as water used for rinsing the cleaning solution such as acid or alkali.

Moreover, the aspect which makes an electrode contact a sample is not restricted to the aspect which immerses an electrode in the sample put in the container, For example, the aspect which immerses an electrode in a river, a measurement tank, etc. may be sufficient. Further, the electrode may be brought into contact with the sample to such an extent that a detection value corresponding to the property of the sample in contact can be obtained. For example, the sample may be sprayed on the electrode.
The sample is not limited to a liquid, and may be a gas or a solid.

In each of the above embodiments, an example in which standard solution calibration is performed manually has been described. However, switching from the first sample to the second sample such as standard solution calibration is automated, and a predetermined time schedule is set. You may make it perform along. In this case, the electrode evaluation is not automatically started when the operation key is manually pressed, but automatically when the first sample is switched to the second sample according to a predetermined time schedule. You can do that.
In the electrode evaluation method of the present invention, part or all of the responsiveness evaluation step, for example, the step of obtaining the evaluation time from the first time and the second time may be performed manually.

  DESCRIPTION OF SYMBOLS 1 ... pH electrode, 9 ... Lead wire, 10 ... Apparatus main body, 11 ... Display apparatus, 12 ... Input / output terminal, 20 ... Calculation control apparatus, 21 ... Conversion part, 22 ... Time measuring part, 23 ... Memory | storage part, 24 ... Calculation Part, 30 ... operation part, 31-34 ... operation key, 40 ... computer, 50 ... container, 51 ... sample solution

Claims (9)

An electrode for obtaining a detection value corresponding to the property of the sample to be contacted, and an arithmetic control device to which the detection value obtained by the electrode is input;
The arithmetic and control unit includes a time measuring unit, and a calculation unit that acquires the time measured by the time measuring unit and the detected value at the time in association with each other,
The arithmetic unit is configured to first time when a change rate per unit time of the detection value becomes a predetermined first change rate after the sample contacting the electrode is exchanged from the first sample to the second sample. And after the first time, based on the time between the second time when the rate of change per unit time of the detected value becomes a predetermined second rate of change that is smaller than the first rate of change, Generating responsiveness information indicating the responsiveness of the electrode;
Measuring system characterized by An electrode for obtaining a detection value corresponding to the property of the sample to be contacted, and an arithmetic control device to which the detection value obtained by the electrode is input;
The arithmetic and control unit includes a time measuring unit, and a calculation unit that acquires the time measured by the time measuring unit and the detected value at the time in association with each other,
The calculation unit is configured to detect the detection value when a change rate per unit time of the detection value becomes a predetermined final change rate after the sample contacting the electrode is exchanged from the first sample to the second sample. After the sample in contact with the electrode is exchanged from the first sample to the second sample, the detected value is a value within a predetermined first allowable range from the final detected value. The time between the first time that has become and the second time after the first time when the detected value becomes a value within a predetermined second allowable range smaller than the first allowable range from the final detected value. Generating responsiveness information indicating the responsiveness of the electrode, based on
Measuring system characterized by   The measurement system according to claim 1, further comprising an output device that outputs the responsiveness information.   The measurement system according to claim 1, wherein the electrode is a pH electrode.   The measurement system according to claim 1, wherein the second sample is a standard sample having a known property. An electrode evaluation method for evaluating the responsiveness of an electrode to obtain a detection value according to the property of a sample to be contacted,
After the sample in contact with the electrode is exchanged from the first sample to the second sample, the time when the rate of change per unit time of the detected value becomes a predetermined first rate of change is defined as the first time,
After the first time, a time at which the change rate per unit time of the detection value becomes a predetermined second change rate smaller than the first change rate is defined as a second time,
A time between the first time and the second time is obtained as an evaluation time;
A method of evaluating the responsiveness of the electrode based on the evaluation time. An electrode evaluation method for evaluating the responsiveness of an electrode to obtain a detection value according to the property of a sample to be contacted,
After the sample in contact with the electrode is exchanged from the first sample to the second sample, the detection value when the change rate per unit time of the detection value becomes a predetermined final change rate is finally detected. Value and
After the sample in contact with the electrode is exchanged from the first sample to the second sample, the time when the detection value becomes a value within a predetermined first allowable range from the final detection value is the first time. Time and
After the first time, the time when the detected value becomes a value within a predetermined second allowable range smaller than the first allowable range from the final detected value is set as a second time,
A time between the first time and the second time is obtained as an evaluation time;
A method of evaluating the responsiveness of the electrode based on the evaluation time. In order to cause a measurement system including an electrode that obtains a detection value corresponding to the property of a sample to be contacted and an arithmetic control device to which the detection value obtained by the electrode is input to generate responsiveness information indicating the responsiveness of the electrode The program of
After the sample in contact with the electrode is exchanged from the first sample to the second sample, the time when the rate of change per unit time of the detected value becomes a predetermined first rate of change is defined as the first time,
After the first time, a time at which the change rate per unit time of the detection value becomes a predetermined second change rate smaller than the first change rate is defined as a second time,
A time between the first time and the second time is obtained as an evaluation time;
A program for causing the arithmetic and control unit to generate responsiveness information indicating the responsiveness of the electrode based on the evaluation time. In order to cause a measurement system including an electrode that obtains a detection value corresponding to the property of a sample to be contacted and an arithmetic control device to which the detection value obtained by the electrode is input to generate responsiveness information indicating the responsiveness of the electrode The program of
After the sample in contact with the electrode is exchanged from the first sample to the second sample, the detection value when the change rate per unit time of the detection value becomes a predetermined final change rate is finally detected. Value and
After the sample in contact with the electrode is exchanged from the first sample to the second sample, the time when the detection value becomes a value within a predetermined first allowable range from the final detection value is the first time. Time and
After the first time, the time when the detected value becomes a value within a predetermined second allowable range smaller than the first allowable range from the final detected value is set as a second time,
A time between the first time and the second time is obtained as an evaluation time;
A program for causing the arithmetic and control unit to generate responsiveness information indicating the responsiveness of the electrode based on the evaluation time.

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