JP2008267838A - Apparatus for analyzing liquid quality - Google Patents

Apparatus for analyzing liquid quality Download PDF

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JP2008267838A
JP2008267838A JP2007107606A JP2007107606A JP2008267838A JP 2008267838 A JP2008267838 A JP 2008267838A JP 2007107606 A JP2007107606 A JP 2007107606A JP 2007107606 A JP2007107606 A JP 2007107606A JP 2008267838 A JP2008267838 A JP 2008267838A
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circuit
voltage
potential
measurement
measurement circuit
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Yuichi Ito
裕一 伊東
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Horiba Ltd
株式会社堀場製作所
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Abstract

<P>PROBLEM TO BE SOLVED: To secure highly accurate measurements in an apparatus for analyzing liquid quality, while having a simple circuit configuration by making the apparatus hardly affected by interferences of a sneak current and so on, between sensors or between a measuring circuit system and a main circuit system. <P>SOLUTION: The apparatus for analyzing liquid quality is provided with a sensor part 1, comprising at least a pair of electrodes 11 and 12 to electrochemically analyze the liquid quality of a liquid to be analyzed LQ, the measurement circuit system 2 for making an electric current flow between the electrodes 11 and 12, the main circuit system 3 having a reference different from a reference of the measurement circuit system 2, and a differential amplifying circuit 5 for outputting a difference voltage of their potentials or a voltage proportional to it, on the basis of the reference of the measuring circuit system 2. An output voltage of the differential amplifying circuit 5 is applied to one electrode 11, and the other electrode 12 is maintained at a reference potential of the measurement circuit system 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、溶存酸素センサや導電率センサなどのように、2つ以上の電極を有するセンサにおいて、一方を参照極として他方の電極との間に電圧を印加し、そのとき電極間に流れる電流を測定することにより水質等を分析する液質分析装置に関するものである。   The present invention relates to a sensor having two or more electrodes, such as a dissolved oxygen sensor or a conductivity sensor, in which a voltage is applied between one electrode as a reference electrode and the current flows between the electrodes. The present invention relates to a liquid quality analyzer that analyzes water quality and the like.

この種の液質分析装置においては、複数のセンサを同時に用いて測定することがあるが、その場合に各々のセンサにおける電気回路系の基準を共通にすると、1つのセンサに電圧を印加することで、他のセンサにも液体を通じ電流が流れ、複数のセンサ間での干渉や、情報処理回路などのメイン回路系と電極を含む測定回路系との間での浮遊容量等に起因したノイズなどが発生して、測定に誤差が生じ得る。このことから、従来は、相互の基準を電気的に絶縁するためにフォトカプラ、DC−DCコンバータを用いたり(特許文献1参照)、あるいはセンサをスイッチで切り替えて回路的に切り離し、選択的にいずれかのセンサのみを使用できるようにする(特許文献2、3参照)といったことが行われてきている。
特開2000−74865号 特開平10−221285号 特開平10−221302号
In this type of liquid quality analyzer, measurement may be performed using a plurality of sensors at the same time. In this case, if the standard of the electric circuit system in each sensor is shared, a voltage is applied to one sensor. In other sensors, current flows through the liquid, causing interference between multiple sensors, noise caused by stray capacitance between the main circuit system such as the information processing circuit and the measurement circuit system including electrodes, etc. May occur and errors may occur in the measurement. For this reason, conventionally, a photocoupler or a DC-DC converter is used to electrically insulate the reference from each other (see Patent Document 1), or the sensor is switched by a switch and separated in a circuit, and selectively. Only one of the sensors can be used (see Patent Documents 2 and 3).
JP 2000-74865 A Japanese Patent Laid-Open No. 10-212285 JP-A-10-221302

しかしながら、前者のような方式では、回路が大掛かりになってコストアップや消費電力の増加を招く。一方、後者の方式では、確かに回路的には前者に比べ簡素化されるが、連続測定や同時測定ができなくなるという問題点が生じる。   However, in the former method, the circuit becomes large, resulting in an increase in cost and an increase in power consumption. On the other hand, the latter method is certainly simpler than the former in terms of circuit, but has a problem that continuous measurement and simultaneous measurement cannot be performed.

本発明は、かかる課題を鑑みて行われたものであって、その主たる目的とするところは、簡単な回路構成でありながら、センサ間あるいは測定回路系とメイン回路系との間の電流回りこみなどによる干渉影響を受けにくくし、精度の高い測定を可能とすることにある。   The present invention has been made in view of such a problem, and the main object of the present invention is to circulate current between sensors or between a measurement circuit system and a main circuit system while having a simple circuit configuration. It is to make it difficult to be affected by interference due to the above, and to enable highly accurate measurement.

かかる課題を解決するために本発明は次のような手段を講じたものである。   In order to solve this problem, the present invention provides the following means.

すなわち、本発明にかかる液質分析装置は、   That is, the liquid quality analyzer according to the present invention is

(1)分析対象液の液質を電気化学分析するための、少なくとも一対の電極からなるセンサ部   (1) A sensor unit comprising at least a pair of electrodes for electrochemically analyzing the quality of the liquid to be analyzed

(2)前記センサ部の電極間に電圧を印加するための測定回路系   (2) Measuring circuit system for applying a voltage between the electrodes of the sensor unit

(3)その測定回路系の基準とは別の基準を有するメイン回路系   (3) Main circuit system having a standard different from the standard of the measurement circuit system

を備えている。   It has.

ここで、前記メイン回路系は、その電圧出力端子に、当該メイン回路系の基準電位を基準とした所定電圧を印加する電圧発生回路を備えたものである。   Here, the main circuit system includes a voltage generation circuit that applies a predetermined voltage based on the reference potential of the main circuit system to the voltage output terminal.

また、前記測定回路系は、当該測定回路系の基準電位を基準としたときの、前記電圧出力端子の電位と前記メイン回路系の基準電位とが入力され、それらの差分電圧又はそれに比例する電圧を、当該測定回路系の基準電位を基準として出力する差動増幅回路を備えており、その差動増幅回路の出力電圧を前記電極の一方に印加するとともに、他方の電極は当該測定回路系の基準電位に維持するものである。   Further, the measurement circuit system receives the voltage output terminal potential and the main circuit system reference potential when the reference potential of the measurement circuit system is used as a reference, and the difference voltage or a voltage proportional thereto. Is provided with a differential amplifier circuit that outputs a reference potential of the measurement circuit system as a reference, the output voltage of the differential amplifier circuit is applied to one of the electrodes, and the other electrode is connected to the measurement circuit system. The reference potential is maintained.

前記センサ部は単一でもよいが、複数としてもよい。その場合、各センサ部にそれぞれ対応付けて測定回路系を設けるとともに、各測定回路系の基準を互いに独立させておくことが好ましい。   The sensor unit may be single or plural. In this case, it is preferable that a measurement circuit system is provided in association with each sensor unit, and that the reference of each measurement circuit system is independent from each other.

このように構成した本発明によれば、メイン回路系においてその基準と電圧出力端子と間で発生させた電位差(又はそれに比例する電位差)を、差動増幅回路によって、別の独立した基準を有する測定回路系にそのまま移行できる。したがって、測定回路系とメイン回路系との間の基準を通じた電流回りこみなどによる干渉影響を受けにくくし、精度の高い測定が可能となる。   According to the present invention configured as described above, the potential difference generated between the reference and the voltage output terminal in the main circuit system (or a potential difference proportional thereto) has another independent reference by the differential amplifier circuit. It can be transferred directly to the measurement circuit system. Therefore, it is less susceptible to interference caused by current wrapping through the reference between the measurement circuit system and the main circuit system, and high-precision measurement is possible.

さらに、前記他方の電極からの出力電流を前記測定回路系の基準電位からの電圧に変換する電流−電圧変換回路と、前記電流−電圧変換回路の出力電圧を前記メイン回路系の基準電位を基準として出力する第2差動増幅回路と、をさらに備えていることが望ましい。   Furthermore, a current-voltage conversion circuit that converts the output current from the other electrode into a voltage from the reference potential of the measurement circuit system, and the output voltage of the current-voltage conversion circuit is referenced to the reference potential of the main circuit system It is desirable to further include a second differential amplifier circuit that outputs as

また、差動増幅回路を巧みに利用しており、フォトカプラやDC−DCコンバータなどのような大掛かりな部品が不要なので、消費電力やコストの低減に寄与し得る。   Further, since the differential amplifier circuit is skillfully used and large components such as a photocoupler and a DC-DC converter are unnecessary, it can contribute to reduction of power consumption and cost.

前記センサ部を複数とし、それらセンサ部にそれぞれ測定回路系を設けるとともに、各測定回路系の基準を互いに独立させておけば、単一の電圧発生回路で複数のセンサ部を駆動しながらも、各測定回路系間での干渉等を防止し、それらセンサ部での同時連続測定を、精度よく行うことができる。   With a plurality of the sensor units, each of the sensor units is provided with a measurement circuit system, and the reference of each measurement circuit system is independent from each other, while driving a plurality of sensor units with a single voltage generation circuit, It is possible to prevent interference between the measurement circuit systems and perform simultaneous and continuous measurement with high accuracy.

以下、本発明の一実施形態について図面を参照して説明する。   Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

本実施形態に係る液質分析装置100は、例えば水などの溶液に含まれる溶存酸素を電気化学的に測定するものであって、図1にその概要ブロック図を、図2に具体的な回路図をそれぞれ示すように、分析対象液たる水LQの液質を電気化学分析するためのセンサ部1と、前記センサ部1に電流を流すための測定回路系2と、その測定回路系2の基準(又はコモン、図中、逆三角形の中に1を記載して表現している)とは別の基準(又はコモン、図中、逆三角形の中に0を記載して表現している)を有するメイン回路系3とを備えている。   The liquid quality analyzer 100 according to the present embodiment electrochemically measures dissolved oxygen contained in a solution such as water, for example. FIG. 1 is a schematic block diagram thereof, and FIG. As shown in the figures, a sensor unit 1 for electrochemically analyzing the quality of water LQ as an analysis target liquid, a measurement circuit system 2 for passing a current through the sensor unit 1, and a measurement circuit system 2 Standard (or common, 1 in the inverse triangle in the figure) and another standard (or 0 in the common, triangle in the figure) And a main circuit system 3 having

各部を詳述する。   Each part will be described in detail.

センサ部1は、測定対象となる水LQに浸される一対の電極、すなわち作用極12及び参照極11を有するものであるが、さらに対極を備えた3極構造のものでもよい(3極構造のものに関しては後述する)。   The sensor unit 1 has a pair of electrodes immersed in the water LQ to be measured, that is, a working electrode 12 and a reference electrode 11, but may further have a three-pole structure having a counter electrode (a three-pole structure). Will be described later).

メイン回路系3は、測定結果を処理する図示しない情報処理回路等とグランドコモンや電源を共通にしたもので、電圧発生回路4を備えている。この電圧発生回路4は、図2に示すように、例えば電源電圧を抵抗により分圧することで、このメイン回路系3の基準電位に対して所定電位差を有する電圧を発生する抵抗回路41と、その抵抗回路41に接続されてインピーダンス変換を行い、前記電圧を電圧出力端子4aから出力するバッファ回路42とを備えたものである。   The main circuit system 3 shares a common ground and power supply with an information processing circuit (not shown) that processes measurement results, and includes a voltage generation circuit 4. As shown in FIG. 2, the voltage generation circuit 4 divides a power supply voltage by a resistor, for example, to generate a voltage having a predetermined potential difference with respect to the reference potential of the main circuit system 3, and its resistance circuit 41 A buffer circuit 42 is connected to the resistor circuit 41, performs impedance conversion, and outputs the voltage from the voltage output terminal 4a.

一方、前記測定回路系2は、電極11、12間に前記所定電圧を印加し、電極11、12を通じて測定対象である水LQに電流を流すためのものであり、この実施形態では差動増幅回路5を備えている。   On the other hand, the measurement circuit system 2 is for applying the predetermined voltage between the electrodes 11 and 12 and for passing a current through the electrodes 11 and 12 to the water LQ to be measured. A circuit 5 is provided.

この差動増幅回路5は、図1に示すように、当該測定回路系2の基準電位を基準とした前記電圧出力端子4aの電位と、同じく測定回路系2の基準電位を基準とした前記メイン回路系3の基準電位とをそれぞれ入力され、それらの差分電圧又はそれに比例する電圧を、当該測定回路系2の基準電位を基準として発生するものである。   As shown in FIG. 1, the differential amplifier circuit 5 includes the main output with reference to the potential of the voltage output terminal 4a based on the reference potential of the measurement circuit system 2 and the reference potential of the measurement circuit system 2. A reference potential of the circuit system 3 is inputted, and a differential voltage or a voltage proportional thereto is generated with reference to the reference potential of the measurement circuit system 2.

この差動増幅回路5の具体的回路構成につき、図2を参照して簡単に説明しておくと、当該差動増幅回路5は、この測定回路系2の基準電位を基準として動作する増幅器51を備えている。この増幅器51の非反転入力端子51aには、前記電圧発生回路4の出力端子4aと、この測定回路系2の基準とが、同じ値の抵抗を介してそれぞれ接続されており、反転入力端子51bには、前記メイン回路系3の基準と当該増幅器51の出力端子51cとが、やはり同じ値の抵抗を介してそれぞれ接続されている。また、前記出力端子51cは、前記参照極11にも接続されている。   A specific circuit configuration of the differential amplifier circuit 5 will be briefly described with reference to FIG. 2. The differential amplifier circuit 5 is an amplifier 51 that operates based on the reference potential of the measurement circuit system 2. It has. The non-inverting input terminal 51a of the amplifier 51 is connected to the output terminal 4a of the voltage generation circuit 4 and the reference of the measurement circuit system 2 via resistors of the same value, respectively, and the inverting input terminal 51b. Are connected to the reference of the main circuit system 3 and the output terminal 51c of the amplifier 51 through resistors of the same value. The output terminal 51 c is also connected to the reference electrode 11.

さらに、この測定回路系2は、電流−電圧変換回路6を備えており、前記作用極12は、この電流−電圧変換回路6の反転入力端子に接続されている。この反転入力端子は、さらに電流−電圧変換抵抗を介して、当該電流−電圧変換回路6の出力端子にも接続されている。一方、この電流−電圧変換回路6の非反転入力端子は、測定回路系2の基準に接続されている。このような構成により、入力端子間のイマジナリショートを利用して作用極12が測定回路系2の基準と等しい電位に保たれ、かつこの作用極12を流れる電流が、測定回路系2の基準電位を基準とした電圧として出力されるようにしている。   Further, the measurement circuit system 2 includes a current-voltage conversion circuit 6, and the working electrode 12 is connected to an inverting input terminal of the current-voltage conversion circuit 6. The inverting input terminal is further connected to the output terminal of the current-voltage conversion circuit 6 via a current-voltage conversion resistor. On the other hand, the non-inverting input terminal of the current-voltage conversion circuit 6 is connected to the reference of the measurement circuit system 2. With such a configuration, the working electrode 12 is maintained at a potential equal to the reference of the measurement circuit system 2 using an imaginary short between the input terminals, and the current flowing through the working electrode 12 is the reference potential of the measurement circuit system 2. Is output as a reference voltage.

そして、前記電流−電圧変換回路6の出力電圧は、メイン回路系3を構成する第2差動増幅回路7によって、メイン回路系3の基準電位を基準にした同じ電圧となって差動増幅回路7にある増幅器の出力端子71cからメイン回路系3に伝達される。   The output voltage of the current-voltage conversion circuit 6 becomes the same voltage with reference to the reference potential of the main circuit system 3 by the second differential amplifier circuit 7 constituting the main circuit system 3. 7 is transmitted from the output terminal 71 c of the amplifier 7 to the main circuit system 3.

次に、前述した参照極11の電位につき考察する。   Next, the potential of the reference electrode 11 will be considered.

メイン回路系3の基準電位をVc1、前記所定電位差をvとすると、前記電圧発生回路4の出力端子4aの電位Vo1は、 When the reference potential of the main circuit system 3 is V c1 and the predetermined potential difference is v, the potential V o1 of the output terminal 4 a of the voltage generation circuit 4 is

o1=Vc1+v ・・・(1) V o1 = V c1 + v (1)

と表せる。以下、特に断りなく電位と言うときは、電位が0である仮想点を基準とした絶対電位を言う。   It can be expressed. Hereinafter, the term “potential” without particular notice refers to an absolute potential based on a virtual point where the potential is zero.

一方、測定回路系2の基準電位をVc2とすると、差動増幅回路5における増幅器51の非反転入力端子51aの電位Vi1は、式(1)を考慮して、 On the other hand, assuming that the reference potential of the measurement circuit system 2 is V c2 , the potential V i1 of the non-inverting input terminal 51 a of the amplifier 51 in the differential amplifier circuit 5 is calculated by considering the equation (1).

i1=(Vo1+Vc2)/2
=(Vc1+Vc2+v)/2 ・・・(2)
V i1 = (V o1 + V c2 ) / 2
= (V c1 + V c2 + v) / 2 (2)

と表せる。   It can be expressed.

ところで、反転入力端子51bの電位Vi2は、イマジナリショートが成立して非反転入力端子51aの電位Vi1と等しいことから、この増幅器51の裸のゲインを実質的に無限大と考えれば、この増幅器51の出力端子51cの電位Vo2は、式(2)を考慮して、 By the way, the potential V i2 of the inverting input terminal 51b is equal to the potential V i1 of the non-inverting input terminal 51a because an imaginary short is established. The potential V o2 of the output terminal 51c of the amplifier 51 is determined in consideration of the equation (2).

o2=2・Vi1−Vc1
=(Vc1+Vc2+v)−Vc1
=Vc2+v ・・・(3)
V o2 = 2 · V i1 −V c1
= (V c1 + V c2 + v) −V c1
= V c2 + v (3)

と表せる。   It can be expressed.

したがって、増幅器出力端子51cの、測定回路系基準電位に対する電位差v1は、   Therefore, the potential difference v1 of the amplifier output terminal 51c with respect to the measurement circuit system reference potential is

v1=Vo2−Vc2
=v ・・・(4)
v1 = V o2 −V c2
= V (4)

となり、結局、メイン回路系3でその基準電位を基準として発生させた所定電位差vと等しくなる。   Eventually, it becomes equal to the predetermined potential difference v generated with the reference potential as a reference in the main circuit system 3.

このことは、メイン回路系3において、その基準と電圧出力端子4aと間で発生させた電位差(又はそれに比例する電位差)を、差動増幅回路5によって、別の独立した基準を有する測定回路系2にそのまま移行できることを示している。   This is because, in the main circuit system 3, a potential difference (or a potential difference proportional thereto) generated between the reference and the voltage output terminal 4a is measured by the differential amplifier circuit 5 to have another independent reference. 2 shows that it can be transferred as it is.

したがって、測定回路系2とメイン回路系3との間の基準を通じた電流回りこみなどによる干渉影響を受けにくくし、精度の高い測定が可能となる。   Therefore, it is difficult to be affected by interference caused by current flow through the reference between the measurement circuit system 2 and the main circuit system 3, and highly accurate measurement is possible.

また、差動増幅回路5を巧みに利用しており、フォトカプラやDC−DCコンバータなどのような大掛かりな部品が不要なので、消費電力やコストの低減に寄与し得る。   Further, since the differential amplifier circuit 5 is skillfully used and large components such as a photocoupler and a DC-DC converter are unnecessary, it can contribute to reduction of power consumption and cost.

さらに、前述した作用極12の電位は、上記と同様に、電流−電圧変換回路6及び第2差動変換回路7によりVc1、Vc2とは無関係に第2差動変換回路7の出力端子71cから出力される。 Further, the potential of the working electrode 12 described above is output from the output terminal of the second differential conversion circuit 7 by the current-voltage conversion circuit 6 and the second differential conversion circuit 7 independently of V c1 and V c2 , as described above. 71c.

なお、本発明は前記実施形態に限られるものではない。   The present invention is not limited to the above embodiment.

例えば、図3に示すように、センサ部1が3極構造の場合、増幅器8をさらに設け、その増幅器8の非反転入力端子8aに、前記差動増幅回路5の出力端子51cを接続するとともに、反転端子8bに参照極11を接続し、対極13に増幅器8の出力端子8cを接続した構成が一例として考えられる。このようなものであれば、参照極11には電流が流れない一方で、その電位は、前記増幅器8の入力端子8a、8b間がイマジナリショートであることから差動増幅回路5の出力端子の電位と等しく保たれる。また、この構成の場合、対極から電流が作用極12に供給されることとなり、その対極の電位は、増幅器8のフィードバック作用によって参照極11と等しく保たれることとなる。   For example, as shown in FIG. 3, when the sensor unit 1 has a three-pole structure, an amplifier 8 is further provided, and the output terminal 51 c of the differential amplifier circuit 5 is connected to the non-inverting input terminal 8 a of the amplifier 8. A configuration in which the reference electrode 11 is connected to the inverting terminal 8b and the output terminal 8c of the amplifier 8 is connected to the counter electrode 13 is considered as an example. In such a case, no current flows through the reference electrode 11, but the potential is an imaginary short between the input terminals 8 a and 8 b of the amplifier 8. It is kept equal to the potential. In the case of this configuration, a current is supplied from the counter electrode to the working electrode 12, and the potential of the counter electrode is kept equal to the reference electrode 11 by the feedback action of the amplifier 8.

また、図4に示すように、同種又は異種のセンサ部1を複数設けるようにしてもよい。ここでは、それらセンサ部1にそれぞれ測定回路系2を設けるとともに、各測定回路系2の基準を互いに独立させ、さらに電圧発生回路4は共通にしている。   Further, as shown in FIG. 4, a plurality of the same type or different types of sensor units 1 may be provided. Here, the measurement circuit system 2 is provided in each of the sensor units 1, the reference of each measurement circuit system 2 is made independent from each other, and the voltage generation circuit 4 is made common.

このようなものであれば、単一の電圧発生回路4で済むうえに、各測定回路系2間あるいはメイン回路系3との間での干渉等を防止し、それらセンサ部1での同時連続測定を、精度よく行うことができる。なお、図3、図4で、前記実施形態に対応する部材には同一の符号を付している。   In such a case, a single voltage generation circuit 4 is sufficient, and interference between the measurement circuit systems 2 or the main circuit system 3 is prevented. Measurement can be performed with high accuracy. In FIGS. 3 and 4, members corresponding to those of the above embodiment are denoted by the same reference numerals.

さらに、前記実施形態では、液質分析装置100を、水の溶存酸素を測定する水質分析装置として使用していたが、電極間に電圧を印加することで測定を行う残留塩素、導電率など水の他の属性を測定するものに応用しても構わないし、水のみならず、他の液体の分析に用いても構わない。   Furthermore, in the said embodiment, although the liquid quality analyzer 100 was used as a water quality analyzer which measures the dissolved oxygen of water, water, such as residual chlorine and electrical conductivity which measure by applying a voltage between electrodes, is measured. You may apply to what measures other attributes, and may use it for analysis of not only water but other liquids.

その他、本発明は前記図示例に限られるものではなく、その趣旨を逸脱しない範囲で、種々変形が可能である。   In addition, the present invention is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

本発明の一実施形態における液質分析装置の模式的機能ブロック図。The typical functional block diagram of the liquid quality analyzer in one embodiment of the present invention. 同実施形態における液質分析装置の概略回路構成図。The schematic circuit block diagram of the liquid quality analyzer in the same embodiment. 本発明の一変形例における液質分析装置の概略回路構成図。The schematic circuit block diagram of the liquid quality analyzer in one modification of this invention. 本発明のさらに他の変形例における液質分析装置の模式的機能ブロック図。The typical functional block diagram of the liquid quality analyzer in the further another modification of this invention.

符号の説明Explanation of symbols

LQ・・・分析対象液(水)
11、12・・・電極(参照極、作用極)
100・・・液質分析装置
1・・・センサ部
2・・・測定回路系
3・・・メイン回路系
4・・・電圧発生回路
4a・・・電圧出力端子
21・・・差動増幅回路


LQ: Analysis target liquid (water)
11, 12 ... Electrode (reference electrode, working electrode)
DESCRIPTION OF SYMBOLS 100 ... Liquid quality analyzer 1 ... Sensor part 2 ... Measurement circuit system 3 ... Main circuit system 4 ... Voltage generation circuit 4a ... Voltage output terminal 21 ... Differential amplifier circuit


Claims (4)

分析対象液の液質を電気化学分析するための、少なくとも一対の電極からなるセンサ部と、前記センサ部の電極間に電圧を印加するための測定回路系と、その測定回路系の基準とは別の基準を有するメイン回路系と、を備えたものであり、
前記メイン回路系は、その電圧出力端子に当該メイン回路系の基準電位に対して所定電位差を有する電圧を印加する電圧発生回路を備えており、
前記測定回路系は、当該測定回路系の基準電位に基づく前記電圧出力端子の電位と前記メイン回路系の基準電位とが入力され、入力されたそれら電位の差分電圧又はそれに比例する電圧を、当該測定回路系の基準電位を基準として出力する差動増幅回路を備えており、その差動増幅回路の出力電圧を前記電極の一方に印加するとともに、他方の電極は当該測定回路系の基準電位に維持するものである液質分析装置。
A sensor unit composed of at least a pair of electrodes for electrochemical analysis of the quality of the liquid to be analyzed, a measurement circuit system for applying a voltage between the electrodes of the sensor unit, and a reference for the measurement circuit system A main circuit system having another standard, and
The main circuit system includes a voltage generation circuit that applies a voltage having a predetermined potential difference to a reference potential of the main circuit system to a voltage output terminal thereof,
The measurement circuit system is inputted with the potential of the voltage output terminal based on the reference potential of the measurement circuit system and the reference potential of the main circuit system, and calculates the difference voltage of the inputted potentials or a voltage proportional thereto. A differential amplifier circuit that outputs the reference potential of the measurement circuit system as a reference is provided, and the output voltage of the differential amplifier circuit is applied to one of the electrodes, and the other electrode is set to the reference potential of the measurement circuit system. Liquid quality analyzer that is to be maintained.
前記他方の電極からの出力電流を前記測定回路系の基準電位からの電圧に変換する電流−電圧変換回路と、
前記電流−電圧変換回路の出力電圧を前記メイン回路系の基準電位を基準として出力する第2差動増幅回路と、をさらに備えている請求項1記載の液質分析装置。
A current-voltage conversion circuit that converts an output current from the other electrode into a voltage from a reference potential of the measurement circuit system;
The liquid quality analyzer according to claim 1, further comprising: a second differential amplifier circuit that outputs an output voltage of the current-voltage conversion circuit with reference to a reference potential of the main circuit system.
複数のセンサ部と、それら各センサ部にそれぞれ対応する複数の測定回路系を具備し、各測定回路系の基準を互いに独立させている請求項1又は2記載の液質分析装置。   The liquid quality analyzer according to claim 1, further comprising a plurality of sensor units and a plurality of measurement circuit systems respectively corresponding to the sensor units, wherein the standards of the measurement circuit systems are independent from each other. 水質分析に用いられるものであって、前記センサ部が、溶存酸素、残留塩素、又は導電率を測定するためのものである請求項1、2又は3記載の液質分析装置。
4. The liquid quality analyzer according to claim 1, wherein the liquid quality analyzer is used for water quality analysis, wherein the sensor unit is for measuring dissolved oxygen, residual chlorine, or conductivity.
JP2007107606A 2007-04-16 2007-04-16 Apparatus for analyzing liquid quality Pending JP2008267838A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104122376A (en) * 2014-06-30 2014-10-29 南京领先环保技术有限公司 Multi-parameter water quality analyzer
CN105955333A (en) * 2016-07-05 2016-09-21 杭州美仪自动化有限公司 Ph controller
KR101959533B1 (en) * 2018-11-06 2019-03-18 (주)신우에프에이 Metal type PH sensor for acid and alkali distinguishing

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104122376A (en) * 2014-06-30 2014-10-29 南京领先环保技术有限公司 Multi-parameter water quality analyzer
CN104122376B (en) * 2014-06-30 2016-05-25 南京领先环保技术股份有限公司 A kind of multiparameter water quality analyzer
CN105955333A (en) * 2016-07-05 2016-09-21 杭州美仪自动化有限公司 Ph controller
KR101959533B1 (en) * 2018-11-06 2019-03-18 (주)신우에프에이 Metal type PH sensor for acid and alkali distinguishing

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