JPS6111655Y2 - - Google Patents
Info
- Publication number
- JPS6111655Y2 JPS6111655Y2 JP14619679U JP14619679U JPS6111655Y2 JP S6111655 Y2 JPS6111655 Y2 JP S6111655Y2 JP 14619679 U JP14619679 U JP 14619679U JP 14619679 U JP14619679 U JP 14619679U JP S6111655 Y2 JPS6111655 Y2 JP S6111655Y2
- Authority
- JP
- Japan
- Prior art keywords
- cell
- constant
- conductivity meter
- equation
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005259 measurement Methods 0.000 claims description 11
- 238000010586 diagram Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 3
- 230000003321 amplification Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
Description
【考案の詳細な説明】
本考案は測定セルを用いて液体の導電率を測定
する装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the conductivity of a liquid using a measuring cell.
周知のように、測定セルを用いる導電率計は、
測定セルに被測定液を満たし、測定セルの電極間
に一定振幅の交番電圧を印加し、液中に流れる電
流を測定する方式が一般的である。すなわち、電
極間抵抗Reは被測定液の導電率Ｋの逆数に比例
することから(1)式の関係となり、電極間の印加電
圧ＶKとすれば、電極間を流れる電流Ｉおよび導
電率計の出力Vo（表示部への入力）との間に(2)
式の関係が成り立つ。 As is well known, a conductivity meter using a measuring cell is
A common method is to fill a measurement cell with a liquid to be measured, apply an alternating voltage of constant amplitude between the electrodes of the measurement cell, and measure the current flowing in the liquid. In other words, since the interelectrode resistance Re is proportional to the reciprocal of the conductivity K of the liquid to be measured, the relationship is expressed by equation (1).If the applied voltage between the electrodes is VK , then the current I flowing between the electrodes and the conductivity meter (2) between the output Vo (input to the display) of
The relationship of the formula holds true.
Rc＝Ｊ・１／Ｋ (1)
但し、Ｊはセル定数（比例定数）
Vo ∝Ｉ＝ＶＫ／Ｒｃ＝ＶＫ／Ｊ・Ｋ (2)
(2)式において、ＶKおよびＪが一定であれば、
表示部の表示値は導電率Ｋに比例したものにな
る。しかしながら、セル定数Ｊは機械構造的な寸
法（電極の形状）によつて決まる性質のものであ
つて、製造上のばらつきは避け難い。したがつ
て、通常、測定セル個々に、あらかじめセル定数
を求めておいて、測定時に信号変換器に内蔵する
電気的調整手段でセル定数のばらつきを補正する
ようになつている。 Rc=J・1/K (1) However, J is a cell constant (proportional constant) Vo ∝I=V K /Rc=V K /J・K (2) In formula (2), V K and J are constant If,
The value displayed on the display section is proportional to the conductivity K. However, the cell constant J is a property determined by mechanical structural dimensions (electrode shape), and manufacturing variations are unavoidable. Therefore, normally, cell constants are determined in advance for each measurement cell, and variations in cell constants are corrected during measurement using electrical adjustment means built into the signal converter.
第１図は、従来の導電率計の基本回路構成図で
ある。差動増幅器U1は抵抗R1および可変抵抗R2
からなる感度調整手段を具備するバツフア増幅回
路を構成して、その入力端子に波高値V1が一定
な交番電圧が印加されている。可変抵抗R2のブ
ラシは第２図のようなダイヤルと連動する構成と
なつている。バツフア増幅回路の出力V2は、そ
の出力端子T2と後述する同期整流回路の入力端
子T3との間に接続される測定セルRc（電極間抵
抗もRc）の印加電圧となる。 FIG. 1 is a basic circuit configuration diagram of a conventional conductivity meter. Differential amplifier U 1 consists of resistor R 1 and variable resistor R 2
A buffer amplification circuit is constructed which includes a sensitivity adjustment means consisting of the following, and an alternating voltage with a constant peak value V1 is applied to its input terminal. The brush of the variable resistor R2 is configured to work in conjunction with a dial as shown in Figure 2. The output V 2 of the buffer amplifier circuit becomes the voltage applied to a measurement cell Rc (also has an interelectrode resistance Rc) connected between its output terminal T 2 and an input terminal T 3 of a synchronous rectification circuit described later.
同期整流回路は、コンデンサＣからなる負帰還
回路を具備する差動増幅器U2、この増幅器U2に
交番電圧に同期し、かつ交番電圧の一方のみ（図
では負電圧）を与える手段、すなわち半導体スイ
ツチS1およびS2からなる増幅器U2の入力回路な
らびに増幅器U2の出力V3を同期整流回路の入力
端子T3に帰還する抵抗Ｒfで構成されている。 The synchronous rectifier circuit consists of a differential amplifier U 2 equipped with a negative feedback circuit consisting of a capacitor C, a means for synchronizing this amplifier U 2 with an alternating voltage, and supplying only one of the alternating voltages (the negative voltage in the figure), that is, a semiconductor device. It consists of an input circuit of an amplifier U 2 consisting of switches S 1 and S 2 and a resistor R f that feeds back the output V 3 of the amplifier U 2 to the input terminal T 3 of the synchronous rectifier circuit.
上記構成において、各符号は各々の値をも示す
ものとして以下の式を得る。 In the above configuration, the following equation is obtained assuming that each code also indicates each value.
V2＝Ｒ１＋ρＲ２／Ｒ１V1 (3) 但し、ρは可変抵抗R3の係数 V3＝Ｒｆ／Ｒｃ・Ｒ１＋ρＲ２／Ｒ１・V1 (4) (4)式に(1)式を代入して(5)式を得る。 V 2 = R 1 + ρR 2 /R 1 V 1 (3) However, ρ is the coefficient of variable resistor R 3 V 3 = R f /R c・R 1 + ρR 2 /R 1・V 1 (4) (4) Substitute equation (1) into equation to obtain equation (5).
V3＝Ｋ／Ｊ・Ｒ１＋ρＲ２／Ｒ１・Ｒf・V1(5)
(5)式において、R1，R2，ＲfおよびV1は一定で
あり、いま、セル定数Ｊのばらつきに合せてρを
可変することによつて、出力V3は補正された信
号として得ることができる。 V 3 =K/J・R 1 +ρR 2 /R 1・R f・V 1 (5) In formula (5), R 1 , R 2 , R f and V 1 are constant, and now the cell constant J By varying ρ in accordance with the variations in ρ, the output V 3 can be obtained as a corrected signal.
このような従来の導電率計において、補正操作
は可変抵抗R2のブラシに連結するダイヤルの目
盛を、ばらつき量に対応して合せていた。この時
の問題として、
(1) この補正の精度は、補正回路の抵抗値および
ダイヤルの目盛の精度によつて決まる。 In such a conventional conductivity meter, the correction operation was performed by adjusting the scale of a dial connected to the brush of the variable resistor R2 in accordance with the amount of variation. The problems at this time are: (1) The accuracy of this correction is determined by the resistance value of the correction circuit and the accuracy of the dial scale.
(2) 可変抵抗のブラシとダイヤルの連結には位置
合せ（抵抗値と目盛の対応を決めること）が必
要で工数を要する。(2) Connecting the variable resistance brush and dial requires alignment (determining the correspondence between resistance value and scale), which requires a lot of man-hours.
があつた。It was hot.
本考案は上述の点に鑑みてなされたものであ
り、その目的は、セル定数の補正を精度よくなし
得る導電率計を提供するにある。 The present invention has been made in view of the above-mentioned points, and its purpose is to provide a conductivity meter that can accurately correct cell constants.
本考案の第２の目的は、調整手段にダイヤル目
盛を必要とせず、したがつて製造工数を軽減した
導電率計を提供するにある。 A second object of the present invention is to provide a conductivity meter that does not require a dial scale for the adjustment means, thus reducing the number of manufacturing steps.
以下、図面を参照して本考案について詳説す
る。 Hereinafter, the present invention will be explained in detail with reference to the drawings.
第３図は本考案の一実施例による導電率計の基
本回路構成説明図である。第３図において、第１
図と同一符号は同一構成および同一作用をなすも
のなので、ここでの説明を省略する。 FIG. 3 is an explanatory diagram of the basic circuit configuration of a conductivity meter according to an embodiment of the present invention. In Figure 3, the first
Since the same reference numerals as those in the drawings have the same configuration and the same function, the description thereof will be omitted here.
第３図の構成の特徴は、測定セルRcに並列的
構成で、かつ回路接続がスイツチS3によつて択一
される基準抵抗ＲKを具備した点にある。また、
従来例において、セル定数の補正操作に必ずしも
必要としなかつた導電率計の表示部Ｍを具備する
こととした点にある。本実施例においては表示部
Ｍはデジタル表示であるため、アナログデジタル
変換部Ａ／Ｄを具備している。 A feature of the configuration shown in FIG. 3 is that the measurement cell Rc is provided with a reference resistor RK which is arranged in parallel and whose circuit connection is selected by a switch S3 . Also,
In the conventional example, a display section M of a conductivity meter is provided, which is not necessarily required for cell constant correction operations. In this embodiment, since the display section M is a digital display, it is equipped with an analog-to-digital conversion section A/D.
このような本考案による導電率計のセル定数の
補正は以下のとおりである。 Correction of the cell constant of the conductivity meter according to the present invention is as follows.
あらかじめ、基準抵抗ＲKの値は基準の測定セ
ル（セル定数はJo）の電極間の最小抵抗値Rco
（測定レンジによつて決まる値で一定値）に選定
されているものとする。 In advance, the value of the reference resistance R K is determined from the minimum resistance value Rco between the electrodes of the reference measurement cell (cell constant Jo).
(a constant value determined by the measurement range).
いま、セル定数Ｊが(6)式の関係を有する測定セ
ルを使用するときについて説明する。 Now, a case will be described in which a measurement cell in which the cell constant J has the relationship expressed by equation (6) is used.
Ｊ＝ρJo (6)
βはセル定数のばらつきを示す量で個々のセル
によつて定まり、定数として扱うことができる。 J=ρJo (6) β is a quantity indicating variation in cell constants, is determined by each individual cell, and can be treated as a constant.
スイツチS3をｂ側にしたときの出力V3′は(7)式
となる。 The output V 3 ' when the switch S 3 is set to the b side is expressed by equation (7).
V3′＝Ｒｆ／ＲＫ・Ｒ１＋ρＲ２／Ｒ１・V1 (7)
また、スイツチS3をａ側にしたときの出力
V3′は(4)′式となる。 V 3 ′=R f /R K・R 1 +ρR 2 /R 1・V 1 (7) Also, the output when switch S 3 is set to a side
V 3 ′ becomes equation (4)′.
V3′＝Ｒｆ／Ｒｃ・Ｒ１＋ρＲ２／Ｒ１・V1＝V3(4)
′
そして、(7)式で得られる出力V3′による表示部
Ｍの指示が(8)式となるように、可変抵抗R2を可
変して合わせる。 V 3 ′=R f /R c・R 1 +ρR 2 /R 1・V 1 =V 3 (4)
' Then, the variable resistor R 2 is adjusted so that the indication on the display section M based on the output V 3 ' obtained by the equation (7) becomes the equation (8).
V3′＝Ｒｆ／ＲＫ・Ｒ１＋ρＲ２／Ｒ１・V1＝ｋ・β
(8)
但し、ｋは表示値で一定値
(5)式に(6)式および(8)式を代入して(9)式を得る
（スイツチS3をａ側にしたときの出力を示す）。 V 3 ′=R f /R K・R 1 +ρR 2 /R 1・V 1 =k・β
(8) However, k is a constant display value Substitute equations (6) and (8) into equation (5) to obtain equation (9) (shows the output when switch S 3 is set to side a) ).
V3＝Ｒｋ／Ｊｏ・ｋ・Ｋ (9)
(9)式において、Jo，Rkおよびｋは一定である
ので出力V3は導電率Ｋに比例する。また、(9)式
には出圧V1が含まれていない。したがつて、セ
ル定数の補正をなすことによつて電圧V1の長期
変動に対しても補正されることになる。 V 3 =R k /Jo·k·K (9) In equation (9), since Jo, Rk, and k are constant, the output V 3 is proportional to the conductivity K. Moreover, the output pressure V 1 is not included in equation (9). Therefore, by correcting the cell constant, long-term fluctuations in voltage V1 can also be corrected.
以上、詳しく説明したように、本考案の導電率
計によれば、セル定数の正確な補正が可能とな
り、しかもダイヤル目盛を必要としないので製造
上の工数軽減にも効果がある。さらに、上記セル
補正操作は導電率計のキヤリプレーシヨンを同時
行なつているのでより高い精度が期待できる。 As described above in detail, the conductivity meter of the present invention enables accurate correction of cell constants, and also eliminates the need for dial scales, which is effective in reducing manufacturing man-hours. Furthermore, since the cell correction operation described above is performed simultaneously with the calibration of the conductivity meter, higher accuracy can be expected.
第１図は、従来の導電率計の構成説明図、第２
図は、それのダイヤルの構成説明図、第３図は、
本考案の一実施例による導電率計の構成説明図で
ある。
U1およびU2……差動増幅器、Rc……測定セル
（電極間抵抗）、R1，Ｒf，ＲK……抵抗、R2……可
変抵抗、Ｍ……表示部。
Figure 1 is an explanatory diagram of the configuration of a conventional conductivity meter;
The figure is an explanatory diagram of the dial configuration, and Figure 3 is
FIG. 1 is a configuration explanatory diagram of a conductivity meter according to an embodiment of the present invention. U 1 and U 2 ... Differential amplifier, Rc ... Measurement cell (resistance between electrodes), R 1 , R f , R K ... Resistance, R 2 ... Variable resistance, M ... Display section.
Claims (1)
ばらつきを調整する手段および該測定セルに流れ
る電流に対応する信号を入力とする表示部を具備
する導電率計において、 前記測定セルに並列的構成で、かつ回路接続が
スイツチによつて択一される基準抵抗を具備し、
該基準抵抗を択一すると共に前記表示部をみなが
ら前記調整をすることを特徴とする導電率計。[Claims for Utility Model Registration] A conductivity meter comprising means for adjusting variations in cell constant by varying the voltage applied to a measuring cell, and a display unit receiving as input a signal corresponding to the current flowing through the measuring cell. , comprising a reference resistor configured in parallel to the measurement cell and whose circuit connection is selected by a switch;
A conductivity meter characterized in that the reference resistance is selected and the adjustment is made while looking at the display section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14619679U JPS6111655Y2 (en) | 1979-10-22 | 1979-10-22 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14619679U JPS6111655Y2 (en) | 1979-10-22 | 1979-10-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5665478U JPS5665478U (en) | 1981-06-01 |
| JPS6111655Y2 true JPS6111655Y2 (en) | 1986-04-12 |
Family
ID=29377359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14619679U Expired JPS6111655Y2 (en) | 1979-10-22 | 1979-10-22 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6111655Y2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8513956B2 (en) * | 2010-07-26 | 2013-08-20 | Mettler-Toledo Thornton, Inc. | Calibration of conductivity measurement system |
| JP5691653B2 (en) * | 2011-03-03 | 2015-04-01 | 東亜ディーケーケー株式会社 | Electric conductivity meter |
-
1979
- 1979-10-22 JP JP14619679U patent/JPS6111655Y2/ja not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5665478U (en) | 1981-06-01 |
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