JP2802814B2 - Resistance measuring instrument - Google Patents
Resistance measuring instrumentInfo
- Publication number
- JP2802814B2 JP2802814B2 JP13294990A JP13294990A JP2802814B2 JP 2802814 B2 JP2802814 B2 JP 2802814B2 JP 13294990 A JP13294990 A JP 13294990A JP 13294990 A JP13294990 A JP 13294990A JP 2802814 B2 JP2802814 B2 JP 2802814B2
- Authority
- JP
- Japan
- Prior art keywords
- operational amplifier
- input terminal
- inverting input
- integrating
- reference voltage
- 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 - Fee Related
Links
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
- Measurement Of Current Or Voltage (AREA)
- Analogue/Digital Conversion (AREA)
Description
【発明の詳細な説明】 「産業上の利用分野」 この発明は基準電圧が基準抵抗器を通じて反転入力端
へ印加された演算増幅器の反転入力端及び出力端間に被
測定抵抗器を接続し、その演算増幅器の出力電圧を２重
積分形AD変換器で測定する抵抗測定器に関する。DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" This invention connects a resistor to be measured between an inverting input terminal and an output terminal of an operational amplifier in which a reference voltage is applied to an inverting input terminal through a reference resistor, The present invention relates to a resistance measuring instrument for measuring the output voltage of the operational amplifier with a double integration type AD converter.
「従来の技術」 第４図に従来の抵抗測定器を示す。端子11から基準電
圧−Vr1が基準抵抗器12を通じて演算増幅器13の反転入
力端へ供給され、演算増幅器13の非反転入力端は接地さ
れ、演算増幅器13の反転入力端と出力端との間に被測定
抵抗器14が接続される。基準抵抗器12の抵抗値をRS、被
測定抵抗器14の抵抗値をRXとすると、演算増幅器13の出
力電圧VOは（Vr1/RS）RXとなる。つまり出力電圧VOは被
測定抵抗器14の抵抗値RXと比例する。この出力電圧VOが
二重積分形AD変換器15でデジタル値に変換され、そのデ
ジタル値が抵抗値として表示器16に表示される。つまり
演算増幅器13の出力電圧VOはスイッチ17を通じ、更に積
分抵抗器18は通じて積分用演算増幅器19の反転入力端へ
供給され、積分用演算増幅器19の反転入力端と出力端と
の間に積分コンデンサ21が接続され、積分用演算増幅器
19の反転入力端に端子22から基準電圧−Vr2がスイッチ2
3−積分抵抗器24を通じて供給される。積分用演算増幅
器19の非反転入力端はコンデンサ25を通じて接地され、
出力端はスロープ増幅器26の反転入力端に接続され、ス
ロープ増幅器26の非反転入力端は接地され、出力端はス
イッチ27を通じて積分用演算増幅器19の非反転入力端に
接続されると共に比較器28の一方の入力端に接続され、
比較器28の他方の入力端は接地され、比較器28の出力端
はCPUよりなる制御部29に接続される。"Prior Art" FIG. 4 shows a conventional resistance measuring instrument. A reference voltage −V r1 is supplied from the terminal 11 to the inverting input terminal of the operational amplifier 13 through the reference resistor 12, the non-inverting input terminal of the operational amplifier 13 is grounded, and the voltage between the inverting input terminal and the output terminal of the operational amplifier 13 is Is connected to the resistor 14 to be measured. Assuming that the resistance value of the reference resistor 12 is R S and the resistance value of the measured resistor 14 is R X , the output voltage V O of the operational amplifier 13 is (V r1 / R S ) R X. That is, the output voltage V O is proportional to the resistance value R X of the resistor 14 to be measured. This output voltage V O is converted into a digital value by the double integral type AD converter 15, and the digital value is displayed on the display 16 as a resistance value. That is, the output voltage V O of the operational amplifier 13 is supplied to the inverting input terminal of the integrating operational amplifier 19 through the switch 17 and further through the integrating resistor 18, so that the output voltage V O between the inverting input terminal and the output terminal of the integrating operational amplifier 19 is obtained. Is connected to an integrating capacitor 21 and an integrating operational amplifier
The reference voltage −V r2 is switched from terminal 22 to the inverting input terminal of
3—Supplied through integrating resistor 24. The non-inverting input terminal of the integrating operational amplifier 19 is grounded through the capacitor 25,
The output terminal is connected to the inverting input terminal of the slope amplifier 26, the non-inverting input terminal of the slope amplifier 26 is grounded, the output terminal is connected to the non-inverting input terminal of the integrating operational amplifier 19 through the switch 27, and the comparator 28 Connected to one input terminal of
The other input terminal of the comparator 28 is grounded, and the output terminal of the comparator 28 is connected to a control unit 29 including a CPU.
制御部29はスイッチ17,23をオフとし、スイッチ27を
オンとして、積分用演算増幅器19、スロープ増幅器26の
各オフセットに対応する電圧をコンデンサ25に充電し、
いわゆるオートゼロを行う。次にスイッチ27をオフ、ス
イッチ17をオンとして、演算増幅器13の出力電圧VOを積
分コンデンサ21に積分する。この積分を一定時間行う。
これは第１積分期間と言われる。次にスイッチ17,27を
オフ、スイッチ23をオンとして基準電圧−Vr2を積分
し、積分用演算増幅器19の出力がゼロになると、比較器
28の出力が反転する。この基準電圧−Vr2の積分開始か
ら比較器28が反転するまでの時間（第２積分期間）を測
定する。この測定値は演算増幅器13の出力電圧VOと比例
する。この測定電圧から抵抗値RXを演算して表示器16を
表示する。The control unit 29 turns off the switches 17 and 23, turns on the switch 27, and charges the capacitor 25 with a voltage corresponding to each offset of the integrating operational amplifier 19 and the slope amplifier 26,
Perform so-called auto-zero. Next, the switch 27 is turned off and the switch 17 is turned on to integrate the output voltage V O of the operational amplifier 13 into the integrating capacitor 21. This integration is performed for a fixed time.
This is called the first integration period. Then turn off the switch 17, 27, integrates the reference voltage -V r2 turns on the switch 23, the output of the integration operational amplifier 19 is zero, the comparator
The output of 28 is inverted. Comparator 28 from the integral start of the reference voltage -V r2 measures the time (second integration period) until the inversion. This measured value is proportional to the output voltage V O of the operational amplifier 13. The resistance value RX is calculated from the measured voltage, and the display 16 is displayed.
「発明が解決しようとする課題」 被測定抵抗値RXに対し、出力電圧VOは第５図に示すよ
うに比例する。被測定抵抗値RXの測定可能範囲は演算増
幅器13の出力電圧の変化可能範囲で決まるが、実線で示
す範囲しか利用しておらず点線で示す出力電圧変化可能
範囲は利用していなかった。つまり従来においては演算
増幅器13の利用範囲を有効に使っておらず、それだけ抵
抗値の測定可能範囲が狭いものであった。"Problem to be Solved by the Invention" The output voltage V O is proportional to the measured resistance value R X as shown in FIG. The measurable range of the measured resistance value R X is determined by the change range of the output voltage of the operational amplifier 13, but only the range indicated by the solid line is used, and the change range of the output voltage indicated by the dotted line is not used. That is, conventionally, the use range of the operational amplifier 13 has not been effectively used, and the measurable range of the resistance value has been narrowed accordingly.
「課題を解決するための手段」 この発明によれば被測定抵抗器が接続される演算増幅
器の非反転入力端は接地されることなく、その反転入力
端へ供給される第１の基準電圧と同極性の第２基準電圧
が印加され、またこの第２基準電圧はコンデンサを通じ
て積分用演算増幅器の非反転入力端へ供給され、更にこ
の第２基準電圧は比較器へその接地側入力として供給さ
れ、かつ第２基準電圧はスイッチを通じ、更に積分抵抗
器を通じて積分用演算増幅器の反転入力端へ供給され
る。According to the present invention, the non-inverting input terminal of the operational amplifier to which the resistor to be measured is connected is not grounded, and the first reference voltage supplied to the inverting input terminal is not A second reference voltage of the same polarity is applied, and the second reference voltage is supplied to the non-inverting input terminal of the integrating operational amplifier through a capacitor, and the second reference voltage is supplied to the comparator as its ground side input. And the second reference voltage is supplied to the inverting input terminal of the integrating operational amplifier through a switch and further through an integrating resistor.
「実施例」 第１図にこの発明の実施例を示し、第４図と対応する
部分に同一符号を付けてある。この発明においては端子
31に端子11の基準電圧−Vr1と同一極性の基準電圧−Ｖ
が印加され、演算増幅器13の非反転入力端は接地される
ことなく、端子31に接続され、同様にコンデンサ25も接
地されることなく、端子31に接続され、かつ比較器28の
接地側入力端は接地されることなく端子31に接続され
る。更に端子31はスイッチ32に積分抵抗器33を通じて積
分用演算増幅器19の反転入力端に接続される。"Embodiment" FIG. 1 shows an embodiment of the present invention, in which parts corresponding to those in FIG. In the present invention, the terminal
31 has a reference voltage −V of the same polarity as the reference voltage −V r1 of the terminal 11
Is applied, the non-inverting input terminal of the operational amplifier 13 is connected to the terminal 31 without being grounded, and the capacitor 25 is similarly connected to the terminal 31 without being grounded, and the ground-side input terminal of the comparator 28 is The end is connected to the terminal 31 without being grounded. Further, a terminal 31 is connected to an inverting input terminal of the integrating operational amplifier 19 through a switch 32 and an integrating resistor 33.
この構成によれば演算増幅器13の反転入力端が端子31
の基準電圧−Ｖになるように帰還動作するから、演算増
幅器13の出力端の電圧VOは となり、RXとVOとの関係は第２図に示すようになり、電
圧VOの変化可能範囲を有効に利用でき、被測定抵抗値RX
の測定範囲が広くなる。なお出力電圧VOの変化可能範囲
は演算増幅器13の電源電圧から定まる。According to this configuration, the inverting input terminal of the operational amplifier 13 is connected to the terminal 31
The feedback operation is performed so that the reference voltage becomes −V, so that the voltage V O at the output terminal of the operational amplifier 13 is The relationship between R X and V O is as shown in FIG. 2, and the changeable range of the voltage V O can be effectively used, and the measured resistance value R X
Measurement range becomes wider. Note that the changeable range of the output voltage V O is determined by the power supply voltage of the operational amplifier 13.
この演算増幅器13の出力電圧を二重積分形AD変換器15
で測定するには、先ずスイッチ17,23をオフ、スイッチ2
7,32をオンとし、つまりオートゼロの状態とする。この
時は第３図に示す接続状態となり、抵抗器33に電流が流
れないという条件から、各部の電圧を求めると、積分用
演算増幅器19の反転入力端は−Ｖとなり、演算増幅器19
のオフセットがゼロであるとすると、スロープ増幅器26
の出力電圧も−Ｖとなり、スロープ増幅器26のオフセッ
トもゼロであるとすると、積分用演算増幅器19の出力電
圧はゼロとなる。The output voltage of the operational amplifier 13 is converted to a double integral type AD converter 15
To measure with, first turn off switches 17 and 23, switch 2
7, 32 is turned on, that is, the state of auto zero is set. At this time, the connection state shown in FIG. 3 is established, and the voltage at each part is obtained from the condition that no current flows through the resistor 33. When the inverting input terminal of the integrating operational amplifier 19 becomes -V, the operational amplifier 19
Is zero, the slope amplifier 26
Is also -V, and the offset of the slope amplifier 26 is also zero, the output voltage of the integrating operational amplifier 19 becomes zero.
次にスイッチ23,27,32をオフ、スイッチ17をオンとし
て第１積分を行う。この時、積分用演算増幅器19の反転
入力端が−Ｖであるから、（１）式より、 を積分抵抗器18の抵抗値で割った電流値と、積分コンデ
ンサ21の容量値で決る積分が行われ、この積分を一定時
間行った後、スイッチ17,27,32をオフ、スイッチ23をオ
ンとして第２積分が行われ、比較器28の出力が反転する
まで端子22の基準電圧−Vr2が積分される。この第２積
分の時間は被測定抵抗値RXに比例し、制御部29で第２積
分の時間から抵抗値RXが演算され、これが表示器16に表
示される。Next, the switches 23, 27, and 32 are turned off and the switch 17 is turned on to perform the first integration. At this time, since the inverting input terminal of the integrating operational amplifier 19 is −V, from the equation (1), Is divided by the resistance value of the integrating resistor 18 and the capacitance value of the integrating capacitor 21.After performing this integration for a certain period of time, the switches 17, 27 and 32 are turned off and the switch 23 is turned on. Is performed, and the reference voltage −V r2 at the terminal 22 is integrated until the output of the comparator 28 is inverted. The time of the second integration is proportional to the measured resistance value R X , and the control unit 29 calculates the resistance value R X from the time of the second integration, which is displayed on the display 16.
なお端子31をスイッチ32を通じて、スイッチ17及び積
分抵抗器18の接続点はスイッチ23及び積分抵抗器24の接
続点に接続してもよい。The connection point between the switch 17 and the integration resistor 18 may be connected to the connection point between the switch 23 and the integration resistor 24 via the terminal 31 through the switch 32.
「発明の効果」 以上述べたようにこの発明によれば演算増幅器13の非
反転入力端に基準電圧−Ｖを印加すると共に積分用演算
増幅器19及び比較器28の基準側を基準電圧−Ｖとするこ
とにより、演算増幅器13の出力電圧変化可能範囲を有効
に利用でき、抵抗値の測定可能範囲を広くすることがで
きる。しかも基準電圧−Ｖは多少変動しても大きな影響
を受けない。As described above, according to the present invention, the reference voltage -V is applied to the non-inverting input terminal of the operational amplifier 13, and the reference sides of the integrating operational amplifier 19 and the comparator 28 are set to the reference voltage -V. By doing so, the output voltage changeable range of the operational amplifier 13 can be effectively used, and the measurable range of the resistance value can be widened. Moreover, even if the reference voltage -V fluctuates somewhat, it is not greatly affected.
第１図はこの発明の実施例を示す接続図、第２図はその
被測定抵抗値−増幅器出力電圧特性の例を示す図、第３
図は二重積分形AD変換器15をオートゼロ状態にした接続
図、第４図は従来の抵抗測定器を示す接続図、第５図は
その被測定抵抗値−増幅器出力電圧特性を示す図であ
る。FIG. 1 is a connection diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a measured resistance-amplifier output voltage characteristic, and FIG.
FIG. 4 is a connection diagram in which the double-integration type AD converter 15 is set to an auto-zero state, FIG. 4 is a connection diagram showing a conventional resistance measuring device, and FIG. 5 is a diagram showing a measured resistance value-amplifier output voltage characteristic. is there.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) G01R 27/08 G01R 19/255 H03M 1/52──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 6 , DB name) G01R 27/08 G01R 19/255 H03M 1/52
Claims (1)
幅器の反転入力端へ供給され、 その演算増幅器の反転入力端と出力端との間に被測定抵
抗器が接続され、 上記演算増幅器の非反転入力端に上記第１基準電圧と同
極性の第２基準電圧が与えられ、 上記演算増幅器の出力端が第１スイッチを通じ、更に積
分抵抗器を通じて積分用演算増幅器の反転入力端へ接続
され、 第３基準電圧が第２スイッチを通じ、更に積分抵抗器を
通じて上記積分用演算増幅器の反転入力端へ供給され、 上記第２基準電圧が第３スイッチを通じ、更に積分抵抗
器を通じて上記積分用演算増幅器の反転入力端へ供給さ
れ、 上記積分用演算増幅器の反転入力端と出力端との間に積
分コンデンサが接続され、 上記積分用演算増幅器の出力がスロープ増幅器の反転入
力端へ供給され、 上記スロープ増幅器の非反転入力端が接地され、 上記スロープ増幅器の出力端は第４スイッチを通じて上
記積分用演算増幅器の非反転入力端に接続され、 上記第２基準電圧がコンデンサを通じて上記積分用演算
増幅器の非反転入力端へ供給され、 上記スロープ増幅器の出力が比較器の一方の入力端へ供
給され、 その比較器の他方の入力端へ上記第２の基準電圧が供給
されている抵抗測定器。A first reference voltage is supplied to an inverting input terminal of an operational amplifier through a reference resistor, and a resistor to be measured is connected between the inverting input terminal and the output terminal of the operational amplifier. A second reference voltage having the same polarity as the first reference voltage is applied to a non-inverting input terminal, and an output terminal of the operational amplifier is connected to the inverting input terminal of the integrating operational amplifier through a first switch and further through an integrating resistor. A third reference voltage is supplied to the inverting input terminal of the integrating operational amplifier through a second switch and further through an integrating resistor; and the second reference voltage is supplied through a third switch and further through an integrating resistor. And an integrating capacitor is connected between the inverting input terminal and the output terminal of the integrating operational amplifier. The output of the integrating operational amplifier is connected to the inverting input terminal of the slope amplifier. A non-inverting input terminal of the slope amplifier is grounded, an output terminal of the slope amplifier is connected to a non-inverting input terminal of the integrating operational amplifier through a fourth switch, and the second reference voltage is supplied through a capacitor. The output of the slope amplifier is supplied to one input terminal of a comparator, and the second reference voltage is supplied to the other input terminal of the comparator. Resistance measuring instrument.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13294990A JP2802814B2 (en) | 1990-05-23 | 1990-05-23 | Resistance measuring instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13294990A JP2802814B2 (en) | 1990-05-23 | 1990-05-23 | Resistance measuring instrument |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0427881A JPH0427881A (en) | 1992-01-30 |
| JP2802814B2 true JP2802814B2 (en) | 1998-09-24 |
Family
ID=15093264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13294990A Expired - Fee Related JP2802814B2 (en) | 1990-05-23 | 1990-05-23 | Resistance measuring instrument |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2802814B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539925A (en) * | 2010-12-30 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | High-accuracy dynamic testing method for sensor |
| CN102539924A (en) * | 2010-12-13 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | Wide-range precise measuring circuit for resistance of nano sensor and method |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002112905A (en) * | 2000-10-11 | 2002-04-16 | Toto Ltd | Washroom cabinet |
| JP4734767B2 (en) * | 2001-05-31 | 2011-07-27 | Ｔｏｔｏ株式会社 | Exterior cover device |
| JP3755487B2 (en) | 2002-06-21 | 2006-03-15 | コベルコ建機株式会社 | Oil filter for construction machinery |
-
1990
- 1990-05-23 JP JP13294990A patent/JP2802814B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102539924A (en) * | 2010-12-13 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | Wide-range precise measuring circuit for resistance of nano sensor and method |
| CN102539925A (en) * | 2010-12-30 | 2012-07-04 | 北京中科微纳物联网技术股份有限公司 | High-accuracy dynamic testing method for sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0427881A (en) | 1992-01-30 |
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