JPS6221958Y2 - - Google Patents
Info
- Publication number
- JPS6221958Y2 JPS6221958Y2 JP1980190536U JP19053680U JPS6221958Y2 JP S6221958 Y2 JPS6221958 Y2 JP S6221958Y2 JP 1980190536 U JP1980190536 U JP 1980190536U JP 19053680 U JP19053680 U JP 19053680U JP S6221958 Y2 JPS6221958 Y2 JP S6221958Y2
- Authority
- JP
- Japan
- Prior art keywords
- lead wire
- resistor
- voltage
- resistance
- constant current
- 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
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical group [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 claims description 32
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 238000005259 measurement Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
Description
【考案の詳細な説明】
この考案は、測温抵抗体の抵抗変化を電圧変化
として取り出す抵抗−電圧変換回路に関するもの
である。[Detailed Description of the Invention] This invention relates to a resistance-voltage conversion circuit that extracts a change in resistance of a temperature-measuring resistor as a change in voltage.
一般に、白金測温抵抗体の抵抗変化を電圧に変
換して、温度を測定するような抵抗−電圧変換回
路において、リード線の抵抗が測定誤差となるこ
とを除去することや、リード線の断線を検出して
バーンアウトさせることが要望されている。従来
は、いたずらに回路を複雑にして行つており、そ
れだけ高価なものとなつてしまう欠点があつた。 In general, in a resistance-voltage conversion circuit that converts the resistance change of a platinum resistance thermometer into voltage to measure temperature, it is necessary to eliminate measurement errors caused by lead wire resistance, and to eliminate lead wire breakage. It is desired to detect and burn out. Conventionally, the circuit has been unnecessarily complicated, which has the disadvantage of making it more expensive.
この考案の目的は、簡単な回路にて、これらの
欠点を解消する抵抗−電圧変換回路を提供するこ
とである。 The purpose of this invention is to provide a resistance-voltage conversion circuit that eliminates these drawbacks with a simple circuit.
第１図は、この考案の一実施例を示す構成説明
図である。図においてＩは、電圧Ｖを有し演算増
幅器Ao、トランジスタTrよりなる定電流源、Ro
は、一端に第１のリード線ｒ１を介して端子Ａよ
り定電流源Ｉが接続され、他端には第２のリード
線r2および第３のリード線r3が接続された測温抵
抗体で、第２のリード線r2は端子Ｂより第１の抵
抗R1を介してアースされ、第３のリード線r3には
端子B′を介して第２の抵抗R2が接続され、第１
の抵抗R1と第２の抵抗R2との間にダイオードＤ
が接続され、ダイオードＤの一端に抵抗R3が接
続してアースされ、第２のリード線r2と第１の抵
抗R1との接続点の端子Ｂより定電流源Ｉの演算
増幅器Aoに電圧Voと比較して定電流化するため
の負帰還がかかつている。そして、定電流源Ｉと
第１のリード線r1との接続点の端子Ａは入力抵抗
R4、帰還抵抗R5を有する演算増幅器A1の反転入
力端子に接続され、非反転入力端子には第２の抵
抗R2が接続され、出力端子ｔより出力電圧eoが
取り出せるようになつている。 FIG. 1 is a configuration explanatory diagram showing an embodiment of this invention. In the figure, I is a constant current source having a voltage V and consisting of an operational amplifier Ao, a transistor Tr, and Ro
is a temperature measuring resistor with one end connected to a constant current source I from a terminal A via a first lead wire r1, and the other end connected to a second lead wire r2 and a third lead wire r3 . In the main body, the second lead wire r2 is grounded from terminal B through the first resistor R1 , and the third lead wire r3 is connected to the second resistor R2 through terminal B'. , 1st
A diode D is connected between the resistor R 1 and the second resistor R 2
is connected, a resistor R3 is connected to one end of the diode D and grounded, and the operational amplifier Ao of the constant current source I is connected from the terminal B at the connection point of the second lead wire R2 and the first resistor R1 . Negative feedback is applied to make the current constant compared to the voltage Vo. Terminal A at the connection point between constant current source I and first lead wire r1 is an input resistor.
R 4 is connected to the inverting input terminal of an operational amplifier A 1 having a feedback resistor R 5 , and a second resistor R 2 is connected to the non-inverting input terminal, so that the output voltage eo can be taken out from the output terminal t. There is.
正常に動作しているとき、第１のリード線r1、
測温抵抗体Ro、第２のリード線r2を流れる電流
をｉ、端子Ｂの電圧をVo、リード線r1，r2，r3の
抵抗を等しくｒ、抵抗R4，R5の抵抗を等しくＲ
とし、演算増幅器A1の出力電圧をeoとすれば次
式が成り立つ。 During normal operation, the first lead r 1 ,
The current flowing through the resistance temperature detector Ro and the second lead wire r2 is i, the voltage at terminal B is Vo, the resistances of the lead wires r1 , r2 , and r3 are equal to r, and the resistances of resistors R4 and R5 are is equal to R
If the output voltage of operational amplifier A1 is eo, the following equation holds true.
（Vo＋2ir＋iRo）−Ｒ３／ｒ＋Ｒ２＋Ｒ３（Vo＋ir）＝Ｒ３／ｒ＋Ｒ２＋Ｒ３（Ｖp＋ir）−eo ……(1)
これにより、eoを求めると
となる。ここでｒ＋R2≪R3より
eo≒２（Vo＋ir）
−（Vo＋2ir＋iRo）＝Vo−iRo ……(3)
となる。これにより電圧Vo分を差し引いて、符
号を反転させてやれば、リード線の配線抵抗の影
響が除去された抵抗−電圧出力が得られる。この
出力電圧eoは、ブリツジ回路等より得られる電圧
と異なり、抵抗変化に対してリニアで比例した温
度変化特性電圧となる。 (Vo+2ir+iRo) -R3 /r+ R2 + R3 (Vo+ir)= R3 /r+ R2 + R3 ( Vp +ir)-eo......(1) From this, eo can be calculated. becomes. Here, from r+R 2 ≪R 3 , eo≒2(Vo+ir) −(Vo+2ir+iRo)=Vo−iRo ……(3). By subtracting the voltage Vo and reversing the sign, a resistance-voltage output can be obtained in which the influence of the wiring resistance of the lead wire has been removed. Unlike the voltage obtained from a bridge circuit or the like, this output voltage eo is a temperature change characteristic voltage that is linear and proportional to the resistance change.
また、バーンアウト動作は次の通りである。 Moreover, the burnout operation is as follows.
第１のリード線r1が断線したとすると、演算増
幅器A1の非反転入力端子の電圧はゼロで、端子
Ａより正の電圧Ｖが反転入力端子に供給され、出
力電圧eoはマイナスに大となりバーンアウトす
る。 Assuming that the first lead wire r1 is disconnected, the voltage at the non-inverting input terminal of operational amplifier A1 is zero, a positive voltage V is supplied from terminal A to the inverting input terminal, and the output voltage eo becomes negative and large. Burnout.
第２のリード線r2が断線すると、電流ｉは、第
１のリード線r1、測温抵抗体Ro、第３のリード
線r3、第２の抵抗R2、ダイオードＤと流れるの
で、ダイオードＤの両端の電圧をVDとして出力
電圧eoは次のようになる。 When the second lead wire r 2 is disconnected, the current i flows through the first lead wire r 1 , the resistance temperature detector Ro, the third lead wire r 3 , the second resistor R 2 , and the diode D. Assuming that the voltage across diode D is VD, the output voltage eo is as follows.
eo＝２（Vo＋VD）
−（Vo＋VD＋iR2＋2ir＋iRo）
＝Vo＋VD−iR2−2ir−iRo ……(4)
ここで、iR2≫VD，iRoと選んでおけば、出力
電圧eoはマイナスに大となりバーンアウトする。 eo = 2 (Vo + VD) - (Vo + VD + iR 2 + 2ir + iRo) = Vo + VD - iR 2 - 2ir - iRo ... (4) Here, if you choose iR 2 ≫ VD, iRo, the output voltage eo becomes negative and burns out. Go out.
第３のリード線r3が断線すると電流ｉは、第１
のリード線r1、測温抵抗体Ro、第２のリード線r2
と流れ、演算増幅器A1の非反転入力端子の電圧
はダイオードＤによりカツトオフされゼロである
ので次式が成り立つ。 When the third lead wire r3 is disconnected, the current i is
lead wire r 1 , resistance temperature detector Ro, second lead wire r 2
Since the voltage at the non-inverting input terminal of the operational amplifier A1 is cut off by the diode D and is zero, the following equation holds true.
eo＝−（Vo＋2ir＋iRo） ……（ ）
この電圧もマイナスに十分大きいのでバーンア
ウトする。 eo=-(Vo+2ir+iRo)... ( ) This voltage is also negative enough to cause burnout.
このように、いずれのリード線が断線してもバ
ーンアウトすることができるわけである。 In this way, burnout can occur even if any lead wire is disconnected.
又、抵抗R1の抵抗値を変えることにより、測
温抵抗体の種類等により異なる定格電流に応じた
電流値を選ぶことができるので、それだけ測定精
度が向上する。 Furthermore, by changing the resistance value of the resistor R1 , it is possible to select a current value that corresponds to the rated current, which varies depending on the type of resistance temperature detector, etc., and thus the measurement accuracy is improved accordingly.
以上述べたように、この考案は、３本のリード
線を有する測温抵抗体に定電流を供給し、演算増
幅器にて、差電圧を取り出すようにした抵抗−電
圧変換回路である。 As described above, this invention is a resistance-voltage conversion circuit in which a constant current is supplied to a temperature-measuring resistor having three lead wires, and a differential voltage is extracted using an operational amplifier.
従つて、定電流回路と１個の演算増幅器を含む
簡単な回路で、リード線の影響の除去を図れると
ともにバーンアウトも確実にできるものであり、
実用的効果が極めて大きい。又、抵抗変化に比例
した温度変化特性電圧が取り出せるので、記録計
に記録させる等の使用や、その後の信号処理が容
易である。又、測温抵抗体の種類等により異なる
定格電流に応じた電流値が選べるので、それだけ
測定精度が向上する。 Therefore, with a simple circuit including a constant current circuit and one operational amplifier, it is possible to eliminate the influence of the lead wire and also ensure burnout.
The practical effect is extremely large. Further, since a temperature change characteristic voltage proportional to the resistance change can be obtained, it is easy to record the voltage on a recorder and to perform subsequent signal processing. Furthermore, since the current value can be selected according to the rated current, which varies depending on the type of resistance temperature detector, the measurement accuracy is improved accordingly.
第１図は、この考案の一実施例を示す構成説明
図である。
Ｉ……定電流源、Ro……測温抵抗体、r1，r2，
r3……リード線、R1，R2，R3，R4，R5……抵
抗、Ｄ……ダイオード、A1……演算増幅器。
FIG. 1 is a configuration explanatory diagram showing an embodiment of this invention. I... Constant current source, Ro... Resistance temperature detector, r 1 , r 2 ,
r 3 ... Lead wire, R 1 , R 2 , R 3 , R 4 , R 5 ... Resistor, D ... Diode, A 1 ... Operational amplifier.
Claims (1)
体と、この測温抵抗体の他端に接続された第２
のリード線および第３のリード線と、第２のリ
ード線とアースとの間に接続する第１の抵抗
と、第３のリード線に接続する第２の抵抗と、
第１の抵抗と第２の抵抗との間に接続されたダ
イオードと、第２のリード線と第１の抵抗との
接続点の電圧が所定の電圧となるよう比較して
負帰還をかけ定電流を前記第１のリード線を介
して測温抵抗体に供給する定電流源と、定電流
源と第１のリード線との接続点および第２の抵
抗とダイオードとの接続点より取り出された電
圧が供給される演算増幅器とを備えたことを特
徴とする抵抗−電圧変換回路。 ２ 前記定電流源として、演算増幅器を含み、そ
の反転入力端子に第２のリード線と第１の抵抗
との接続点の電圧を印加し、その非反転入力端
子に所定電圧を印加し、両電圧が一致するよう
に第１のリード線を介して測温抵抗体に定電流
を供給するものを用いたことを特徴とする実用
新案登録請求の範囲第１項記載の抵抗−電圧変
換回路。 ３ 前記第１の抵抗として、得たい電流値に対応
した抵抗値としたものを用いたことを特徴とす
る実用新案登録請求の範囲第１項または第２項
記載の抵抗−電圧変換回路。[Claims for Utility Model Registration] 1. A resistance temperature detector with a first lead wire connected to one end, and a second lead wire connected to the other end of the resistance temperature detector.
a first resistor connected between the lead wire and the third lead wire, the second lead wire and the ground, and a second resistor connected to the third lead wire;
A diode connected between the first resistor and the second resistor is compared with the voltage at the connection point between the second lead wire and the first resistor to a predetermined voltage, and negative feedback is applied to determine the voltage. A constant current source that supplies current to the resistance temperature sensor through the first lead wire, and a current that is taken out from a connection point between the constant current source and the first lead wire and a connection point between the second resistor and the diode. 1. A resistance-voltage conversion circuit comprising: an operational amplifier to which a voltage is supplied. 2 The constant current source includes an operational amplifier, the voltage at the connection point between the second lead wire and the first resistor is applied to its inverting input terminal, the predetermined voltage is applied to its non-inverting input terminal, and both 2. The resistance-voltage conversion circuit according to claim 1, wherein a constant current is supplied to the temperature-measuring resistor through the first lead wire so that the voltages match. 3. The resistance-voltage conversion circuit according to claim 1 or 2, wherein the first resistor has a resistance value corresponding to a desired current value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1980190536U JPS6221958Y2 (en) | 1980-12-29 | 1980-12-29 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1980190536U JPS6221958Y2 (en) | 1980-12-29 | 1980-12-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57114498U JPS57114498U (en) | 1982-07-15 |
| JPS6221958Y2 true JPS6221958Y2 (en) | 1987-06-04 |
Family
ID=29994926
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1980190536U Expired JPS6221958Y2 (en) | 1980-12-29 | 1980-12-29 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6221958Y2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6316732B2 (en) * | 2014-11-11 | 2018-04-25 | アズビル株式会社 | Temperature measuring system and temperature measuring instrument |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55134328A (en) * | 1979-04-06 | 1980-10-20 | Hitachi Ltd | Temperature converter |
-
1980
- 1980-12-29 JP JP1980190536U patent/JPS6221958Y2/ja not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55134328A (en) * | 1979-04-06 | 1980-10-20 | Hitachi Ltd | Temperature converter |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57114498U (en) | 1982-07-15 |
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