JPH0455729A - Temperature measuring resistor circuit - Google Patents
Temperature measuring resistor circuitInfo
- Publication number
- JPH0455729A JPH0455729A JP16742790A JP16742790A JPH0455729A JP H0455729 A JPH0455729 A JP H0455729A JP 16742790 A JP16742790 A JP 16742790A JP 16742790 A JP16742790 A JP 16742790A JP H0455729 A JPH0455729 A JP H0455729A
- Authority
- JP
- Japan
- Prior art keywords
- operational amplifier
- terminal
- switches
- resistor
- switch
- 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.)
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- Measuring Temperature Or Quantity Of Heat (AREA)
Abstract
Description
【発明の詳細な説明】
〈産業上の利用分野〉
本発明は測温抵抗体回路に関し、更に詳しくは、半導体
スイッチなどのオン抵抗の大きいリレーをスキャナとし
て用いる測温抵抗体回路の改善に関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a resistance temperature detector circuit, and more particularly to an improvement in a resistance temperature detector circuit that uses a relay with a large on-resistance, such as a semiconductor switch, as a scanner.
〈従来の技術〉
一般に、多点温度測定装置の温度測定手段として、３線
式の測温抵抗体が用いられることが多い。<Prior Art> Generally, a three-wire resistance temperature detector is often used as a temperature measuring means of a multi-point temperature measuring device.
ところで、従来の多点温度測定装置では、多点の測温抵
抗体の切換要素として機械的な接点を有する電磁リレー
が用いられていた。By the way, in conventional multi-point temperature measurement devices, electromagnetic relays having mechanical contacts have been used as switching elements for the multi-point resistance temperature detectors.
機械的な接点はオン抵抗が１００ｍΩ以下と非常に小さ
く、測温抵抗体の測定にあたってオン抵抗の値は実用上
無視できるという利点はあるものの、信頼性が低いとい
う問題がある。Mechanical contacts have a very small on-resistance of 100 mΩ or less, and although they have the advantage that the on-resistance value can be practically ignored when measuring a resistance temperature sensor, they have the problem of low reliability.
そこで、最近はこのような機械的な接点に代わって寿命
が半永久的な半導体スイッチが用いられつつある。Therefore, recently, semi-permanent semiconductor switches are being used in place of such mechanical contacts.
〈発明が解決しようとする課題〉
しかし、半導体スイッチのオン抵抗値は数１００Ωと比
較的大きく、測温抵抗体の測定精度に大きな影響を及ぼ
してしまうという問題がある。<Problems to be Solved by the Invention> However, there is a problem in that the on-resistance value of the semiconductor switch is relatively large at several hundreds of ohms, which greatly affects the measurement accuracy of the resistance temperature sensor.
本発明はこのような点に着目してなされたものであり、
その目的は、半導体スイッチなどの大きなオン抵抗値の
影響を受けることなく高精度の温度）ＦＪ定が行える測
温抵抗体回路を提供することにある。The present invention has been made with attention to these points,
The purpose is to provide a resistance temperature measuring circuit that can perform highly accurate temperature (FJ) determination without being affected by large on-resistance values such as semiconductor switches.
く課題を解決するための手段〉
上記課題を解決する本発明は、
端子Ａ、Ｂ、ｂを有し、等しい抵抗値ｒのリード線を有
し、抵抗値Ｒ１を有する３線式の測温抵抗体と、
該測温抵抗体の端子Ａに接続され、ＩＩＦＩ定用電流■
を供給する定電流源と、
非反転入力端子が第１のスイッチを介して前記測温抵抗
体の端子Ａに接続されるとともに第２のスイッチを介し
て前記側温抵抗体の端子Ｂに接続された第１の演算増幅
器と、
非反転入力端子が第３のスイッチを介して前記測温抵抗
体の端子Ｂに接続されるとともに第４のスイッチを介し
て前記測温抵抗体の端子すに接続された第２の演算増幅
器と、
前記測温抵抗体の端子すと接地間に接続された第５のス
イッチと、
一端が前記第１の演算増幅器の出力端子に接続され他端
が前記第１の演算増幅器の反転入力端子に接続された第
１の抵抗Ｒ１と、
一端が前記第１の演算増幅器の反転入力端子に接続され
他端が前記第２の演算増幅器の出力端子に接続された第
２の抵抗Ｒ２と、
一端が前記第２の演算増幅器の出力端子に接続され他端
が前記第２の演算増幅器の反転入力端子に接続された第
３の抵抗Ｒ３と、
一端が前記第２の演算増幅器の反転入力端子に接続され
他端が接地された第４の抵抗Ｒ４とを具備し、
前記各抵抗Ｒ１〜Ｒ４が等しい抵抗値に設定され、
前記第１．第３及び第５のスイッチをオンにして第２及
び第４のスイッチをオフにすることにより、
Ｖｏｕｔｌ−２（Ｒｔ＋ｒ） １
を求め、
前記第１．第２及び第４のスイッチをオンにして第３及
び第５のスイッチをオフにすることにより、
Ｖｏｕｔ２＝２ｒ＋１
を求め、
これらＶｏｕｔｌ及びＹｏｕ ｔ ２から、（Ｖｏｕｔ
ｌ−Ｖｏｕｔ２）／２＝Ｒｔ弓を求めることを特徴とす
るものである。Means for Solving the Problems> The present invention to solve the above problems is as follows: A three-wire temperature measuring system having terminals A, B, and b, lead wires with equal resistance r, and resistance R1. The IIFI constant current is connected to the resistor and the terminal A of the resistance temperature detector.
a constant current source that supplies a constant current source; a first operational amplifier whose non-inverting input terminal is connected to terminal B of the resistance temperature detector through a third switch, and connected to terminal B of the resistance temperature detector through a fourth switch; a fifth switch connected between a terminal of the resistance temperature detector and ground, one end of which is connected to the output terminal of the first operational amplifier and the other end of which is connected to the output terminal of the first operational amplifier; a first resistor R1 connected to the inverting input terminal of the first operational amplifier; one end connected to the inverting input terminal of the first operational amplifier and the other end connected to the output terminal of the second operational amplifier; a second resistor R2; a third resistor R3 having one end connected to the output terminal of the second operational amplifier and the other end connected to the inverting input terminal of the second operational amplifier; a fourth resistor R4 connected to the inverting input terminal of the operational amplifier, the other end of which is grounded; each of the resistors R1 to R4 is set to an equal resistance value; By turning on the third and fifth switches and turning off the second and fourth switches, Voutl-2(Rt+r) 1 is determined, and the first. By turning on the second and fourth switches and turning off the third and fifth switches, find Vout2=2r+1, and from these Voutl and You t2, (Vout
This method is characterized by finding l-Vout2)/2=Rt bow.
〈作用〉
本発明の測温抵抗体回路において、第１の演算増幅器は
非反転入力に対して２倍のゲインを持ち、反転入力は第
２の演算増幅器の出力信号を一１倍するゲインを持つ差
動アンプとして動作する。第２の演算増幅器は人力信号
に対して２倍のゲインを持つ。<Operation> In the resistance temperature detector circuit of the present invention, the first operational amplifier has a gain of twice the non-inverting input, and the inverting input has a gain of 11 times the output signal of the second operational amplifier. It operates as a differential amplifier with The second operational amplifier has a gain of twice the human input signal.
これにより、第１ 第３及び第５のスイッチをオンにし
て第２及び第４のスイッチをオフにした場合の第１の演
算増幅器の出力電圧ＶｏｕＬｌは、Ｖｏｕｔｌ＝２（Ｒ
ｔ＋ｒ） ・Ｉになり、第１．第２及び第４のスイッチ
をオンにして第３及び第５のスイッチをオフにした場合
の第１の演算増幅器の出力電圧ＶｏｕＬ２は、
Ｖｏｕｔ２−２ｒ弓になる。As a result, the output voltage VouLl of the first operational amplifier when the first third and fifth switches are turned on and the second and fourth switches are turned off is Voutl=2(R
t+r) ・Becomes I, 1st. The output voltage VouL2 of the first operational amplifier when the second and fourth switches are turned on and the third and fifth switches are turned off is Vout2-2r.
そして、これらＶｏｕｔｌ及びＶｏｕｔ２から、（Ｖｏ
ｕｔｌ−Ｖｏｕｔ２）／２−Ｒ１・１を求める。ここで
、電流Ｉは定電流である。Then, from these Voutl and Vout2, (Vo
Find utl-Vout2)/2-R1·1. Here, the current I is a constant current.
従って、リード線の抵抗値及び第５のスイッチのオン抵
抗値の影響を全く受けることなく、高精度で＃ＩｍＩ抗
体の抵抗値Ｒｔを測定できる。Therefore, the resistance value Rt of the #ImI antibody can be measured with high accuracy without being affected by the resistance value of the lead wire and the on-resistance value of the fifth switch.
〈実施例〉
以下、図面を参照して本発明の実施例を詳ＩＩＩに説明
する。<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
第１図は本発明の一実施例を示す回路図である。FIG. 1 is a circuit diagram showing an embodiment of the present invention.
図において、３線式の測温抵抗体１は端子Ａ、 Ｂ。In the figure, a three-wire resistance temperature detector 1 has terminals A and B.
ｂを有し、等しい抵抗値ｒのリード線を有し、抵抗値Ｒ
ｔを有している。定電流源２は１ｌＦＩ温抵抗体１の端
子Ａに接続され、抵抗値を測定するための一定の電流■
を測温抵抗体１に供給する。第１の演算増幅器３の非反
転入力端子は第１のスイッチＳＷＩを介して測温抵抗体
１の端子Ａに接続されるとともに第２のスイッチＳＷ２
を介して７Ｉ−１温抵抗体１の端子Ｂに接続されている
。第２の演算増幅器４の非反転入力端子は第３のスイッ
チＳＷ３を介して＃Ｉ温低抵抗体１端子Ｂに接続される
とともに第４のスイッチＳＷ４を介して＃Ｉ温低抵抗体
１端子すに接続されている。測温抵抗体１の端子すと接
地間には第５のスイッチＳＷ５が接続されている。なお
、これらこれら第１のスイッチＳＷ１乃至第５のスイッ
チＳＷ５としては半導体スイッチを用いる。第１の抵抗
Ｒ】の一端は第１の演算増幅器３の出力端子に接続され
、他端は第１の演算増幅器３の反転入力端子に接続され
ている。b, has lead wires of equal resistance r, and has a resistance R
It has t. A constant current source 2 is connected to the terminal A of the 11FI temperature resistor 1, and supplies a constant current for measuring the resistance value.
is supplied to the resistance temperature detector 1. A non-inverting input terminal of the first operational amplifier 3 is connected to a terminal A of the resistance temperature detector 1 via a first switch SWI, and a second switch SW2.
It is connected to the terminal B of the temperature resistor 1 via 7I-1. The non-inverting input terminal of the second operational amplifier 4 is connected to the #I low temperature resistor 1 terminal B via the third switch SW3, and is connected to the #I low temperature resistor 1 terminal via the fourth switch SW4. connected to. A fifth switch SW5 is connected between the terminal of the resistance temperature detector 1 and the ground. Note that semiconductor switches are used as these first switch SW1 to fifth switch SW5. One end of the first resistor R is connected to the output terminal of the first operational amplifier 3, and the other end is connected to the inverting input terminal of the first operational amplifier 3.
第２の抵抗Ｒ２の一端は第１の演算増幅器３の反転入力
端子に接続され、他端は第２の演算増幅器４の出力端子
に接続されている。第３の抵抗Ｒ３の一端は第２の演算
増幅器４の出力端子に接続され、他端は第２の演算増幅
器４の反転入力端子に接続されている。第４の抵抗Ｒ４
の一端は第２の演算増幅器４の反転入力端子に接続され
、他端は接地されている。ここで、各抵抗Ｒ１〜Ｒ４は
等しい抵抗値Ｒに設定されている。One end of the second resistor R2 is connected to the inverting input terminal of the first operational amplifier 3, and the other end is connected to the output terminal of the second operational amplifier 4. One end of the third resistor R3 is connected to the output terminal of the second operational amplifier 4, and the other end is connected to the inverting input terminal of the second operational amplifier 4. Fourth resistor R4
One end is connected to the inverting input terminal of the second operational amplifier 4, and the other end is grounded. Here, each of the resistors R1 to R4 is set to the same resistance value R.
このように各抵抗Ｒ１〜Ｒ４の抵抗値を等しく設定する
ことにより、第１の演算増幅器３は非反転入力に対して
２倍のゲインを持ち、反転入力は第２の演算増幅器４の
出力信号を一１倍するゲインを持つ差動アンプとして動
作する。そして、第２の演算増幅器４は人力信号に対し
て２倍のゲインを持つ。By setting the resistance values of the resistors R1 to R4 to be equal in this way, the first operational amplifier 3 has a gain twice that of the non-inverting input, and the inverting input has the output signal of the second operational amplifier 4. It operates as a differential amplifier with a gain of 11 times. The second operational amplifier 4 has a gain twice that of the human input signal.
次に第１図の回路の動作を説明する。Next, the operation of the circuit shown in FIG. 1 will be explained.
動作は、第２図及び第３図に示す２段階に分かれる。The operation is divided into two stages shown in FIGS. 2 and 3.
まず第１段階では、第２図に示すように第１のスイッチ
ＳＷＩ、第３のスイッチＳＷ３及び第５のスイッチＳＷ
５をオンにして第２のスイッチＳＷ２及び第４のスイッ
チＳＷ４をオフにする。この場合の第１の演算増幅器３
の出力電圧ＶｏｕＬ１として２（ＶＡ −Ｖｎ ）が出
力され、ＶｏｕｔＪ−２（ＶＡ −Ｖｅ ）
−２（Ｒｔ＋ｒ）・１
になる。First, in the first stage, as shown in FIG. 2, the first switch SWI, the third switch SW3, and the fifth switch SW
5 is turned on, and the second switch SW2 and the fourth switch SW4 are turned off. The first operational amplifier 3 in this case
2(VA-Vn) is output as the output voltage VouL1, which becomes VoutJ-2(VA-Ve)-2(Rt+r)·1.
そして、第２の段階では、第３図に示すように第１のス
イッチＳＷＩ、第２のスイッチＳＷ２及び第４のスイッ
チＳＷ４をオンにして第３のスイッチＳＷ３及び第５の
スイッチＳＷ５をオフにする。この場合の第１の演算増
幅器３の出力電圧Ｖ。Then, in the second stage, as shown in FIG. 3, the first switch SWI, the second switch SW2, and the fourth switch SW4 are turned on, and the third switch SW3 and the fifth switch SW5 are turned off. do. The output voltage V of the first operational amplifier 3 in this case.
ｕｔ２とし”ｒ２＜ Ｖｅ −Ｖ、 ）が出力され、Ｖ
ｏｕｔ２＝２（ＶＢ−Ｖｂ ）
−２ｒ 弓
になる。ut2, "r2< Ve -V, )" is output, and V
out2=2(VB-Vb)-2r It becomes a bow.
これらＶｏｕｔｌ及びＶｏｕｔ２から、（ＶｏｕＬ １
−ＶｏｕＬ２） ／２−２Ｒｔ 弓／２−Ｒ１弓
を求める。ここで、電流Ｉは定電流である。From these Voutl and Vout2, (VouL 1
-VouL2) /2-2Rt Bow/2-R1 Find the bow. Here, the current I is a constant current.
これにより、リード線の抵抗値「及び第５のスイッチＳ
Ｗ５のオン抵抗値ｒｏｎの影響を全く受けることなく、
高精度で測温抵抗体１の抵抗値Ｒｔを測定できる。As a result, the resistance value of the lead wire and the fifth switch S
Without being affected by the on-resistance value ron of W5,
The resistance value Rt of the resistance temperature detector 1 can be measured with high accuracy.
また、ｆｆｏｕｔｌ−ＶｏｕＬ２）の演算処理を行うこ
とにより、演算増幅器３，４全体のオフセット電圧も除
去できる。すなわち、演算増幅器３．４全体のオフセッ
ト電圧をＶ。Ｐとすると、
Ｖｏｕｔｌ＝２１（Ｒｔ＋ｒ）ｌ＋ ＶｏｐｌＶｏｕｔ
２＝２ｒ！＋ ２Ｖｏｐ
になる。Furthermore, by performing the arithmetic processing of ffoutl-VouL2), the offset voltage across the operational amplifiers 3 and 4 can also be removed. That is, the offset voltage of the entire operational amplifier 3.4 is V. When P, Voutl=21(Rt+r)l+ VoplVout
2=2r! +2 Vop.
従って、（ＶｏｕＬｌ−ＶｏｕＬ２＞の演算処理を行つ
コトにより、演算増幅器３．４全体のオフセット電圧ｖ
ｏ、も同時に除去されることになる。Therefore, by performing the calculation process of (VouLl−VouL2>), the offset voltage v of the entire operational amplifier 3.4
o, will also be removed at the same time.
なお、具体的な演算処理にあたっては、Ｖｏｕｔｌ及び
ＶｏｕＬ２をＡ／Ｄ変換器でディジタル信号に変換して
各部の制御を行うマイクロプロセッサに加え、該マイク
ロプロセッサで上述の演算を行うようにする。In addition to the microprocessor that converts Voutl and VouL2 into digital signals using an A/D converter and controls each section, the above-mentioned calculations are performed using the microprocessor.
〈発明の効果〉
以上詳細に説明したように、本発明によれば、簡単な回
路構成で、半導体スイッチのオン抵抗値の影響を受ける
ことなく高精度の温度測定が行える測温抵抗体回路を提
供することができる。<Effects of the Invention> As explained in detail above, according to the present invention, a resistance temperature detector circuit is provided which can perform highly accurate temperature measurement with a simple circuit configuration and without being affected by the on-resistance value of a semiconductor switch. can be provided.
第１図は本発明の一実施例を示す回路図、第２図及び第
３図は第１図の動作の説明図である。
１・・・測温抵抗体 ２・・・定電流源３・・・第
１の演算増幅器
４・・・第２の演算増幅器
ＳＷＩ〜ＳＷ５・・・スイッチ（半導体スイッチ）Ｒ１
−Ｒ６・・・抵抗
節１図
第３図
第 ２図FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are explanatory diagrams of the operation of FIG. 1. 1... Resistance temperature detector 2... Constant current source 3... First operational amplifier 4... Second operational amplifier SWI to SW5... Switch (semiconductor switch) R1
-R6...Resistance node Figure 1 Figure 3 Figure 2
Claims (1)
し、抵抗値Ｒｔを有する３線式の測温抵抗体と、 該測温抵抗体の端子Ａに接続され、測定用電流Ｉを供給
する定電流源と、 非反転入力端子が第１のスイッチを介して前記測温抵抗
体の端子Ａに接続されるとともに第２のスイッチを介し
て前記測温抵抗体の端子Ｂに接続された第１の演算増幅
器と、 非反転入力端子が第３のスイッチを介して前記測温抵抗
体の端子Ｂに接続されるとともに第４のスイッチを介し
て前記測温抵抗体の端子ｂに接続された第２の演算増幅
器と、 前記測温抵抗体の端子ｂと接地間に接続された第５のス
イッチと、 一端が前記第１の演算増幅器の出力端子に接続され他端
が前記第１の演算増幅器の反転入力端子に接続された第
１の抵抗Ｒ１と、 一端が前記第１の演算増幅器の反転入力端子に接続され
他端が前記第２の演算増幅器の出力端子に接続された第
２の抵抗Ｒ２と、 一端が前記第２の演算増幅器の出力端子に接続され他端
が前記第２の演算増幅器の反転入力端子に接続された第
３の抵抗Ｒ３と、 一端が前記第２の演算増幅器の反転入力端子に接続され
他端が接地された第４の抵抗Ｒ４とを具備し、 前記各抵抗Ｒ１〜Ｒ４が等しい抵抗値に設定され、 前記第１、第３及び第５のスイッチをオンにして第２及
び第４のスイッチをオフにすることにより、 Ｖｏｕｔ１＝２（Ｒｔ＋ｒ）・Ｉ を求め、 前記第１、第２及び第４のスイッチをオンにして第３及
び第５のスイッチをオフにすることにより、 Ｖｏｕｔ２＝２ｒ・Ｉ を求め、 これらＶｏｕｔ１及びＶｏｕｔ２から、 （Ｖｏｕｔ１−Ｖｏｕｔ２）／２＝Ｒｔ・Ｉを求めるこ
とを特徴とする測温抵抗体回路。[Claims] A three-wire resistance temperature detector having terminals A, B, and b, lead wires with equal resistance r, and a resistance Rt, and terminal A of the resistance temperature detector. a constant current source that is connected to the terminal A of the temperature sensing resistor through a first switch, and a constant current source that supplies the measurement current I; a first operational amplifier connected to terminal B of the resistance temperature sensor; a non-inverting input terminal connected to terminal B of the resistance temperature sensor via a third switch; and a first operational amplifier connected to terminal B of the resistance temperature sensor via a fourth switch; a second operational amplifier connected to terminal b of the resistance temperature detector; a fifth switch connected between terminal b of the resistance temperature detector and ground; one end of which is an output terminal of the first operational amplifier; a first resistor R1 connected to the inverting input terminal of the first operational amplifier and having the other end connected to the inverting input terminal of the first operational amplifier; a second resistor R2 connected to the output terminal of the amplifier; and a third resistor, one end of which is connected to the output terminal of the second operational amplifier, and the other end connected to the inverting input terminal of the second operational amplifier. R3; and a fourth resistor R4 having one end connected to the inverting input terminal of the second operational amplifier and the other end grounded, each of the resistors R1 to R4 being set to an equal resistance value, and the fourth resistor R4 having an equal resistance value. By turning on the first, third, and fifth switches and turning off the second and fourth switches, calculate Vout1=2(Rt+r)・I, and then turn the first, second, and fourth switches on. The measurement is characterized in that by turning on the switch and turning off the third and fifth switches, Vout2=2r・I is obtained, and from these Vout1 and Vout2, (Vout1−Vout2)/2=Rt・I is obtained. Temperature resistor circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16742790A JP2764646B2 (en) | 1990-06-26 | 1990-06-26 | RTD circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16742790A JP2764646B2 (en) | 1990-06-26 | 1990-06-26 | RTD circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0455729A true JPH0455729A (en) | 1992-02-24 |
| JP2764646B2 JP2764646B2 (en) | 1998-06-11 |
Family
ID=15849504
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16742790A Expired - Fee Related JP2764646B2 (en) | 1990-06-26 | 1990-06-26 | RTD circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2764646B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113432743A (en) * | 2021-06-21 | 2021-09-24 | 力高(山东)新能源技术有限公司 | Acquisition circuit and method for improving acquisition precision of temperature sensor |
-
1990
- 1990-06-26 JP JP16742790A patent/JP2764646B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113432743A (en) * | 2021-06-21 | 2021-09-24 | 力高(山东)新能源技术有限公司 | Acquisition circuit and method for improving acquisition precision of temperature sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2764646B2 (en) | 1998-06-11 |
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