JPS63229338A - Thermometric circuit - Google Patents
Thermometric circuitInfo
- Publication number
- JPS63229338A JPS63229338A JP6284587A JP6284587A JPS63229338A JP S63229338 A JPS63229338 A JP S63229338A JP 6284587 A JP6284587 A JP 6284587A JP 6284587 A JP6284587 A JP 6284587A JP S63229338 A JPS63229338 A JP S63229338A
- Authority
- JP
- Japan
- Prior art keywords
- terminal
- resistance
- voltage
- amplifier
- connection
- 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.)
- Granted
Links
- 238000009529 body temperature measurement Methods 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 4
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 4
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
- 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、測温抵抗体を使用した温度測定回路に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a temperature measuring circuit using a resistance temperature detector.
測温抵抗体を使用した温度測定回路の従来例を第４図に
示す。図において、ＲＴＤは測温抵抗体。FIG. 4 shows a conventional example of a temperature measurement circuit using a resistance temperature sensor. In the figure, RTD is a resistance temperature detector.
Ａ、Ｂ、ｂは接続端子である。測温抵抗体ＲＴＤの一端
はリード線１１を介して端子Ａに、他端はリード線１２
．１３を介して端子Ｂ、ｂに夫々接続されている。ｒ１
〜ｒ３はリード線１１〜１３の抵抗値を示すもので、ｒ
ｌ＝ｒ２＝ｒ３＝ｒとなっている。ＩＳは定電流源、Ｒ
８は基準抵抗で、定電流源ＩＳは端子Ａに接続され、基
串抵抗Ｒ３は接続線１４介して端子すと基準電位点ＣＯ
Ｍの間に接続されている。ＢＵはバッファ増幅器、ＳＵ
は差動増幅器である。接続端子Ａはバッファ増幅器ＢＵ
を介して差動増幅器ＳＵの一方の入力端子に接続され、
端子Ｂは直接に差動増幅器ＳＵの他方の入力端子に接続
されている。A, B, and b are connection terminals. One end of the resistance temperature detector RTD is connected to terminal A via lead wire 11, and the other end is connected to lead wire 12.
．． 13 to terminals B and b, respectively. r1
~r3 indicates the resistance value of the lead wires 11 to 13, and r
l=r2=r3=r. IS is a constant current source, R
8 is a reference resistor, constant current source IS is connected to terminal A, and basic resistor R3 is connected via connecting wire 14 to reference potential point CO.
It is connected between M. BU is a buffer amplifier, SU
is a differential amplifier. Connection terminal A is buffer amplifier BU
connected to one input terminal of the differential amplifier SU via
Terminal B is directly connected to the other input terminal of the differential amplifier SU.
このような構成において、定電流源ＩＳにより供給され
る定電流工は端子Ａよりリード線１１→測温抵抗体ＲＴ
Ｄ→リード線１３→基準抵抗Ｒ８を介して基準電位点Ｃ
ＯＭに流れる。この電流■により端子Ａ、Ｂに生じる電
圧降下をＶｌ、Ｖ２とし、ＲＴを測温抵抗体ＲＴＤ、Ｒ
８を基準抵抗Ｒ５の抵抗値とすると、
Ｖ１＝ （ＲＴ＋Ｒ５＋２ｒ） ・ＩＶ２＝ （ＲＳ
＋ｒ） ・Ｉ
となる。従って、差動増幅器ＳＵの出力電圧をＶｏとす
ると、Ｖｏは下式で表わされる。In such a configuration, the constant current supplied by the constant current source IS is connected from the terminal A to the lead wire 11 → the resistance temperature detector RT.
D → Lead wire 13 → Reference potential point C via reference resistor R8
Flows to OM. The voltage drops caused at terminals A and B by this current ■ are Vl and V2, and RT is the resistance temperature detector RTD, R
8 is the resistance value of the reference resistor R5, V1= (RT+R5+2r) ・IV2= (RS
+r) ・I becomes. Therefore, when the output voltage of the differential amplifier SU is Vo, Vo is expressed by the following formula.
Ｖｏ＝２Ｖ２−Ｖ１＝ （Ｒ５−ＲＴ）−（１）（１）
式において基準抵抗Ｒ８の値を測温抵抗体ＲＴＤのＯ’
Ｃの時の抵抗値と同じ値にすると、出力電圧Ｖｏは被測
定温度に対応する。Vo=2V2-V1= (R5-RT)-(1)(1)
In the formula, the value of the reference resistance R8 is set to O' of the resistance temperature detector RTD.
If the resistance value is set to be the same as the resistance value at C, the output voltage Vo corresponds to the temperature to be measured.
ここで、第４図の回路において基準抵抗Ｒ３は接続線１
４を介して端子すに接続されているが、その接続線１４
にも同様に抵抗が存在する。この抵抗を図でｒｓとして
示しであるが、第２図の回路においてはこの抵抗ｒｓが
測定値Ｖｏの誤差要因となる。Here, in the circuit of FIG. 4, the reference resistor R3 is the connection line 1
4 is connected to the terminal via the connecting wire 14.
There is resistance as well. This resistance is shown as rs in the figure, but in the circuit of FIG. 2, this resistance rs becomes a factor of error in the measured value Vo.
本発明はこのような問題点を解決するためになされたも
ので、基準抵抗Ｒ５を接続する接続線１４の抵抗値が測
定結果に影響を及ぼさないようにしたものである。The present invention was made to solve these problems, and is designed to prevent the resistance value of the connection line 14 connecting the reference resistor R5 from affecting the measurement results.
本発明は端子すの電位を定電圧化することにより上記の
目的を達成したもので、以下実施例について詳細に説明
する。The present invention achieves the above object by making the potential of the terminal a constant voltage, and examples thereof will be described in detail below.
第１図は本発明に係る温度測定回路の一実施例の接続図
である。なお、第１図において第４図と同一部分は第４
図と同一符号を付してその再説明は省略する。第１図に
おいて、ＯＰは演算増幅器で、その出力端は接続線１５
を介して、又反転入力端子は接続＃Ｉｉ！ｉ６を介して
夫々端子すに接続されている。０℃の時の測温抵抗体Ｒ
ＴＤの抵抗値をＲＴ （０）とすると、Ｅ＝Ｉ・ＲＴ
（０）で表おされる電圧が演算増幅器ＯＰの非反転入力
端子には加えられている。この構成により、印加電圧Ｅ
は演算増幅器○Ｐにより定電圧化されて端子すに加えら
れる。従って、このような構成においてＶｌ、Ｖ２は、
Ｖ１＝Ｅ＋ （ＲＴ＋２ ｒ） ・ＩＶ ２ ＝ Ｅ
＋ ｒ・工
で表すされ、Ｖｏは
Ｖｏ＝２Ｖ２−Ｖｌ ＝Ｅ＋ＲＴ 弓
＝ （（ＲＴ （０）−ＲＴ）−Ｉ −（２）とな
る。（２）式から明らかなように、出力電圧Ｖ。FIG. 1 is a connection diagram of an embodiment of a temperature measuring circuit according to the present invention. Note that the same parts in Figure 1 as in Figure 4 are shown in Figure 4.
The same reference numerals as those in the figure are used to omit the redundant explanation. In FIG. 1, OP is an operational amplifier whose output terminal is connected to the connection line 15.
Also, the inverting input terminal is connected via #Ii! They are connected to the respective terminals via i6. Resistance temperature detector R at 0℃
If the resistance value of TD is RT (0), then E=I・RT
A voltage represented by (0) is applied to the non-inverting input terminal of operational amplifier OP. With this configuration, the applied voltage E
is made into a constant voltage by the operational amplifier ○P and applied to the terminal S. Therefore, in such a configuration, Vl and V2 are as follows: V1=E+ (RT+2 r) ・IV 2 = E
+ r・Equation, and Vo is Vo = 2V2 - Vl = E + RT Bow = ((RT (0) - RT) - I - (2). As is clear from equation (2), the output voltage V .
は被測定温度に対応したものとなる。なお、演算増幅器
ＯＰの出力端及び反転入力端子は接続線１５．１６を介
して端子すに接続されており、それらの接続線にも抵抗
ｒ５．ｒ６が存在する。しかし、これらの抵抗は端子す
の電位が定電圧化されている為に誤差要因とならない。corresponds to the temperature to be measured. The output terminal and the inverting input terminal of the operational amplifier OP are connected to the terminals via connection lines 15 and 16, and these connection lines are also connected to resistors r5. r6 exists. However, these resistors do not cause errors because the potential of the terminal is kept at a constant voltage.
なお、第４図の従来例ではスキャナ等を使用して入力を
切換える場合にはそのスキャナのリレーの接触抵抗のバ
ラツキなどにより出力電圧ｖＯに誤差が生じる。第２図
及び第３図はこのようなスキャナリレーの接触抵抗に影
響されないようにしたものである。第２図及び第３図に
おいてＳＣはそのスキャナで、第２図においては端子Ａ
、Ｂ。In the conventional example shown in FIG. 4, when the input is switched using a scanner or the like, an error occurs in the output voltage vO due to variations in the contact resistance of the scanner's relay. FIGS. 2 and 3 are diagrams in which the contact resistance of such a scanner relay is not affected. In FIGS. 2 and 3, SC is the scanner, and in FIG.
,B.
ｂをすべてスキャナ接点５１〜ｓ５により切換えるよう
になっている。この場合、スキャナ接点Ｓ４、ｓ５は端
子すと演算増幅器ＯＰを結ぶ接続線１５．１６に接続さ
れているので、スキャナ接点５１〜ｓ３はもちろんのこ
と、スキャナ接点ｓ５゜ｓ６の接触抵抗も第１図で説明
したように誤差要因とならないものとなっている。第３
図は端子すをすべてのチャネル間で共用させるようにし
たもので、この場合第１図で説明したように接続線１５
．１６による誤差要因はなくなる。なお、端子すを何チ
ャネル間で共用させる場合があり、そのときは接続線Ｚ
５．Ｚ５における点Ｘ、Ｙで別のスキャナ接点を用いる
必要があるが、その場合もそのスキャナ接点の接触抵抗
による影響はない。b are all switched by scanner contacts 51 to s5. In this case, since the scanner contacts S4 and s5 are connected to the connecting wire 15.16 that connects the terminals and the operational amplifier OP, the contact resistance of not only the scanner contacts 51 to s3 but also the scanner contacts s5 and s6 is also the first. As explained in the figure, this is not a cause of error. Third
In the figure, the terminal is shared between all channels, and in this case, as explained in Figure 1, the connecting wire 15
．． The error factor caused by No. 16 is eliminated. Note that the terminal may be shared between several channels, in which case the connection wire Z
5. Although it is necessary to use separate scanner contacts at points X and Y at Z5, the contact resistance of the scanner contacts does not affect this.
以上説明したように、本発明においては３線式で接続す
る測温抵抗体の接続端子すの電位を定電圧化するように
構成したので、この接続端子すに接続される接続線の抵
抗値或いはスキャナ接点の接触抵抗による影響のない温
度測定回路を極めてＷ単な構成によって得ることができ
る。As explained above, in the present invention, the potential of the connection terminal of the RTD connected in a three-wire system is made constant voltage, so the resistance value of the connection wire connected to this connection terminal is Alternatively, a temperature measuring circuit that is not affected by the contact resistance of the scanner contacts can be obtained with an extremely simple configuration.
第１図乃至第３図は夫々本発明に係る温度測定回路の実
施例の接続図、第４図は従来のこの種の回路の一例の接
続図である。
ＲＴＤ・・・測温抵抗体、Ａ、Ｂ、ｂ・・・接続端子、
■Ｓ・・・定電流源、ＳＵ・・・差動増幅器、ＯＰ・・
・演算増幅器、Ｅ・・・電圧。
第１図
■５
第２図
Ｃ1 to 3 are connection diagrams of embodiments of the temperature measuring circuit according to the present invention, and FIG. 4 is a connection diagram of an example of a conventional circuit of this type. RTD...Resistance temperature sensor, A, B, b...Connection terminal,
■S...constant current source, SU...differential amplifier, OP...
- Operational amplifier, E...voltage. Figure 1 ■5 Figure 2 C
Claims (1)
より供給される定電流により端子Ａ、Ｂ間に生じる電圧
降下の差を差動増幅器を用いて取出すようにした温度測
定回路において、前記端子ｂの電位を定電圧化したこと
を特徴とする温度測定回路。Connect the resistance temperature detector using three terminals A, B, and b, and connect terminal A
A temperature measurement circuit configured to use a differential amplifier to extract the difference in voltage drop that occurs between terminals A and B due to a constant current supplied from the terminal B, characterized in that the potential of the terminal b is made into a constant voltage. measurement circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62062845A JP2512934B2 (en) | 1987-03-18 | 1987-03-18 | Temperature measurement circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62062845A JP2512934B2 (en) | 1987-03-18 | 1987-03-18 | Temperature measurement circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63229338A true JPS63229338A (en) | 1988-09-26 |
| JP2512934B2 JP2512934B2 (en) | 1996-07-03 |
Family
ID=13212048
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62062845A Expired - Lifetime JP2512934B2 (en) | 1987-03-18 | 1987-03-18 | Temperature measurement circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2512934B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008009676A1 (en) * | 2006-07-17 | 2008-01-24 | Mettler-Toledo Ag | Temperature measurement device and measurement method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57182133A (en) * | 1981-05-02 | 1982-11-09 | Yokogawa Hokushin Electric Corp | Temperature measuring circuit by temperature measuring resistor |
-
1987
- 1987-03-18 JP JP62062845A patent/JP2512934B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57182133A (en) * | 1981-05-02 | 1982-11-09 | Yokogawa Hokushin Electric Corp | Temperature measuring circuit by temperature measuring resistor |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008009676A1 (en) * | 2006-07-17 | 2008-01-24 | Mettler-Toledo Ag | Temperature measurement device and measurement method |
| JP2009544029A (en) * | 2006-07-17 | 2009-12-10 | メトラー−トレド アクチェンゲゼルシャフト | Temperature measuring apparatus and measuring method |
| US7775711B2 (en) | 2006-07-17 | 2010-08-17 | Mettler-Toledo Ag | Temperature measurement device and measurement method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2512934B2 (en) | 1996-07-03 |
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