JPH0469446B2 - - Google Patents
Info
- Publication number
- JPH0469446B2 JPH0469446B2 JP58086764A JP8676483A JPH0469446B2 JP H0469446 B2 JPH0469446 B2 JP H0469446B2 JP 58086764 A JP58086764 A JP 58086764A JP 8676483 A JP8676483 A JP 8676483A JP H0469446 B2 JPH0469446 B2 JP H0469446B2
- Authority
- JP
- Japan
- Prior art keywords
- input
- input terminal
- voltage
- resistor
- terminal
- 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 - Lifetime
Links
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 239000000284 extract Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
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- Amplifiers (AREA)
Description
【発明の詳細な説明】
(1) 発明の分野
この発明は、熱電対、電圧、抵抗入力のいずれ
にも対応できる入力装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to an input device that can accept thermocouple, voltage, and resistance inputs.
(2) 従来技術
従来、測温抵抗体の抵抗値変化を電流を流すこ
とにより電圧に変換して取り出す入力回路と、熱
電対・電圧を入力する入力回路とは別回路構成と
されていた。(2) Prior Art Conventionally, an input circuit that converts the change in resistance value of a resistance temperature sensor into a voltage by passing a current and extracts the voltage, and an input circuit that inputs a thermocouple and voltage have been configured as separate circuits.
このため、用途に応じて別個の回路を用意せね
ばならず煩雑であり、又、種々の入力を混在させ
て取り込むデータ集録装置等において、入力信号
の種類により別個の回路を用意しなければなら
ず、スペースを多く必要とし、複雑、高価なもの
となる欠点があつた。 For this reason, it is necessary to prepare separate circuits depending on the application, which is cumbersome. Also, in data acquisition devices etc. that take in a mixture of various inputs, separate circuits must be prepared depending on the type of input signal. However, the disadvantages are that it requires a lot of space, is complicated, and is expensive.
(3) 発明の目的
この発明の目的は、以上の点に鑑み、抵抗入力
および熱電、電圧入力のいずれにも共用できる入
力装置を提供することである。(3) Purpose of the Invention In view of the above points, the purpose of the present invention is to provide an input device that can be used commonly for resistance input, thermoelectric input, and voltage input.
(4) 発明の実施例
第１図は、この実施例の一実施例を示す構成説
明図である。(4) Embodiment of the Invention FIG. 1 is a configuration explanatory diagram showing one embodiment of this embodiment.
図において、１１，１２，１３は入力信号が供
給される第１、第２、第３の入力端子、A1は第
１の入力端子１１に入力抵抗R1を介してその反
転入力端子（−）が接続されるとともに第２の入
力端子１２にその非反転入力端子（＋）が接続さ
れる演算増幅器、R2は、演算増幅器A1の出力端
子１４と反転入力端子（−）との間に接続される
抵抗R1と等しい抵抗値をもつ帰環抵抗、R0は第
３の入力端子１３に接続される補償用の抵抗、２
は、第１の入力端子１１に基準（アース）点また
は定電流源Ｉのいずれかを選択して接続するスリ
ツト、スイツチ等の選択手段である。 In the figure, 11 , 12, and 13 are the first, second, and third input terminals to which input signals are supplied, and A1 is the inverting input terminal (- ) is connected and its non-inverting input terminal (+) is connected to the second input terminal 12, R 2 is connected between the output terminal 14 of the operational amplifier A 1 and the inverting input terminal (-) A return resistor with a resistance value equal to the resistor R 1 connected to R 0 is a compensation resistor connected to the third input terminal 13, and R 0 is a compensation resistor connected to the third input terminal 13.
is a selection means such as a slit or a switch that selects and connects either the reference (earth) point or the constant current source I to the first input terminal 11.
次に場合を分けて動作を説明する。第２図に、
熱電対、電圧入力の場合の接続図を示す。 Next, the operation will be explained in different cases. In Figure 2,
The connection diagram for thermocouple and voltage input is shown.
第１、第２の入力端子１１，１２に熱電対等の
測定電圧Ｅを接続し、選択手段２は２０，２１間
が短絡で、第１の入力端子１１は基準点に接続さ
れている。 A measuring voltage E from a thermocouple or the like is connected to the first and second input terminals 11 and 12, and the selection means 2 has a short circuit between 20 and 21, and the first input terminal 11 is connected to a reference point.
この場合、演算増幅器A1の反転入力端子（−）
にはゼロ電位、非反転入力端子（＋）には−Ｅが
供給されているため、出力端子１４の出力電圧
V0は次式となる。（なおR1＝R2である。）
V0＝（１＋R2／R1）（−Ｅ）＝−2E ……(1)
次に、第３図に抵抗入力の場合の接続図を示
す。 In this case, the inverting input terminal (−) of operational amplifier A1
Since zero potential is supplied to and -E is supplied to the non-inverting input terminal (+), the output voltage of output terminal 14 is
V 0 is given by the following formula. (Note that R 1 = R 2. ) V 0 = (1+R 2 /R 1 ) (-E) = -2E (1) Next, FIG. 3 shows a connection diagram in the case of resistance input.
測温抵抗（体）Rtの一端は第１のリード線r1を
介して第１の入力端子１１に接続され、他線は第
２のリード線r2を介して第２の入力端子１２、お
よび第３のリード線r3を介して第３の入力端子１
３に接続される。選択手段２は、２０，２２が短
絡で、第１の入力端子１１に定電流源Ｉが接続さ
れる。 One end of the temperature sensing resistor (body) Rt is connected to the first input terminal 11 via the first lead wire r1, and the other wire is connected to the second input terminal 12 via the second lead wire r2. , and the third input terminal 1 via the third lead r 3
Connected to 3. In the selection means 2, 20 and 22 are short-circuited, and the constant current source I is connected to the first input terminal 11.
この場合、定電流源Ｉより一定電流ｉが第１の
リード線r1、測温抵抗Rt、第３のリード線r3、補
償抵抗R0と流れるため、第１の入力端子１１の
電圧V1、第２の入力端子の電圧V2は次式となる。
なお各リード線r1，r2，r3の抵抗値を等しくｒと
する。 In this case, since a constant current i flows from the constant current source I through the first lead wire r 1 , the temperature measuring resistor R t , the third lead wire r 3 , and the compensation resistor R 0 , the voltage at the first input terminal 11 V 1 and the voltage V 2 at the second input terminal are expressed by the following equation.
Note that the resistance values of each lead wire r 1 , r 2 , and r 3 are assumed to be equal to r.
V1＝ｉ（r1＋Rt＋r3＋R0）＝ｉ（Rt＋R0＋2r）
V2＝ｉ（R0＋r3）＝ｉ（R0＋ｒ）
従つて演算増幅器A1の出力端子１４より取り
出せる出力電圧V0は次式となる。V 1 = i (r 1 + R t + r 3 + R 0 ) = i (R t + R 0 + 2r) V 2 = i (R 0 + r 3 ) = i (R 0 + r) Therefore, the output terminal 14 of operational amplifier A 1 The output voltage V 0 that can be extracted from the equation is as follows.
V0＝2V2−V1
＝2i（R0＋ｒ）−ｉ（Rt＋R0＋2r）＝ｉ（R0−Rt）
……(2)
ここで、測温抵抗Rtの温度係数をαとすれば、
ある温度ｔでは、Rt＝（１＋αt）R0（R0は０℃で
の抵抗値）となり、これを(2)式に代入すれば、
V0＝ｉ｛R0−（１＋αt）R0｝＝−iαtR0 ……(3)
となり、温度ｔに比例した電圧が取り出せる。リ
ード線（配線）抵抗の影響も除去されている。V 0 = 2V 2 −V 1 = 2 i (R 0 + r) − i (R t + R 0 + 2r) = i (R 0 − Rt)
...(2) Here, if the temperature coefficient of the temperature sensing resistance R t is α, then
At a certain temperature t, R t = (1 + αt) R 0 (R 0 is the resistance value at 0°C), and by substituting this into equation (2), V 0 = i {R 0 - (1 + αt) R 0 }=-iαtR 0 ...(3), and a voltage proportional to the temperature t can be extracted. The influence of lead wire (wiring) resistance is also removed.
このように、第１図の回路を用いることによ
り、熱電対入力、電圧入力および抵抗入力のいず
れにも容易に対応することができる。 In this manner, by using the circuit shown in FIG. 1, it is possible to easily accommodate any of thermocouple input, voltage input, and resistance input.
また、第４図で示すように、演算増幅器A1の
出力側に抵抗R3，R4をもつ演算増幅器A3を接続
すると出力端子１５より得られる電圧入力につい
ての出力電圧V0は(1)式より次式となる。 Furthermore, as shown in FIG. 4, when an operational amplifier A 3 having resistors R 3 and R 4 is connected to the output side of the operational amplifier A 1 , the output voltage V 0 for the voltage input obtained from the output terminal 15 is (1 ) gives the following equation.
V0＝＋R4／R32E ……(1)′
ここでR4＝KR3とすれば、
V0＝2KE ……(1)″
となり、所定の倍率とされた正の電圧出力が取り
出せる。 V 0 = +R 4 /R 3 2E ……(1)′ Here, if R 4 = KR 3 , then V 0 = 2KE ……(1)″, and a positive voltage output with a predetermined magnification can be obtained. .
また、第５図で示すように、抵抗入力の場合、
第４図の回路において、演算増幅器A2の出力を
抵抗R5を介して正帰環を施すことにより、測温
抵抗の非直線性を補償して抵抗に比例したリニア
ライズ出力電圧が出力端子１５より得られる。 Also, as shown in Figure 5, in the case of resistance input,
In the circuit shown in Figure 4, by applying positive feedback to the output of the operational amplifier A2 through the resistor R5 , the nonlinearity of the temperature-measuring resistor is compensated, and a linearized output voltage proportional to the resistance is output to the output terminal. 15.
なお、これら回路をハイブリツドLC化しても
よく、多種多点入力においても回路と共通化を図
ることができる。 Note that these circuits may be made into a hybrid LC, and the circuits can be used in common even in various types of multi-point inputs.
(5) 発明の要約
以上述べたように、この発明は、第１、第２、
第３の入力端子、演算増幅器、定電流源の選択手
段、補償抵抗を含む入力装置である。(5) Summary of the invention As stated above, this invention comprises the first, second,
The input device includes a third input terminal, an operational amplifier, constant current source selection means, and a compensation resistor.
(6) 発明の効果
１個の演算増幅器、定電流源等を用意するだけ
で、ｍＶ、電圧入力、熱電対入力、抵抗入力のい
ずれに同一回路でその入力が取り込める。又、電
圧入力等では演算増幅器の非反転入力端子で受け
ているのでハイインピーダンスで受けることにな
り、抵抗入力については、配線抵抗の除去、０℃
抵抗分の除去、リニアライズ等も可能である。(6) Effects of the invention By simply preparing one operational amplifier, constant current source, etc., the input can be input to mV, voltage input, thermocouple input, or resistance input using the same circuit. Also, voltage input, etc. is received at the non-inverting input terminal of the operational amplifier, so it is received at high impedance, and resistance input, by removing wiring resistance,
Removal of resistance components, linearization, etc. are also possible.
第１図、第２図、第３図、第４図、第５図は、
この発明の一実施例を示す構成説明図である。
１１，１２，１３……入力端子、R1〜R5……
抵抗、R0……補償抵抗、A1，A2……演算増幅
器、Ｉ……定電流源、２……選択手段。
Figures 1, 2, 3, 4, and 5 are
FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention. 11, 12, 13...Input terminals, R1 to R5 ...
Resistor, R0 ...compensation resistor, A1 , A2 ...operational amplifier, I...constant current source, 2...selection means.
Claims (1)
力端子と、前記第１の入力端子に入力抵抗を介し
てその反転入力端子が接続されるとともに前記第
２の入力端子にその非反転入力端子が接続される
演算増幅器と、この演算増幅器の出力端子と反転
入力端子との間に接続される前記入力抵抗の抵抗
値と等しい抵抗値をもつ帰還抵抗と、前記第３の
入力端子に接続される抵抗と、熱電対等の電圧が
第１、第２の入力端子間に接続されたときには第
１の入力端子に基準点を選択して接続し、測温抵
抗体等の抵抗体の一端が第１の入力端子に接続し
他端が第２、第３の入力端子に接続されたときは
第１の入力端子に定電流源を選択して接続する選
択手段とを備えたことを特徴とする入力装置。1 first, second, and third input terminals to which an input signal is supplied; an inverting input terminal thereof is connected to the first input terminal via an input resistor; and its non-inverting input terminal is connected to the second input terminal. an operational amplifier to which an inverting input terminal is connected; a feedback resistor having a resistance value equal to the resistance value of the input resistor connected between the output terminal of the operational amplifier and the inverting input terminal; and the third input terminal. When the voltage of a resistor such as a thermocouple is connected between the first and second input terminals, the reference point is selected and connected to the first input terminal. and selecting means for selecting and connecting a constant current source to the first input terminal when one end is connected to the first input terminal and the other end is connected to the second and third input terminals. Characteristic input device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58086764A JPS59212008A (en) | 1983-05-18 | 1983-05-18 | Input device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58086764A JPS59212008A (en) | 1983-05-18 | 1983-05-18 | Input device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59212008A JPS59212008A (en) | 1984-11-30 |
| JPH0469446B2 true JPH0469446B2 (en) | 1992-11-06 |
Family
ID=13895808
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58086764A Granted JPS59212008A (en) | 1983-05-18 | 1983-05-18 | Input device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59212008A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4998068A (en) * | 1989-05-16 | 1991-03-05 | In-Situ, Inc. | Bias current control for providing accurate potentiometric measurements |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6031301Y2 (en) * | 1977-12-27 | 1985-09-19 | 横河電機株式会社 | dc amplifier |
-
1983
- 1983-05-18 JP JP58086764A patent/JPS59212008A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59212008A (en) | 1984-11-30 |
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