JPH0235250B2 - - Google Patents
Info
- Publication number
- JPH0235250B2 JPH0235250B2 JP58215657A JP21565783A JPH0235250B2 JP H0235250 B2 JPH0235250 B2 JP H0235250B2 JP 58215657 A JP58215657 A JP 58215657A JP 21565783 A JP21565783 A JP 21565783A JP H0235250 B2 JPH0235250 B2 JP H0235250B2
- Authority
- JP
- Japan
- Prior art keywords
- thermocouple
- reference junction
- converter
- circuit
- signal
- 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
- 238000001514 detection method Methods 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 2
- 238000009529 body temperature measurement Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
- G01K7/10—Arrangements for compensating for auxiliary variables, e.g. length of lead
- G01K7/12—Arrangements with respect to the cold junction, e.g. preventing influence of temperature of surrounding air
- G01K7/13—Circuits for cold-junction compensation
Description
【発明の詳細な説明】
(1) 発明の分野
この発明は、基準接点補償を行う熱電対入力回
路に関するものである。DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention The present invention relates to a thermocouple input circuit that performs reference junction compensation.
(2) 従来技術
熱電対による温度測定は、従来、第１図で示す
ように測定対象に熱電対１の温接点、端子板の端
子ｔに基準接点を形成し、この端子ｔの温度を検
出回路２で測定し、熱電対１からの熱電対入力信
号e1に検出回路２の基準接点温度信号e2を加算器
A1で加算し、Ａ−Ｄ変換器３でデジタル信号に
変換し、マイクロコンピユータのような中央処理
装置よりなる演算回路４でリニアライズその他の
演算を行うようにしていた。(2) Prior art Conventionally, in temperature measurement using a thermocouple, as shown in Fig. 1, a hot junction of thermocouple 1 is formed as the object to be measured, a reference junction is formed at terminal t of a terminal board, and the temperature of this terminal t is detected. It is measured by circuit 2 and the reference junction temperature signal e 2 of detection circuit 2 is added to the thermocouple input signal e 1 from thermocouple 1 by an adder.
A 1 adds the signals, an A-D converter 3 converts the signals into digital signals, and an arithmetic circuit 4 comprising a central processing unit such as a microcomputer performs linearization and other calculations.
この場合、第２図で示すように、特定の熱電対
入力信号e1の起電力特性に合つた基準接点温度信
号e2を加算しているので、１つの回路で、ある特
定の熱電対の種類および測定範囲のものしかでき
ず、目盛の切換、交換は複雑なものとなる欠点が
あつた。 In this case, as shown in Figure 2, the reference junction temperature signal e 2 that matches the electromotive force characteristics of the specific thermocouple input signal e 1 is added, so one circuit It had the disadvantage that only types and measurement ranges were available, and switching and replacing scales was complicated.
また、第３図で示すように、熱電対１の熱電対
入力信号e1と、検出回路２の基準接点温度信号e2
とを切換スイツチＳ１，Ｓ２で交互に切り換えて
取り込み、Ａ−Ｄ変換器３で両信号e1、e2を交互
にデジタル信号に変換し、演算回路４で両信号
e1、e2に基いて基準接点補償を行う方法もある。 In addition, as shown in FIG. 3, the thermocouple input signal e 1 of the thermocouple 1 and the reference junction temperature signal e 2 of the detection circuit 2
The A-D converter 3 converts both signals e 1 and e 2 alternately into digital signals, and the arithmetic circuit 4 converts both signals into digital signals.
There is also a method of performing reference junction compensation based on e 1 and e 2 .
この場合、演算回路４により複数の種類の熱電
対および測定範囲の補償は可能であるが、切換ス
イツチＳ１，Ｓ２があるため、その接点による誤
差が生じ、また、第４図で示すように信号e1、e2
は交互にＡ−Ｄ変換されるので、入力処理時間を
多く必要とするものだつた。 In this case, it is possible to compensate for multiple types of thermocouples and measurement ranges using the arithmetic circuit 4, but since there are changeover switches S1 and S2, errors occur due to their contacts, and as shown in FIG. e1 , e2
Since the data are alternately A-to-D converted, a lot of input processing time is required.
(3) 発明の目的
この発明の目的は、以上の点に鑑み、高精度、
高速処理を可能とした熱電対入力回路を提供する
ことである。(3) Purpose of the invention In view of the above points, the purpose of the invention is to provide high precision,
An object of the present invention is to provide a thermocouple input circuit that enables high-speed processing.
(4) 発明の実施例
第５図は、この発明の一実施例を示す構成説明
図で、第１図、第３図と同一符号は同一構成要素
を示す。(4) Embodiment of the Invention FIG. 5 is a configuration explanatory diagram showing an embodiment of the invention, and the same reference numerals as in FIGS. 1 and 3 indicate the same components.
図において、熱電対１の熱電対入力信号e1は、
端子ｔを介し増幅器Ａ３で増幅され、第１のＡ−
Ｄ変換器３１でデジタル信号に変換される。ま
た、同時に、端子ｔの基準接点温度を検出回路２
で検出し、その基準接点温度信号e2は、第２のＡ
−Ｄ変換器３２でデジタル信号に変換される。そ
して、マイクロコンピユータのような中央処理装
置よりなる演算回路４は、これら両信号e1、e2を
常時取り込み、複数種の熱電対目盛に応じた基準
点補償、リニアライズ演算等を行つている。 In the figure, the thermocouple input signal e 1 of thermocouple 1 is
Amplified by amplifier A3 through terminal t, the first A-
It is converted into a digital signal by a D converter 31. At the same time, the reference junction temperature of the terminal t is detected by the detection circuit 2.
The reference junction temperature signal e 2 is detected by the second A
- It is converted into a digital signal by the D converter 32. Then, an arithmetic circuit 4 consisting of a central processing unit such as a microcomputer constantly takes in both signals e 1 and e 2 and performs reference point compensation, linearization calculation, etc. according to multiple types of thermocouple scales. .
つまり、第６図で示すように、両信号e1、e2を
同時にＡ−Ｄ変換しているので、入力処理時間の
短縮化が図れ、また、切換スイツチも不要とな
る。 That is, as shown in FIG. 6, since both signals e 1 and e 2 are A-to-D converted at the same time, the input processing time can be shortened and a changeover switch is not required.
(5) 発明の要約
以上述べたように、この発明は、熱電対入力信
号を第１のＡ−Ｄ変換器でデジタル信号に変換
し、基準接点の温度信号を第２のＡ−Ｄ変換器で
デジタル信号に変換し、演算回路により、第１、
第2A−Ｄ変換器の出力から基準接点補償を行う
ようにした熱電対入力回路である。(5) Summary of the Invention As described above, the present invention converts a thermocouple input signal into a digital signal with a first A-D converter, and converts a temperature signal of a reference junction into a digital signal with a second A-D converter. is converted into a digital signal by an arithmetic circuit.
This is a thermocouple input circuit that performs reference junction compensation from the output of the second A-D converter.
(6) 発明の効果
切換スイツチ等を用いていないので、スイツチ
による誤差は除去でき、また、Ａ−Ｄ変換は熱電
対入力、基準接点入力の各々別個に同時に行つて
いるので高速処理が可能で、演算回路により多種
類の熱電対および目盛範囲の補償が容易に可能と
なる。(6) Effects of the invention Since no changeover switch is used, errors caused by the switch can be eliminated, and A-D conversion is performed simultaneously for each thermocouple input and reference junction input, allowing high-speed processing. , compensating for many types of thermocouples and scale ranges is easily possible using arithmetic circuits.
第１図、第２図、第３図、第４図は、従来例を
示す説明図、第５図は、この発明の一実施例を示
す構成説明図、第６図は、動作説明図である。
１……熱電対、２……検出回路、３１，３２…
…Ａ−Ｄ変換器、４……演算回路。
1, 2, 3, and 4 are explanatory diagrams showing a conventional example, FIG. 5 is a configuration explanatory diagram showing an embodiment of the present invention, and FIG. 6 is an explanatory diagram of the operation. be. 1... Thermocouple, 2... Detection circuit, 31, 32...
...A-D converter, 4... Arithmetic circuit.
Claims (1)
号をデジタル信号に変換する第１のＡ−Ｄ変換器
と、前記端子の基準接点温度を検出する検出回路
と、この検出回路の基準接点温度信号をデジタル
信号に変換する第２のＡ−Ｄ変換器と、これら第
１、第２のＡ−Ｄ変換器出力に基いて基準接点補
償を行う演算回路とを備えたことを特徴とする熱
電対入力回路。1 A first A-D converter that converts a thermocouple input signal amplified by an amplifier through a terminal into a digital signal, a detection circuit that detects a reference junction temperature of the terminal, and a reference junction temperature signal of this detection circuit. A thermocouple comprising: a second A-D converter that converts the output into a digital signal; and an arithmetic circuit that performs reference junction compensation based on the outputs of the first and second A-D converters. input circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21565783A JPS60107534A (en) | 1983-11-16 | 1983-11-16 | Thermocouple input circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21565783A JPS60107534A (en) | 1983-11-16 | 1983-11-16 | Thermocouple input circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60107534A JPS60107534A (en) | 1985-06-13 |
| JPH0235250B2 true JPH0235250B2 (en) | 1990-08-09 |
Family
ID=16676016
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21565783A Granted JPS60107534A (en) | 1983-11-16 | 1983-11-16 | Thermocouple input circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60107534A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE8618463U1 (en) * | 1986-07-10 | 1987-05-21 | Werner Eidam Medizintechnologie Gmbh, 6307 Linden, De | |
| US8118484B2 (en) * | 2009-03-31 | 2012-02-21 | Rosemount Inc. | Thermocouple temperature sensor with connection detection circuitry |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5152878A (en) * | 1974-11-02 | 1976-05-10 | Tokyo Electric Power Co | Denkiryono kenshutsuhoshiki |
-
1983
- 1983-11-16 JP JP21565783A patent/JPS60107534A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5152878A (en) * | 1974-11-02 | 1976-05-10 | Tokyo Electric Power Co | Denkiryono kenshutsuhoshiki |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60107534A (en) | 1985-06-13 |
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