KR930004426Y1 - Circuit for detecting resistance temperature detector - Google Patents
Circuit for detecting resistance temperature detector Download PDFInfo
- Publication number
- KR930004426Y1 KR930004426Y1 KR2019880010039U KR880010039U KR930004426Y1 KR 930004426 Y1 KR930004426 Y1 KR 930004426Y1 KR 2019880010039 U KR2019880010039 U KR 2019880010039U KR 880010039 U KR880010039 U KR 880010039U KR 930004426 Y1 KR930004426 Y1 KR 930004426Y1
- Authority
- KR
- South Korea
- Prior art keywords
- circuit
- relay switch
- differential amplifier
- constant current
- amplifier circuit
- 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 - Fee Related
Links
- 238000005259 measurement Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
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
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
- G01K7/20—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit
- G01K7/21—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer in a specially-adapted circuit, e.g. bridge circuit for modifying the output characteristic, e.g. linearising
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Indication And Recording Devices For Special Purposes And Tariff Metering Devices (AREA)
Abstract
내용 없음.No content.
Description
제1도는 종래의 회로도.1 is a conventional circuit diagram.
제2도는 본 고안의 회로도.2 is a circuit diagram of the present invention.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
1,2,4 : 정전류원 3 : 측온저항체(RTD)1,2,4: constant current source 3: RTD
5 : 차동증폭회로 6,7,8 : 릴레이스위치5: Differential amplifier circuit 6,7,8: Relay switch
본 고안은 RTD(Resistance Temperature Detector) 측정회로에 관한 것으로, 특히 정전류원의 오차보정과 연산증폭기의 오프셋 전압보정에 적당하도록 한 비브릿지(Non-bridge)방식의 RTD측정회로에 관한 것이다.The present invention relates to a resistance temperature detector (RTD) measurement circuit, and more particularly, to a non-bridge RTD measurement circuit suitable for error correction of a constant current source and offset voltage compensation of an operational amplifier.
종래의 RTD 측정회로는 제1도에 도시되어 있다.The conventional RTD measurement circuit is shown in FIG.
도면에서 알 수 있는 바와 같이 종래에는 두 개의 정전류원을 이용하여 브릿지형식으로 구성된 회로를 이용하였으며, 두 개의 정전류원(1,2)의 값이 동일하고 정전류의 방향이 제1도의 화살표와 같을 때 RTD 저항의 가변에 따른 출력전압(V0)은 다음과 같이 계산된다.As can be seen from the figure, conventionally, a circuit composed of a bridge type using two constant current sources is used. When the values of the two constant current sources 1 and 2 are the same and the direction of the constant current is the same as the arrow of FIG. The output voltage (V 0 ) according to the variable RTD resistance is calculated as follows.
여기에서 도선 저항이 서로 같다고 하면(R11=R12) 출력전압(V0)은Here, if the wire resistances are the same (R1 1 = R1 2 ), the output voltage (V 0 ) is
로 된다.It becomes
따라서 출력전압은 도선저항이 같을 때에 도선저항에 의한 영향을 받지 않는다.Therefore, the output voltage is not affected by the lead resistance when the lead resistance is the same.
그러나 제1도와 같은 구성을 위해서는 동일한 정전류원이 2개가 필요하고 식(1)에서 알 수 있는 바와 같이 정전류(I)가 변화하는 경우에는 출력전압을 보정할 수가 없으며 출력저항(R0)의 저항값의 변화에 의한 측정오차도 보정할 수가 없게 된다However, for the same configuration as in FIG. 1, two identical constant current sources are required, and as shown in equation (1), when the constant current I changes, the output voltage cannot be corrected and the resistance of the output resistance R 0 Measurement error caused by change of value cannot be corrected
따라서 본 고안에서는 단일 정전류원을 이용하여 소프트웨어에 의한 선형방식에 의해 정전류 오차에 대한 측정오차 및 차등 증폭회로에에 사용되는 연산증폭기의 오프셋전압을 함께 보정함으로써 정밀도를 개선한 RTD 측정회로의 제공을 목적으로 한다.Therefore, the present invention provides a RTD measurement circuit with improved accuracy by compensating the measurement error for the constant current error and the offset voltage of the operational amplifier used in the differential amplifier circuit by a linear method by software using a single constant current source. The purpose.
이를 위하여 본 고안은 제2도에 도시된 바와 같이 하나의 정전류원(4), 차동증폭회로(5), 릴레이스위치(6,7,8), 기준저항(R0) 및 오프셋 보정용 저항(R'0)등으로 구성 하였다.To this end, the present invention provides a constant current source 4, a differential amplifier circuit 5, a relay switch 6, 7, 8, a reference resistor R 0 and an offset correction resistor R as shown in FIG. ' 0 ) and so on.
제1도에 있어서 전류원중의 하나(2)를 제거하고 출력전압단자(V0)와 기준저항(R0)의 일단을 차동증폭회로(V0=2VB-VA를 만족시키는 것)(5)에 접속하고 이들에서의 측정전압을 각각 VA, VB라 한다. 도선저항(R11, R12, R13)과 차등증폭회로(5) 및 기준저항 사이에는 릴레이스위치(6)를 접속하고 상기 릴레이스위치(6)의 차등증폭회로측 단자는 릴레이스위치(7,8)의 일단에 접속한다. 릴레이스위치(7)의 타단은 공통으로 접속하고 릴레이스위치(8)의 타단에서 VA측과 VB측의 단자 사이에는 오프셋보정용 저항(R'0)을 접속하고 VB측과 R0측의 단자는 접속한다.In Figure 1, one of the current sources is removed and one end of the output voltage terminal (V 0 ) and the reference resistor (R 0 ) is satisfied with the differential amplifier circuit (V 0 = 2 V B -V A ). Connect to (5) and measure the measured voltages in these as V A and V B , respectively. The relay switch 6 is connected between the lead resistances R1 1 , R1 2 , R1 3 , the differential amplifier circuit 5 and the reference resistor, and the terminal of the differential amplifier circuit side of the relay switch 6 is a relay switch 7,. Connect to one end of 8). The other end of the relay switch 7 is connected in common, and an offset correction resistor R ' 0 is connected between the terminals of the V A side and the V B side at the other end of the relay switch 8, and the V B side and the R 0 side The terminal is connected.
이와 같이 구성된 본 고안의 동작은 다음과 같다.The operation of the present invention configured as described above is as follows.
정전류원(4)의 전류방향이 화살표와 같을 때 릴레이스위치(6)만 온되었으면 VA, VB의 전압은When only the relay switch 6 is turned on when the current direction of the constant current source 4 is the same as the arrow, the voltages of V A and V B are
가 된다. 따라서 차동증폭회로(5)를 통한 출력전압(V0)은Becomes Therefore, the output voltage (V 0 ) through the differential amplifier circuit (5)
이다. 만일 R11= R12이면to be. If R1 1 = R1 2
로 된다.It becomes
다음에 릴레이스위치(7)가 온되었으면 VA, VB의 전압은When the relay switch 7 is turned on next, the voltages of V A and V B are
이며, 차동증폭회로를 통과한 출력전압(V0)의 전압은The voltage of the output voltage (V 0 ) through the differential amplifier circuit is
로 된다.It becomes
릴레이스위치(8)가 온되었으면 VA, VB의 전압은When relay switch 8 is on, the voltage of V A , V B is
이고, 차동증폭회로(5)를 통과한 출력전압(V0)은The output voltage (V 0 ) passing through the differential amplifier circuit (5) is
상기 식(2),(3).(4)에서 얻은 값을 소프트웨어에 의하여 선형화하게 되면 RTD의 값을 얻을 수 있다.If the values obtained in Equations (2), (3) and (4) are linearized by software, RTD values can be obtained.
이상 설명한 바와 같이 본 고안에 의하면 RTD측정회로에서 하나의 정전류원만을 사용할 수 있고 소프트웨어에 대한 선형화방식에 의해 정전류 오차에 대한 측정오차 및 차동증폭회로에 사용되는 연산증폭기의 오프셋전압을 함께 보정함으로써 RTD측정에서의 정밀도를 크게 향상시킬 수가 있다.As described above, according to the present invention, only one constant current source can be used in the RTD measurement circuit, and the linearization method for software corrects the measurement error against the constant current error and the offset voltage of the operational amplifier used in the differential amplifier circuit together. The precision in a measurement can be improved significantly.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019880010039U KR930004426Y1 (en) | 1988-06-28 | 1988-06-28 | Circuit for detecting resistance temperature detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019880010039U KR930004426Y1 (en) | 1988-06-28 | 1988-06-28 | Circuit for detecting resistance temperature detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR900001186U KR900001186U (en) | 1990-01-18 |
| KR930004426Y1 true KR930004426Y1 (en) | 1993-07-14 |
Family
ID=19276765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR2019880010039U Expired - Fee Related KR930004426Y1 (en) | 1988-06-28 | 1988-06-28 | Circuit for detecting resistance temperature detector |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR930004426Y1 (en) |
-
1988
- 1988-06-28 KR KR2019880010039U patent/KR930004426Y1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| KR900001186U (en) | 1990-01-18 |
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| UA0108 | Application for utility model registration |
Comment text: Application for Utility Model Registration Patent event code: UA01011R08D Patent event date: 19880628 |
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| UG1604 | Publication of application |
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