JP2517537B2 - Humidity measurement circuit - Google Patents
Humidity measurement circuitInfo
- Publication number
- JP2517537B2 JP2517537B2 JP62285934A JP28593487A JP2517537B2 JP 2517537 B2 JP2517537 B2 JP 2517537B2 JP 62285934 A JP62285934 A JP 62285934A JP 28593487 A JP28593487 A JP 28593487A JP 2517537 B2 JP2517537 B2 JP 2517537B2
- Authority
- JP
- Japan
- Prior art keywords
- humidity
- characteristic correction
- sensor
- correction resistor
- characteristic
- 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
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- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Description
【発明の詳細な説明】 ［発明の目的］ （産業上の利用分野） 本発明は湿度測定回路に関する。DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a humidity measuring circuit.
（従来の技術） 従来から使用されているセラミックなどからなる電気
抵抗変化形湿度センサは、第７図に示すようにセンサ周
辺の相対湿度とセンサの電気抵抗の対数が反比例する特
性を有する。そのため第８図のごとく交流信号源と抵
抗，センサを直列にし、センサ両端の電圧を増幅回路に
接続した回路や、第９図のごとく交流信号源と抵抗，セ
ンサを直列に接続し、抵抗両端の電圧を増幅回路に接続
した回路を使用してセンサの電気抵抗を測定し、これを
電圧や電流の変化に変換することを行っているが、誤差
が大きくて正確な結果が得られなかった。このような問
題を解決するために、第10図に示すように対数増幅器A1
を使用するものもある。センサＳの出力は対数増幅器A1
において対数変換されるため、対数増幅器A1の電気出力
量と相対湿度とは略比例関係となる。ところがセンサ特
性において、相対湿度とセンサの電気抵抗の対数が完全
に反比例関係にあるわけでないので、測定範囲が広くな
ると急激に誤差が増大する。このような第10図に示した
測定回路の特性を第11図に示す。また、この対数増幅器
は回路が複雑で調整も難しく、更に対数特性を得るため
に半導体の電圧−電流特性を利用するので温度による特
性変化も大きく、回路に温度補償を必要とするなど、使
いにくい問題点もあった。(Prior Art) A conventional electric resistance change type humidity sensor made of ceramic or the like has a characteristic that the relative humidity around the sensor and the logarithm of the electric resistance of the sensor are inversely proportional to each other, as shown in FIG. Therefore, as shown in Fig. 8, a circuit in which an AC signal source, a resistor, and a sensor are connected in series and the voltage across the sensor is connected to an amplifier circuit, or an AC signal source, a resistor, and a sensor are connected in series as shown in Fig. 9, and both ends of the resistor are connected. I measured the electrical resistance of the sensor using a circuit connected to the amplifier circuit and converted it into changes in voltage and current, but the error was large and accurate results could not be obtained. . In order to solve such a problem, as shown in FIG. 10, a logarithmic amplifier A 1
Some use. The output of the sensor S is a logarithmic amplifier A1
Since the logarithmic conversion is performed at, the electrical output amount of the logarithmic amplifier A 1 and the relative humidity have a substantially proportional relationship. However, in the sensor characteristics, the relative humidity and the logarithm of the electrical resistance of the sensor are not completely inversely proportional to each other, so that the error increases rapidly when the measurement range becomes wide. The characteristics of the measuring circuit shown in FIG. 10 are shown in FIG. In addition, this logarithmic amplifier has a complicated circuit and is difficult to adjust. Further, since the voltage-current characteristic of the semiconductor is used to obtain a logarithmic characteristic, the characteristic change due to temperature is large, and the circuit needs temperature compensation, which makes it difficult to use. There were also problems.
（発明が解決しようとする問題点） 本発明は、上記の点に鑑みてなされたもので、簡単な
回路構成で高精度で、かつ安定な湿度測定を可能とする
工業的価値の高い湿度測定回路を提供することを目的と
するものである。(Problems to be Solved by the Invention) The present invention has been made in view of the above points, and is a highly accurate and stable industrial humidity measurement with a simple circuit configuration. It is intended to provide a circuit.
［発明の構成］ （問題点を解決するための手段） 本発明になる湿度測定回路は、電気抵抗変化形の湿度
センサと、この湿度センサの一方の端子に直列に接続さ
れた第１の特性補正抵抗と、該湿度センサのもう一方の
端子に直列接続された第２の特性補正抵抗と、前記第１
の特性補正抵抗のもう一方の端子と第２の特性補正抵抗
のもう一方の端子間に接続されたセンサ駆動信号源とを
具備し、第１の特性補正抵抗と前記湿度センサの接合点
と第２の特性補正抵抗とセンサ駆動信号源の接合点間、
あるいは第１の特性補正抵抗両端から湿度検知信号を取
り出す分圧形湿度測定回路からなり、センサ駆動信号を
一定値としたとき、湿度変化に伴って変化する湿度検知
信号を３〜４点の湿度点について直線近似したとき、近
似直線に対する相関係数の二乗値が0.800〜1.000の範囲
になる第1,第２の特性補正抵抗を接続して構成された湿
度測定回路である。[Configuration of Invention] (Means for Solving Problems) A humidity measuring circuit according to the present invention includes an electric resistance change type humidity sensor and a first characteristic connected in series to one terminal of the humidity sensor. A compensation resistor, a second characteristic compensation resistor connected in series to the other terminal of the humidity sensor, and the first characteristic compensation resistor.
And a sensor drive signal source connected between the other terminal of the characteristic correction resistor and the other terminal of the second characteristic correction resistor, the junction point of the first characteristic correction resistor and the humidity sensor, and Between the junction of the characteristic correction resistor of 2 and the sensor drive signal source,
Alternatively, it is composed of a partial pressure type humidity measuring circuit that extracts the humidity detection signal from both ends of the first characteristic correction resistor, and when the sensor drive signal is set to a constant value, the humidity detection signal that changes with the humidity change is set to 3 to 4 points of humidity. This is a humidity measurement circuit configured by connecting first and second characteristic correction resistors in which a square value of a correlation coefficient with respect to an approximate straight line is in a range of 0.800 to 1.000 when the points are linearly approximated.
（作用） 二つの変量、すなわち湿度とそれぞれの湿度に対する
湿度検知信号、すなわち分圧されたセンサ駆動信号との
特性において、湿度の３〜４点について直線近似を行
い、そのとき得られる相関係数の二乗値、すなわち下式
によって求められる値を求める。(Function) In the characteristics of two variables, that is, the humidity and the humidity detection signal for each humidity, that is, the divided sensor drive signal, linear approximation is performed at 3 to 4 points of the humidity, and the correlation coefficient obtained at that time The squared value of, that is, the value obtained by the following equation is obtained.
ここでｒは相関係数、xiは各近似点における湿度の値、
yiは各近似点における湿度検知信号の値、ｎは近似点の
数を表わす。 Where r is the correlation coefficient, x i is the humidity value at each approximation point,
y i represents the value of the humidity detection signal at each approximation point, and n represents the number of approximation points.
この相関係数の二乗値は無相関で0,近似直線に完全に
一致したとき１となり、常に０と１の間の値を取ること
が統計学上知られている。It is known statistically that the square value of this correlation coefficient is 0 without correlation and is 1 when it completely matches the approximate line, and always takes a value between 0 and 1.
したがって、相関係数の二乗値によって直線化の度合
を知ることができる。すなわち、相関係数の二乗値が0.
800〜1.000の範囲に入るように前述第1,第２の特性補正
抵抗の値を求めることによって、湿度に比例した湿度検
知出力を得ることができる。Therefore, the degree of linearization can be known from the square value of the correlation coefficient. That is, the square value of the correlation coefficient is 0.
By obtaining the values of the first and second characteristic correction resistors so that they fall within the range of 800 to 1.000, it is possible to obtain a humidity detection output proportional to the humidity.
（実施例） 実施例１ 第１図は電気抵抗変化形、例えばセラミック湿度セン
サ１に第１の特性補正抵抗２及び第２の特性補正抵抗３
を接続した本発明の一実施例に係る湿度測定回路を示す
ものである。なお、４はセンサ駆動信号源である。該湿
度測定回路を用い、30％RH,50％RH,70％RHの各湿度につ
いて直線近似を行い、そのとき得られる相関係数の二乗
値を第1,第２の特性補正抵抗の和の値に対して表わした
のが第３図である。このようにセラミック湿度センサ１
に第1,第２の特性補正抵抗2,3を接続するとき、湿度の
変化に対する電気抵抗の変化が最も直線に近くなる二つ
の特性補正抵抗の和が存在するわけであるが，その特性
補正抵抗値の和は、第３図から明らかなように250KΩで
あり、そのときの相関係数の二乗値は0.9999である。こ
のときの湿度に対する分圧電圧の出力特性を第４図に示
す。一方、相関係数の二乗値が0.800未満では直線関係
が乏しく、高精度の測定は困難で実用的ではない。参考
までに相関係数の二乗値が0.750になる特性補正抵抗を
組み合せて接続したときの湿度に対する分圧電圧の出力
特性を第５図に示すようになった。(Embodiment) Embodiment 1 FIG. 1 shows an electric resistance change type, for example, a ceramic humidity sensor 1 having a first characteristic correction resistor 2 and a second characteristic correction resistor 3.
2 shows a humidity measuring circuit according to an embodiment of the present invention, in which the In addition, 4 is a sensor drive signal source. Using the humidity measurement circuit, linear approximation is performed for each humidity of 30% RH, 50% RH, 70% RH, and the square value of the correlation coefficient obtained at that time is calculated as the sum of the first and second characteristic correction resistors. FIG. 3 shows the values. In this way, the ceramic humidity sensor 1
When connecting the first and second characteristic compensation resistors 2 and 3, there is a sum of the two characteristic compensation resistors that make the change in electric resistance with respect to the change in humidity closest to a straight line. As is clear from FIG. 3, the sum of the resistance values is 250 KΩ, and the square value of the correlation coefficient at that time is 0.9999. The output characteristics of the divided voltage with respect to humidity at this time are shown in FIG. On the other hand, if the square value of the correlation coefficient is less than 0.800, the linear relationship is poor, and high-precision measurement is difficult and not practical. For reference, Fig. 5 shows the output characteristics of the divided voltage with respect to humidity when the characteristic correction resistors with which the square value of the correlation coefficient is 0.750 are combined and connected.
よって、上記実施例から相関係数の二乗値は0.800〜
1.000の範囲がよいことがわかる。しかして、第４図に
示すように第１図に示した本発明による湿度測定回路
は、従来の測定回路である第10図による特性曲線第11図
に比較し著しい測定精度の向上がみられ、湾曲が修正さ
れた形の値を得ることができる。Therefore, the square value of the correlation coefficient from the above example is 0.800 ~
It turns out that the range of 1.000 is good. Therefore, as shown in FIG. 4, the humidity measuring circuit according to the present invention shown in FIG. 1 shows a marked improvement in measurement accuracy as compared with the characteristic curve shown in FIG. 11 which is a conventional measuring circuit. , The value of the shape with the corrected curvature can be obtained.
実施例２ 次に本発明の他の実施例について述べる。すなわち、
第２図は湿度センサ１に第１の特性補正抵抗２と第２の
特性補正抵抗３を直列に接続し、センサ駆動信号を第１
の特性補正抵抗２のもう一方の端子と、第２の特性補正
抵抗３のもう一方の端子に接続すると共に、該センサ駆
動信号が分圧された出力信号を第１の特性補正抵抗２間
から取り出した。Second Embodiment Next, another embodiment of the present invention will be described. That is,
FIG. 2 shows a humidity sensor 1 in which a first characteristic correction resistor 2 and a second characteristic correction resistor 3 are connected in series, and a sensor drive signal
Is connected to the other terminal of the characteristic correction resistor 2 and the other terminal of the second characteristic correction resistor 3, and an output signal obtained by dividing the sensor drive signal is output from between the first characteristic correction resistors 2. I took it out.
この回路において、実施例１で述べたように30％RH,5
0％RH,70％RHの各湿度について直線近似を行って、その
とき得られる相関係数の二乗値と特性補正抵抗の関係に
は、前述した第３図と同じ関係、すなわち最大の直線性
を与える特性補正抵抗の和があることがわかった。しか
して、相関係数の二乗値として0.9999を与える特性補正
抵抗の和250KΩを満足するように第１の特性補正抵抗を
150KΩ，第２の特性補正抵抗を100KΩとして、第２図に
示した回路の湿度−出力電圧特性を測定した結果第６図
に示すようになり、実施例１と同様に著しい測定精度の
向上がみられた。In this circuit, as described in the first embodiment, 30% RH, 5
A linear approximation is performed for each humidity of 0% RH and 70% RH, and the relationship between the squared value of the correlation coefficient and the characteristic correction resistance obtained at that time is the same as that shown in Fig. 3, that is, the maximum linearity. It was found that there is a sum of characteristic correction resistors that give Therefore, the first characteristic correction resistor is set so as to satisfy the sum of characteristic correction resistors of 250 KΩ which gives 0.9999 as the square value of the correlation coefficient.
As a result of measuring the humidity-output voltage characteristic of the circuit shown in FIG. 2 with 150 KΩ and the second characteristic correction resistance being 100 KΩ, the result is as shown in FIG. It was seen.
なお、実施例1,実施例２共に特性補正抵抗は１個の抵
抗として説明したが、複数の抵抗が直・並列に組み合せ
られたものでもかまわない。また、湿度センサも１個の
センサのみの例を示したが、センサと抵抗が直・並列に
接続されたものでもよい。In addition, although the characteristic correction resistor is described as one resistor in both the first and second embodiments, a plurality of resistors may be combined in series / parallel. Further, although the humidity sensor has only one sensor in the example, the humidity sensor may be connected in series or in parallel with the resistor.
また、第１図，第２図共２を第１の特性補正抵抗,3を
第２の特性補正抵抗としたが、入れかわっていても全く
同じ考え方で、湿度測定回路を構成できることは言うま
でもない。Further, both FIG. 1 and FIG. 2 are referred to as the first characteristic correction resistor and 2 as the second characteristic correction resistor, but it goes without saying that the humidity measuring circuit can be configured with the same idea even if they are replaced. .
［発明の効果］ 本発明によれば、セラミック湿度センサなど電気抵抗
変化形の湿度センサと、第1,第２の特性補正抵抗を直列
に接続した回路でセンサ駆動信号を分圧する湿度測定回
路において、３〜４点の湿度について直線近似したと
き、その相関係数の二乗値が0.800〜1.000の範囲になる
特性補正抵抗を接続するだけで、湿度に対する分圧電圧
の変化を比例的に直すことができる簡単で低価格、しか
も高精度の湿度の測定を可能とし、安定で工業的価値の
高い湿度測定回路を得ることができる。[Effect of the Invention] According to the present invention, in a humidity measuring circuit for dividing a sensor drive signal by a circuit in which an electric resistance change type humidity sensor such as a ceramic humidity sensor and first and second characteristic correction resistors are connected in series. By linearly approximating the humidity at three or four points, the square of the correlation coefficient is in the range of 0.800 to 1.000. It is possible to obtain a stable humidity measuring circuit of high industrial value that enables simple, low-cost and highly accurate humidity measurement.
第１図は本発明になる湿度測定回路の一実施例を示す回
路図、第２図は本発明になる湿度測定回路の他の実施例
を示す回路図、第３図は本発明になる特性補正抵抗の和
と相関係数の二乗値の関係を示す曲線図、第４図は本発
明で最も直線性が得られる特性補正抵抗の組み合せによ
る湿度と出力電圧特性との関係を示す曲線図、第５図は
参考例で相関係数が0.75のときの湿度と出力電圧特性を
示す曲線図、第６図は本発明の他の実施例による湿度と
出力電圧特性の関係を示す曲線図、第７図は従来例にな
るセラミック湿度センサの湿度−抵抗特性を示す曲線
図、第８図〜第10図は従来の湿度測定回路をそれぞれ示
す回路図、第11図は従来の対数増幅回路による湿度測定
回路の特性を示す曲線図である。 １……湿度センサ ２……第１の特性補正抵抗 ３……第２の特性補正抵抗 ４……センサ駆動信号源FIG. 1 is a circuit diagram showing an embodiment of the humidity measuring circuit according to the present invention, FIG. 2 is a circuit diagram showing another embodiment of the humidity measuring circuit according to the present invention, and FIG. 3 is a characteristic showing the present invention. FIG. 4 is a curve diagram showing the relationship between the sum of the correction resistors and the square value of the correlation coefficient. FIG. 4 is a curve diagram showing the relationship between the humidity and the output voltage characteristic due to the combination of the characteristic correction resistors that provides the most linearity in the present invention. FIG. 5 is a reference example showing a curve showing humidity and output voltage characteristics when the correlation coefficient is 0.75, and FIG. 6 is a curve showing a relationship between humidity and output voltage characteristics according to another embodiment of the present invention. FIG. 7 is a curve diagram showing the humidity-resistance characteristic of a conventional ceramic humidity sensor, FIGS. 8 to 10 are circuit diagrams showing a conventional humidity measuring circuit, and FIG. 11 is a humidity by a conventional logarithmic amplifier circuit. It is a curve figure which shows the characteristic of a measurement circuit. 1 ... Humidity sensor 2 ... 1st characteristic correction resistor 3 ... 2nd characteristic correction resistor 4 ... Sensor drive signal source
Claims (1)
化形湿度センサと、この湿度センサの一方の端子に直列
に接続された第１の特性補正抵抗と、該湿度センサのも
う一方の端子に直列接続された第２の特性補正抵抗と、
前記第１の特性補正抵抗のもう一方の端子と第２の特性
補正抵抗のもう一方の端子間に接続されたセンサ駆動信
号源とを具備し、第１の特性補正抵抗と前記湿度センサ
の接合点と第２の特性補正抵抗とセンサ駆動信号源の接
合点間、あるいは第１の特性補正抵抗両端から湿度検知
信号を取り出す分圧形湿度測定回路からなり、湿度に対
する分圧電圧の変化特性を３〜４点の各湿度について直
線近似させたとき、直線近似直線に対する相関係数の二
乗値が0.800〜1.000の範囲となるような特性補正抵抗を
接続して構成された湿度測定回路。1. An electric resistance change type humidity sensor such as a ceramic type humidity sensor, a first characteristic correction resistor connected in series to one terminal of the humidity sensor, and a series connected to the other terminal of the humidity sensor. A second characteristic correction resistor connected,
A sensor drive signal source connected between the other terminal of the first characteristic correction resistor and the other terminal of the second characteristic correction resistor, wherein the first characteristic correction resistor and the humidity sensor are joined together. Point, the second characteristic correction resistor and the junction point of the sensor drive signal source, or a partial pressure type humidity measuring circuit that extracts the humidity detection signal from both ends of the first characteristic correction resistor. A humidity measuring circuit configured by connecting characteristic correction resistors so that the squared value of the correlation coefficient with respect to the linear approximation line is in the range of 0.800 to 1.000 when linear approximation is performed for each of the three to four points of humidity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62285934A JP2517537B2 (en) | 1987-11-11 | 1987-11-11 | Humidity measurement circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62285934A JP2517537B2 (en) | 1987-11-11 | 1987-11-11 | Humidity measurement circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01126536A JPH01126536A (en) | 1989-05-18 |
| JP2517537B2 true JP2517537B2 (en) | 1996-07-24 |
Family
ID=17697885
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62285934A Expired - Lifetime JP2517537B2 (en) | 1987-11-11 | 1987-11-11 | Humidity measurement circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2517537B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012037371A (en) * | 2010-08-06 | 2012-02-23 | Denso Corp | Sensor controller |
-
1987
- 1987-11-11 JP JP62285934A patent/JP2517537B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012037371A (en) * | 2010-08-06 | 2012-02-23 | Denso Corp | Sensor controller |
| US9316574B2 (en) | 2010-08-06 | 2016-04-19 | Denso Corporation | Sensor controller |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01126536A (en) | 1989-05-18 |
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