JPS6154173B2 - - Google Patents
Info
- Publication number
- JPS6154173B2 JPS6154173B2 JP12661779A JP12661779A JPS6154173B2 JP S6154173 B2 JPS6154173 B2 JP S6154173B2 JP 12661779 A JP12661779 A JP 12661779A JP 12661779 A JP12661779 A JP 12661779A JP S6154173 B2 JPS6154173 B2 JP S6154173B2
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- voltage
- humidity sensor
- relative humidity
- output
- 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
Links
- 238000006243 chemical reaction Methods 0.000 claims description 22
- 230000001360 synchronised effect Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 3
- 229910014497 Ca10(PO4)6(OH)2 Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052588 hydroxylapatite Inorganic materials 0.000 description 1
- 206010025482 malaise Diseases 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- XYJRXVWERLGGKC-UHFFFAOYSA-D pentacalcium;hydroxide;triphosphate Chemical compound [OH-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O XYJRXVWERLGGKC-UHFFFAOYSA-D 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Description
【発明の詳細な説明】
この発明は、大気中の相対湿度を電気的に測定
する電気湿度計に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric hygrometer that electrically measures relative humidity in the atmosphere.
抵抗値Ｒが相対湿度ｈにより変化するような抵
抗体において、抵抗値Ｒと相対湿度ｈの関係があ
らかじめ一義的に定まつていれば、抵抗値Ｒを測
定することによつて、相対湿度ｈを求めることが
できる。 In a resistor whose resistance value R changes depending on the relative humidity h, if the relationship between the resistance value R and the relative humidity h is uniquely defined in advance, then by measuring the resistance value R, the relative humidity h can be determined by measuring the resistance value R. can be found.
相対湿度ｈに比例した電気信号を得んとすれ
ば、まず、抵抗値Ｒに比例した電気信号を発生さ
せ、この電気信号を、あらかじめ一義的に定まつ
た抵抗値Ｒと相対湿度ｈの関係を表わす、いわゆ
る関数変換回路に入力することにより、この関数
変換回路の出力からは、相対湿度ｈに比例した電
気信号を取出すことができる。 To obtain an electrical signal proportional to the relative humidity h, first generate an electrical signal proportional to the resistance value R, and then convert this electrical signal into a relationship between the resistance value R and the relative humidity h that is uniquely defined in advance. By inputting the signal to a so-called function conversion circuit representing the relative humidity h, an electrical signal proportional to the relative humidity h can be extracted from the output of this function conversion circuit.
ところで、抵抗値Ｒと相対湿度ｈの関係が第(1)
式の指数関数で表わされるような抵抗体（以下湿
度センサと呼ぶ）においては、直流電源より湿度
センサに電圧、または電流を供給し、湿度センサ
の端子間電圧、あるいは湿度センサに流れる電流
の対数変換回路に入力することにより、この回路
の出力からは、相対湿度ｈに比例した信号が得ら
れる。 By the way, the relationship between resistance value R and relative humidity h is expressed as (1)
For a resistor (hereinafter referred to as a humidity sensor) that is expressed by the exponential function of the equation, voltage or current is supplied to the humidity sensor from a DC power supply, and the voltage or current flowing between the terminals of the humidity sensor or the logarithm of the current flowing through the humidity sensor is By inputting it to a conversion circuit, a signal proportional to the relative humidity h is obtained from the output of this circuit.
Ｒ＝Ro・ε-ah ……(1)
但し、Ro，ａは湿度センサ固有の定数であ
る。 R=Ro·ε -ah (1) However, Ro and a are constants specific to the humidity sensor.
湿度センサのうちある種のものは、直流電圧を
印加し続けると、相対湿度ｈが一定にもかかわら
ず、その抵抗値Ｒが変化する性質を持つているの
で、みかけ上電気出力としての相対湿度ｈが変化
したことになり具合が悪い。この不具合を解決す
る方法として、湿度センサに交流電圧を印加し
て、抵抗値Ｒが変化するのを防ぐことによつて解
決できる。 Some types of humidity sensors have the property that when a DC voltage is continuously applied, the resistance value R changes even though the relative humidity h is constant, so the apparent relative humidity as an electrical output Since h has changed, I feel unwell. This problem can be solved by applying an alternating current voltage to the humidity sensor to prevent the resistance value R from changing.
ところが交流を用いれば、対数変換回路の出力
も、当然交流信号が出力されるが、相対湿度ｈに
比例した信号が得られない。 However, if alternating current is used, the output of the logarithmic conversion circuit is naturally an alternating current signal, but a signal proportional to the relative humidity h cannot be obtained.
そこで、湿度センサに流れる交流電流を交流−
直流変換回路により直流信号に変換し、しかる
後、対数変換回路にかけることによつて、この対
数変換回路の出力より相対湿度ｈに比例した直流
の電気信号を得る方法が従来より多用されて来
た。 Therefore, the AC current flowing through the humidity sensor is
Conventionally, a method has been frequently used in which a DC signal is converted into a DC signal using a DC conversion circuit, and then applied to a logarithmic conversion circuit, thereby obtaining a DC electrical signal proportional to the relative humidity h from the output of the logarithmic conversion circuit. Ta.
しかし、従来の方法においては、以下に述べる
欠点がある。すなわち、相対湿度ｈが０〜100％
変化したとき、湿度センサの抵抗値Ｒは普通、４
〜６桁ほど変化する。湿度センサの印加電圧を一
定とすれば流れる電流は、当然、４〜６桁変化す
るので交流−直流交換回路も同様の変化域を持つ
ている。 However, the conventional method has the following drawbacks. That is, relative humidity h is 0 to 100%
When the humidity sensor changes, the resistance value R of the humidity sensor is normally 4.
It changes by ~6 orders of magnitude. If the voltage applied to the humidity sensor is kept constant, the current that flows naturally varies by four to six orders of magnitude, so the AC-DC exchange circuit also has a similar variation range.
演算増幅器を利用した交流−直流交換回路にお
いて、精度良く変換できるのはフルスケールの
高々３〜４桁である。このことより、上記の４〜
６桁の入力変化域にはとても応じきれなく、その
結果、対数変換回路の出力である相対湿度ｈも誤
差が増大する。 In an AC-DC switching circuit using an operational amplifier, accurate conversion can be achieved up to 3 to 4 digits of the full scale. From this, the above 4~
It is difficult to respond to a six-digit input change range, and as a result, the error in the relative humidity h, which is the output of the logarithmic conversion circuit, increases.
上記第(1)式からも解るように、相対湿度ｈが低
下すれば湿度センサの抵抗値Ｒが増大し、湿度セ
ンサに流れる交換電流は小さくなり、交流−直流
変換回路の出力も小さくなる。この交流−直流変
換回路は一般的にオフセツト電圧などの固定誤差
を有しているので、相対湿度ｈの低い部分で誤差
が増大する。 As can be seen from the above equation (1), when the relative humidity h decreases, the resistance value R of the humidity sensor increases, the exchange current flowing through the humidity sensor decreases, and the output of the AC-DC converter circuit also decreases. Since this AC-DC conversion circuit generally has fixed errors such as offset voltage, the errors increase in areas where the relative humidity h is low.
この発明は、上記に述べたような相対湿度ｈの
誤差の増大をなくし、簡単な回路構成で高精度の
相対湿度ｈの測定を可能にした電気湿度計を提供
することを目的とする。 An object of the present invention is to provide an electric hygrometer that eliminates the increase in error in relative humidity h as described above and that enables highly accurate measurement of relative humidity h with a simple circuit configuration.
以下、この発明の電気湿度計の実施例について
図面に基づき説明する。第１図はその一実施例の
ブロツク図である。この第１図において、１は湿
度センサ、２は湿度センサ１に交流電流を流すた
めの交流電源である。湿度センサ１に流れる交流
電流を対数変換回路３で対数変換して出力し、そ
の入力が仮想接地されるようになつている。 Embodiments of the electric hygrometer of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of one embodiment. In FIG. 1, 1 is a humidity sensor, and 2 is an AC power source for supplying an AC current to the humidity sensor 1. In FIG. The alternating current flowing through the humidity sensor 1 is logarithmically converted by a logarithmic conversion circuit 3 and outputted, and its input is virtually grounded.
対数変換回路３の出力はサンプル指令信号によ
つてサンプルホールド回路４でサンプルするよう
になつており、サンプルホールド回路４から相対
湿度に比例した電圧が出力端子５に送出するよう
になつている。 The output of the logarithmic conversion circuit 3 is sampled by a sample hold circuit 4 in response to a sample command signal, and a voltage proportional to relative humidity is sent from the sample hold circuit 4 to an output terminal 5.
一方、６は交流電源２の出力があらかじめ設定
された比較レベル信号（入力端子７より入力され
る。）と比較し、そのレベルに達すればレベル一
致信号をサンプル指令回路８に出力するようにな
つており、、このサンプル指令回路８から上述の
ようにサンプル指令信号をサンプルホールド回路
４に選出するようになつている。 On the other hand, 6 compares the output of the AC power supply 2 with a preset comparison level signal (input from the input terminal 7), and when it reaches that level, outputs a level matching signal to the sample command circuit 8. The sample command signal is selected from the sample command circuit 8 to the sample hold circuit 4 as described above.
また第２図は上記実施例のブロツク内の具体的
な回路構成例を示す図である。ここで、湿度セン
サ１は、Na添加水酸アパタイトセラミツクスを
用い、感湿特性が第３図に示される如く相対湿度
と抵抗値とが指数関数で表わされる抵抗体で構成
されており、第３図中Ｘは、
Ca10（PO4）6（OH）2：Naで表わされるNa含有
値をパラメータとしたものである。 Further, FIG. 2 is a diagram showing a specific example of the circuit configuration within the block of the above embodiment. Here, the humidity sensor 1 is made of Na-added hydroxyapatite ceramics, and is composed of a resistor whose humidity-sensitive characteristics are represented by an exponential function of relative humidity and resistance value as shown in FIG. In the figure, X is a parameter representing the Na content value expressed as Ca 10 (PO 4 ) 6 (OH) 2 :Na.
次に、以上のように構成されたこの発明の電気
湿度計の動作について説明する。第２図に交流電
圧ｅiと出力電圧ｅpの関係を示す。交流電源２か
ら交流電圧ｅiを湿度センサ１に印加すると、湿
度センサ１の低抗値Ｒによつて後に示す第(2)式で
表わされるような交流電流ｉが流れ、対数変換回
路３の入力となる。対数変換回路３の出力電圧ｅ
hは後に示す第(3)式で表わされるような交流電流
ｉの対数変換値として出力される。 Next, the operation of the electric hygrometer of the present invention configured as described above will be explained. FIG. 2 shows the relationship between AC voltage e i and output voltage e p . When an AC voltage e i is applied to the humidity sensor 1 from the AC power supply 2, an AC current i as expressed by equation (2) shown later flows due to the low resistance value R of the humidity sensor 1, and the logarithmic conversion circuit 3 It becomes input. Output voltage e of logarithmic conversion circuit 3
h is output as a logarithmically converted value of alternating current i as expressed by equation (3) shown later.
一方、入力端子７に比較レベル電圧ｅrを定め
ておくと、交流電源２からの交流電圧ｅiと比較
して、レベル電圧ｅrと同値になつた時点でレベ
ル比較回路６からレベル一致信号が出力され、サ
ンプル指令回路８の入力となり、サンプル指令回
路８の出力がサンプルホールド回路４のサンプル
指令信号となり、出力端子５に相対湿度ｈに比較
した出力電圧ｅpが出力され第４式で表わすごと
くになる。 On the other hand, if a comparison level voltage e r is determined at the input terminal 7, when the AC voltage e i from the AC power supply 2 becomes the same value as the level voltage e r , a level match signal is sent from the level comparison circuit 6. is output and becomes the input of the sample command circuit 8, the output of the sample command circuit 8 becomes the sample command signal of the sample hold circuit 4, and the output voltage e p compared to the relative humidity h is output to the output terminal 5, and is expressed by the fourth equation. It becomes as shown.
レベル比較回路６は演算増巾器の加算回路であ
り、その出力はe2＝Ａ（ｅr−ｅi，Ａ＝Ｒ４／Ｒ３で表
わ
され、その出力値の正負値によつてサンプル指令
回路８のワンシヨツト回路でサンプルホールドの
タイミングをとる。また、そのタイミング時間は
Ｔ＝Ｃ・Ｒで表わされる。 The level comparison circuit 6 is an addition circuit of an operational amplifier, and its output is expressed as e 2 =A ( er - e i , A = R 4 /R 3 , and the positive and negative values of the output value are The one-shot circuit of the sample command circuit 8 determines the timing of sample and hold.The timing time is expressed as T=C.R.
湿度センサ２に流れる電流ｉは
ｉ＝ｅｒ／Ｒ ……(2)
但し、ｅrはレベル比較回路の比較レベル値で
あり、対数変換回路３の入力は仮想接地とす
る。 The current i flowing through the humidity sensor 2 is i= er /R (2) where e r is the comparison level value of the level comparison circuit, and the input of the logarithmic conversion circuit 3 is assumed to be virtual ground.
対数変換回路３の出力電圧ｅhは ｅh＝Ｋ・logｉ／ｉｒ ……(3) 但し、irは対数変換回路の基準電流 Ｋは比例定数である。 The output voltage e h of the logarithmic conversion circuit 3 is e h =K·logi/ir (3) where ir is the reference current of the logarithmic conversion circuit, and K is a proportionality constant.
第(1)〜(3)式より出力電圧ｅpは
ｅp＝ｅh＝Ｋ・log（１／ｉｒ・ｅｒ／Ｒ）
＝Ｋ・log（１／ｉｒ・１／Ｒｏ・εah・ｅr
＝Ｋ・log（ｅｒ／ｉｒ・Ｒｏ）＋Ｋ・ａ・ｈ……(4)
なお、上記実施例では、一般的な交流波形を印
加した場合について説明したが、特殊例として交
流電源の代りにパルス電源を用いても良い。この
場合はレベル比較回路６を省略できる。 From equations (1) to (3), the output voltage e p is e p =e h =K・log(1/ir・er /R) =K・log(1/ir・1/Ro・ε ah・e r =K・log( er /ir・Ro)+K・a・h……(4) In the above embodiment, the case where a general AC waveform was applied was explained, but as a special example, an AC power supply A pulse power source may be used instead. In this case, the level comparison circuit 6 can be omitted.
このように、パルス電源を交流電源の代りに用
いると、湿度センサ１に流れる電流はパルス電流
となり、対数変換回路３に入力され、対数変換回
路３の出力ｅhは相対湿度ｈに比例する。 In this way, when a pulse power source is used instead of an AC power source, the current flowing through the humidity sensor 1 becomes a pulse current, which is input to the logarithmic conversion circuit 3, and the output e h of the logarithmic conversion circuit 3 is proportional to the relative humidity h.
一方、パルス電源から供給されるパルス電圧が
サンプル指令回路８に入力されるとサンプル指令
回路８からパルス電源の波形周期に同期したサン
プル指令信号が出力され、サンプルホールド回路
４に与えられて相対湿度ｈに比例した出力ｅpが
出力端子５に得られる。 On the other hand, when the pulse voltage supplied from the pulse power supply is input to the sample command circuit 8, the sample command circuit 8 outputs a sample command signal synchronized with the waveform period of the pulse power supply, and the sample command signal is given to the sample hold circuit 4 to control the relative humidity. An output e p proportional to h is obtained at the output terminal 5.
以上のように、この発明の電気湿度計によれ
ば、湿度センサに交流電圧またはパルス電圧を印
加し、湿度センサに流れる電流を直接に対数変換
して相対湿度ｈに比例した値を得るように構成し
たので安定度が増し精度の高いものが簡単に得ら
れる効果がある。 As described above, according to the electric hygrometer of the present invention, an AC voltage or a pulse voltage is applied to the humidity sensor, and the current flowing through the humidity sensor is directly logarithmically converted to obtain a value proportional to the relative humidity h. This configuration has the effect of increasing stability and easily obtaining high accuracy.
第１図はこの発明の電気湿度計の実施例の構成
を示すブロツク図、第２図は第１図のブロツクの
具体的な回路構成例を示す図、第３図は湿度セン
サーの感湿特性図、第４図は同上電気湿度計に適
用される交流電圧と出力電圧の波形関係を示す図
である。
１……湿度センサ、２……交流電源、３……対
数変換回路、４……サンプルホールド回路、５…
…出力端子、６……レベル比較回路、７……入力
端子、８……サンプル指令回路。
FIG. 1 is a block diagram showing the configuration of an embodiment of the electric hygrometer of the present invention, FIG. 2 is a diagram showing a specific example of the circuit configuration of the block in FIG. 1, and FIG. 3 is the humidity sensitivity characteristic of the humidity sensor. FIG. 4 is a diagram showing the waveform relationship between the AC voltage and the output voltage applied to the electric hygrometer. 1... Humidity sensor, 2... AC power supply, 3... Logarithmic conversion circuit, 4... Sample hold circuit, 5...
...Output terminal, 6...Level comparison circuit, 7...Input terminal, 8...Sample command circuit.
Claims (1)
れる湿度センサに交流電流またはパルス電流を流
すための電源、入力信号を上記湿度センサの関数
に対応した出力信号に変換する関数変換回路、こ
の関数変換回路の出力をサンプル指令信号によつ
てサンプルホールドするとともに上記相対湿度に
比例した電圧を出力するサンプルホールド回路、
上記電源からのパルスの波形周期に同期した上記
サンプル指令信号を出力するかあるいは上記電源
の電圧が所定のレベルになると上記サンプル指令
信号を出力するサンプル指令回路を備えてなる電
気湿度計。 ２ 湿度センサに交流電流を流す交流電源を使用
する場合にはこの交流電源の電圧と所定の比較レ
ベル電圧とを比較して両者が一致すると上記サン
プル指令回路に出力するレベルに比較回路を使用
することを特徴とする特許請求の範囲第１項記載
の電気湿度計。[Claims] 1. A power source for passing an alternating current or a pulse current to a humidity sensor whose electrical resistance is expressed as a function of the relative humidity in the atmosphere, and converting an input signal into an output signal corresponding to the function of the humidity sensor. a function conversion circuit; a sample and hold circuit that samples and holds the output of the function conversion circuit according to a sample command signal and outputs a voltage proportional to the relative humidity;
An electric hygrometer comprising a sample command circuit that outputs the sample command signal synchronized with the waveform period of the pulse from the power source or outputs the sample command signal when the voltage of the power source reaches a predetermined level. 2. When using an AC power supply that supplies an AC current to the humidity sensor, a comparison circuit is used to compare the voltage of this AC power supply with a predetermined comparison level voltage, and when the two match, outputs the level to the sample command circuit. An electric hygrometer according to claim 1, characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12661779A JPS5649949A (en) | 1979-10-01 | 1979-10-01 | Electric hygrometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12661779A JPS5649949A (en) | 1979-10-01 | 1979-10-01 | Electric hygrometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5649949A JPS5649949A (en) | 1981-05-06 |
| JPS6154173B2 true JPS6154173B2 (en) | 1986-11-21 |
Family
ID=14939631
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12661779A Granted JPS5649949A (en) | 1979-10-01 | 1979-10-01 | Electric hygrometer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5649949A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6511597B2 (en) | 2015-07-13 | 2019-05-15 | 和則 川島 | scale |
-
1979
- 1979-10-01 JP JP12661779A patent/JPS5649949A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5649949A (en) | 1981-05-06 |
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