JPH0627657B2 - Sensor drive method - Google Patents
Sensor drive methodInfo
- Publication number
- JPH0627657B2 JPH0627657B2 JP4121085A JP4121085A JPH0627657B2 JP H0627657 B2 JPH0627657 B2 JP H0627657B2 JP 4121085 A JP4121085 A JP 4121085A JP 4121085 A JP4121085 A JP 4121085A JP H0627657 B2 JPH0627657 B2 JP H0627657B2
- Authority
- JP
- Japan
- Prior art keywords
- detection
- sensitive
- circuit
- output signal
- driving method
- 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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- Testing Or Calibration Of Command Recording Devices (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【発明の詳細な説明】 技術分野 本発明は、パルス電流を利用するセンサの駆動方式に関
し、より詳細には、ガスセンサ、温度センサ、湿度セン
サ又はアルコールセンサ等に適用可能なセンサ駆動方法
に関するものである。TECHNICAL FIELD The present invention relates to a sensor driving method using a pulse current, and more particularly to a sensor driving method applicable to a gas sensor, a temperature sensor, a humidity sensor, an alcohol sensor, or the like. is there.
従来技術 従来、電池を電源として用いるセンサの駆動方式におい
ては、消費電力を節約する為に、間欠的にパルス状波形
で電力を印加する方法がよく用いられている。この場
合、定常的に電圧を印加している場合に比して、温度や
湿度等の外部環境条件の変動に対して或いは一般的動作
の安定性においてそれ相応の難点を有している。この傾
向は、電力の節約を促進する為に信号のオンとオフのデ
ューティ比を小さくすればする程、顕著となる。従っ
て、そのような難点を解消するには、高価な補償用素子
を設ける等の回路面での工夫が必要となり、センサのコ
ストアップにつながる。2. Description of the Related Art Conventionally, in a driving method of a sensor using a battery as a power source, a method of intermittently applying power in a pulsed waveform is often used in order to save power consumption. In this case, as compared with the case where the voltage is constantly applied, there are corresponding difficulties with respect to changes in external environmental conditions such as temperature and humidity or in stability of general operation. This tendency becomes more remarkable as the duty ratio of turning on and off the signal is reduced in order to promote power saving. Therefore, in order to eliminate such a difficulty, it is necessary to devise a circuit surface such as providing an expensive compensation element, which leads to an increase in the cost of the sensor.
目 的 本発明は、以上の点に鑑みなされたものであって、小さ
い消費電力で信頼度の高い信号を安定して検出可能なセ
ンサ駆動方法を提供することを目的とする。Aim The present invention has been made in view of the above points, and an object of the present invention is to provide a sensor driving method capable of stably detecting a highly reliable signal with low power consumption.
構 成 本発明は、感応物質を電熱器で所定温度に加熱すると共
に前記感応物質に通電し感応作用に応じた出力信号を検
出するセンサ駆動方法において、通常は前記電熱器及び
前記感応物質に所定間隔で間欠的に通電し、前記出力信
号に異常を検出したら前記電熱器及び前記感応物質に定
常電流を通電して前記出力信号を再検出することを特徴
とするセンサ駆動方法、を提供するものである。The present invention is a sensor driving method for heating a sensitive substance to a predetermined temperature by an electric heater and energizing the sensitive substance to detect an output signal according to the sensitive action. A sensor driving method, characterized in that current is intermittently applied at intervals, and when an abnormality is detected in the output signal, a constant current is applied to the electric heater and the sensitive substance to re-detect the output signal. Is.
以下、本発明の１実施例に基づき具体的に説明する。第
１図は本発明の１実施例としての駆動方法が実施される
ガス検出装置の構成を示したブロック図である。第１図
において、平行に延在させた一対の検出リード部１ａ，
１ｂ間にガス感応物質から成る検出部２が架橋状に設け
てセンサＳが形成されている。一対の検出リード部１
ａ，１ｂの内の一方の検出リード部１ａは検出部２の一
方の電極として機能すると共に検出部２を加熱するヒー
タとしても機能する。本例の検出部２は、金属酸化物半
導体のＳｎＯ2から成り熱容量を小さくするため薄膜状
に形成されており、ヒータとしての検出リード部１ａに
より３５０〜４００℃に加熱されると、ガスに対して吸
着・離脱の作用を行う。従って、雰囲気にガスが存在す
る場合はガス分子を吸着してガス感応物質自体の抵抗値
を小さくし、ガスが無くなると離脱させて抵抗値を大き
くする。この抵抗値の異常変化を後述する検出回路より
電流を流して検出し、ガスの存在を知らせる。Hereinafter, a specific description will be given based on one embodiment of the present invention. FIG. 1 is a block diagram showing the configuration of a gas detection device in which a driving method as one embodiment of the present invention is implemented. In FIG. 1, a pair of detection lead portions 1a extending in parallel,
A sensor S is formed by arranging a detecting portion 2 made of a gas sensitive material in a bridge shape between 1b. A pair of detection leads 1
One of the detection lead portions 1a of a and 1b functions as one electrode of the detection portion 2 and also as a heater for heating the detection portion 2. The detection unit 2 of this example is made of SnO 2 which is a metal oxide semiconductor, and is formed in a thin film shape in order to reduce the heat capacity. When it is heated to 350 to 400 ° C. by the detection lead unit 1 a as a heater, it becomes gas. On the other hand, it acts to adsorb and desorb. Therefore, when gas is present in the atmosphere, gas molecules are adsorbed to reduce the resistance value of the gas-sensitive substance itself, and when the gas is exhausted, it is released to increase the resistance value. An abnormal change in the resistance value is detected by passing a current from a detection circuit described later, and the presence of gas is notified.
ヒータとしての検出リード部１ａの両端は、パルス状及
び定常の双方の電圧を適宜印加可能な電源を備えたヒー
タ駆動回路３に接続されており、これから、通常時は例
えば１．５〜３Ｖのパルス電圧が、目的ガスを検出した
異常時には同程度のレベルの定常電圧が、夫々検出リー
ド部１ａに加えられ、検出リード部１ａを発熱させる。
又、他方の検出リード部１ｂの一端と検出リード部１ａ
の一端が同様なパルス状及び定常の双方の電圧を適宜印
加可能な電源を備えた検出回路４に接続されており、こ
れから、通常時は例えば１．５〜３Ｖのパルス電圧が、
目的ガスを検出した異常時には同程度のレベルの定常電
圧が、夫々検出部２に加えられその抵抗値変化による電
流変化を電圧変動として検出する構成となっている。Both ends of the detection lead portion 1a as a heater are connected to a heater drive circuit 3 provided with a power source capable of appropriately applying both pulsed and steady voltage, and from this, in normal times, for example, 1.5 to 3V. When the pulse voltage is abnormal when the target gas is detected, a steady voltage of the same level is applied to the detection lead portion 1a, and the detection lead portion 1a is caused to generate heat.
Further, one end of the other detection lead portion 1b and the detection lead portion 1a
Is connected to a detection circuit 4 equipped with a power source capable of appropriately applying both a pulsed voltage and a steady voltage, and from this, a pulse voltage of, for example, 1.5 to 3 V is normally generated.
At the abnormal time when the target gas is detected, the steady voltage of the same level is applied to the detection unit 2 and the current change due to the change of the resistance value is detected as the voltage change.
而して、上述したヒータ駆動回路３及び検出回路４に
は、夫々の回路における電圧の印加タイミングを指示す
るタイミング回路５が接続されている。タイミング回路
５は、第２図に示す如く、夫々適数個のインバータ５
ａ、抵抗５ｂ、ダイオード５ｃ及びコンデンサ５ｄを組
み合わせて基本となるパルス信号を発生する基本パルス
発生回路ｂを形成し、これからヒータ駆動回路３に至る
回路にはＯＲゲート５ｅを介設してある。又、検出回路
５からＯＲゲート５ｅの他方の入力端に至る回路には第
一モノマルチバイブレータ５ｆが介設されている。この
場合、第一モノマルチバイブレータ５ｆの時定数は定常
駆動と等価な特性が得られる用に設定されている。更
に、検出回路４から後述する警報を発生させる警報部７
へ至る回路には、第二、第三のモノマルチバイブレータ
５ｇ，５ｈが直列に介設されている。A timing circuit 5 is connected to the heater drive circuit 3 and the detection circuit 4 to instruct the application timing of the voltage in each circuit. As shown in FIG. 2, the timing circuit 5 includes a proper number of inverters 5 each.
A basic pulse generating circuit b for generating a basic pulse signal is formed by combining a, a resistor 5b, a diode 5c, and a capacitor 5d, and an OR gate 5e is provided in a circuit from the basic pulse generating circuit b to the heater driving circuit 3. A first mono-multivibrator 5f is provided in the circuit from the detection circuit 5 to the other input terminal of the OR gate 5e. In this case, the time constant of the first mono-multivibrator 5f is set so that a characteristic equivalent to that in steady driving can be obtained. Further, an alarm unit 7 for issuing an alarm described later from the detection circuit 4
Second and third mono-multi vibrators 5g and 5h are provided in series in the circuit leading to.
第１図に戻って、検出回路４から目的ガスの存在を知ら
せる警報部７に至る回路には、ＡＮＤゲート６が介設さ
れ、このゲート６の片方の入力端子は上述したタイミン
グ回路５の第三モノマルチバイブレータ５ｈに接続され
ている。Returning to FIG. 1, an AND gate 6 is provided in the circuit from the detection circuit 4 to the alarm unit 7 for notifying the presence of the target gas, and one input terminal of this gate 6 is the same as that of the timing circuit 5 described above. It is connected to the three mono multivibrator 5h.
次に、上記の如く構成されたガス検出装置において実施
される本発明方法の１実施例としての駆動動作につい
て、第３図のタイミングチャート図に基づき説明する。
尚、第３図の各信号波形Ｉ〜VIIは、夫々第２図の回路
における主要箇所〜で採取される信号を示してい
る。Next, a driving operation as one embodiment of the method of the present invention which is carried out in the gas detecting apparatus configured as described above will be explained based on the timing chart of FIG.
Each of the signal waveforms I to VII in FIG. 3 represents a signal sampled at a main part of the circuit in FIG.
目的とするガスが検出部２の雰囲気中に存在しない通常
時においては、電力節約の為、第２図の回路中の基本パ
ルス発生回路ｂ出力部で得られる規則的なパルス波形
の信号波Ｉに基づき、信号波IVで示される如く、所定の
間隔で間欠的に駆動されている。In the normal time when the target gas is not present in the atmosphere of the detection unit 2, in order to save power, a signal wave I having a regular pulse waveform obtained at the output unit of the basic pulse generation circuit b in the circuit of FIG. 2 is used. On the basis of the above, as shown by the signal wave IV, it is driven intermittently at a predetermined interval.
今、上述の如き駆動状態下において、検出部２の雰囲気
に検出すべき目的ガスが流入したとする。この時、検出
リード１ａにヒータ駆動回路３からパルス電圧が加えら
れ、検出部２が３５０〜４００℃に加熱されると、その
表面にガス分子が吸着して抵抗値が低下する。従って、
これに応じて検出信号波形IIにその検出信号αが現わ
れ、これを受けて第一モノマルチバイブレータ５ｆが起
動され定常的なオン信号βがＯＲゲート５ｅへ供給さ
れ、これに応じた定常駆動信号γがヒータ駆動回路３に
出力され、ヒータとしてのリード部１ａが定常的に駆動
される。検出信号αは、第一モノマルチバイブレータに
送られると同時に第二モノマルチバイブレータ５ｇにも
送られてそれを起動させ、安定した検出信号α′を得る
のに充分な時間間隔ｔをとった後第三モノマルチバイブ
レータ５ｈを起動させ、ゲート６への出力信号δを発生
させる。ゲート６では、第三モノマルチバイブレータ５
ｈからの出力信号δと検出回路４からの安定した検出信
号α′との論理積をとり、成立した時に初めて警報部７
に警報信号εが出力され、目的ガスの存在を知らせる警
報が発っせられる。Now, it is assumed that the target gas to be detected has flowed into the atmosphere of the detection unit 2 under the driving state as described above. At this time, when a pulse voltage is applied from the heater drive circuit 3 to the detection lead 1a and the detection unit 2 is heated to 350 to 400 ° C., gas molecules are adsorbed on the surface thereof and the resistance value is lowered. Therefore,
In response to this, the detection signal α appears in the detection signal waveform II, and in response to this, the first mono-multivibrator 5f is activated and the steady ON signal β is supplied to the OR gate 5e. γ is output to the heater drive circuit 3, and the lead portion 1a as a heater is constantly driven. The detection signal α is sent to the first mono-multivibrator at the same time as it is also sent to the second mono-multivibrator 5g to activate it, and after a sufficient time interval t is obtained to obtain a stable detection signal α ′. The third monomultivibrator 5h is activated to generate the output signal δ to the gate 6. At the gate 6, the third mono multivibrator 5
When the logical product of the output signal δ from h and the stable detection signal α ′ from the detection circuit 4 is obtained and the condition is satisfied, the alarm unit 7 is not activated.
An alarm signal ε is output to, and an alarm is issued to notify the presence of the target gas.
以上の如く、通常時においては間欠的にパルス駆動を行
い、検出信号が現われた異常時には定常駆動に近い駆動
方式に切り換えて動作を充分に安定させた後改めて検出
信号を採取して目的ガスの存否を判断する構成とすれ
ば、パルス駆動と定常駆動の双方の長所を利用し、電池
駆動によっても信頼度の高い検出性能を長期に亘って安
定して得ることができる。尚、従来のセンサにおいて
は、検出部２の熱容量が大きく性能が安定するのに数分
から数十分を要していた為、本例の如き駆動方法を採用
することができなかったが、本例の如き架橋構造の薄膜
状検出部２は熱容量が極めて小さく数秒で安定状態とな
るので、上述した如き駆動方法を採用することが可能と
なっている。As described above, the pulse drive is carried out intermittently in the normal time, and when the detection signal appears abnormally, the drive system is switched to the drive system close to the steady drive to sufficiently stabilize the operation, and then the detection signal is sampled again to obtain the target gas. With the configuration for determining the presence or absence, the advantages of both pulse driving and steady driving can be utilized, and highly reliable detection performance can be stably obtained over a long period even by battery driving. Incidentally, in the conventional sensor, since the heat capacity of the detection unit 2 is large and it takes several minutes to several tens of minutes to stabilize the performance, the driving method as in this example cannot be adopted. Since the thin film-shaped detection unit 2 having the cross-linked structure as in the example has a very small heat capacity and becomes stable in a few seconds, it is possible to adopt the driving method as described above.
効 果 以上、詳述した如く、本発明によれば、通常時は間欠的
に駆動し、異常を検出した時は定常的な駆動に切り換え
た後正式に再検出することにより、低消費電力で外部環
境の変化等に影響されず信頼性の高い検出性能を長期に
亘って安定して発揮させることができる。尚、本発明は
上記の特定の実施例に限定されるものではなく、本発明
の技術的範囲内において種々の変形が可能であることは
勿論である。例えば、検出対象はガスに限らず、例えば
気相中に浮遊する液体粒子等の如くガス感応物質に吸着
・離脱作用を行う種々の物質の検出に本発明を適用する
ことができる。Effect As described above in detail, according to the present invention, the drive is intermittent during normal operation, and when an abnormality is detected, the drive is switched to steady drive and then formally re-detected, resulting in low power consumption. It is possible to stably exhibit highly reliable detection performance for a long period of time without being affected by changes in the external environment. The present invention is not limited to the above-mentioned specific embodiments, and it goes without saying that various modifications can be made within the technical scope of the present invention. For example, the object to be detected is not limited to gas, and the present invention can be applied to the detection of various substances such as liquid particles suspended in the gas phase that adsorb and desorb gas sensitive substances.
第１図は本発明の１実施例におけるガス検出装置の構成
を示したブロック図、第２図は本発明の１実施例におけ
るタイミング回路を示した回路図、第３図は本発明の１
実施例における動作を説明するタイミングチャート図で
ある。 （符号の説明） １ａ： 検出リード部 ２： 検出部 ３： ヒータ駆動回路 ４： 検出回路 ５： タイミング回路 ６： ゲートFIG. 1 is a block diagram showing a configuration of a gas detection device in one embodiment of the present invention, FIG. 2 is a circuit diagram showing a timing circuit in one embodiment of the present invention, and FIG.
It is a timing chart figure explaining operation in an example. (Explanation of reference numerals) 1a: Detection lead part 2: Detection part 3: Heater drive circuit 4: Detection circuit 5: Timing circuit 6: Gate
Claims (4)
共に前記感応物質に通電し感応作用に応じた出力信号を
検出するセンサ駆動方法において、 通常は前記電熱器及び前記感応物質に所定間隔で間欠的
に通電し、前記出力信号に異常を検出したら前記電熱器
及び前記感応物質に定常電流を通電して前記出力信号を
再検出することを特徴とするセンサ駆動方法。1. A sensor driving method for heating a sensitive substance to a predetermined temperature with an electric heater and energizing the sensitive substance to detect an output signal according to the sensitive action, which is usually a predetermined interval between the electric heater and the sensitive substance. The method for driving a sensor is characterized in that the output signal is re-detected by supplying a steady current to the electric heater and the sensitive material when an abnormality is detected in the output signal.
信号は前記感応物質への感応対象物の吸着・離脱作用に
応じた前記感応物質の抵抗値の変化に起因する信号であ
ることを特徴とするセンサ駆動方法。2. The output signal according to claim 1, wherein the output signal is a signal resulting from a change in the resistance value of the sensitive substance according to the adsorption / desorption action of the sensitive object on the sensitive substance. Characteristic sensor driving method.
て、前記感応対象物は気体であることを特徴とするセン
サ駆動方法。3. The sensor driving method according to claim 1 or 2, wherein the sensitive object is gas.
ずれか１項において、前記感応物質は金属酸化物半導体
であることを特徴とするセンサ駆動方法。4. A sensor driving method according to any one of claims 1 to 3, wherein the sensitive material is a metal oxide semiconductor.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4121085A JPH0627657B2 (en) | 1985-03-04 | 1985-03-04 | Sensor drive method |
| CA000503176A CA1272779A (en) | 1985-03-04 | 1986-03-03 | Sensor with periodic heating |
| DE19863607065 DE3607065A1 (en) | 1985-03-04 | 1986-03-04 | SENSING DEVICE |
| US06/836,151 US4775838A (en) | 1985-03-04 | 1986-03-04 | Sensor with periodic heating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4121085A JPH0627657B2 (en) | 1985-03-04 | 1985-03-04 | Sensor drive method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61201115A JPS61201115A (en) | 1986-09-05 |
| JPH0627657B2 true JPH0627657B2 (en) | 1994-04-13 |
Family
ID=12602042
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4121085A Expired - Lifetime JPH0627657B2 (en) | 1985-03-04 | 1985-03-04 | Sensor drive method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0627657B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63200028A (en) * | 1987-02-17 | 1988-08-18 | Japan Atom Energy Res Inst | Method and apparatus for measuring weight by means of piezoelectric vibrator |
| JP2777372B2 (en) * | 1988-04-08 | 1998-07-16 | シチズン時計株式会社 | Sensor signal processing device |
| JPH0283906A (en) * | 1988-09-20 | 1990-03-26 | Taiyo Yuden Co Ltd | Troidal coil device and manufacture thereof |
| JP4608061B2 (en) * | 2000-08-28 | 2011-01-05 | 株式会社ハーマンプロ | Gas concentration detector |
-
1985
- 1985-03-04 JP JP4121085A patent/JPH0627657B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61201115A (en) | 1986-09-05 |
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