JPS6088302A - Eddy current type displacement gauge - Google Patents
Eddy current type displacement gaugeInfo
- Publication number
- JPS6088302A JPS6088302A JP19516583A JP19516583A JPS6088302A JP S6088302 A JPS6088302 A JP S6088302A JP 19516583 A JP19516583 A JP 19516583A JP 19516583 A JP19516583 A JP 19516583A JP S6088302 A JPS6088302 A JP S6088302A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- oscillator
- detection coil
- changes
- coaxial cable
- 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.)
- Pending
Links
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は渦電流式変位計に係り、特に温度補償を行な
う渦電流式変位計に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an eddy current displacement meter, and more particularly to an eddy current displacement meter that performs temperature compensation.
渦電流式変位計は、検出コイルに高周波電流を流して検
出コイル近傍に交流磁界を形成し、これによって金属の
被測定物内に渦電流を発生させ、この渦電流による検出
コイルのインピータンスの変化を測定して検出コイルと
被測定物との距離を検出するものである。この渦電流式
かつ構造が単純であり、タービンやコンブレンサ等の振
動変位やスラスト変位を測定するために用いられている
。Eddy current displacement meters pass high-frequency current through the detection coil to form an alternating magnetic field near the detection coil, which generates eddy currents within the metal object to be measured.This eddy current causes the impedance of the detection coil to The distance between the detection coil and the object to be measured is detected by measuring the change. This eddy current type and simple structure are used to measure vibration displacement and thrust displacement of turbines, condensers, etc.
従来この渦電流式変位計としては、第１図に７１＜すよ
うな回路構成としたものがある。この渦電流式変位計は
、電源１、発振器２、伸出コイル３、同軸ケーブル４、
検波器５、リニアライザ６及び増幅器７から構成されて
おり１発振器２は第２図に示すように、検出コイル３を
一辺のインピーダンス素子とするブリ・ンジ回路Ｂを形
成して、このブリッジ回路Ｂの両端部ａ、ａに高周波電
流を加え、このブリッジ回路Ｂの他の両端す、ｂに出力
される測定出力を基に、検出コイル３と金属である被測
定物８との距離を４１１定するようにしている。即ち、
被１１１Ｍ定物８との距離によって変化する検出コイル
３のインピータンスによって、上記ブリッジ回路Ｂに出
力される測定出力が定まり、この信号を検波器５で検波
した後リニアティザ６で線型化するようにして 増Ｉｌ
ｌ！ｌｌ：Ａ７を介して端子９に出力するようにしてい
る。Conventionally, this eddy current type displacement meter has a circuit configuration as shown in FIG. 1 at 71. This eddy current displacement meter consists of a power source 1, an oscillator 2, an extension coil 3, a coaxial cable 4,
It is composed of a detector 5, a linearizer 6, and an amplifier 7, and the oscillator 2 forms a bridge circuit B with the detection coil 3 as an impedance element on one side, as shown in FIG. A high frequency current is applied to both ends a and a of the bridge circuit B, and the distance between the detection coil 3 and the metal object to be measured 8 is determined by 411 based on the measurement output output to the other ends a and b of this bridge circuit B. I try to do that. That is,
The measurement output output to the bridge circuit B is determined by the impedance of the detection coil 3, which changes depending on the distance to the 111M constant object 8, and after this signal is detected by the detector 5, it is linearized by the linear teaser 6. te increase Il
l! ll: Output to terminal 9 via A7.
ここで検出コイル３及び発振器２における共振回路は第
２１ａに示す回路と等価であり、この回路のインピータ
ンスＺは。Here, the resonant circuit in the detection coil 3 and the oscillator 2 is equivalent to the circuit shown in No. 21a, and the impedance Z of this circuit is.
と表わされる。It is expressed as
ここにＲは検出コイル３の抵抗、Ｌは同じく検出コイル
３のインダクタンス、Ｃは並列コンデンサのキャパシタ
ンス、ωは周波数を示し、ｊはｆ〒を示す。ここでＲ，
Ｌ、ｃのうち、Ｒの（＋ｆｊはり、Ｃに比べて温度変化
の影響を大きく受けるので、Ｚの値はＲの温度変化に大
きく依存することとなり、測定系の環境温度によって検
知したコイル３と被測定物８との距離の測定値か異なる
という不具合か生ずる。Here, R is the resistance of the detection coil 3, L is the inductance of the detection coil 3, C is the capacitance of the parallel capacitor, ω is the frequency, and j is f〒. Here R,
Among L and c, the value of R (+fj) is greatly affected by temperature changes compared to C, so the value of Z greatly depends on the temperature change of R, and the coil 3 detected by the environmental temperature of the measurement system A problem arises in that the measured value of the distance between the measured distance and the object to be measured 8 is different.
さらに現実には、検出コイル３と発振器２とは同軸ケー
ブル４で接続されているから、この同軸ケーブルへの抵
抗Ｒ°、インダクタンスＬ゛。Furthermore, in reality, since the detection coil 3 and the oscillator 2 are connected by a coaxial cable 4, the resistance R° and the inductance L′ to this coaxial cable.
キャパシタンスＣ′等を考慮すると、等価回路は第３図
にボすものとなり、回路全体のインピータンス中の抵抗
的は更に増加し、温１■変化の影響か更に大いものとな
る。このことによって検出コイル３と発振器２とを接合
する同軸ケーブル４の長さはおのずと限られたものとな
っていた。When the capacitance C' and the like are taken into account, the equivalent circuit becomes as shown in FIG. 3, and the resistance in the impedance of the entire circuit increases further, and the influence of the temperature change becomes even greater. As a result, the length of the coaxial cable 4 that connects the detection coil 3 and the oscillator 2 is naturally limited.
この発明は、以上の不具合に鑑みなされたものであって
、温度の影響を受けることなく、また同軸ケーブルの延
長を大きくすることかできる過電流式変位計を提供する
ことを［１０′ｌとする。This invention was made in view of the above-mentioned problems, and an object of the present invention is to provide an overcurrent displacement meter that is not affected by temperature and can extend the length of a coaxial cable. do.
そしてこの目的は、検出コイルに高周波電流を供給する
発振器の両出力端子間の直流電位差を検出するｌ！８Ｊ
路と、この直流電位差の（ｉ（ｉに基ついて」二足発振
器に温度誤差を補止する信−Ｊを発する回路とからなる
温度補償回路を右することを４□＋ｆ徴とする渦電流式
変位計によって達成される。The purpose of this is to detect the DC potential difference between both output terminals of the oscillator that supplies high-frequency current to the detection coil! 8J
An eddy current with a characteristic of 4□+f that causes a temperature compensation circuit consisting of a circuit that emits a signal -J to compensate for the temperature error to a bipedal oscillator (based on i) of this DC potential difference (i (based on i) This is achieved by a displacement meter.
次に本発明の実施例に係る渦電流式変位、ｉｌを図面に
基づいて詳細に説明する。Next, the eddy current type displacement, il, according to the embodiment of the present invention will be explained in detail based on the drawings.
第５図は本実施例に係る渦電流式変位計を示すブロック
図である。本実施例に係る渦電流式変位Ａ１は、従来の
渦電流式変位、ｉｌと略同様の構成を有する本体部２０
と、検出コイル３等の温度変化に基づき補正信号を発生
する温度補償回路３０とからなる。FIG. 5 is a block diagram showing the eddy current displacement meter according to this embodiment. The eddy current type displacement A1 according to the present embodiment is a main body portion 20 having approximately the same configuration as the conventional eddy current type displacement, il.
and a temperature compensation circuit 30 that generates a correction signal based on temperature changes in the detection coil 3 and the like.
本体部２０は、定電流電源１を電源とし、検出コイル３
に高周波電流を加えて定電流の直流電流を流している他
は、前述した従来の渦電流式変位計と同一であり、同一
の部位には同一、−の符号を付して説明は省略する。The main body part 20 uses the constant current power supply 1 as a power source, and the detection coil 3
Other than applying a high-frequency current to a constant DC current, it is the same as the conventional eddy current displacement meter described above, and the same parts are marked with a - symbol and their explanation will be omitted. .
温度補償回路３０は、発振器２の出力端子両端の電位差
を増幅する差動増幅器ｌＯと、この差動増幅器１０の出
力の直流成分だけを通過させる低域濾波器１１と、この
低域濾波器１１の出力信号に基づき温度誤差を補正する
信号を発振器２に人力して測定系の温度変化に拘らず測
定出力が一定となるように発振器２の発振電圧を制御す
る発振電圧調整器１２とで構成されている。The temperature compensation circuit 30 includes a differential amplifier lO that amplifies the potential difference between the output terminals of the oscillator 2, a low-pass filter 11 that passes only the DC component of the output of the differential amplifier 10, and the low-pass filter 11. The oscillation voltage regulator 12 controls the oscillation voltage of the oscillator 2 so that the measured output is constant regardless of temperature changes in the measurement system by manually inputting a signal to the oscillator 2 to correct temperature errors based on the output signal of the oscillator 2. has been done.
次に本実施例に係る渦電流式変位計の作動について説明
する。Next, the operation of the eddy current displacement meter according to this embodiment will be explained.
ａｌｌｌ 足糸の温度変化に基づいて検出コイル３及び
同軸ケーブル４の抵抗Ｒ，Ｒ’の伯が変化すると、回路
全体のインピータンスが変化して、端子９に出力される
検出コイル３と被測定物８との距離を示す値も変化する
。ここで差動増幅器ｌＯで増幅され低域濾波器１１を通
過する信号は、発振器２の両端子の直流電位差に応じた
出力であって、温度によって変化する抵抗Ｒ，Ｒ“に比
例した出力となっている。この信号は発振電圧調整器１
２に人力され、発振器２に温度補正信号を供給して、抵
抗変化による温度誤差を補正する。all When the resistances R and R' of the detection coil 3 and coaxial cable 4 change based on the temperature change of the byssus, the impedance of the entire circuit changes, and the detection coil 3 and the measured object output to the terminal 9 change. The value indicating the distance to the object 8 also changes. Here, the signal that is amplified by the differential amplifier lO and passes through the low-pass filter 11 is an output that corresponds to the DC potential difference between both terminals of the oscillator 2, and is an output that is proportional to the resistances R and R'' that change depending on the temperature. This signal is the oscillation voltage regulator 1.
2 and supplies a temperature correction signal to the oscillator 2 to correct temperature errors due to resistance changes.
即ち前記ブリッジ回路によれば、抵抗Ｒ，Ｒ’の温度変
化に基づくインピーダンスＺの変化によって、同ブリッ
ジ回路Ｂの端子す、ｂに出力される測定出力が変化する
のであるが、検出コイル３及び同軸ケーブル４の抵抗変
化による直流電位差に基づいて発振電圧調整信号によっ
て端子ａ、ａに加える゛電圧を変化させて、測定系の温
亀変化があっても、端子す、ｂには同一距離に対して同
一のＡ１１１定イ１６か得られるようにしている。That is, according to the bridge circuit, the measurement output output to terminals S and B of the bridge circuit B changes due to a change in impedance Z based on a temperature change of the resistors R and R'. By changing the voltage applied to terminals a and a by using an oscillation voltage adjustment signal based on the DC potential difference caused by the resistance change of the coaxial cable 4, even if there is a temperature change in the measurement system, terminals a and b are kept at the same distance. In contrast, the same A111 constant A16 can be obtained.
以−Ｌ説明したように、この発明は渦′ｌ［゛流式変位
１，１に温度補償回路を設けて、検出コイルおよびこの
検出コイルに発振信号を伝える同軸ケーブルの温度によ
る抵抗の変化を検出して発振器に帰還して’Ａ振電電圧
調整して温度変化に基づく変化を相殺するようにしたか
ら、測定系の温度か変化しても常に同一の４１１定結果
をｔすることができるという効果を有する他、同軸ケー
ブルを長くしても温度変化を受けることがないため、同
軸ケーブルを長くすることができ、検出コイルをＡｌＩ
３定機本体から離して使用することかできるという効果
を奏するものである。As explained above, the present invention provides a temperature compensation circuit in the vortex type displacement 1, 1 to compensate for changes in resistance due to temperature of the detection coil and the coaxial cable that transmits the oscillation signal to the detection coil. Since it is detected and fed back to the oscillator and the oscillation voltage is adjusted to cancel out changes due to temperature changes, it is possible to always obtain the same 411 constant result even if the temperature of the measurement system changes. In addition to this effect, even if the coaxial cable is made long, there is no temperature change, so the coaxial cable can be made longer, and the detection coil can be made of AlI.
This has the advantage that it can be used separately from the main body of the 3-station machine.
第３図は従来の渦電流式変位３１を７Ｉ＼すプロンク図
、第２図は第１図に示した渦電流式変位計のブリッジ回
路を示す説明図、第３図は第１図に示した渦電流式変位
計の検出コイル及び発振器における共振回路の等価回路
を示す回路図、第４図は第２図に示す共振回路に１Ｆｊ
ｌ軸ケーブルの抵抗等を加えた場合の等価回路を示す回
路図、第５図は本発明の実施例を小オブロック図である
。
１・・・定電流電ａ２・・・発振器
３・・・検出コイル ４・・・同軸ケーブル５・・・検
波器 Ｇ・・・リニアライザ７・・・増幅器 ８・・・
被測定物
ｌＯ・・・差動増幅器 １１・・・低域濾波器１２・・
・発振電圧調整器 １３・・・定電圧電源時み１出願人
株式会社明石製作所Fig. 3 is a Pronk diagram showing the conventional eddy current displacement meter 31 at 7I, Fig. 2 is an explanatory diagram showing the bridge circuit of the eddy current displacement meter shown in Fig. 1, and Fig. 3 is the diagram shown in Fig. 1. A circuit diagram showing an equivalent circuit of a resonant circuit in a detection coil and an oscillator of an eddy current displacement meter.
FIG. 5 is a circuit diagram showing an equivalent circuit when the resistance of the l-axis cable is added, and FIG. 5 is a small block diagram of an embodiment of the present invention. 1... Constant current voltage a2... Oscillator 3... Detection coil 4... Coaxial cable 5... Detector G... Linearizer 7... Amplifier 8...
Object to be measured lO...Differential amplifier 11...Low pass filter 12...
・Oscillation voltage regulator 13... Constant voltage power supply 1 Applicant: Akashi Seisakusho Co., Ltd.
Claims (1)
間の直流電位差を検出する回路と、このＩ＃、流電位差
の値に基づいて上記発振器に温度誤差を補正する信号を
発する回路とからなる温度補償回路を有することを特徴
とする渦電流式変位計。The temperature control circuit consists of a circuit that detects the DC potential difference between both output terminals of an oscillator that supplies high-frequency current to the detection coil, and a circuit that issues a signal to the oscillator to correct the temperature error based on the value of this I# and current potential difference. An eddy current displacement meter characterized by having a compensation circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19516583A JPS6088302A (en) | 1983-10-20 | 1983-10-20 | Eddy current type displacement gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19516583A JPS6088302A (en) | 1983-10-20 | 1983-10-20 | Eddy current type displacement gauge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6088302A true JPS6088302A (en) | 1985-05-18 |
Family
ID=16336507
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19516583A Pending JPS6088302A (en) | 1983-10-20 | 1983-10-20 | Eddy current type displacement gauge |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6088302A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0187846U (en) * | 1987-12-01 | 1989-06-09 |
-
1983
- 1983-10-20 JP JP19516583A patent/JPS6088302A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0187846U (en) * | 1987-12-01 | 1989-06-09 |
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