JPH0814967A - Electromagnetic flowmeter - Google Patents
Electromagnetic flowmeterInfo
- Publication number
- JPH0814967A JPH0814967A JP14770194A JP14770194A JPH0814967A JP H0814967 A JPH0814967 A JP H0814967A JP 14770194 A JP14770194 A JP 14770194A JP 14770194 A JP14770194 A JP 14770194A JP H0814967 A JPH0814967 A JP H0814967A
- Authority
- JP
- Japan
- Prior art keywords
- coils
- magnetic field
- exciting
- signal
- electromagnetic
- 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
- Measuring Volume Flow (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、測定流体の流量を電気
信号に変換しこの流量に対応する流量信号を出力する電
磁流量計に係り、特に、磁界分布の非対称により生じる
電磁結合性ノイズを抑制した電磁流量計に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic flow meter which converts a flow rate of a measurement fluid into an electric signal and outputs a flow rate signal corresponding to the flow rate, and more particularly to an electromagnetic coupling noise caused by asymmetry of magnetic field distribution. It relates to a suppressed electromagnetic flow meter.
【０００２】[0002]
【従来の技術】電磁流量計は導管を流れる被測定流体の
流れ方向に対して直角な方向に一対のコイルにより磁界
を作用させ、この磁界により被測定流体中にその流量に
応じて発生した電圧を前記磁界に対して直角な方向に設
けた一対の検出用電極で取り出す様にしたものである。
本来この種の電磁流量計は、測定管内を流れる流速分布
がパイプの軸に対称であれば、流れの方向と磁界の方向
とに直交する電極間には平均流量に比例した起電力が発
生することを利用したものである。2. Description of the Related Art An electromagnetic flow meter applies a magnetic field by a pair of coils in a direction perpendicular to the flow direction of a fluid to be measured flowing through a conduit, and the magnetic field causes a voltage generated in the fluid to be measured according to its flow rate. Is taken out by a pair of detection electrodes provided in a direction perpendicular to the magnetic field.
Originally, this type of electromagnetic flow meter generates an electromotive force proportional to the average flow rate between the electrodes orthogonal to the flow direction and the magnetic field direction if the flow velocity distribution flowing in the measuring pipe is symmetrical with respect to the pipe axis. This is what was used.
【０００３】[0003]
【発明が解決しようとする課題】ところでこのような構
成においては、コイルに非対称性があると信号に電磁誘
導性ノイズが重畳し、測定誤差の原因となる。従って従
来は磁場内にワンターンコイルを設け、信号起電力に含
まれる電磁誘導性ノイズと同じノイズを発生させて相殺
する方法がとられている。しかしながら、ワンターンコ
イルを設けることは組み立て工数及び部品点数の増加に
繋がりできればないほうが望ましい。However, in such a structure, if the coil has asymmetry, electromagnetic induction noise is superimposed on the signal, which causes a measurement error. Therefore, conventionally, a method has been adopted in which a one-turn coil is provided in the magnetic field and the same noise as the electromagnetic induction noise included in the signal electromotive force is generated to cancel the noise. However, it is preferable that the provision of the one-turn coil does not lead to an increase in the number of assembly steps and the number of parts.
【０００４】本発明は上記従来技術の問題点を解決する
ためになされたもので、ワンターンコイルを設けること
なく電磁誘導性ノイズの除去が可能な電磁流量計を提供
することを目的とする。The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an electromagnetic flow meter capable of removing electromagnetic induction noise without providing a one-turn coil.
【０００５】[0005]
【課題を解決するための手段】上記課題を解決するため
の本発明の構成は、磁場を発生させる一対の励磁コイル
と、この磁場が印加され測定流量に対応して発生する信
号電圧を検出する信号検出手段を有する電磁流量計にお
いて、前記一対のコイルを独立して駆動するための励磁
コイル切り替え手段と、少なくとも一方のコイルに流れ
る電流を制御する電流制御手段を具備することを特徴と
するものである。The structure of the present invention for solving the above problems detects a pair of exciting coils for generating a magnetic field and a signal voltage generated in response to a measured flow rate when the magnetic field is applied. An electromagnetic flowmeter having a signal detecting means, comprising: an exciting coil switching means for independently driving the pair of coils, and a current control means for controlling a current flowing through at least one of the coils. Is.
【０００６】[0006]
【作 用】独立しているコイルの極性を互いに反転させ
ると、もし励磁コイルが対称にできていれば出力信号が
ゼロになり、非対称であればその度合に対応して信号出
力が得られる。電流制御手段で信号出力がゼロになるよ
うに制御すれば励磁コイルをみかけ上対称にすることが
できる。[Operation] When the polarities of the independent coils are reversed, the output signal becomes zero if the exciting coil is made symmetrical, and if asymmetric, a signal output corresponding to that degree is obtained. If the current control means controls so that the signal output becomes zero, the exciting coil can be made apparently symmetrical.
【０００７】[0007]
【実施例】以下、本発明の実施例について図を用いて説
明する。図１は本発明の１実施例を示す構成図である。
図１において１は測定流体が流れる管路，２ａ，２ｂは
測定流体と接液する一対の電極で導管とは絶縁されて固
定されている。３ａ，３ｂは測定流体に磁場を印加する
励磁コイルで導管１に近接して配置され、これらの励磁
コイルには励磁回路４から励磁電流が供給されるが、励
磁コイル３ｂ側には極性反転スイッチ５ａとスイッチオ
フ装置５ｂが挿入されている。６は励磁コイル３ａ側に
配置された可変抵抗（図では励磁コイルに対して並列に
挿入しているが直列に挿入してもよい）である。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.
In FIG. 1, 1 is a conduit through which a measurement fluid flows, and 2a and 2b are a pair of electrodes that come into contact with the measurement fluid and are insulated and fixed to the conduit. Reference numerals 3a and 3b denote exciting coils for applying a magnetic field to the measurement fluid, which are arranged close to the conduit 1. An exciting current is supplied to these exciting coils from an exciting circuit 4, but a polarity reversing switch is provided on the exciting coil 3b side. 5a and the switch-off device 5b are inserted. Reference numeral 6 denotes a variable resistor arranged on the side of the exciting coil 3a (in the figure, the variable resistor is inserted in parallel to the exciting coil, but may be inserted in series).
【０００８】測定電極２ａ，２ｂには差動増幅器７が接
続され、この差動増幅器の出力端は信号処理装置８の入
力端に接続され、信号処理装置８はこの出力端に現れる
測定電圧を用いて流量信号ＶQを演算して出力端９に出
力する。なお、信号処理装置８には図では省略するが極
性反転スイッチ５ａとスイッチオフ装置５ｂの切替えを
行うためのタイミング回路が含まれており、第１モード
では磁束が同方向となるように励磁コイル３ａ，３ｂに
磁場を印加し、第２モードでは逆方向になるように励磁
コイル３ａ，３ｂに磁場を印加する。また、信号処理装
置８は励磁回路のスイッチングも行う。A differential amplifier 7 is connected to the measuring electrodes 2a and 2b, the output end of this differential amplifier is connected to the input end of a signal processing device 8, and the signal processing device 8 applies the measured voltage appearing at this output end. The flow rate signal V Q is calculated by using it and output to the output end 9. Although not shown in the figure, the signal processing device 8 includes a timing circuit for switching between the polarity reversing switch 5a and the switch-off device 5b. In the first mode, the exciting coil is arranged so that the magnetic fluxes are in the same direction. A magnetic field is applied to 3a and 3b, and a magnetic field is applied to the exciting coils 3a and 3b so as to be in opposite directions in the second mode. The signal processing device 8 also switches the excitation circuit.
【０００９】次に、以上の様に構成された実施例におい
て、測定に先立って行う励磁コイルの対称性を調整する
動作について説明する。始めに管路１には流量に変化の
ない一定の流量の流体を流しておく。そして信号処理装
置８からの指令により第１モードにおいて励磁コイル３
ａ，３ｂに磁束が同方向となる磁場を印加する。その結
果電極２ａ，２ｂは流速に対応した電気信号を発生し信
号処理装置８の出力端には流量に対応した信号が現れ
る。Next, the operation of adjusting the symmetry of the exciting coil prior to the measurement in the embodiment configured as described above will be described. First, the fluid having a constant flow rate and having a constant flow rate is flown through the pipe line 1. Then, in accordance with a command from the signal processing device 8, the exciting coil 3 is operated in the first mode.
A magnetic field in which the magnetic flux has the same direction is applied to a and 3b. As a result, the electrodes 2a and 2b generate an electric signal corresponding to the flow velocity, and a signal corresponding to the flow rate appears at the output end of the signal processing device 8.
【００１０】次に第２モードでは信号処理装置８からの
指令により励磁コイル３ｂ側の極性を反転させる。その
結果もし励磁コイルが対称にできていれば出力信号がゼ
ロになり、非対称であればその度合に対応して信号出力
が得られる。電流制御手段である可変抵抗６を調整して
その出力電流がゼロになるように制御することにより励
磁コイルをみかけ上対称にすることができる。なお、本
実施例においては可変抵抗６を励磁コイル３ａ側に取り
付けた例を図示したが励磁コイル３ｂ側に取り付けても
よく、また、両側に取り付けてもよい。Next, in the second mode, the polarity on the exciting coil 3b side is reversed by a command from the signal processing device 8. As a result, if the exciting coil is made symmetrical, the output signal becomes zero, and if it is asymmetric, a signal output corresponding to the degree is obtained. The exciting coil can be made apparently symmetrical by adjusting the variable resistor 6 which is the current control means so that the output current thereof becomes zero. Although the variable resistor 6 is attached to the exciting coil 3a side in this embodiment, it may be attached to the exciting coil 3b side or both sides.
【００１１】[0011]
【発明の効果】以上、実施例と共に具体的に説明したよ
うに本発明によれば、一対のコイルを独立して駆動する
ための励磁コイル切り替え手段と、少なくとも一方のコ
イルに流れる電流を制御する電流制御手段を備えている
ので、励磁コイルが非対称であっても電流制御手段で信
号出力がゼロになるように制御すれば励磁コイルをみか
け上対称にすることができ、電磁結合性ノイズを除去す
ることができる。As described above in detail with the embodiments, according to the present invention, the exciting coil switching means for independently driving the pair of coils and the current flowing through at least one of the coils are controlled. Since the current control means is provided, even if the excitation coil is asymmetrical, if the current control means is controlled so that the signal output becomes zero, the excitation coil can be made apparently symmetrical, and electromagnetic coupling noise is removed. can do.
【図１】本発明の一実施例を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of the present invention.
１ 管路 ２ａ，２ｂ 電極 ３ａ，３ｂ 励磁コイル ４ 励磁回路 ５ａ 極性反転スイッチ ５ｂ スイッチオフ装置 ６ 可変抵抗 ７ 差動増幅器 ８ 信号処理装置 ９ 出力端 1 Pipeline 2a, 2b Electrodes 3a, 3b Excitation coil 4 Excitation circuit 5a Polarity inversion switch 5b Switch-off device 6 Variable resistance 7 Differential amplifier 8 Signal processing device 9 Output terminal
Claims (1)
の磁場が印加され測定流量に対応して発生する信号電圧
を検出する信号検出手段を有する電磁流量計において、
前記一対のコイルを独立して駆動するための励磁コイル
切り替え手段と、少なくとも一方のコイルに流れる電流
を制御する電流制御手段を具備することを特徴とする電
磁流量計。1. An electromagnetic flow meter having a pair of exciting coils for generating a magnetic field and a signal detecting means for detecting a signal voltage generated in response to a measured flow rate when the magnetic field is applied,
An electromagnetic flowmeter, comprising: an exciting coil switching means for independently driving the pair of coils; and a current control means for controlling a current flowing through at least one of the coils.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14770194A JPH0814967A (en) | 1994-06-29 | 1994-06-29 | Electromagnetic flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14770194A JPH0814967A (en) | 1994-06-29 | 1994-06-29 | Electromagnetic flowmeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0814967A true JPH0814967A (en) | 1996-01-19 |
Family
ID=15436303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14770194A Pending JPH0814967A (en) | 1994-06-29 | 1994-06-29 | Electromagnetic flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0814967A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016200415A (en) * | 2015-04-07 | 2016-12-01 | 横河電機株式会社 | Electromagnetic flowmeter and method for measuring flow rate of electromagnetic flowmeter |
-
1994
- 1994-06-29 JP JP14770194A patent/JPH0814967A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016200415A (en) * | 2015-04-07 | 2016-12-01 | 横河電機株式会社 | Electromagnetic flowmeter and method for measuring flow rate of electromagnetic flowmeter |
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