JPH02143121A - Electromagnetic flowmeter - Google Patents
Electromagnetic flowmeterInfo
- Publication number
- JPH02143121A JPH02143121A JP29890188A JP29890188A JPH02143121A JP H02143121 A JPH02143121 A JP H02143121A JP 29890188 A JP29890188 A JP 29890188A JP 29890188 A JP29890188 A JP 29890188A JP H02143121 A JPH02143121 A JP H02143121A
- Authority
- JP
- Japan
- Prior art keywords
- resistor
- voltage
- measuring tube
- detector
- electrodes
- 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.)
- Granted
Links
- 238000009413 insulation Methods 0.000 claims abstract description 31
- 230000005284 excitation Effects 0.000 claims description 20
- 238000001514 detection method Methods 0.000 claims description 7
- 239000012530 fluid Substances 0.000 claims description 5
- 230000007547 defect Effects 0.000 claims description 3
- 238000005259 measurement Methods 0.000 description 8
- 239000003990 capacitor Substances 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 241000252233 Cyprinus carpio Species 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
Landscapes
- Measuring Volume Flow (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は電磁流量計、特に検出器の絶縁不良を検知し
得るようにした電磁流量計に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic flowmeter, and particularly to an electromagnetic flowmeter capable of detecting insulation failure of a detector.
一般に、電磁流量計は、内面が絶版（ライニング）され
ｔ測定管と、この測定管の内壁面に対設さルる一対の電
極と、測定管の軸方向及び電極の配置方向にそルぞｎ直
交する方向に磁界を印加する励磁コイルとからなる検出
器と、ｍＩ記電極で検出された信号を演算処理し流ｉ信
号を得る変換器と全備え、前記測定管を被測定かし路に
配管し、コイルに正負に極性の変化するパルス電流を流
し、電極間に誘起される電圧紮導出し、この信号電圧全
変換器に導き流体流′Ｉｋ全算出して出力するようにな
つている。In general, an electromagnetic flowmeter consists of a measuring tube whose inner surface is lined, a pair of electrodes arranged opposite to each other on the inner wall of the measuring tube, and a pair of electrodes arranged in the axial direction of the measuring tube and in the direction in which the electrodes are arranged. A detector consisting of an excitation coil that applies a magnetic field in orthogonal directions, and a converter that processes the signal detected by the mI electrode to obtain a current i signal, and connects the measurement tube to the path to be measured. A pulse current whose polarity changes between positive and negative is passed through the coil, the voltage induced between the electrodes is derived, and the signal is guided to a voltage total converter to calculate and output the total fluid flow 'Ik. There is.
上記構成の電磁流量計で、特に検出器の故障には次の２
つがある。In the electromagnetic flowmeter with the above configuration, the following two problems occur especially when the detector malfunctions.
There is one.
■励磁コイルの断線と短絡
■電極やライニング、ならびに測定管のシール部分の劣
化によりて起る液漏ルによる励磁コイル−測定管間やｔ
極−測定管間の絶縁不良、前記故障の内■については、
変換器で励磁電流の大きさを励磁のつど測定することに
よって検知することができる。■ Disconnections and short circuits in the excitation coil ■ Fluid leakage caused by deterioration of electrodes, linings, and seals of the measurement tube.
Regarding poor insulation between the electrode and the measuring tube, among the above failures,
The magnitude of the excitation current can be detected with a transducer by measuring each excitation.
ところが■の絶縁不良についてはそれを検出する機能を
従来の電磁流量計に備えておらず、中央の制御室から検
出器の絶縁不良？知ることができなかつ友。However, conventional electromagnetic flowmeters do not have a function to detect defective insulation in (■), and the detector's insulation defect can be detected from the central control room. A friend who cannot be known.
そのため異状が起る度に人が検出器の設置さｎている所
まで出かけて検出器の絶縁抵抗を測定する必要があった
。Therefore, whenever an abnormality occurred, it was necessary for a person to go to the location where the detector was installed and measure the insulation resistance of the detector.
しかしこれには次の問題がある。However, this has the following problem.
■ 検出器＃′Ｓ、現場に設置されているので、チエツ
クするには現場に行く必要があるが、出かけるにも距離
が遠い場合が多い。■ Detector #'S is installed at the site, so it is necessary to go to the site to check it, but it is often a long distance away.
Ｏ検出器の絶縁を調べるには絶縁抵抗計を使用するが、
その際検出器に高電圧（ＤＣ１００へ５００ｖ程度）を
印加するので、変換器の入力回路の保護の几め検出器−
変換器間のケープｙを全て外す必要があり、労力と時間
ｔ−要する作業になる。An insulation resistance meter is used to check the insulation of the O detector, but
At that time, a high voltage (approximately 500V to DC100) is applied to the detector, so please carefully protect the input circuit of the converter.
It is necessary to remove all the capes between the converters, which is a labor-intensive and time-consuming task.
θ 絶縁不良は急激に起こることはまれである。θ Insulation failure rarely occurs suddenly.
しかも軽度の絶縁不良では、誤差は大きくなるが、ある
程度出力は出るので！磁流置針の出力を見ているだけで
はなかなかそれ全発見することができず、誤差が大きい
ことに気づかずに運転を継続してしまう恐ｎがある。Moreover, if there is a slight insulation defect, the error will be large, but a certain amount of output will still be produced! It is difficult to detect all the errors just by looking at the output of the magnetic current positioner, and there is a risk that operation may continue without realizing that the error is large.
この発明は上記に鑑み、検出器の絶縁不良を検知し得る
ｔｆｆｉｆｉ量計を提供置針ことｔ目的としている。In view of the above, an object of the present invention is to provide a tffifi quantity meter capable of detecting poor insulation of a detector.
この発明は上記課題を解決するために検出器の測定管と
励磁コイ／Ｌ’または電極間に抵抗？介して電圧を印加
する電圧供＠１ｆｉｌ路と、この回路に流れるｔＳまｆ
ｃは前記抵抗の端子電圧を検出する検出手段と、この検
出手段で検出された検出出力と、基準値とを比較し検出
器の絶縁不良を判別する手段とより構成される。This invention solves the above problems by creating a resistance between the measuring tube and the excitation coil/L' or electrode of the detector. The voltage supply @1fil path that applies voltage through the circuit, and the tSmaf that flows through this circuit.
c is composed of a detecting means for detecting the terminal voltage of the resistor, and a means for comparing the detection output detected by the detecting means with a reference value to determine insulation failure of the detector.
電圧供給回路は抵抗を介して測定管と励磁コイルま友は
電極間に高電圧ｒ印加する。The voltage supply circuit applies a high voltage r between the electrodes of the measuring tube and the excitation coil via a resistor.
その際電圧供給回路に流れる電流まｔは抵抗の端子電圧
は測定管−励磁コイｙ間の絶縁抵抗に工９定まり、測定
管−励磁コイル間（検出器）の絶縁状態により変化する
。（絶縁不良が大なる程回路の電流ま几は電圧が大きく
なる。）検出手段は前記電圧供給回路に流れる電はま几
は抵抗の端子電圧を検出する。At this time, the current flowing through the voltage supply circuit or the terminal voltage of the resistor is determined by the insulation resistance between the measuring tube and the exciting coil y, and varies depending on the insulation state between the measuring tube and the exciting coil (detector). (The greater the insulation failure, the greater the current or voltage in the circuit.) The detection means detects the terminal voltage of the resistor when the current flows through the voltage supply circuit.
判別手段は検出手段で検出され几検出信号と基準信号と
を比較し、検出１６号が基準信号より大きくなった場合
は絶縁不良と判別し、判別倍８′（絶縁不良信号）を出
力する。The determining means compares the detection signal detected by the detecting means with the reference signal, and when the detection signal No. 16 becomes larger than the reference signal, it determines that there is an insulation failure and outputs a determination multiple of 8' (insulation failure signal).
以下夾施例によりこの発明１ｉ−説明する。 This invention will be explained below by way of examples.
第１図はこの発明の一実施例を示す電磁流量計りブロッ
ク図である。FIG. 1 is a block diagram of an electromagnetic flow meter showing an embodiment of the present invention.
同図において配管に接続さｉ′Ｌ友測定管（１）の内壁
面に互いに対面して一対の′＊Ｌ極（２１）（２りが配
設されている。なお測定管（１）の内面は絶縁物質がラ
イニングされている。In the figure, a pair of '*L poles (21) (2) are arranged facing each other on the inner wall surface of the i'L measurement tube (1) connected to the pipe. The inner surface is lined with an insulating material.
測定管（１）の外部には、測定管（１）の軸方向及び電
極（２ａ ）（２ｂ ）の配置方向にそｎぞ九直交する
方向に磁界を印加するように励磁コイρ（３）が配置さ
れている。励磁コイル（３）には、励ｍ回路（４）より
、抵抗Ｒｉ介して低周波の矩形波状の励磁電流が流され
る。すなわち、マイクロプロセッサ（ＣＰＵ）（幻から
のタイミング信号によ夕、励磁回路（４）のスイッチ（
Ｓ＋ ） 、（８２）と、スイッチ（Ｓ３〕、（Ｓ４）
が交互にオン・オフされ、定電流源σＶがらの励磁コイ
／ｌ’ ＋３１に正・負の間欠的な矩形波電流が供給さ
ｎる。（第２図のａ、励磁電流参照）。Excitation coils ρ (3) are placed outside the measurement tube (1) so as to apply a magnetic field in a direction perpendicular to the axial direction of the measurement tube (1) and the arrangement direction of the electrodes (2a) (2b). is located. A low frequency rectangular wave excitation current is applied to the excitation coil (3) from an excitation m circuit (4) via a resistor Ri. That is, depending on the timing signal from the microprocessor (CPU), the excitation circuit (4) switch (
S+), (82) and switches (S3], (S4)
is turned on and off alternately, and intermittent positive and negative rectangular wave currents are supplied to the exciting coil /l'+31 from the constant current source σV. (See Figure 2a, excitation current).
測定管（１）に被測定流体が流れていると、を極（２ａ
）、（２ｂ）間に電磁誘導作用により、九量に応じた誘
起電圧が発生する（第２図のす、電極間の発生電圧参照
）、この誘起電圧が、バッファアンプ（５ａ入（５ｂ）
でインビーダンヌ変換さｎ、差動アンプ（６）で差動増
幅され、Ａ／’Ｄ変換器（７）でデジタル信号に変換さ
れてｃ Ｐ Ｕ （ｓ）に取り込まれる。ま几、励磁電
流の変動による誤差を除去する几めに励磁電流は抵抗Ｒ
で電圧ｇ１号に変換され、アンプ（９）ヲ経てデジタル
信号に変換され、ＣＰＵ（８）に取り込まれる。Ａ／Ｄ
変換器（７）のサンプリング動作は、第２図のＣで示す
ように励磁１！流の安定するタイミングに行われる。Ｉ
ＣＰＵ（８）は、こｎらの入力に基づいて流量ｋｔｌ″
算する。この計算結果、つまりは量はＤ／Ａに換器αＯ
でアナログ宅号に変換さ九出力される。上記構成は通常
の電磁流量計と同等である。When the fluid to be measured is flowing through the measuring tube (1), the pole (2a
) and (2b), an induced voltage corresponding to the quantity is generated due to the electromagnetic induction effect (see the voltage generated between the electrodes in Figure 2).
The signal is subjected to Inbee-Danne conversion, differentially amplified by a differential amplifier (6), converted to a digital signal by an A/'D converter (7), and taken into cPU(s). However, in order to eliminate errors due to fluctuations in the excitation current, the excitation current is connected to a resistor R.
The signal is converted into voltage g1 by the amplifier (9), converted into a digital signal, and taken into the CPU (8). A/D
The sampling operation of the converter (7) is as shown by C in FIG. This is done when the flow is stable. I
The CPU (8) determines the flow rate ktl″ based on these inputs.
Calculate. This calculation result, that is, the amount, is converted into D/A. αO
It is converted into an analog house number and output as nine. The above configuration is equivalent to a normal electromagnetic flowmeter.
餞へα・は検出器の絶縁抵抗を測定検知する几めにこの
発明により設けらｎたものである。In addition, α is provided according to the present invention to measure and detect the insulation resistance of the detector.
励磁コイ／ｌ’ １３１と測定管（１１との間には電圧
供給回路１ｉ？ｖＩ成する抵抗（１４、スイッチ０少、
直波高圧電源（ト）の直列（８）路が接続されている。A resistor (14, switch 0,
A series (8) path of a direct wave high voltage power supply (G) is connected.
なお電源Ｑ５は電池あるいＦｉ顔用電源を整訛平清し九
安定電圧源である。ａＱは抵抗（至）の両端電圧を増幅
するアンプでらる。The power source Q5 is a nine-stable voltage source, which is a battery or a Fi face power source. aQ is an amplifier that amplifies the voltage across the resistor.
スイッチ（１４１ｋオンするタイミングはＩＪ２図ｄに
示すように励磁コイ／’ （３１Ｋ ［ｆｉ ｋ Ｉｌ
ｌしていないときに、数分へ数時間に１回程度の適当な
割合でオンするように設定される。Switch (141k ON timing is as shown in IJ2 figure d)
It is set to turn on at an appropriate rate, about once every few minutes to several hours, when the computer is not on.
スイッチα尋がオンすると、励磁コイル（３）−測定管
（１）間には高電圧電源（至）の電圧が抵抗ＣＬ３を介
して印力口さｎ、この直列回路の電流に応じ定電圧が抵
抗（６）の両端に生じる。When the switch α is turned on, the voltage of the high voltage power supply (to) is applied between the excitation coil (3) and the measuring tube (1) through the resistor CL3, and a constant voltage is applied depending on the current of this series circuit. occurs across the resistor (6).
一般に励磁コイｐ−測定管間の抵抗は、正常なときには
概ね１００ＭΩ以上である。したがって高電圧電源α・
の電圧１Ｆ−１００Ｖ 、抵抗０４１の抵抗値１１ＭΩ
とすｎば抵抗（至）に接続されたアンプαりの出力が１
００Ａ上になｎば絶縁抵抗が１００ＭΩ以下となつ几こ
とが検知できる。Generally, the resistance between the excitation coil p and the measuring tube is approximately 100 MΩ or more under normal conditions. Therefore, high voltage power supply α・
voltage 1F-100V, resistance value of resistor 041 11MΩ
If n, the output of the amplifier α connected to the resistor (to) is 1.
If it is above 00A, it can be detected that the insulation resistance is 100MΩ or less.
アンプＯＱの出力はマルチプレクサａ３ｔ−経てＡ／Ｄ
変換器αηでデジタル信号に変換されｃｐＵ（８）に取
込まれる。ＣＰＵ（８）は取込まれ比値があらかじめ設
定さｎｘ値より大きいかどうか判定し、大きい場合は検
出器の絶縁抵抗が下がっていると判断し、外部に絶縁不
良信号りを出力する。The output of amplifier OQ is sent to A/D via multiplexer a3t.
The signal is converted into a digital signal by the converter αη and taken into the cpU (8). The CPU (8) determines whether the taken-in ratio value is greater than a preset nx value, and if so, determines that the insulation resistance of the detector has decreased, and outputs an insulation failure signal to the outside.
なお実施例では電圧供給回路の高電圧電源（至）として
安定し比電圧を印加する几めに電池等の別電源上用いた
が、検出器の正確な絶縁抵抗を正確に検出する必要がな
く、検出器の絶縁抵抗がある程度下がったことが検知で
きｎばよいことから、図中二点鎖線で囲んだようにダイ
オード叫およびコンデンサ０１で構成し、励磁コイルに
流す電流を休止する瞬間に発生する逆起電力をコンデン
サに充電し、この充電電圧を電源にするようにしてもよ
い。In the example, it was used on a separate power source such as a battery in order to apply a stable specific voltage as a high voltage power source for the voltage supply circuit, but there is no need to accurately detect the exact insulation resistance of the detector. Since it is only necessary to be able to detect that the insulation resistance of the detector has decreased to a certain extent, a diode and a capacitor 01 are used as shown in the figure, as shown by the two-dot chain line. It is also possible to charge a capacitor with the back electromotive force and use this charging voltage as a power source.
この様に構成すれば、絶縁抵抗の測定のために別電源を
必要としないので構成がより簡単となると共に励磁コイ
μに蓄えらＡ皮エネμギーを利用するので、消費電力が
１加することもなく、供給電圧はコンデンサの容量を適
当に選ぶことにより自由に設定できる。ま几、実施例で
は励磁コイ！−シグナルコモンである測定管間に電圧を
印加することにより励磁コイル−測定管間の絶縁抵抗を
検知するようにしたが、電極−測定管間に印加するよう
にしてもよい。With this configuration, a separate power supply is not required for measuring insulation resistance, making the configuration simpler, and since the A skin energy μ stored in the excitation coil μ is used, the power consumption increases by 1. The supply voltage can be freely set by appropriately selecting the capacitance of the capacitor. Well, the example is an excited carp! - Although the insulation resistance between the excitation coil and the measurement tube is detected by applying a voltage between the signal common and the measurement tube, it may also be applied between the electrode and the measurement tube.
いずれにしても通常検出器の電極と測定管とは検出器内
部で同じ空間に位置しているので、一方の絶縁抵抗が判
ｎば十分である。In any case, since the electrode of the detector and the measuring tube are normally located in the same space inside the detector, it is sufficient to determine the insulation resistance of one of them.
さらに実施例では絶縁抵抗全電圧の変化より検知したが
、［流の変化より検知するよう罠してもよい。Further, in the embodiment, the detection was performed based on a change in the total voltage of the insulation resistance, but it may also be detected based on a change in current.
この発明によれば、検出器の絶縁抵抗の検知手段を備え
ているので、検出器の設置さｎ友現場に出向くことなく
絶縁不良が検知でき、その構成も極めて簡単である。According to the present invention, since the detector is provided with a means for detecting the insulation resistance, an insulation failure can be detected without going to the site where the detector is installed, and its configuration is extremely simple.
第１図はこの発明の一実施例を示す１！母流量計のブロ
ック図、第２図は第１図の動作を説明するための信号波
形タイムチャートである。FIG. 1 shows an embodiment of the present invention. A block diagram of the mother flowmeter, FIG. 2 is a signal waveform time chart for explaining the operation of FIG. 1.
Claims (1)
の測定管内に互に対設された一対の電極と、前記測定管
の軸方向及び電極の配設方向にそれぞれ直交する方向に
磁界を与える励磁コイルとで構成された検出器と、前記
一対の電極間に誘起する流体流量に応じた電気信号を演
算処理し流量信号を得る変換器とを有する電磁流量計に
おいて、 前記測定管と前記励磁コイルまたは電極間に抵抗を介し
て電圧を印加する電圧供給回路と、前記回路に流れる電
流または前記抵抗の端子電圧を検出する検出手段と、検
出された検出出力と基準値とを比較し、検出器の絶縁不
良の有無を判別する手段とを備えたことを特徴とする電
磁流量計。(1) A measuring tube whose inner surface is insulated and through which a fluid to be measured flows, a pair of electrodes installed opposite each other in this measuring tube, and a pair of electrodes arranged in directions perpendicular to the axial direction of the measuring tube and the arrangement direction of the electrodes. An electromagnetic flowmeter comprising: a detector configured with an excitation coil that applies a magnetic field; and a converter that obtains a flow rate signal by processing an electric signal corresponding to the fluid flow rate induced between the pair of electrodes; and a voltage supply circuit that applies a voltage between the excitation coil or the electrodes via a resistor, a detection means that detects the current flowing in the circuit or the terminal voltage of the resistor, and a comparison between the detected detection output and a reference value. and means for determining whether there is an insulation defect in the detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63298901A JP2751269B2 (en) | 1988-11-25 | 1988-11-25 | Electromagnetic flow meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63298901A JP2751269B2 (en) | 1988-11-25 | 1988-11-25 | Electromagnetic flow meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02143121A true JPH02143121A (en) | 1990-06-01 |
| JP2751269B2 JP2751269B2 (en) | 1998-05-18 |
Family
ID=17865629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63298901A Expired - Lifetime JP2751269B2 (en) | 1988-11-25 | 1988-11-25 | Electromagnetic flow meter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2751269B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010085349A (en) * | 2008-10-02 | 2010-04-15 | Oval Corp | Electromagnetic flowmeter and insulation resistance measuring method |
| WO2013137445A1 (en) * | 2012-03-15 | 2013-09-19 | アズビル株式会社 | Excitation circuit for electromagnetic flow meter and electromagnetic flow meter |
| JP2016017945A (en) * | 2014-07-11 | 2016-02-01 | 横河電機株式会社 | Flow meter and electrical insulation deterioration diagnostic system |
| 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 |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61139425U (en) * | 1985-02-20 | 1986-08-29 |
-
1988
- 1988-11-25 JP JP63298901A patent/JP2751269B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61139425U (en) * | 1985-02-20 | 1986-08-29 |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010085349A (en) * | 2008-10-02 | 2010-04-15 | Oval Corp | Electromagnetic flowmeter and insulation resistance measuring method |
| WO2013137445A1 (en) * | 2012-03-15 | 2013-09-19 | アズビル株式会社 | Excitation circuit for electromagnetic flow meter and electromagnetic flow meter |
| JP2013195064A (en) * | 2012-03-15 | 2013-09-30 | Azbil Corp | Excitation circuit of electromagnetic flow meter |
| CN104169691A (en) * | 2012-03-15 | 2014-11-26 | 阿自倍尔株式会社 | Excitation circuit for electromagnetic flow meter and electromagnetic flow meter |
| US9267827B2 (en) | 2012-03-15 | 2016-02-23 | Azbil Corporation | Electromagnetic flow meter excitation circuit and electromagnetic flow meter |
| CN104169691B (en) * | 2012-03-15 | 2016-11-09 | 阿自倍尔株式会社 | The field circuit of electromagnetic flowmeter and electromagnetic flowmeter |
| JP2016017945A (en) * | 2014-07-11 | 2016-02-01 | 横河電機株式会社 | Flow meter and electrical insulation deterioration diagnostic system |
| US9726526B2 (en) | 2014-07-11 | 2017-08-08 | Yokogawa Electric Corporation | Flowmeter, insulation deterioration diagnosis system, and insulation deterioration diagnosis method |
| 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 |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2751269B2 (en) | 1998-05-18 |
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