JPS5844314A - Electromagnetic flow meter - Google Patents
Electromagnetic flow meterInfo
- Publication number
- JPS5844314A JPS5844314A JP14666882A JP14666882A JPS5844314A JP S5844314 A JPS5844314 A JP S5844314A JP 14666882 A JP14666882 A JP 14666882A JP 14666882 A JP14666882 A JP 14666882A JP S5844314 A JPS5844314 A JP S5844314A
- Authority
- JP
- Japan
- Prior art keywords
- current
- excitation
- switch
- circuit
- value
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/60—Circuits therefor
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Volume Flow (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は励振コイル仁励磁電流を断続して供給するこ
とをその断続周期よりも長い周期で繰返す事6:よって
励損コイル&:矩形波状電流を流すよう6−シた電磁流
量計−一関する。DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized by repeating the intermittent supply of excitation current to the excitation coil with a cycle longer than the intermittent cycle. Related to electromagnetic flowmeters.
〈発明の背景〉
従来一般櫨;使用されている電磁流量針はその励磁電源
として商用電源を用いていた。この商用電源周液数と得
られた測定信号周波数とが同一であるため商用電源から
の誘導雑音の影響を受は易い。<Background of the Invention> Conventionally used electromagnetic flow needles have used commercial power as their excitation power source. Since the frequency of this commercial power source and the obtained measurement signal frequency are the same, it is easily influenced by induced noise from the commercial power source.
発信器の電極から引出される信号線が・励磁磁束を横切
るため測定信号と90度位相が興なるいわゆる90度雑
音が発生し、この雑音を除去する回路が必要となり変換
器全体が複雑となる。Since the signal line drawn from the transmitter electrode crosses the excitation magnetic flux, so-called 90 degree noise occurs, which is 90 degrees out of phase with the measurement signal, and a circuit to remove this noise is required, making the entire converter complex. .
このような点より励磁周波数を商用電源周波数より下げ
て励振を行う電磁流量計が提案されている。これはいわ
ゆる低周波励磁といわれ、この低周波励磁C;よれば商
用電源周波数と測定信号周波数とが異なるため商用電源
からの誘導雑音が少な(、それだけ回路設計が容易とな
り、シールド等も簡略化する事ができる。又これ6二と
もなって測定信号出力の大きさが小さくても良いため必
要な励損電流を少なくする事が可能である。・更C:9
0度雑音が周波数−二比例して小さくなるため、90度
雑書除去回路が不要となり、変換回路が簡略化される。From this point of view, an electromagnetic flowmeter has been proposed in which the excitation frequency is lowered than the commercial power supply frequency. This is called low-frequency excitation, and according to this low-frequency excitation C, the commercial power supply frequency and the measurement signal frequency are different, so there is less induced noise from the commercial power supply (which makes circuit design easier and shielding etc. In addition, since the magnitude of the measurement signal output may be small, the required excitation current can be reduced.・Modification C: 9
Since the 0-degree noise is reduced in proportion to the frequency, a 90-degree scribble removal circuit is not required, and the conversion circuit is simplified.
この低周波励磁を行うため励振コイルー二励磁電流を断
続的に供給する事を、その断続周期よりも長い周期で繰
返し、これ1:よりその断続中(二おいては励振コイル
による時定数に従って電流が平滑されて励振コイルに矩
形波状の電流が流れるよう6:する事が提案されている
。このよう5ニジて矩形波状の低い周波数の電流が励振
コイルー二供給されるが、その励振電流の立上Oにおい
てその電流が定常状態になるまで6二時間がかかる。つ
まり励損電流が流れ起こった時点ではその電流値が変化
するためこれが定常状態I:なった後における電極間出
力信号をチンプルして取出し、つまり矩形波状励損電流
の後縁の近<C:おいて出力をチンプルする方が正確な
測定が行なえる。このよう(二十分定常状態(;なって
から測定出力をチンプルするよう(=するため(:はそ
のチンプル周期が長くなり、つまり矩形波状電流の周期
を長くしなくてはならなくなる。言換えれば励磁電流を
断続する事の繰返しが長くなり、それだけ流量変動−:
対する応答適度が遅くなる。In order to perform this low frequency excitation, the excitation coil is supplied with two excitation currents intermittently with a cycle longer than the intermittent cycle, and during the intermittent period (in the second case, the current is supplied according to the time constant by the excitation coil). It has been proposed that the rectangular wave-like current is smoothed and a rectangular wave-like current flows through the excitation coil.In this way, a rectangular-wave-like low frequency current is supplied to the excitation coil, but the rise of the excitation current It takes 62 hours for the current to reach a steady state in the upper O.In other words, at the time when the excitation current flows, the current value changes, which causes the output signal between the electrodes to chimp after reaching the steady state I. In other words, it is more accurate to measure by chimpling the output at <C: near the trailing edge of the rectangular wave excitation current. In order to do (=), the chimple period becomes longer, which means that the period of the rectangular wave current must be lengthened.In other words, the repetition of intermittent excitation current becomes longer, and the flow rate fluctuation -:
The response moderation becomes slow.
一方このよう1;繰返し周波数が低くなり矩形波状電流
周期が長くなって直流(:近い電流が流れると、測定信
号i;無関係な電圧が電極に発生し、この電圧の周期は
比較的長いため、この周期(−矩形波状励振電流の周期
とが近すき、これ等を分離する事ができなくなる。即ち
電極に生ずる直流電位変化の影響を受は島くなる。On the other hand, like this 1: When the repetition frequency becomes low and the rectangular wave current period becomes long, and a current close to DC (:) flows, an unrelated voltage is generated at the electrode, and the period of this voltage is relatively long, so This period (-the period of the rectangular wave excitation current) is so close that it is impossible to separate them. That is, the influence of the DC potential change occurring at the electrode becomes an island.
矩形波状励振電流の立上りが遅れるのを改善する署;は
励振コイルの時定数、即ちインダクタンス値を小さくす
れば早く定常電流に達するが、励磁電源として商用電源
の出力を整流したものを使用する場合は単4:整流した
だけでは励振電流のリップル分が大きくなり性能が劣化
する。よってP波器が必要となり励振電流は最大十数ア
ンペアとなるのでP波器として電力容量の非常に大きな
ものが必要となり、実用的でない。従って励振コイルの
時定数を小さくすることは好ましくなく、この時定数を
大きくして励振コイルC;よって断続電流を平滑化する
事が望まれる。The key to improving the delay in the rise of the rectangular wave excitation current is to reduce the time constant of the excitation coil, that is, the inductance value, so that the steady current is reached more quickly, but when using a rectified commercial power supply output as the excitation power source AAA: If only rectification is performed, the ripple of the excitation current will increase and the performance will deteriorate. Therefore, a P-wave device is required, and the excitation current is at most ten-odd amperes, so a P-wave device with a very large power capacity is required, which is not practical. Therefore, it is not preferable to reduce the time constant of the excitation coil, and it is desirable to increase the time constant to smooth the intermittent current in the excitation coil C.
このため励振電流を断続させて励損コイル(:供給する
ことをその断続よりも長い周期で実行停止を繰返し、励
振コイル(:矩形波状の励振電流を流すようにした電磁
流量計が考えられている。その−例を第1図を用いて説
明する。第1図C;おいてパイプ11内C二は測定され
るべき流体が流され、そのパイプll内において対向し
て電極12.13が設けられ、これ等電極間に誘起され
た信号は増幅器14にて増幅され、割算回路15におい
て電源変動が補償されて標本化保持回路16c;供給さ
れ、これより測定出力として端子17(二得られる。For this reason, an electromagnetic flowmeter has been devised in which the excitation current is supplied intermittently to the excitation coil, and the excitation coil is repeatedly executed and stopped at a cycle longer than the intermittence, and a rectangular-wave excitation current is caused to flow through the excitation coil. An example of this will be explained using FIG. 1. In FIG. The signals induced between these electrodes are amplified by the amplifier 14, compensated for power fluctuations by the divider circuit 15, and supplied to the sampling and holding circuit 16c; It will be done.
パイプ11には励振コイル18が設けられ、このコイル
C;流された電流5;基ずく磁束が、パイプ11を流れ
る流体の流れ方向と、電極12及び13を結ぶ方向との
両者に対して略直角−二生じるようにされている。励振
コイル18の両端はスイッ?19を通じて整流回路21
の出力側に接−され、整流回路21の入力側には例えば
商用電源22が接−される。この励振コイル18と直列
C二励秦電流検出抵抗器23が挿入され、その両端の電
圧は比較増幅器24−二供給され、その出力は割算回路
15に供給される。励損コイル18と並列(:その逆電
圧を側路する回路25が接続される。スイッチ19は駆
動回路26C;よってオン、オフ制御される。The pipe 11 is provided with an excitation coil 18, and this coil C; the current 5 caused by the current 5; Right angles - two are made to occur. Are both ends of the excitation coil 18 switched? 19 through the rectifier circuit 21
For example, a commercial power source 22 is connected to the input side of the rectifier circuit 21 . A C two-excitation current detection resistor 23 is inserted in series with this excitation coil 18, the voltage across it is supplied to a comparator amplifier 24-2, and its output is supplied to a divider circuit 15. A circuit 25 is connected in parallel with the excitation coil 18 (which bypasses its reverse voltage). The switch 19 is controlled on and off by the drive circuit 26C.
従来Cお塾1てはスイッチ19は第2図ムC:示すよう
Cニ一定周期T、で断続され、その断続比は5〇−とさ
れ、更C二この断続周期T、よりも長い周期でその断続
が繰返され、つまりT1毎1;断続が繰返されて髪する
。これC:より励振プイル18の両端には第2図Bに示
すような電圧が生じ、この励振コイル18の平滑作用に
よって励振コイル18には第2図Cに示すようζ;漸次
立上る矩形波電流が流れる。In the conventional C cram school 1, the switch 19 is switched on and off at a constant period T, as shown in Figure 2, and the on/off ratio is 50-, and the cycle is longer than this on/off period T. The interruption is repeated, that is, once every T1; the interruption is repeated. This C: Therefore, a voltage as shown in FIG. 2B is generated at both ends of the excitation coil 18, and due to the smoothing action of the excitation coil 18, a rectangular wave ζ that gradually rises as shown in FIG. 2C is generated in the excitation coil 18. Current flows.
このよう(;励振ブイル18を流れる電流は初期r−お
いては安定しないため、これが一定値となってからの電
極12. 、13間の誘起信号が正しい信号である。従
って第2図Dt=示すように矩形波状電流の前縁よりT
、だけ遍れた後縁C電通い部分C;おいて標本化パルス
ーーより割算回路1Bの出力は標本化保持回路16(:
て標本化され、端子17に測を出力が得られる。先(:
述ぺたよう(;この励磁電流が一定値になるまでの時間
が長いと、この標本化パルスの周期を長くせざるを得な
くなり、つまり断続の繰返し周期2Tlが長くなる。従
って応答速度の週いものとなる。In this way, since the current flowing through the excitation coil 18 is not stable at the initial value r-, the induced signal between the electrodes 12. and 13 after this becomes a constant value is the correct signal. Therefore, in Fig. 2, Dt= As shown, T from the leading edge of the rectangular wave current
, the output of the divider circuit 1B is the sampling pulse from the sampling holding circuit 16 (:
The signal is sampled and a measurement output is obtained at terminal 17. Destination (:
As mentioned above, if the time it takes for this excitation current to reach a constant value is long, the period of this sampling pulse must be lengthened, which means that the intermittent repetition period 2Tl becomes longer. Become something.
ここでスイッチ19の断続を、その各断続の初めC:お
いて−デユティ比を太きく 100IC近いように制御
する。例えば第2図Bに示すよう&:スイッf19を制
御し、その断続の繰返し周期T:の初めi;おける期間
T1の部分はスイッチ19をオンーーしたままとする。Here, the on/off of the switch 19 is controlled so that the duty ratio is increased to approximately 100 IC at the beginning of each on/off at C:. For example, as shown in FIG. 2B, the &: switch f19 is controlled, and the switch 19 is kept on during a period T1 at the beginning i; of the intermittent repetition period T:.
従ってこの場合の励振コイル18C;印加される電圧は
第2図P c示すようC:なり、励振コイル18を流れ
る電流は第2図G(;示すようにその立上りが早くなり
、つまり定常値に達する時間が短くなって!J2図H1
:示すよう(:断続の開始より標本化保持パルスまでの
期間T二を従来のT、よりも短くする事ができ、それだ
け応答速度が早くなる。尚スイン?19がオンの時は電
源22の整流出力は励振コイル18に供給されるがオフ
の時は励損コイルに生じる電力により逆電圧抑制回路2
5を通じて電流が流される。この電流の立上りは励磁コ
イル18のインダクタンス分と抵抗弁とによって決まる
時定数で立上る。この時定数よりも、各電流供給油めに
おけるスイッチ19の断続時間を早くしているためその
励磁電流の立上りが早くなる。Therefore, in this case, the voltage applied to the excitation coil 18C becomes C: as shown in Fig. 2, and the current flowing through the excitation coil 18 rises quickly, as shown in Fig. The time to reach it is shorter! J2 figure H1
: As shown (: The period T2 from the start of intermittent to the sampling hold pulse can be made shorter than the conventional T, and the response speed is correspondingly faster. In addition, when the switch 19 is on, the power supply 22 is The rectified output is supplied to the excitation coil 18, but when it is off, the reverse voltage suppression circuit 2 is caused by the power generated in the excitation coil.
A current is passed through 5. This current rises with a time constant determined by the inductance of the exciting coil 18 and the resistance valve. Since the on/off time of the switch 19 in each current supply lubricant is set earlier than this time constant, the excitation current rises earlier.
スイッチ19の駆動回路26の具体的構成を第**に示
す。商用電源22の出力は波形整形回路!7(;で周期
T:の矩形波とされ、これは分周回路28によって分周
されて第4図人(;示すように周期2T:の矩形波とさ
れる。その矩形波によってゲート29が開かれると共に
単安定マルチバイブレータ31が駆動される。ゲー)
29 g::はパルス発生器32からデユティ1のパル
スが与えられ、ゲート29から第4図B&二示すように
T8毎i:断続出力が得られる。又単安定マルチバイブ
レータ31繻矩形波の立上り(二て駆動されて幅T、の
パルスが114図C区:示すように生じ、これがオアゲ
ート33に、ゲート29の出力と共4:供給される。従
ってゲート33の出力は第2図1に示した波形と同一と
なり、これが出力回路34に供給されてスイッチ19が
駆動される。The specific configuration of the drive circuit 26 of the switch 19 is shown in No. **. The output of the commercial power supply 22 is a waveform shaping circuit! 7(; is used as a rectangular wave with a period of T:, and this is frequency-divided by the frequency dividing circuit 28 to become a rectangular wave with a period of 2T: as shown in FIG. When opened, the monostable multivibrator 31 is driven.
29g:: is given a duty 1 pulse from the pulse generator 32, and an intermittent output is obtained from the gate 29 every T8 as shown in FIG. 4B&2. Further, the monostable multivibrator 31 is driven at the rising edge of the rectangular wave (second drive), and a pulse with a width T is generated as shown in section C of FIG. Therefore, the output of the gate 33 has the same waveform as shown in FIG. 2, and is supplied to the output circuit 34 to drive the switch 19.
ところで上述ではスイン?19の駆動回路はパルス発生
器32、波形整形回路27、分周回路28、単安定マル
チバイブレータ31、ゲート回路29等を必要とし構造
が複雑となる欠点がある。By the way, what about Suin in the above? The drive circuit No. 19 requires a pulse generator 32, a waveform shaping circuit 27, a frequency dividing circuit 28, a monostable multivibrator 31, a gate circuit 29, etc., and has a disadvantage that the structure is complicated.
更−2高周波の周期T・が一定であるため直流電源の電
圧が変動すると励磁電流値が変動する欠点がある。この
欠点を解消するため(電率1図の実施例では励磁電流を
抵抗器23で検出し、その検出値−一より割算回路15
6:おいて流速測定値を励磁電流値で割算し、励磁電流
の変動分を除去するよう一一シていや。Furthermore, since the period T of the high frequency wave is constant, there is a drawback that the excitation current value fluctuates when the voltage of the DC power source fluctuates. In order to eliminate this drawback (in the embodiment of the electric rate diagram 1, the excitation current is detected by the resistor 23, and the detected value - 1 is divided by the circuit 15).
6: Divide the measured flow velocity value by the excitation current value to remove the variation in the excitation current.
〈発明の目的〉
この発明の第1の目的は簡単な回路構造C:より上記し
たと同様の動作を行なうスイッチ19の駆動回路を持つ
電磁流量針を提供しようとするものである。<Objects of the Invention> The first object of the invention is to provide an electromagnetic flow needle having a simple circuit structure C: a drive circuit for a switch 19 that performs the same operation as described above.
この発明のIn2の目的は割算回路15を必ずしも必要
としない電磁流量針を提供する(:ある。The purpose of In2 of this invention is to provide an electromagnetic flow needle that does not necessarily require a divider circuit 15.
〈発明の概要〉
この発明では励磁コイル18(:流れる電流値を検出す
ると共にその電流値と基準値とを比較してその偏差値を
求め、偏差値をデユティサイクルC;変換してスイッチ
19をオン、オフ制御するように構成したものである。<Summary of the Invention> In the present invention, the excitation coil 18 (: detects the value of the flowing current, compares the current value with a reference value to determine its deviation value, converts the deviation value into the duty cycle C; It is configured to control on/off.
従ってこの発明−一よれば励磁回路とスイッチ駆動回路
が閉ループを構成し、励磁電流の変動はスイン?19の
デニテイチイクルの変化の形で帰還され、励磁電流を一
定し保持するよう一=動作する。Therefore, according to this invention-1, the excitation circuit and the switch drive circuit constitute a closed loop, and the fluctuation of the excitation current is caused by a swing. It is fed back in the form of a change in the density cycle of 19, and operates to keep the excitation current constant.
〈発明の実施例〉
第5図にこの発明の一実施例を示す。この実施例では第
1図で説明した低周波励磁形電磁流量針と岡等の動作を
行なうように構成した場合を示す。<Embodiment of the Invention> FIG. 5 shows an embodiment of the invention. In this embodiment, a configuration is shown in which the low frequency excitation type electromagnetic flow needle described in FIG. 1 is operated.
1I5WJ仁おいて第1図と対応する部分には同一符号
を付してその重複説明は省略するが、この発明では電流
検出手険として励磁回路C:挿入した抵抗@23を流用
し、この抵抗器23−一発生する電流値を増幅器24で
増幅し、その増幅出力を偏差増幅器35の一方の入力端
子(:供給する。偏差増幅器35の他方の入力端子(:
は基準値発生回路28から基準値を与える。この基準値
はここでは第4図人に示す1周期T:を持つ矩形波とし
て与えることとする。In 1I5WJ, parts corresponding to those in FIG. The current value generated by the amplifier 23-1 is amplified by the amplifier 24, and the amplified output is supplied to one input terminal (:) of the deviation amplifier 35.The other input terminal (:
gives a reference value from the reference value generation circuit 28. This reference value is here given as a rectangular wave having one period T: as shown in FIG.
偏差増幅器3sの出力はスイッチ駆動回路26に供給さ
れる。スイッチ駆動回路26はこの発明では電圧−デュ
テイ夛イクル変換回路を用いるものとする。The output of the deviation amplifier 3s is supplied to the switch drive circuit 26. In the present invention, the switch drive circuit 26 uses a voltage-duty cycle conversion circuit.
〈発明の動作説明〉
スイッチ駆動回路26は基準値発生回路28の出力矩形
波が立上り、高レベルC:なった瞬間(:は励振コイル
18には電流が流れてなく、従って抵抗器23における
電圧は小さく、この時偏差増幅回路315より大きな出
力が生じてデニテイサイクルは100−となり、スイッ
チ19はオンの状態を保持する。これにより電流が励振
コイルに流れ、かつ増加して定常状態−二近ず<C:従
って偏差増幅器35の出力が小さくなり、スイッチ19
を制御するデエテイチイクルは小さくなり、スインfi
lの断続比が小さくなる。<Description of operation of the invention> The switch drive circuit 26 operates at the moment when the output rectangular wave of the reference value generation circuit 28 rises and reaches the high level C: (: indicates that no current is flowing through the excitation coil 18, and therefore the voltage at the resistor 23 is small, and at this time a larger output is generated from the deviation amplification circuit 315, the deni- ty cycle becomes 100-, and the switch 19 remains on.As a result, the current flows to the excitation coil and increases to reach the steady state -2. Near <C: Therefore, the output of the deviation amplifier 35 becomes small, and the switch 19
The data cycle that controls the
The discontinuation ratio of l becomes small.
従って基準値発生回路28から偏差増幅器284二基準
値が与えられている状態C:おいて励磁電流の値が変動
すると、その変動に応じてスインf−19の断続比が変
化し、励磁電流の値を調整する。よって励磁電流は基準
値で決まる一定の値となるよう(:動作する。この実施
例では割算回路15を設けた例を示しているが、上記し
た理由からこの発明4−よれば励磁電流が一定となるよ
うにスイッチ19の断続比が制御されるため、割算回路
15は必ずしも必要としない。Therefore, when the value of the excitation current fluctuates in state C, where two reference values are given to the deviation amplifier 284 from the reference value generation circuit 28, the intermittent ratio of the swing f-19 changes in accordance with the fluctuation, and the excitation current Adjust values. Therefore, the excitation current is operated at a constant value determined by the reference value. Although this embodiment shows an example in which the divider circuit 15 is provided, for the above-mentioned reason, according to the present invention 4-, the excitation current is adjusted to a constant value determined by the reference value. Since the on/off ratio of the switch 19 is controlled to be constant, the divider circuit 15 is not necessarily required.
〈発明の効果〉
上述したよう(−この発明によればスイッチ駆動回路2
6は電圧デユティサイクル変換回路C−よって構成でき
る。電圧デユティサイクル変換回路は例えば演算増幅器
とシュミツ))リガ回路のループ接続(−より構成でき
るため構造は簡単である。<Effects of the Invention> As mentioned above (--According to this invention, the switch drive circuit 2
6 can be constituted by a voltage duty cycle conversion circuit C-. The structure of the voltage duty cycle conversion circuit is simple because it can be constructed from, for example, an operational amplifier and a loop connection of a Schmitts) trigger circuit.
然も励磁回路とスイッチ19の駆動回路26が閉ループ
を構成し、この閉ループC:より励磁電流が基準値と対
応して一定値となるよう(二制御されるから、特1:割
算回路15を必要としない。また割算回路15を用いる
ときは測定精度な6廟向上できる利点が得られ、高精度
の電磁流量針を得ることができる。However, the excitation circuit and the drive circuit 26 of the switch 19 constitute a closed loop, and this closed loop C: The excitation current is controlled to a constant value corresponding to the reference value. Further, when the dividing circuit 15 is used, there is an advantage that the measurement accuracy can be improved, and a highly accurate electromagnetic flow needle can be obtained.
また偏差増幅器35c−基準値を低周波の電形波として
与えるとと響ユよりスイッチ19が断続動作を開始する
初期において、そのデニティナイクルが自動的に100
−となるよう−一動作するから励磁電流の立上りを速く
することができる、よってそれだけ励振周波数を上げる
事ができ応答速度を上げることができる。更に同一励振
周波数であれば励振電流の変化C:よって生ずる誘導雑
音の影響が少なくなり、それだけ性能が向上する。更に
偏差増幅器35C:与える基準値を変える事によって励
振電流値の大きさを簡単C:調節できるので同一の電源
電圧でも各種の大きさの発信器を同一の回路で駆動する
事が可能である。つまり従来においては商用電源用に設
定された励振コイルを例えば低周波励磁するには発信器
の大きさ6;よってその電源電圧値を変えて励振電流を
調節する必要があったが、この発明(二よれば基準値を
変える事1:よって簡単(二行う事ができる。又一般に
商用電源用に設計された励振コイルはその時定数が大き
く、この発明の電磁流量計を適用する事によって低周波
励磁にそのまま利用しても、その励振電流の立上りが速
いため利用する蓼が可能である。又特にこの励損コイル
の時定数を小さくする必要6がなく、つまり電源のフィ
ルタとして平滑性がよい大電力用のフィルタを使用する
事なく、励振コイルの時定数の大きいものを使用する事
ができる。Furthermore, when the reference value is applied to the deviation amplifier 35c as a low-frequency electric wave, its density is automatically set to 100 at the initial stage when the switch 19 starts intermittent operation.
Since it operates in one motion so that -, the excitation current can rise faster, so the excitation frequency can be increased and the response speed can be increased accordingly. Furthermore, if the excitation frequency is the same, the influence of the induced noise caused by the change in excitation current C will be reduced, and the performance will be improved accordingly. Furthermore, since the magnitude of the excitation current value can be easily adjusted by changing the reference value given to the deviation amplifier 35C, it is possible to drive oscillators of various sizes with the same circuit even with the same power supply voltage. In other words, in the past, in order to excite, for example, a low frequency excitation coil set for commercial power supply, it was necessary to adjust the excitation current by changing the power supply voltage value of the oscillator. According to 2, it is easy to change the reference value (1), so it can be done (2).In addition, excitation coils designed for commercial power supply generally have a large time constant, and by applying the electromagnetic flowmeter of this invention, it is possible to change the reference value with low frequency excitation. It is possible to use it as it is because the excitation current rises quickly.Also, there is no need to particularly reduce the time constant of this excitation coil, and in other words, it is possible to use a large coil with good smoothness as a filter for the power supply. An excitation coil with a large time constant can be used without using a power filter.
尚上述C:おいては励振コイル18に対する電流の供給
の休止区間を設けたが、その休止区間においては第2図
工に示すように逆方向に電流を流すようCニジても良い
。その場合においても逆方向(二おける断続の初めにデ
ユティを大きへくする。又上述は商用電源を整流し、そ
の出方を断続して励振コイル纏;供給したが、直流電源
があればこれを直接利用して断続供給しても良い。In the above-mentioned C:, there is a pause period in the supply of current to the excitation coil 18, but during the pause period, the current may be passed in the opposite direction as shown in the second diagram. Even in that case, the duty is increased in the opposite direction (at the beginning of the intermittent cycle).Also, in the above example, the commercial power supply was rectified and its output was intermittently connected to the excitation coil; It is also possible to directly utilize the intermittent supply.
【図面の簡単な説明】
第1図はこの発明の基本となる電磁流量針の一例を示す
ブロック図、第2図は第1図に示した電】流量針の動作
の説明に供するための波形図−1第3図は第1図に示し
た電磁流量針のスイッチ駆動回路の一例を示すブロック
図、第4図はその説明−2供するための波形図、第5図
はこの発明4:よる電磁流量計の一実施例を示すブロッ
ク図である。
11:パイプ、12.13:電極、14:信号増幅器、
16:サンプル保持回路、18:励損コイル、19:ス
イッテ、21:整流回路、23:電流検出手段を構成す
る抵抗器、26:スイッチ駆動回路、35:偏差増幅器
。
特許出願人 株式会社北辰電機製作所
代理人革野 卓
オ 1 図
手続補正書
特許庁長官 殿
1、事件の表示
昭和57年 特 許 願第146668号2、発明の名
称
電磁流量針
3、補正をする者
事件との関係 特 許 出願人
住 所〒146東京都大田区下丸子3丁目30番1号電
話 東京759局4141番
4、補正指令の日付
6、補正の内容
(1)明細書の特許請求の範囲の欄を別紙の通g補正す
る。
以 上
特許請求の範囲
(1) A 、励磁コイルと直流電源との間に直列接続
したスイッチとよ
り、上記励磁コイルに流れる電流検出す6電流検出手段
と。
C9この電流検出手段の検出側と基準値との偏差を求め
る演算手段と1
D、この演算手段から得られる偏差値をデユティサイク
ルに変換しそのデユティサイクルに従って上記スイッチ
をオンオフ制御tJ6X−i’−y’)lI#l]路と
毒−から成る電IIi流量針。
=69−[Brief Description of the Drawings] Fig. 1 is a block diagram showing an example of the electromagnetic flow needle which is the basis of this invention, and Fig. 2 shows waveforms to explain the operation of the electromagnetic flow needle shown in Fig. 1. Figure-1 Figure 3 is a block diagram showing an example of the switch drive circuit for the electromagnetic flow needle shown in Figure 1, Figure 4 is a waveform diagram for explaining the same, and Figure 5 is a waveform diagram for providing explanation-2. It is a block diagram showing one example of an electromagnetic flow meter. 11: Pipe, 12.13: Electrode, 14: Signal amplifier,
16: sample holding circuit, 18: excitation coil, 19: switch, 21: rectifier circuit, 23: resistor constituting current detection means, 26: switch drive circuit, 35: deviation amplifier. Patent Applicant: Hokushin Electric Manufacturing Co., Ltd. Agent, Takuo Kakino 1. Draft procedure amendment Commissioner of the Japan Patent Office, 1. Indication of the case, 1982 Patent Application No. 146668. 2. Name of the invention, Electromagnetic flow needle 3. Make amendments. Patent Applicant Address: 3-30-1, Shimomaruko, Ota-ku, Tokyo 146 Telephone: Tokyo 759 Bureau 4141-4 Date of amendment order: 6 Contents of amendment (1) Regarding the patent claims in the specification Correct the range column as shown in the attached sheet. Claims (1) A. Current detection means for detecting a current flowing through the excitation coil by a switch connected in series between the excitation coil and a DC power supply. C9 Calculating means for calculating the deviation between the detection side of this current detecting means and a reference value 1 D, converting the deviation value obtained from this calculating means into a duty cycle and controlling the above switch on/off according to the duty cycle tJ6X-i '-y') lI#l] Electron IIi flow needle consisting of tract and poison-. =69-
Claims (1)
たスイッチと。 B、上記電磁コイル(電流れる電流検出する電流検出手
段と。 C1この電流検出手段の検出値と基準値との偏差を求め
4る演算手段と。 D、この演算手段から得られる偏差値をデユティサイク
ルに変換しそのデユティサイクル1:従って上記スイッ
チをオンオツ制御するスイッチ駆動回路と。 から成る電磁流量針。(1) Between the person, the excitation coil and the DC power supply 6: With the switch connected in series. B. Current detecting means for detecting the current flowing in the electromagnetic coil. C1 Calculating means for calculating the deviation between the detected value of the current detecting means and a reference value. D. Duplicate the deviation value obtained from this calculating means. and a switch drive circuit that converts the duty cycle into a duty cycle 1 and therefore controls the on/off of the switch.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP14666882A JPS6048689B2 (en) | 1982-08-23 | 1982-08-23 | electromagnetic flow meter |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP14666882A JPS6048689B2 (en) | 1982-08-23 | 1982-08-23 | electromagnetic flow meter |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2127477A Division JPS584765B2 (en) | 1977-02-28 | 1977-02-28 | electromagnetic flow meter |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5844314A true JPS5844314A (en) | 1983-03-15 |
JPS6048689B2 JPS6048689B2 (en) | 1985-10-29 |
Family
ID=15412910
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP14666882A Expired JPS6048689B2 (en) | 1982-08-23 | 1982-08-23 | electromagnetic flow meter |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6048689B2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4916381A (en) * | 1988-05-12 | 1990-04-10 | Rosemount Inc. | Current source for a variable load with an inductive component |
US5372045A (en) * | 1993-02-12 | 1994-12-13 | Rosemount Inc. | Bridge pulse controlled constant current driver for magnetic flowmeter |
JP2015014575A (en) * | 2013-07-08 | 2015-01-22 | 横河電機株式会社 | Electromagnetic flowmeter and insulation deterioration diagnostic method of exciting coil in electromagnetic flowmeter |
JP2016532087A (en) * | 2013-09-26 | 2016-10-13 | マイクロ モーション インコーポレイテッド | Electromagnetic flow meter with power limiting function and overcurrent detection function |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6317550A (en) * | 1986-07-10 | 1988-01-25 | Yamaichi Electric Mfg Co Ltd | Ic loading and contacting type socket |
JPH02119079A (en) * | 1989-09-20 | 1990-05-07 | Yamaichi Electric Mfg Co Ltd | Ic plating-contact type socket |
-
1982
- 1982-08-23 JP JP14666882A patent/JPS6048689B2/en not_active Expired
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4916381A (en) * | 1988-05-12 | 1990-04-10 | Rosemount Inc. | Current source for a variable load with an inductive component |
US5372045A (en) * | 1993-02-12 | 1994-12-13 | Rosemount Inc. | Bridge pulse controlled constant current driver for magnetic flowmeter |
US5530639A (en) * | 1993-02-12 | 1996-06-25 | Rosemount Inc. | Bridge pulse controlled constant current driver for magnetic flowmeter |
JP2015014575A (en) * | 2013-07-08 | 2015-01-22 | 横河電機株式会社 | Electromagnetic flowmeter and insulation deterioration diagnostic method of exciting coil in electromagnetic flowmeter |
JP2016532087A (en) * | 2013-09-26 | 2016-10-13 | マイクロ モーション インコーポレイテッド | Electromagnetic flow meter with power limiting function and overcurrent detection function |
Also Published As
Publication number | Publication date |
---|---|
JPS6048689B2 (en) | 1985-10-29 |
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