JPS5983016A - Converter for low frequency exciting type electromagnetic flowmeter - Google Patents
Converter for low frequency exciting type electromagnetic flowmeterInfo
- Publication number
- JPS5983016A JPS5983016A JP19372082A JP19372082A JPS5983016A JP S5983016 A JPS5983016 A JP S5983016A JP 19372082 A JP19372082 A JP 19372082A JP 19372082 A JP19372082 A JP 19372082A JP S5983016 A JPS5983016 A JP S5983016A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- external
- commercial power
- period
- converter
- 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】
本発明は零点の安定性向上を目的として低周波励磁を行
ないファラデーの電磁誘導剤を利用して流体の流量を測
定する低周波励磁式電磁流量計において、外部直流電源
による駆動または外部商用電源、外部直流電源の両電源
による駆動が可能で動作信頼性の高い電磁流量計を構成
できる変換器に関する。Detailed Description of the Invention The present invention provides a low frequency excitation type electromagnetic flowmeter that performs low frequency excitation to improve the stability of the zero point and measures the flow rate of fluid using a Faraday electromagnetic induction agent. The present invention relates to a converter that can be driven by an external commercial power source or an external DC power source, and can constitute an electromagnetic flowmeter with high operational reliability.
被測定流体の流速方向に対して垂直方向に磁界を加えた
とき流速方向と磁界方向どの双方に垂直な方向にファラ
デーのｔａ１誘導則に従って発生する起電力を検出して
前記被測定流体の流量を測定する電１磁流量計において
は、当初該流量計の駆動用外部電源として商用電源が用
いられかつこの商用電源を利用して時間的に正弦波状に
変化する磁界が形成されるものが一般的であったが、近
来電磁流量計の零点の安定性を向上させるだめに該流量
計の駆動用外部電源としては商用電源が用いられるもの
の、該電源周期の整数倍の周期を有する矩形波または台
形波状の励磁電圧または励１［流を４用いて磁界が形成
され、かつ発生した起電力の定状状態値が駆動用商用電
源周期の整数倍の期間だけサンプリングされるいわゆる
低周波励磁式の電磁流量計が普及している。When a magnetic field is applied in a direction perpendicular to the flow velocity direction of the fluid to be measured, the electromotive force generated in a direction perpendicular to both the flow velocity direction and the magnetic field direction is detected according to Faraday's ta1 induction law, and the flow rate of the fluid to be measured is determined. In the case of electromagnetic flowmeters used for measurement, commercial power is generally used as an external power source to drive the flowmeter, and a magnetic field that changes sinusoidally over time is created using this commercial power. Recently, however, in order to improve the stability of the zero point of electromagnetic flowmeters, commercial power sources have been used as external power sources for driving the flowmeters, but rectangular or trapezoidal waves having a period that is an integral multiple of the power supply period have been used. A so-called low-frequency excitation type electromagnetic field in which a magnetic field is formed using a wave-like excitation voltage or excitation current, and the steady-state value of the generated electromotive force is sampled for a period that is an integral multiple of the driving commercial power supply cycle. Flowmeters are becoming popular.
次に従来の駆動用外Ｓｔ源として商用電源を用いた低周
波励磁式ｔ＠流量計を図面を参照して説明する。Next, a conventional low frequency excitation type t@flowmeter using a commercial power source as an external St source for driving will be described with reference to the drawings.
第１図はファラデーのｔ磁誘導則を利用した電磁流量計
の動作原理を説明するための構成図である。図において
１は平均流速Ｖ（ｍ／ｓ）をもった被測定流体２の流通
している測定管、Ｄ（ｍ）は測定管１の内径、３は励磁
電流Ｉ（Ａ）の流れる励磁コイル４が巻かれた鉄心、５
は励磁電流Ｉによってつくられた磁界、ＢｃＴ）はその
磁束密度である。図示のように被測定流体２の流速Ｖの
方向に対して垂直に磁束密度Ｂの磁界５を加えるとファ
ラデーのｔｇ１銹導則に従ってＶ、Ｂのいずれに対して
も垂直な方向で測定管１の内壁に被測定流体２に接して
対向して固設された電極６．６間に起電力Ｂ＝ｋ ＢＤ
Ｖ （Ｖ ）を生ずる。ｋは比例定数である。被測定流
体２の流ｔをＱ［＋ｎ７ｓ、）とするとＱ＝π／４ＸＤ
２ＶでろるからＱ＝π／４ｘＤ／ｋｘＢ／Ｂとなり、し
たがってＤ／ｋが既知であればＢ／Ｂを検出して流１’
ｌＱを測定することができることになる。以上が電磁流
量計の動作原理であって、ｌＯは測定管ｌ、鉄心８．励
磁コイル４．′に極６，６からなる検出器、７は電磁流
量計を駆動するための外部電源入を受電して励磁電流Ｉ
を出力し、起電力Ｅと図示されていない手段によって得
られた磁束密度Ｂに相当する信号とを入力として繭記圓
の演算を行ない流量Ｑに相当する信号Ｐを出力するよう
Ｋした変換器、８．８および９．９はそれぞれ電極６，
６および励磁コイル４と変換器７とを接続する電線であ
って、電磁流量計は検出器１０．変換器７．電線８．８
および９．９で構成されている。FIG. 1 is a configuration diagram for explaining the operating principle of an electromagnetic flowmeter using Faraday's t-magnetic induction law. In the figure, 1 is a measurement tube through which a fluid to be measured 2 flows with an average flow velocity V (m/s), D (m) is the inner diameter of the measurement tube 1, and 3 is an excitation coil through which an excitation current I (A) flows. Iron core wrapped with 4, 5
is the magnetic field created by the excitation current I, and BcT) is its magnetic flux density. As shown in the figure, when a magnetic field 5 with a magnetic flux density B is applied perpendicular to the direction of the flow velocity V of the fluid to be measured 2, the measuring tube 1 is applied in a direction perpendicular to both V and B according to Faraday's tg1 principle Electromotive force B=k BD
V (V). k is a proportionality constant. If the flow t of the fluid to be measured 2 is Q[+n7s,), then Q=π/4XD
Since it stops at 2V, Q = π/4xD/kxB/B, so if D/k is known, B/B is detected and the flow 1'
This means that lQ can be measured. The above is the operating principle of the electromagnetic flowmeter, where IO is the measuring tube 1, the iron core 8. Excitation coil 4. ' is a detector consisting of poles 6, 6, 7 receives an external power supply for driving the electromagnetic flowmeter, and receives an excitation current I.
A converter configured to output a signal P corresponding to the flow rate Q by performing the calculation of the cocoon record by inputting the electromotive force E and a signal corresponding to the magnetic flux density B obtained by means not shown in the figure. , 8.8 and 9.9 are electrodes 6,
6 and an electric wire connecting the excitation coil 4 and the converter 7, and the electromagnetic flowmeter has a detector 10. Converter 7. Electric wire 8.8
and 9.9.
電磁流量計は以上に説明したような動作原理にもとづく
ものであるから励ｃＦＩ電流は基本的には直流であって
も交流であっても差し支えない。しかしながら交流励磁
方式は直流励磁方式に比べて電極間電圧が電極における
分槓の影響を受けないなどの利点が多く、また励磁電源
の措成上からも好都合であるところから、当初電磁流量
計には駆動用外部電源として商用電源が用いられかっこ
の商用電源を利用して商用周波数で時間的に正弦波状に
変化する磁界を形成させる商用周波励磁方式が多く採用
されていた。ところがこのような商用周波励磁方式を採
用すると変換器７に入力される起電力ｇＫ商用電源と同
相および直角位相の誘導雑音が混入し信号Ｐの零点が変
動する。この零点変動の機構についてはたとえば次のよ
うな文献〔枝本：“電磁流量計による計測９計測と制御
、５−７゜５１１５７（１９６６）；伊藤、浅田：１′
電磁流量計の進歩と規格の現状１１計測と制御、 １４
−１１．２６／８９（１９７５）；佐島。Since the electromagnetic flowmeter is based on the operating principle as explained above, the exciting cFI current can basically be either direct current or alternating current. However, the AC excitation method has many advantages over the DC excitation method, such as the voltage between the electrodes being unaffected by the splitting of the electrodes, and it is also convenient in terms of the configuration of the excitation power supply, so it was initially used as an electromagnetic flowmeter. A commercial power source was used as an external power source for driving, and a commercial frequency excitation method was often adopted, which uses the commercial power source to form a magnetic field that changes sinusoidally over time at the commercial frequency. However, when such a commercial frequency excitation method is adopted, induction noise in phase and quadrature with the electromotive force gK commercial power supply input to the converter 7 is mixed, and the zero point of the signal P fluctuates. Regarding the mechanism of this zero point fluctuation, for example, the following literature [Edamoto: "Measurement and Control Using Electromagnetic Flowmeters 9, Measurement and Control, 5-7゜51157 (1966); Ito, Asada: 1'
Advances in electromagnetic flowmeters and current status of standards 11 Measurement and control, 14
-11.26/89 (1975); Sashima.
黒森：゛最近の電磁流量針の動向゛°計測と制御、、１
８−５゜２９／８Ｂ （１９７９））で明らかにされて
いる。このため最近のｔｇｉ流量計においては次に説明
するような低周波励磁方式を採用して信号Ｐの零点の安
定性向上をはかることが一般化している。Kuromori: ``Recent trends in electromagnetic flow needles'' measurement and control, 1
8-5°29/8B (1979)). For this reason, in recent TGI flowmeters, it has become common to adopt a low frequency excitation method as described below to improve the stability of the zero point of the signal P.
第２図は従来の商用電源駆動低周波励磁式電磁流量計の
一構成例を示すブロック図、第８図は第２図における要
部の信号または電圧の波形を含めたタイムチャートであ
って第１図と同一の機能または意味を有する部分には同
一の符号が付されている。ｔは時間経過でるる。両図に
おいてＹは電磁流量計の駆動用外部電源としての外部商
用電源、７１は外部商用電源Ｙを変換器７内で必要とす
る条件をもった直流電源に変換するＡＣ／ＤＣコンバー
タ、７２は外部商用電源Ｙによってタイミング信号Ｐ２
゜Ｐ８． Ｐ４を出力するタイミング信号発生回路であ
って「は外部商用電源Ｙの周期、Ｔｓはサンプリング期
間％Ｎは整数である。またこの場合Ｎｓ′ｔｌ−整数と
してＴｓ＝ｒＮｓであってかつＮ ｓ＜Ｎ／２である。FIG. 2 is a block diagram showing a configuration example of a conventional commercial power supply-driven low-frequency excitation type electromagnetic flowmeter, and FIG. 8 is a time chart including signal or voltage waveforms of the main parts in FIG. Parts having the same functions or meanings as in FIG. 1 are given the same reference numerals. t is the passage of time. In both figures, Y is an external commercial power source as an external power source for driving the electromagnetic flowmeter, 71 is an AC/DC converter that converts the external commercial power source Y into a DC power source that meets the required conditions within the converter 7, and 72 is an AC/DC converter Timing signal P2 is generated by external commercial power supply Y.
゜P8. In the timing signal generation circuit that outputs P4, " is the period of the external commercial power supply Y, Ts is the sampling period %N is an integer, and in this case, Ts=rNs as Ns'tl - integer, and Ns< It is N/2.
７３は励ｉｌ妊回路でおって、励磁コイル４を励磁する
ためにＡＣ／圓コンバータ７１によってつくられた直流
電圧をタイミング信号Ｐ２によってｒＮの周期を有する
矩形波励磁電圧Ｅ２に変換して励磁コイル４に出力する
。Reference numeral 73 denotes an excitation circuit which converts the DC voltage generated by the AC/round converter 71 in order to excite the excitation coil 4 into a rectangular wave excitation voltage E2 having a period of rN in accordance with the timing signal P2. Output to 4.
７４は電極６，６間の電圧を増幅して信号Ｓとして出力
する装置増幅回路、７５は信号Ｓに含まれる電源Ｙと同
相および直角位相の雑音を除くために該信号８の正側お
よび負側のほぼ定状状態となった各部分（第８図に斜線
を施して示した部分）をそれぞれタイミング信号Ｐ８お
よびＰ４によって同期整流してサンプリングしそれぞれ
信号Ｓ１およびＳ２として出力する同期整流回路、７６
は信号Ｓ１およびＳ２を差動増幅して被測定流体２に発
生する起電力Ｅ＝ｋ）３ＤＶに相当する信号Ｒを出力す
る差動増幅回路、７７は励磁電圧Ｅ２もしくは助出電流
Ｉを検出するかまたは励磁コイル４によってつくられた
磁界を直接検出するかなどの図示されていない手段によ
って得られた磁束密度Ｂに相当する信号を用いて入力信
号ＲＫ対してＶＢの演算を行ない被測定流体２の流量Ｑ
に相当する信号Ｐを出力する出力回路である。74 is a device amplifier circuit that amplifies the voltage between the electrodes 6 and 6 and outputs it as a signal S; 75 is a device amplifier circuit that amplifies the voltage between the electrodes 6 and 6 and outputs it as a signal S; 75 is a device amplifier circuit that amplifies the voltage between the electrodes 6 and 6; a synchronous rectifier circuit that synchronously rectifies and samples each portion (the shaded portion in FIG. 8) that is in a substantially constant state on the side using timing signals P8 and P4, and outputs the sample as signals S1 and S2, respectively; 76
77 is a differential amplifier circuit that differentially amplifies the signals S1 and S2 and outputs a signal R corresponding to the electromotive force E=k)3DV generated in the fluid 2 to be measured, and 77 detects the excitation voltage E2 or the supplemental current I. VB is calculated for the input signal RK using a signal corresponding to the magnetic flux density B obtained by means not shown, such as by directly detecting the magnetic field created by the excitation coil 4, and detecting the fluid under test. 2 flow rate Q
This is an output circuit that outputs a signal P corresponding to .
すなわち従来の商用電源駆動低周波励磁式電磁流量計は
以上に説明したように構成されているので励磁磁界の周
波数が外部商用電源の周波数より低くなっておシこのた
め信号Ｓに混入する前記誘導雑音が大幅に軽減され、そ
の上励磁磁界がほぼ定状値に達した状態でかつ該磁界が
逆方向に変化する直前のｒＮｓの期間だけ信号Ｓがサン
プリングされて同期整流されるので、信号８１およびＳ
２には外部商用電源周期の誘導雑音および磁界変動によ
って発生する微分雑音の影響は殆んど現われなくなる結
果、出力信号Ｐの零点変動が極めて少なくなる。第４図
は信号Ｓに混入している商用電源周期の誘導雑音がサン
プリングによって消去される理由を示す模式図である。In other words, since the conventional commercial power supply-driven low-frequency excitation type electromagnetic flowmeter is configured as explained above, the frequency of the excitation magnetic field is lower than the frequency of the external commercial power supply. Noise is greatly reduced, and in addition, the signal S is sampled and synchronously rectified only during a period of rNs when the excitation magnetic field has almost reached a constant value and immediately before the magnetic field changes in the opposite direction. and S
2, the effects of induction noise caused by external commercial power supply cycles and differential noise generated by magnetic field fluctuations hardly appear, and as a result, the zero point fluctuation of the output signal P becomes extremely small. FIG. 4 is a schematic diagram showing the reason why the induced noise of the commercial power supply cycle mixed in the signal S is eliminated by sampling.
以上に説明したように従来低周波励磁式ｔａ流量計は商
用電源でのみ駆動されていた。ところが最近一般産業プ
ロセスにおいては操業の安定性。As explained above, conventional low frequency excitation type TA flowmeters have been driven only by commercial power. However, recently in general industrial processes, stability of operation has become an issue.
信頼性を向上させるために電気を使用するプロセス用計
器の無停電化が要請されつつオシ、バッテリバックアッ
プを行なった直流無停電電源によって駆動可能な計器の
出現が要望され、またプロセスの多様化に伴なって交流
または直流のいずれの電源によっても駆動可能なプロセ
ス用計器を望む声も強い。本発明は、これらの要望にも
とづき直流電源によって駆動できてかつ５０Ｈｚ ｔた
は６０Ｈｚの誘導雑音源がそれぞれ単種に存在するかあ
るいは両者が混在する環境下においても零点の安定した
低周波励磁式電磁流量計を構成することができ、さらに
また直流電源、商用電源のいずれによっても駆動できて
使用する現場の電源事情に応じた駆動電源の使用が可能
な低周波励磁式電磁流量計を構成できる変換器を得るこ
とを目的とするものでおる。While there is a demand for uninterruptible process instruments that use electricity to improve reliability, there is also a demand for instruments that can be driven by a DC uninterruptible power supply with battery backup, and with the diversification of processes. Accordingly, there is a strong desire for process instruments that can be driven by either AC or DC power sources. Based on these demands, the present invention has developed a low-frequency excitation type that can be driven by a DC power supply and has a stable zero point even in an environment where a single type of 50Hz or 60Hz induced noise source exists, or a mixture of both. It is possible to configure an electromagnetic flowmeter, and furthermore, it can be configured as a low frequency excitation type electromagnetic flowmeter that can be driven by either a DC power source or a commercial power source, and can use a driving power source depending on the power supply situation at the site where it is used. The purpose is to obtain a converter.
次に本発明による変換器を図面にもとづいて説明する。Next, a converter according to the present invention will be explained based on the drawings.
第５図（ａ）は本発明の第１発明によって直流電源で駆
動できる低周波励磁式１！Ｌ磁流量計変換器の−・実施
例の構成を示すブロック図、第５図（ｂｌは第５図（ａ
ｌにおけるタイミング信号発生回路８ｏの一構成例を示
すブロック図、第６図（ａ）は本発明の第２発明によっ
て直流電源ｔたは商用電源のいずれによっても駆動でき
る低周波励磁式電磁流量計変換器の一実施例の構成を示
すブロック図、第６図０））は第６図（ａ） Ｋおける
タイミング信号発生回路９ｏの一構成例を示すブロック
図であって第５図（ａ）、第６図（ａｔにおいてはそれ
ぞれ以下の説明の便宜上検出器１０が接続されて示され
ている。第７図は第５図。FIG. 5(a) shows a low frequency excitation type 1! which can be driven by a DC power supply according to the first invention of the present invention! A block diagram showing the configuration of an embodiment of the L magnetic flow meter converter, Fig. 5 (bl is Fig. 5 (a)
FIG. 6(a) is a block diagram showing an example of the configuration of a timing signal generating circuit 8o in a low frequency excitation type electromagnetic flowmeter which can be driven by either a DC power supply or a commercial power supply according to the second invention of the present invention. FIG. 6(a) is a block diagram showing the configuration of an embodiment of the converter; FIG. , FIG. 6 (at), the detector 10 is shown connected for convenience of explanation below. FIG. 7 is the same as FIG. 5.
第６図の各図における要部の信号および電圧の波形を含
めたタイムチャートである。第５図ないし第７図の各図
においては第１図ないし第４図の各図に示された各部分
と同一の機能まだは意味を有する部分には同一の符号が
付されている。7 is a time chart including signal and voltage waveforms of important parts in each diagram of FIG. 6. FIG. In each of FIGS. 5 to 7, parts having the same function or meaning as each part shown in each of FIGS. 1 to 4 are given the same reference numerals.
第５図（ａ） ｊｂｌおよび第７図の各図においてＸは
変換器７を駆動するための外部直流電源、７８は外部直
流電源Ｘを変換器７内において必要とする条件の直流電
源に変換する電源Ｘを受電する手段としてのＤＣ／ＤＣ
コンバータ、８ｏはタイミング信号Ｐ２゜Ｐ８． Ｐ４
を出力するタイミング信号発生回路である。In each figure of FIG. 5(a) jbl and FIG. 7, X is an external DC power source for driving the converter 7, and 78 is an external DC power source that converts the external DC power source X into a DC power source with the required conditions within the converter 7. DC/DC as a means of receiving power source X
Converter 8o receives timing signal P2°P8. P4
This is a timing signal generation circuit that outputs .
タイミング信号発生回路８０は、第５図（ｂ）に示すよ
うに、時間幅Ｔｗが周波数の異なる接舷の商用電源たと
えば５０Ｈｚ電源および６０Ｈｚ電源の各周期の公倍数
の時間Ｔｄに等しく周期ｌ１ｌｐが２Ｔｄに等しい基本
クロック信号としての矩形波信号Ｐ１を出力する固定周
波数発信器８１と、信号Ｐ１を１／２分周して励磁回路
７８を動作させるためのタイミング信号Ｐ２を出力する
分周器８２と、信号Ｐ１およびＰ２について論理演算前
・Ｐ２および賃・丙を行ってそれぞれ同期整流回路７５
を動作させるためのタイミング信号Ｐ８およびＰ４とし
て該信号Ｐ８およびＰ４（ｉｌ−出力する二相分割器８
８とから構成されている。Ｉ：１）、（０）は二値信号
のそれぞれ一方である。したがって今、信号Ｐ２によっ
て励磁回路７３が正方向の励磁電圧Ｂｘを出力したとす
ると励磁コイル４の時定数等のため信号Ｓは負側から正
側に移行し若干時間経過した後正側の定常値に達する。As shown in FIG. 5(b), the timing signal generation circuit 80 has a time width Tw equal to a time Td which is a common multiple of each cycle of a commercial power source with different frequencies, for example, a 50 Hz power source and a 60 Hz power source, and a period l1lp of 2 Td. a fixed frequency oscillator 81 that outputs a rectangular wave signal P1 as a basic clock signal equal to , the signals P1 and P2 are subjected to logical operations P2 and P2, respectively, and the synchronous rectification circuits 75
The two-phase divider 8 outputs the signals P8 and P4 (il- as the timing signals P8 and P4 for operating the
It consists of 8. I:1) and (0) are each one of the binary signals. Therefore, if the excitation circuit 73 outputs the excitation voltage Bx in the positive direction due to the signal P2, the signal S shifts from the negative side to the positive side due to the time constant of the excitation coil 4, and after some time elapses, it becomes steady on the positive side. reach the value.
ついで信号Ｐ２によって励磁回路７８が負方向の励磁電
圧Ｅｘを出力すると同様にして信号Ｓは負側の定常値に
達する。信号Ｓの正側および負側の部分はそれぞれ信号
Ｐ８およびＰ４によって同期整流回路７５において該信
号Ｐ８およびＰ４の〔１〕状態の期間だけサンプリング
されて整流される。すなわちこの場合信号Ｓに対するサ
ンプリング期間’Ｉ’ｓ Ｆ′ｉ’、Ｌ”ｓ ＝ Ｔｐ
−Ｔｗ ＝ Ｔｄである。またこの場合励磁電圧Ｂ２
の方向が逆転してから信号Ｓのサンプリングの始まるま
での時間はＴｗすなわちＴｄであってこのＴｗの時間内
に信号Ｓがほぼ定状状態になるように時間Ｔｄが設定さ
れている。このため信号Ｓは励磁電圧Ｂｒの方向が逆転
してから後はぼ定常値になった状態で５０Ｈｚ電源およ
び６０Ｈｚ電源の各周期の公倍数の時間Ｔｄの期間だけ
サンプリングされ同期整流回路７５から信号Ｓ１および
Ｓ２として相方されることになる。Then, when the excitation circuit 78 outputs the excitation voltage Ex in the negative direction in response to the signal P2, the signal S reaches a steady value on the negative side in the same manner. The positive side and negative side parts of the signal S are sampled and rectified by the signals P8 and P4, respectively, in the synchronous rectifier circuit 75 only during the [1] state period of the signals P8 and P4. That is, in this case, the sampling period 'I's F'i' for the signal S, L"s = Tp
−Tw=Td. In this case, the excitation voltage B2
The time from when the direction of is reversed until the sampling of the signal S starts is Tw, that is, Td, and the time Td is set so that the signal S becomes almost in a steady state within this time Tw. Therefore, after the direction of the excitation voltage Br is reversed, the signal S is sampled for a period of time Td, which is a common multiple of each period of the 50 Hz power supply and the 60 Hz power supply, in a state where the value is almost a steady value, and the signal S1 is output from the synchronous rectifier circuit 75. and S2.
本実施例の変換器は以上に説明したように構成されてい
るので検出器１０と組合わせて電磁流量計を構成した場
合、周囲に５０Ｈｚまたは６０Ｈｚの商用電源が誘導雑
音源として単独で存在するがまたは両者が混在する環境
下においても励磁磁界の周波数が該雑音源の周波数よシ
も低くまた信号Ｓがほぼ定常値に達した状態でかつ該信
号Ｓが逆方向に変化する直前のＴｄの期間だけ該信号Ｓ
がサンプリングされるので零点変動の少ない安定した出
力信号Ｐが得られる。通常商用電源の周波数は５０Ｈｚ
または６０Ｈｚを中心として正側または負側にＨ１ｚ以
下の範囲内で変動する。このような誘４雑音源の存在す
る環境下においてはＡｌ１記の周波数変動が原因で本実
施例の変換器の出力信号Ｐには若干の零点変動が発生す
る。しかしながら本発明者の実験によればこの零点変動
の大きさは高々フルスケールの０．２％に過ぎない。し
たがって本実施例の変換器の零点変動は実用上問題にな
らない。Since the converter of this embodiment is configured as described above, when an electromagnetic flowmeter is configured in combination with the detector 10, a commercial power source of 50 Hz or 60 Hz exists in the surrounding area as a sole source of inductive noise. Even in an environment where both are mixed, the frequency of the excitation magnetic field is lower than the frequency of the noise source, and when the signal S has almost reached a steady value and just before the signal S changes in the opposite direction, The corresponding signal S only for a period
is sampled, so a stable output signal P with little zero point fluctuation can be obtained. Normal commercial power frequency is 50Hz
Alternatively, it fluctuates within a range of 1 Hz or less on the positive side or negative side around 60 Hz. In an environment where such a noise source exists, a slight zero point fluctuation occurs in the output signal P of the converter of this embodiment due to the frequency fluctuation indicated by Al1. However, according to the inventor's experiments, the magnitude of this zero point fluctuation is only 0.2% of the full scale. Therefore, the zero point fluctuation of the converter of this embodiment does not pose a practical problem.
次に第６図＜ｍ、（ｂ）および第７図の各図においてＭ
。Next, in each figure of Fig. 6 < m, (b) and Fig. 7, M
.
Ｌはそれぞれ変換器７に設けられた外部直流電源Ｘおよ
び外部商用電源Ｙを接続するための端子でおって端子り
、 ＡＣ／ＤＣコンバータ７１等は外部商用電源Ｙを受
電する手段を構成するものである。ＡＣ／ＤＣコンバー
タ７１またはＤＣ／ＤＣコンバータ７８のいずれの出力
もタイミング信号Ｐ２および励磁回路７３によって励磁
電圧ＢｘＫ変換されつるように構成されている。９０は
変換器７が外部商用電源Ｙで駆動される場合は該電源Ｙ
を用いて、また変悴器７が外部直流電源Ｘで駆動される
場合は第５図のタイミング信号発生回路８０と同様にし
てタイミング信号Ｐ２． Ｐ８． Ｐ４を出力するタイ
ミング信号発生回路である。このタイミング信号発生回
路９０は第６図（１））に示す如く構成されている。す
なわち、８１は第１の基本クロック信号としての矩形波
信号ＰＬを出力する固定周波数発信器であり、９１は入
力としての外部商用電源Ｙと出力としての正弦波信号と
を絶縁する絶縁トランス、９２は絶縁トランス９１の出
力信号を波形整形して矩形波信号として出力するゼロク
ロスコンパレータ、９８１４−ゼロクロスコンパレータ
の出力信号を分周して時間幅Ｔｗが外部商用電、源Ｙの
周期の整数倍の時間Ｔｃに等しく周期Ｔｐが２Ｔｃに等
しい外部商用電源Ｙに同期したパルス列信号としての矩
形波信号Ｐ５を出力する分周器であって、絶縁トランス
９１とゼロクロスコンパレータ９２と分周器９３とで外
部商用電源Ｙに同期した第２の基本クロック信号として
のパルス列信号を発生する手段が構成されている・９４
は矩形波（Ｆ４号ＰＩ−または１〕５を切換えて分周期
８２および二相分割器８３に出力するようにした信号切
換手段と（７ての信号切換器である。したがって切換器
９４によって信号Ｐ１が分周器８２および二相分割器８
３に入力されると、出力信号Ｐ８およびＰ４はそれぞれ
Ｉ’ｌ・Ｐ２および青・四の各論理演算結果に相当する
信号となり、また切換器９４によって信号Ｐ５が分周器
８２および二相分割器８３に入力されると、出力信号Ｐ
３およびＰ４はそれぞれＰ５−Ｐ２およびＰ５−Ｐ２の
各論理演算結果に相当する信号となる。L is a terminal for connecting an external DC power source X and an external commercial power source Y provided in the converter 7, respectively, and the AC/DC converter 71 and the like constitute means for receiving the external commercial power source Y. It is. The output of either the AC/DC converter 71 or the DC/DC converter 78 is configured to be converted into an excitation voltage BxK by the timing signal P2 and the excitation circuit 73. 90 is the power supply Y when the converter 7 is driven by the external commercial power supply Y.
If the converter 7 is driven by the external DC power supply X, the timing signal P2. P8. This is a timing signal generation circuit that outputs P4. This timing signal generation circuit 90 is constructed as shown in FIG. 6(1). That is, 81 is a fixed frequency oscillator that outputs a rectangular wave signal PL as a first basic clock signal, 91 is an isolation transformer that isolates an external commercial power supply Y as an input from a sine wave signal as an output, and 92 9814 is a zero-cross comparator that shapes the output signal of the isolation transformer 91 and outputs it as a rectangular wave signal, and the output signal of the zero-cross comparator 9814 is divided to have a time width Tw that is an integral multiple of the period of the external commercial power source Y. This is a frequency divider that outputs a rectangular wave signal P5 as a pulse train signal synchronized with an external commercial power supply Y whose period Tp is equal to Tc and whose period Tp is equal to 2Tc. A means for generating a pulse train signal as a second basic clock signal synchronized with the power supply Y is configured.94
is a signal switching means (7) which switches the rectangular wave (No. P1 is frequency divider 82 and two-phase divider 8
3, the output signals P8 and P4 become signals corresponding to the logical operation results of I'l/P2 and blue/4, respectively, and the signal P5 is input to the frequency divider 82 and the two-phase divider by the switch 94. When input to the device 83, the output signal P
3 and P4 are signals corresponding to the logical operation results of P5-P2 and P5-P2, respectively.
コノため、今、切換？に９４に信号Ｐ１マたはＰ５が入
力されて信号Ｐ２によって励磁回路７３が駆動されると
、第５図において説明したのと同様にして、信号Ｓが同
期整流回路７５において信号Ｐ８およびＰ４の〔１〕状
態の期間だけサンプリングされる。この場合のサンプリ
ンタ期間ＴｓはＴｃ１ｔたけＴｃであり、また励磁電圧
Ｅ、２−の方向が逆転してがら信号Ｓの→ノー／プリン
グの始まるまでの時間ＴｗもＴｄまたはＴｃであって、
この時間ＴｄまたはＴｃは励磁軍、圧Ｅよの方向が逆転
してから後この時間内に信号Ｓが定状状態になるように
設定されている。したかつで、切換器９４に４３号Ｐ１
が入力された協会は、信号Ｓはほぼ定常値になった状態
で５０Ｈｚ電曽および６０）（ｚ［、源の各周期の公倍
数の時間Ｔｄの期間だけサンプリングされ、切換器９４
に信号Ｐ５が入力された場合は、信号Ｓはほぼ定状値に
なった状態で外部商用電源Ｙの周期の整数倍の時間Ｔｃ
の期間だけサンプリングされて、同期整流回路７５から
信号Ｓ１およびＳ２とし７て出力されることになる。Switching now for Kono? When the signal P1 or P5 is input to the synchronous rectifier circuit 94 and the excitation circuit 73 is driven by the signal P2, the signal S is input to the synchronous rectifier circuit 75 and the excitation circuit 73 is driven by the signal P2. [1] Sampled only during the state. In this case, the sampler period Ts is Tc1t times Tc, and the time Tw until the signal S starts →no/pulling while the direction of the excitation voltages E and 2- is reversed is also Td or Tc,
This time Td or Tc is set so that the signal S reaches a steady state within this time after the directions of the excitation force and pressure E are reversed. After that, switch 94 was set to No. 43 P1.
is input, the signal S is sampled for a period of time Td, which is a common multiple of each period of the source, and the signal S is sampled for a period of time Td, which is a common multiple of each period of the source, and the signal
When signal P5 is input to , the signal S remains at a nearly constant value for a time Tc that is an integer multiple of the period of the external commercial power supply Y.
The signals are sampled for a period of , and are output from the synchronous rectifier circuit 75 as signals S1 and S2.
本実施例の変換器は以上に説明したように構成されてい
るので検出器１０と組合わせてｔ磁流置針を構成すると
、該流量計を外部直流電源Ｘで駆動する場合は該電源Ｘ
を端子Ｍに接続しかつ信号切換に９４によって信号Ｐ１
を分周器８２および二相分割器８８に導くことによυ、
また電磁流皿計を外部商用電源Ｙで駆動する場合は該電
源Ｙを端子りに接続しかつ信号切換器９４によって信号
Ｐ５を分周期８２および二相分割Ｂ１４８Ｂに導くこと
により、いずれの場合にも商用電源よりも低い周波数で
励磁磁界が形成され、信号Ｓがほぼ定常値に達した状態
でかつ信号Ｓが逆方向に変化する直前に、外部ｉｉｈ流
電源Ｘによる駆動の場合は時間Ｔｄの期間だけ、外部商
用電源Ｙによる駆動の場合は該電源Ｙの周１ｕｌｌの整
数倍の時間Ｔｃの期間だけ１９号Ｓがサンプリングされ
るので、零点変動の少ない安定した出力信号Ｐが得られ
ることになる。Since the converter of this embodiment is configured as described above, when it is combined with the detector 10 to configure a magnetic current positioner, when the flowmeter is driven by an external DC power source X, the power source X
is connected to the terminal M and the signal P1 is set by the signal switch 94.
By guiding υ to the frequency divider 82 and the two-phase divider 88,
In addition, when the electromagnetic flowmeter is driven by an external commercial power supply Y, the power supply Y is connected to the terminal and the signal P5 is guided to the frequency division 82 and the two-phase division B148B by the signal switch 94. When the excitation magnetic field is formed at a frequency lower than that of the commercial power supply, and the signal S has almost reached a steady value, and immediately before the signal S changes in the opposite direction, the excitation magnetic field is generated at a frequency lower than that of the commercial power supply. In the case of driving by an external commercial power supply Y, No. 19 S is sampled only for a period of time Tc which is an integral multiple of the cycle 1ull of the power supply Y, so a stable output signal P with little zero point fluctuation can be obtained. Become.
以上に説明したように本発明の第１発明ではファラデー
の電磁誘導期にもとづいて被側定流体の流量を測定する
低周波励磁式の電（品流置針において、該流量計の変換
器をまず外部電源としての外部直流電源を受電する手段
と固定周波数発振器とを備え、かつ該固定周波数発振器
の出力信号を基本クロック信号として用いて励Ｍ１電流
の出力と被測定流体に発生する起電力の正側用常値およ
び負側定常値のそれぞれを前記励＋ｉＨ電流による磁界
の変動に対応して周波数の異なる接舷の商用電源の各周
期の公倍数の期間だけ同期整流するサンプリングとを行
なうように構成したので、このような変換器は直流電源
によって駆動できしたがって〕くソテリバックアンプを
行なった直流無停電電みにｉル続し−Ｃ市、磁流昂、泪
の無停電化が可能でおシ、また誘４雑盲亦として周波数
の異なる複数の商用型砂、がイれぞれ単独に存在するか
または混在する環境下においても零点安定性の良好な流
１３信号を出力する電磁流量計を得ることができる。こ
のためζ、のような変換器は信頼性の高い低周波ｎノ磁
式電Ｉ滋渾、幇泪を構成できる効果がある。As explained above, in the first aspect of the present invention, the converter of the flow meter is first connected to the low frequency excitation type electric current (current flow indicator) that measures the flow rate of the constant fluid on the side based on Faraday's electromagnetic induction period. It includes means for receiving an external DC power source as an external power source and a fixed frequency oscillator, and uses the output signal of the fixed frequency oscillator as a basic clock signal to output the excitation M1 current and correct the electromotive force generated in the fluid to be measured. Sampling is configured to perform synchronous rectification of each of the side normal value and negative side steady value for a period that is a common multiple of each cycle of the commercial power supply on the side having different frequencies in response to fluctuations in the magnetic field due to the excitation + iH current. Therefore, such a converter can be driven by a DC power supply, and therefore, it is possible to create an uninterruptible DC power supply using a back-up amplifier. In addition, we have developed an electromagnetic flowmeter that outputs a flow signal with good zero point stability even in an environment where multiple commercial mold sands with different frequencies exist or are mixed together. Therefore, a converter such as ζ has the effect of constructing a highly reliable low-frequency n-magnetic electromagnetic converter.
さらに本発明の第２発明では低周波励磁式室Ｓ流量計の
変換器を、外部直流電源で駆動できるようにした前記第
１の発明の構成に加えて外部商用電源を受電する手段と
、診外部商用電源に同期した第２の基本クロック信号ど
してのパルス列信号を発生する手段と、該パルス列信号
および固定周波数発信器の出力信号の両信号を切換えて
励磁電源、の出力と起電力のサンプリングとを行なうよ
うにした信号切換手段とを備え、かつ変換器が外部直流
電源によって駆動されるときは信号切換手段によって第
１の基一本タロツク信号としての固定周波数発振１ｉの
出力を用いて励磁電流の出力と周波数の異なる複数の商
用電源の各周期の公倍数の期間だけのサンプリングとを
行ない、変換器が外部商用箱：源によって駆動されると
きは信号切換手段によって第２の基本クロンク信号とし
てのパルス列信号を用いて励確甫流、の出力と外部商用
電源の周期の整数倍の期間だけのサンプリングとを行な
うように構成したので、このような変換器は＊ ６１Ｆ
。Furthermore, in a second aspect of the present invention, in addition to the configuration of the first aspect, in which the converter of the low frequency excitation indoor S flowmeter can be driven by an external DC power source, a means for receiving an external commercial power source is provided; A means for generating a pulse train signal such as a second basic clock signal synchronized with an external commercial power supply, and an excitation power supply that switches both the pulse train signal and the output signal of the fixed frequency oscillator to control the output of the electromotive force. and a signal switching means adapted to perform sampling, and when the converter is driven by an external DC power supply, the signal switching means uses the output of the fixed frequency oscillation 1i as the first basic tally signal. When the converter is driven by an external commercial box source, the output of the excitation current is sampled for a period that is a common multiple of each period of a plurality of commercial power supplies having different frequencies, and when the converter is driven by an external commercial box source, the second basic clock signal is switched by the signal switching means. This type of converter is configured to output the excited current using a pulse train signal of
.
電源でも商用電源でも駆動できてしたがって使用する現
場の電源事情に速応可能でかつ商用電源周波数の誘導雑
音源の存在する環境においても零点の安定した低周波励
磁式電磁流置針を構成できる効果がある。It can be driven by either a power source or a commercial power source, so it can quickly respond to the power supply situation at the site where it is used, and it has the advantage of being able to construct a low-frequency excitation type electromagnetic flow pointer with a stable zero point even in an environment where there is an induced noise source at the commercial power frequency. be.
第１図は電磁流量Ｂ１の動作原理を説明するだめの構成
図、第２図は従来の商用′亀源駆動低周波励磁弐屯ｔａ
流址計の一構成例を示すフロック図、第８図は第２図に
おける要部の信号または電圧の波形を含めたタイムチャ
ート、第４図は商用型Ｗ周期の誘導雑音が消去される理
由を示す模式図、第５図（ａｔは本発明の第１発明によ
る外部商用電源駆１１）用変換語の一実施例のブロック
図、第５図ｆｂｌは′ｖ４５図（ａ）におけるタイミン
グ４ｇ号発生回路の一構成例のブロック図、第６図（ａ
ｌは本発明の第２発明Ｖｒよる外部ｉｎ流市、源および
外部商用箱、源の両電源駆１１ｉＩｌ用変換器の一実施
例のブロック図、第６図（１））は第６図（ａ）におけ
るタイミング信号発生回路の−構成例のブロック図、第
７図は第５図、第６図における要部の信号および電圧の
波形を含めた夕・イムチャートである。
図において２・・・被測定流体、５・・・磁界、７・・
・変換器、１０・・・検出器、７１・・・外部商用電曽
受ｍ１′５手段としてのＡ、Ｃ／］）Ｃコンバータ、７
５・・・同期整流回路１，７８・・・外部向＃１ＶＣ源
受電手段としてのＤＣ／ＤＣコンバータ、８１・・・固
定周波数発振器、 ９１．９２．９８・・・それぞれパ
ルス列信号を発生する手段を構成する絶縁トラソヌ、セ
ロクロスコンパレータ＋ 分周Ｒｉ％、９４・・・信号
切換手段としての信号切換器、■・・・流速、Ｂ・・・
磁束密度、Ｅ・・・起電力、■・・・励磁電流、Ａ・・
・外部電源、Ｘ・・・外部電源としての外部直流電源、
Ｙ・・・外部電源としての外部商用電源、Ｐ・・・出力
流量信号、ｒ・・・商用電源の周期、′Ｉ″Ｓ・・・サ
ンプリング期間、Ｌ・・・外部商用電源受電手段として
の端子、ＰＩ・・・第１の基本クロック信号としての矩
形波信号、Ｐ５・・・第２の基本クロック信号としての
パルス列信号。
□を
才３ 図
（０）
月ｎ
（４）
寸、！−１７１Figure 1 is a configuration diagram for explaining the operating principle of the electromagnetic flow rate B1, and Figure 2 is a conventional commercial 'torque source drive low frequency excitation unit.
A block diagram showing an example of the configuration of a flowmeter, Fig. 8 is a time chart including the main signal or voltage waveforms in Fig. 2, and Fig. 4 shows the reason why commercial type W-cycle induction noise is eliminated. FIG. 5 (at is a block diagram of an embodiment of the conversion word for the external commercial power supply drive 11 according to the first invention of the present invention), FIG. 5 fbl is the timing 4g in FIG. A block diagram of an example of the configuration of a generating circuit, FIG.
1 is a block diagram of an embodiment of a converter for external inflow market, source and external commercial box, source dual power supply drive 11iIl according to the second invention Vr of the present invention, FIG. FIG. 7 is a block diagram of a configuration example of the timing signal generation circuit in a), and is an evening/time chart including signal and voltage waveforms of the main parts in FIGS. 5 and 6. In the figure, 2...Fluid to be measured, 5...Magnetic field, 7...
・Converter, 10...Detector, 71...A, C/])C converter, 7 as an external commercial power receiver m1'5 means
5...Synchronous rectifier circuit 1, 78...DC/DC converter as external #1 VC power receiving means, 81...Fixed frequency oscillator, 91.92.98...Means for generating pulse train signals, respectively Insulation trasonne, cello cross comparator + frequency division Ri%, 94...signal switching device as signal switching means, ■...flow velocity, B...
Magnetic flux density, E...electromotive force, ■...exciting current, A...
・External power supply, X...External DC power supply as external power supply,
Y...External commercial power supply as external power supply, P...Output flow rate signal, r...Period of commercial power supply, 'I''S...Sampling period, L...External commercial power supply as receiving means Terminal, PI... rectangular wave signal as the first basic clock signal, P5... pulse train signal as the second basic clock signal. 171
Claims (1)
台形状を含む矩形状に近い波形の時間的に変動する磁界
を加えてファラデーの電磁誘導剤にもとづいて前記流体
に発生する起電力を検出して前記流体の流量を測定する
低周波励磁式を磁流敞計の、外部電源を受電し、前記磁
界を形成するための励磁電流を出力し、前記起電力をサ
ンプリングし、該サンプリング結果と前記磁界の磁束密
度とのそれぞれに相当する信号を用いて前記流量に相当
する信号を出力する変換器において、前記外部ｔｆＯと
しての外部直流電源を受電する手段と基本クロック信号
を出力する固定周波数発振器とを備え、前記基本クロッ
ク信号を用いて、前記励磁電流の出力と前記起電力の正
側定常値および負側定常値のそれぞれに相当する信号に
対する周波数の異なる複数の商用電源の各周期の公倍数
の期間だけの前記サンプリングとを行なうことを特徴と
する低周波励磁式！、磁流敞計の変換器。 ２）被測定流体に、商用電源周波数よυも低い周波数で
台形状を含む矩形状に近い波形の時間的・に変動する磁
界を加えてファラデーの１！磁誘導則にもとづいて前記
流体に発生する起電力を検出して前記流体の流量を測定
する低周波励磁式電磁流量計の、外部電源を受電し、前
記磁界を形成するための励磁電流を出力し、前記起電力
をサンプリングし、該サンプリング結果と前記磁界の磁
束密度とのそれぞれに相当する信号を用いて前記流量に
相当する信号を出力する変換器において、外部電源とし
ての外部面流電源ならびに外部商用１に源を各個に受電
する手段と、第１の基本クロック信号を出力する固定周
波数発信器と、第２の基本クロック信号としての前記外
部商用電源に同期したパルス列信号を発生する手段と、
前記第１の基本クロック信号と前記第２の基本クロック
信号とを切換える信号切換手段とを備え、＠記外部直流
電のを受電するときは前記信号切換手段により前記第１
の基本クロック信号を用いて前記励磁電流の出力とＡｌ
ｌ記起１に力の正側定常値および負側定常値のそれぞれ
に相当する信号に対する周波数の異なる？Ｊｌ数の商用
電源の各周期の公倍数の期間だけの前記サンプリングと
を行ない、前記外部商用電源を受電するときは酌配信号
切換手段によシ前記第２の基本クロック信号を用いて前
記励磁電流の出力と前記起電力の正側定常値および負側
定常値のそれぞれに相当する信号に対する前記外部商用
電源の周期の整数倍の期間だけの前記サンプリングとを
行なうことを特徴とする低周波励磁式電磁流置引の変換
器。[Scope of Claims] 1) A time-varying magnetic field with a waveform close to a rectangular shape including a trapezoid is applied to the fluid to be measured at a frequency lower than the commercial power frequency, and the fluid is controlled based on Faraday's electromagnetic induction agent. The magnetic current meter is a low-frequency excitation type that detects the electromotive force generated in the flow rate and measures the flow rate of the fluid. A converter that samples and outputs a signal corresponding to the flow rate using signals corresponding to the sampling result and the magnetic flux density of the magnetic field, a means for receiving an external DC power supply as the external tfO, and a basic clock. a fixed frequency oscillator that outputs a signal, using the basic clock signal to generate a plurality of signals with different frequencies corresponding to the output of the excitation current and the positive steady value and negative steady value of the electromotive force, respectively. A low-frequency excitation type characterized by performing the above-mentioned sampling only during a period that is a common multiple of each cycle of the commercial power supply! , magnetic current meter transducer. 2) Apply a temporally varying magnetic field to the fluid to be measured at a frequency υ lower than the commercial power supply frequency and a waveform close to a rectangular shape including a trapezoid shape to obtain Faraday's 1! A low frequency excitation type electromagnetic flowmeter that measures the flow rate of the fluid by detecting an electromotive force generated in the fluid based on the law of magnetic induction receives an external power source and outputs an excitation current for forming the magnetic field. and a converter that samples the electromotive force and outputs a signal corresponding to the flow rate using signals corresponding to the sampling result and the magnetic flux density of the magnetic field, an external surface current power source as an external power source; means for individually receiving power from an external commercial power source 1; a fixed frequency oscillator for outputting a first basic clock signal; and means for generating a pulse train signal synchronized with the external commercial power source as a second basic clock signal. ,
signal switching means for switching between the first basic clock signal and the second basic clock signal; when receiving external DC power, the signal switching means switches between the first and second basic clock signals;
The output of the excitation current and the basic clock signal of Al
1. Are the frequencies different for the signals corresponding to the positive and negative steady values of force? The above-mentioned sampling is performed only for a period that is a common multiple of each cycle of the Jl commercial power supply, and when receiving the external commercial power supply, the excitation current is changed using the second basic clock signal by the consideration signal switching means. and the sampling for a period that is an integral multiple of the period of the external commercial power source for signals corresponding to the positive steady value and negative steady value of the electromotive force, respectively. Electromagnetic flow transducer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19372082A JPS5983016A (en) | 1982-11-04 | 1982-11-04 | Converter for low frequency exciting type electromagnetic flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19372082A JPS5983016A (en) | 1982-11-04 | 1982-11-04 | Converter for low frequency exciting type electromagnetic flowmeter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5983016A true JPS5983016A (en) | 1984-05-14 |
| JPH0216975B2 JPH0216975B2 (en) | 1990-04-19 |
Family
ID=16312667
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19372082A Granted JPS5983016A (en) | 1982-11-04 | 1982-11-04 | Converter for low frequency exciting type electromagnetic flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5983016A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007132803A (en) * | 2005-11-10 | 2007-05-31 | Yamatake Corp | Electromagnetic flowmeter |
| JP2020186935A (en) * | 2019-05-10 | 2020-11-19 | アズビル株式会社 | Electromagnetic flow meter |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0517468U (en) * | 1991-08-02 | 1993-03-05 | サンデン株式会社 | Cool storage device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5489658A (en) * | 1977-10-05 | 1979-07-16 | Flowtec Ag | Method and device for measuring flow rate by induction |
| JPS5615383A (en) * | 1979-07-16 | 1981-02-14 | Ricoh Co Ltd | Carriage supporting device in printer |
-
1982
- 1982-11-04 JP JP19372082A patent/JPS5983016A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5489658A (en) * | 1977-10-05 | 1979-07-16 | Flowtec Ag | Method and device for measuring flow rate by induction |
| JPS5615383A (en) * | 1979-07-16 | 1981-02-14 | Ricoh Co Ltd | Carriage supporting device in printer |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007132803A (en) * | 2005-11-10 | 2007-05-31 | Yamatake Corp | Electromagnetic flowmeter |
| JP2020186935A (en) * | 2019-05-10 | 2020-11-19 | アズビル株式会社 | Electromagnetic flow meter |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0216975B2 (en) | 1990-04-19 |
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