JPS6070023U

JPS6070023U - Electromagnetic flowmeter with low frequency excitation method

Info

Publication number: JPS6070023U
Application number: JP16185983U
Authority: JP
Inventors: 茂後藤
Original assignee: 横河電機株式会社
Priority date: 1983-10-19
Filing date: 1983-10-19
Publication date: 1985-05-17
Also published as: JPH0450507Y2

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of the drawing]

第１図は本考案電磁流量計の一実施例を示す接続図、第
２図および第３図はその動作説明のための波形図、第４
図は動作説明のためのフローチャートである。１・・・電源回路、２・・・電磁流量計発信器、２１・
・・励磁コイル、３・・・励磁回路、３１・・・スイッ
チングレギュレータ、３２ａ、３２ｂ・・・スイッチ、
３３・・・電流検出抵抗、４・・・信号処理回路、４１
・・・入力増幅器、４２・・・検出増幅器、４３　ａ、
　　４３　ｂ・・・サンプリングスイッチ、４４・・・
ＡＤ変換器、４５・・・マイクロコンピュータ、４８・
・・パルス幅電圧変換回路。Fig. 1 is a connection diagram showing one embodiment of the electromagnetic flowmeter of the present invention, Figs. 2 and 3 are waveform diagrams for explaining its operation, and Fig. 4
The figure is a flowchart for explaining the operation. 1... Power supply circuit, 2... Electromagnetic flow meter transmitter, 21.
... Excitation coil, 3... Excitation circuit, 31... Switching regulator, 32a, 32b... Switch,
33... Current detection resistor, 4... Signal processing circuit, 41
... input amplifier, 42 ... detection amplifier, 43 a,
43 b...sampling switch, 44...
AD converter, 45... microcomputer, 48.
...Pulse width voltage conversion circuit.

Claims

[Scope of utility model registration request]

Using an excitation circuit that has a switching regulator and supplies an excitation current to the excitation coil repeatedly in the order of zero, positive, zero, and negative to a steady value, the signal processing circuit calculates the steady value during the excitation period when the excitation current is positive or negative. A low-frequency excitation method that uses sampling to control the set voltage value during the rest period and the set voltage value during the excitation period of the switching regulator, making the positive and negative steady-state values of the excitation current constant and flat. In an electromagnetic flowmeter, a means for determining whether a sampling value of a steady value during an excitation period is within a preset tolerance range, and determining and detecting that a short-circuit accident has occurred in the excitation coil when it exceeds the tolerance range. When a short-circuit accident is detected, the set voltage value for the switching regulator's rest period and the set voltage value for the excitation period are made equal, and the value of the set voltage is controlled so that the excitation current becomes the normal value. or the negative excitation period, the steady value of the excitation current is sampled twice, the two sampling values are compared, and when the two values are equal, the signal processing circuit is provided with a means for determining that a short-circuit accident is occurring. An electromagnetic flowmeter using a low frequency excitation method. ′