发明名称 |
Electromagnetic flowmeter system having a feedback loop |
摘要 |
An electromagnetic flowmeter system in which the flow rate signal yielded by the flowmeter primary is applied as an input to a secondary which acts to measure the ratio of the input signal to a reference voltage proportional to the magnetic flux established in the primary, the reference voltage reflecting variations in this flux. Ratio measurement is effected in the secondary by means of a feedback loop in which the reference voltage is pulse-modulated by pulses having a constant width and a frequency which varies in accordance with the flow rate, the pulses having a duty cycle sufficient to cancel the input signal at the input of a summing amplifier. When the variable frequency pulse output from the secondary accurately represents the flow rate, the pulse-modulated reference voltage will then be equal in magnitude and opposite in phase to the input signal.
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申请公布号 |
US4417479(A) |
申请公布日期 |
1983.11.29 |
申请号 |
US19810298457 |
申请日期 |
1981.09.01 |
申请人 |
FISCHER & PORTER COMPANY |
发明人 |
SCHMOOCK, ROY F.;SHAUGER, HERBERT A. |
分类号 |
G01F1/60;(IPC1-7):G01F1/60 |
主分类号 |
G01F1/60 |
代理机构 |
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地址 |
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