| 摘要 |
PURPOSE:To raise an elimination rate of a commercial power source noise, and to measure a flow rate with high accuracy by controlling magnetic sampling and exciting of an exciting coil, by an oscillating circuit whose output frequency is shifted by a prescribed range from a commercial power source frequency. CONSTITUTION:An oscillating circuit 30 formed by a free-running crystal oscillating circuit 31 for outputting a frequency signal shifted by a range of 0.5-10% from frequency of a commercial power source, a frequency dividing circuit 32, etc. is connected to a controlling circuit of an electromagnetic flowmeter. In this way, magnetic flux sampling of an exciting coil is executed stably by an output of the circuit 30, and also exciting of the exciting coil is also executed stably by a prescribed frequency dividing output of the output of the circuit 30. Accordingly, an elimination rate of a commercial power source noise is raised, and a flow rate is measured with high accuracy.
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