| 摘要 |
PROBLEM TO BE SOLVED: To provide a Coriolis mass flowmeter capable of performing deterioration diagnosis of a measuring conduit based on a signal in an online state, without adding a special measuring device for deterioration diagnosis. SOLUTION: In this Coriolis mass flowmeter having an excitation circuit part, for operating a mass flow rate of a fluid flowing in the measuring conduit based on a first signal of an upstream side sensor and a second signal of a downstream side sensor which are arranged at a prescribed distance in the measuring conduit vibrated by an excitor, inputting the first signal or the second signal, and controlling a drive signal of the excitor so that its amplitude agrees with a target value, the Coriolis mass flowmeter includes; a first effective value acquisition part and a second effective value acquisition part for acquiring an effective value of the first signal and an effective value of the second signal; a ratio operation part for inputting the acquired effective value of the first signal and effective value of the second signal, and operating the ratio between both values; and an abnormality diagnosis part for comparing the operated ratio with a prescribed threshold, and generating an alarm. COPYRIGHT: (C)2011,JPO&INPIT
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