| 摘要 |
PROBLEM TO BE SOLVED: To provide a mass flowmeter having a highly-reliable self-diagnostic function.SOLUTION: A mass flowmeter that comprises two flow sensor units having the same specifications preliminarily measures flow rate deviations of these two flow sensor units at various mass flow rates in an environment having variation factors identical to those at the time of actual measurement of mass flow rate. Then, the mass flowmeter calculates a correction value for matching mass flow rate values measured by these two flow sensor units, on the basis of these flow rate deviations, and stores it in a data storage device. After that, the mass flowmeter corrects the measured values on the basis of the correction value when measuring the mass flow rate, and then calculates a flow rate deviation after removing an influence of individual differences among responses of these two flow sensor units to the variation factors. The mass flowmeter determines the presence or absence of abnormality on the basis of whether or not this flow rate deviation exceeds a prescribed threshold t. |
