Neugeboren O'Dowd PC
Mass flow meter with self-diagnostic function and mass flow controller using the same
In a mass flow meter comprising two flow sensor units with identical specifications, flow rate deviations between these two flow sensor units are initially measured at various mass flow rates under a circumstance having the same fluctuating factors as those when a mass flow is actually measured. Subsequently, based on these flow rate deviations, a correction value for matching the values of the mass flow rates measured by these two flow sensor units is calculated and stored in a data storage device. Thereafter, when measuring a mass flow rate, a flow rate deviation, from which the influence by the individual difference in the response to a fluctuating factor between these two flow sensor units has been removed, is calculated by correcting a measured value based on the correction value. The existence or non-existence of an occurrence of a malfunction is judged based on whether the flow rate deviation exceeds a predetermined threshold value t or not.
Hitachi Metals, Ltd.
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Hiroyuki
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