| 摘要 |
The present invention relates to flow devices that measure a characteristic of a flowing substance and methods for operating flow devices. In one embodiment, a drive (40) is provided that receives a first signal (55) for vibrating at least one conduit (20) at a resonance frequency and a second signal (56) for vibrating the at least one conduit (20) at a frequency that is different than the resonance frequency. In another embodiment, a drive (140) is provided that alternates between receiving a drive signal (155) to vibrate at least one conduit (120) at a resonance frequency and providing a pick-off signal (145) for measuring motion of the at least one conduit (120). In another embodiment, one or more electronics (50, 150) are provided that determine a mode of vibration of at least one conduit (20, 120) and compare the determined mode of vibration to one or more reference modes of vibration to determine whether a substance is flowing within the at least one conduit (20, 120). The principals of the present invention may be used to determine whether a substance is flowing within a conduit (20), the direction which a substance is flowing within a conduit (20), and the mass flow rate of a substance flowing within a conduit (20). Furthermore, the principals of the present invention may be used to determine whether a pick-off (30) and another pick-off (30) are functioning properly on a flow device.
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