| 摘要 |
A measuring and operating circuit for a coriolis mass flowmeter comprising a transducer assembly (1) with at least one flow tube (4) on which a first and a second vibration sensor (17, 18), spaced a given distance apart in the direction of fluid flow, and a vibration sensor (16) are mounted, the measuring and operating circuit comprising: a first amplifier (V1) for the output signal of the first vibration sensor (17); a second amplifier (V2) for the output signal of the second vibration sensor (18); a first A/D converter (AW1) for generating a vibration signal (Sl) proportional to the output signal of the first vibration sensor (17); a second A/D converter (AW2), preceded by a difference stage (D1), for generating a difference signal (D) proportional to the difference of the amplified output signals of the first and second vibration sensors (17, a digital processor (DSP) which, of the vibration Sensor signals, evaluates only the difference signal (D) and the one sensor signal (S1), and which performs the following steps: a) Determining the amplitude (AMS1) of the sensor signal (S1); b) determining the in-phase component (I) and the quadrature components (Q) of the difference signal (D) with respect to the sensor signal (S1) as a reference signal; c) controlling the gain of the second amplifier in such a way that the in-phase component (I1 of the difference signal (D) disappears; d) calculating the mass flow rate m via. the remaining quadrature component Q according to the formula m ~Q/(AMS1*f).
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