Measuring and Operational Circuit For a Coriolis-Mass Flow Meter Comprising Three Measuring Channels
AssigneeEndress + Hauser Flowtec AG
InventorsChristian Matt, Philipp Alber
Life of this patent
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Abstract
In a method for determining mass-flow with the aid of a Coriolis mass-flow meter in which mass-flow ({dot over (m)}) is won from the phase difference of two sensor signals X17, X18, three measuring channels K1, K2, K3 are provided for the two sensor signals X17, X18. By selective switching of the sensor signals X17, X18 onto the measuring channels K1, K2, K3, phase error caused by the different signal paths can be determined and taken into consideration when calculating mass-flow ({dot over (m)}).
Claims6
1-5. (canceled)
A method for determining mass-flow with a Coriolis mass-flow meter, wherein the mass-flow is won from a phase difference of a first sensor signal, and a second sensor signal, wherein there is provided, for the two sensor signals, three measuring channels, via which the signals are fed to a digital signal processor, and switches are provided, which enable switching of the sensor signals to the individual measuring channels K1, K2, K3, comprising the steps of:
- switching the first sensor signal to a measuring channel K1;
- switching the second sensor signal to the measuring channels K2, K3;
- ascertaining phase error of the measuring channels K2, K3 by measuring phase shift of output signals of these two measuring channels;
- storing the phase error;
- measuring the phase shift between the output signals of the measuring channel pair K1 and K2;
- ascertaining the mass-flow from the phase shift taking into consideration a phase error of the measuring channel pair K1, K2 won at an earlier point in time.
An apparatus for performing a method for determining mass-flow with a Coriolis mass-flow meter, comprising:
- a first sensor producing a first sensor signal;
- a second sensor producing a second sensor signal;
- three measuring channels, K1, K2 and K3;
- a digital signal processor for receiving the first sensor signal and the second sensor signal via said measuring channels;
- and
- three switches which enable switching of the sensor signals to said measuring channels, wherein:
- the first sensor signal is switched to said measuring channel K1 and the second sensor signal is switched to said measuring channels K2 and K3;
- a phase error of said measuring channels K2 and K3 is ascertained from measured phase shift of output signals from said measuring channels K2 and K3;
- a phase shift of the output signals of said measuring channels K1 and K2;
- and
- ascertaining mass-flow from said phase shift taking into consideration a phase error of said measuring channel pair K1 and K2.
Dependencies are inferred from the claim text.