Experimental study and implementation of a novel digital closed-loop control system for coriolis mass flowmeter

Closed-loop control system undertakes the foundational task of maintaining the permanent vibration of the measuring tube for Coriolis Mass Flowmeter (CMF). In order to overcome the disadvantages of bad anti-jamming, slow response speed and high zero drift existing in conventional analog closed-loop system, a novel digital closed-loop control system is proposed in which the Multiplying Digital to Analog Converter is introduced to track the vibration signal of CMF in real time, together with the non-linear amplitude control method to vary the amplitude gain of the excitation signal, so that the measuring tube can be adjusted to vibrate with stable amplitude promptly. The real flow calibration experimental result shows that the maximum steady state relative error and repeatability are 0.147% and 0.039%, respectively. In addition, the start-up time of measuring tube can reach to 2.75 s.