The flow measuring principle is based on the Coriolis Effect. The SITRANS FC430 flowmeter consists of a sensor type FCS400 and a transmitter FCT030.

The FCS400 sensor’s measuring tubes are energized by an electro-mechanical driver circuit which oscillates them at their resonance frequency. Two pick-ups are placed symmetrically upstream and down- stream of the central driver. When a process fluid passes through the sensor, the Coriolis Effect will act on the vibrating tubes and cause deflection which can be measured as a phase shift between pick-ups 1 and 2. The phase shift is proportional to the mass flow rate.

The amplitude of the driver is automatically regulated to ensure a stable output from both of the pickups. The temperatures of the sensor tubes and frame are measured with high precision to provide compensation for changes with temperature in the measuring properties. The sensor signals are analyzed for flow, density and fluid tem- perature in the sensor front end. The digital signal is controlled to conform to high Safety Integrated Level (SIL) and sent digitally to the transmitter via standard cable. The transmitter further cal- culates total mass and volume, fraction, dosing control and many other functions.

 The front-end module has a process noise filter, which can be used to improve the meter’s performance when installation and application conditions are not ideal. Typical interferences from process conditions such as pump pulsations, mechanical vibra- tions, oscillating valves can be reduced considerably.