Approvals - Siemens SITRANS FC430 Operating Instructions Manual

Description
3.5 Theory of operation
● Oil & Gas: filling of gas bottles, furnace control, test separators, bore-hole plasticizer dosing,
water-cut metering
● Water & Waste Water: dosing of chemicals for water treatment
3.4

Approvals

Note
For further details see Bus communication (Page 239).
The device is available with approvals for general purpose and for hazardous areas. In all
cases, check the nameplate on your device, and confirm the approval rating.
3.5 Theory of operation
The Coriolis principle of measurement
The flow measurement is based on the Coriolis law of motion. Particles moving in a rotating /
oscillating system will resist imposed oscillations in a manner consistent with their mass and
velocity (momentum). Oscillation produced by a Coriolis flowmeter where the process media
is accelerated around bends results in phase distortions of the measuring tubes.
The SITRANS F C sensors are energized by an electromagnetic (voice coil) driver circuit which
oscillates the pipes at their resonant frequency. Two pickups are placed symmetrically on either
side of the driver to provide position signals for digital processing.
When the media flows through the sensor, Coriolis force will act on the measuring tubes and
cause deflection which can be measured as a phase shift between Pickup 1 and Pickup 2.
The phase shift is proportional to the mass flowrate.
The frequency (or period) of the vibration is a direct function of the process media density.
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FC430 (From firmware 4.0)
Operating Instructions, 06/2017, A5E39789392-AA