Application; Measurement Principle - Omega FMG600 Series User Manual

1. APPLICATION

Flow meters FMG600 SERIES are primarily used for measuring instantaneous flow rate and volume of water
or similar liquids passed through the meter. Flow meters shall only be used in standard non-explosive
environments.
Any installation of flow meter must be in conformity with technical conditions mentioned in this manual.
Measurements can be done in both flow directions, with high measurement accuracy over a wide range of
flow rates 0.33 to 32.8 ft/s (0.1 to 10 m/s). The minimum required conductivity of the measured medium is 20
µS/cm.
The measurement evaluation electronic unit includes a two-line alphanumeric display to show the measured
values where various operational parameters of the meter can be selected by means of an associated
keyboard. Available are two passive binary outputs (frequency, pulse and limit values), one active current
output and an output to connect a digital communication line. All meter functions and output parameters can
be reset during the meter operation.
Should the need arise; the user may combine any sensor of the FMG600 series with any electronic units
without re-calibration of the meter on a test stand. The only thing that needs be done is to enter into the
electronic unit memory the calibration constants and excitation frequency of the selected sensor; these data
are given on the rating plate of the sensor. The value of threshold flow rate shall be set between 0.5 and 1%
of the specified maximum flow rate.

2. MEASUREMENT PRINCIPLE

The function of an induction flow meter is based on Faraday's induction law. The meter sensor consists
of a non-magnetic and non-conductive tube with two embedded measuring electrodes to pick up the induced
voltage. To create an alternating magnetic field, two coils are fitted onto the tube in parallel with the plane
defined by the active parts of the measuring electrodes. Now if a conductive liquid flows across magnetic
field B, voltage U will appear on the measuring electrodes proportional to the flow velocity v and the
conductor length l.
U = B x l x v
induced voltage
U
magnetic flux density
B
distance between the measuring electrodes
l
liquid flow velocity
v
Design, Assembly and Service Manual
Induction flow meter FMG600 series
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