JUMO 406060, Руководство по эксплуатации

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2 Design and function
10
2.2 Model variants
Integral mount design
The transmitter and the flow sensor form a mechanical unit in
devices featuring a compact (integral mount) design.
Remote mount design
The transmitter and the flow sensor are mounted physically
separated from one another in devices featuring a separate
(remote mount) design.
The electrical connection between the transmitter and the sensor
is provided by a signal cable.
With a minimum conductivity of 20 µS/cm of the medium being
measured, a maximum signal cable length of 50 m (164 ft) is
possible.
Information regarding JUMO flowTRANS MAG S10
JUMO flowTRANS MAG S10 flow sensors are available in two
different versions, variant 1 and variant 2. See
Design and
function on page 7.
2.3 Measuring principle
Measurements performed by the electromagnetic flowmeter are
based on Faraday’s law of induction. A voltage is generated in a
conductor when it moves through a magnetic field.
1
Magnet coil
2
Measuring tube in electrode plane
3
Measuring electrode
Figure 3: Electromagnetic flowmeter diagram
v D B U
 
~
1
v
D
qv



4
2

qv U ~
1
U
1
Measuring span
B Magnetic induction
D Electrode spacing
v Average flow velocity
qv Volume flow rate
With the device-relevant application of this measuring principle, a
conductive measuring medium flows through a tube in which a
magnetic field is generated perpendicular to the flow direction
(see Figure 3).
The voltage induced in the measuring medium is tapped by two
diametrically opposed electrodes. This measurement voltage is
proportional to the magnetic induction, the electrode spacing and
the average medium velocity v.
Taking into account that the magnetic induction and the electrode
spacing are constant values results in a proportion between the
measurement voltage U
1
and the average medium velocity.
From the calculation of the volume flow rate follows that the
measurement voltage is linear and proportional to the volume
flow rate
The induced voltage is converted by the transmitter to
standardized, analog and digital signals.