SICK LFV 330, Руководство по эксплуатации

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3
.
2
P rinciple of operation
LFV
330
is a point level sensor with tuning fork for level detection
.
I t is designed for industrial use in all areas of process technology and
can be used in liquids
.
T ypical applications are over
fi
ll and dry run protection
.
T he small
tuning fork allows use in all kinds of tanks and vessels
.
T hanks to its
simple and rugged measuring system
,
LFV 330 is virtually una
ff
ected
by the chemical and physical properties of the liquid
.
I t functions even under di
ffi
cult conditions such as turbulence
,
air
bubbles
,
foam generation
,
buildup
,
strong external vibration or
changing products
.
F ault monitoring
T he electronics module of LFV 330 continuously monitors via
frequency evaluation the following criteria
:
l
S trong corrosion or damage on the tuning fork
l
loss of vibration
l
L ine break to the piezo drive
I f a malfunction is detected or in case of power failure
,
the electronics
takes on a de
fi
ned switching condition
,
i
.
e
.
the contactless electronic
switch opens
(
safe condition
).
T he tuning fork is piezoelectrically energised and vibrates at its
mechanical resonance frequency of approx
.
1200
H z
.
T he piezos are
fi
xed mechanically and are hence not subject to temperature shock
limitations
.
T he frequency changes when the tuning fork is covered by
the medium
.
T his change is detected by the integrated electronics
module and converted into a switching command
.
LFV 330 is a compact instrument
,
i
.
e
.
it can be operated without
external evaluation system
.
T he integrated electronics evaluates the
level signal and outputs a switching signal
.
W ith this switching signal
,
a
connected device can be operated directly
(
e
.
g
.
a warning system
,
a
PLC
,
a pump etc
.).
T he data for power supply are speci
fi
ed in chapter
" T echnical data " .
3
.
3
O peration
T he switching condition of LFV
330
with plastic housing can be
checked when the housing is closed
(
signal lamp
).
I n the basic
adjustment
,
products with a density
>
0
.
7
g
/
cm
³
(
0
.
025
lbs
/
in
³
)
can be
detected
.
T he instrument can be adapted if products with lower density
should be measured
.
O n the electronics module you will
fi
nd the following indicating and
adjustment elements
:
l
S ignal lamp for indication of the switching condition
(
green
/
red
)
l
DIL switch for sensitivity adjustment
A pplication area
F
unctional principle
P ower supply
8
LFV
330
• -
contactless electronic switch
3
P roduct description
35914
-
EN
-
091126