Siemens SITRANS LVL200E - Principle of Operation; Instrument Adjustment Settings

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MAN-100411
SITRANS LVL200E - Operating Instructions
55328-EN-170712
3.2 Principle of operation
SITRANS LVL200E is a point level sensor with tuning fork for point
level detection.
It is designed for industrial use in all areas of process technology and
can be used in liquids.
Typicalapplicationsareoverllanddryrunprotection.Thesmall
tuning fork allows use in all kinds of tanks and vessels. Thanks to its
simple and rugged measuring system, SITRANS LVL200E is virtually
unaectedbythechemicalandphysicalpropertiesoftheliquid.
Itfunctionsevenunderdicultconditionssuchasturbulence,airbub-
bles, foam generation, buildup, strong external vibration or changing
products.
Function monitoring
The electronics module of SITRANS LVL200E continuously monitors
the following criteria via frequency evaluation:
•
Strong corrosion or damage on the tuning fork
•
Loss of vibration
•
Linebreaktothepiezodrive
If one of these faults is detected, the electronics signals it via a
denedcurrenttothesignalconditioninginstrument.Theconnection
cable to the sensor is also monitored for line break and short-circuit.
Thetuningforkispiezoelectricallyenergisedandvibratesatits
mechanicalresonancefrequencyofapprox.1200Hz.Thepiezosare
xedmechanicallyandarehencenotsubjecttotemperatureshock
limitations. The frequency changes when the tuning fork is covered
by the medium. This change is detected by the integrated electronics
module, transferred as a current value to the processing system and
converted there into a switching command.
Depending on your requirements, SITRANS LVL200E with two-
wireelectronicscanbeconnectedtodierentsignalconditioning
instruments. Compatible signal conditioning instruments are listed in
chapter "Technical data".
Thedataforpowersupplyarespeciedinchapter"Technical data".
3.3 Adjustment
The switching condition of SITRANS LVL200E with plastic housing
can be checked when the housing is closed (signal lamp). With the
basicsetting,productswithadensity≥0.7g/cm³(0.025lbs/in³)can
be detected. The instrument can be adapted if products with lower
density are to be measured.
Ontheelectronicsmoduleyouwillndthefollowingdisplayand
adjustment elements:
•
Signal lamp for indication of the switching condition (green/red)
•
DIL switch for adaptation to the product density
Application area
Functional principle
Voltage supply