Principle Of Operation - Siemens SITRANS LG270 Operating Instructions Manual

Application area
Functional principle -
level measurement
Functional principle - in-
terface measurement
PBD-51041071
Information:
In this operating instructions manual, the optional instrument features
are described. The respective scope of delivery results from the order
specification.
3.2

Principle of operation

The SITRANS LG270 is a level sensor with coax probe for continuous
level or interface measurement, suitable for applications in liquids
with high temperatures up to 450 °C (842 °F).
High frequency microwave pulses are guided along a steel cable or
a rod. Upon reaching the product surface, the microwave pulses are
reflected. The running time is evaluated by the instrument and output-
ted as level.
h
Fig. 2: Level measurement
1 Sensor reference plane (seal surface of the process fitting)
d Distance to the level
h Height - Level
High frequency microwave impulses are guided along a steel cable or
rod. Upon reaching the product surface, a part of the microwave im-
pulses is reflected. The other part passes through the upper product
and is reflected by the interface. The running times to the two product
layers are processed by the instrument.
SITRANS LG270 - Operating Instructions
1
d
9