BERTHOLD TECHNOLOGIES LB4710-050, User Manual

Page: 36 / 227

Chapter 4 Instrument Description
Mini-Switch LB 471
36
Chapter 4. Instrument Description
4.1
Function
The limit switch system Mini Switch LB 471 is working on the basis
of non-contact Gamma absorption measurement. The system can
also be employed with heavy process conditions and aggressive
media.
In order to obtain an optimum measurement effect at minimum
source activity the best measurement geometry is calculated for
the respective measuring point and the source is designed on the
basis of this calculation.
The system comprises three major components:

shielding with radiation source


Detector


evaluation unit

.
The shielded radiation source

is installed outside the container
on the level to be measured. A detector

is installed on the op-
posite side of the container. The evaluation unit

is connected to
the detector by a 2-wire line.
If the level of the medium inside the container comes up to the
level of the detector or the source, the radiation is absorbed and
the evaluation unit sends a corresponding signal.
The following radiation sources are used:
Figure 5:
Measuring system



2 wires