Density Meter LB 444 SECTION 3. INSTALLATION
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3.4 Installation of Resistance Thermometer Pt 100
A temperature measurement must made to ensure that the measured tempera-
ture is fairly similar to the product temperature at the density measuring location.
The resistance thermometer must not obstruct the path of radiation.
If the resistance thermometer cannot be installed in the pipeline, it may also be
mounted on the outside of the pipeline.
This type of installation requires that the pipeline including the resistance ther-
mometer must be provided with a temperature insulation over a length of 1 - 2
m, ensuring that the surface temperature of the pipeline at the temperature
measuring point is practically equal to the product temperature. Nevertheless, it
may happen, particularly with plastic or coated pipelines, that very sudden tem-
perature changes in the product to be measured lead to measuring errors
caused time lag. Correction is possible by operating the system with a large time
constant.
Before connecting the resistance thermometer to the detector, a Pt 100 adjust-
ment has to be performed in the Service menu (see section 5 GETTING
STARTED) .
3.5 Installation of Evaluation Unit
When installing the evaluation unit, please remember:
a) According to the Ex protection criteria, the evaluation unit must only be used
outside
the Ex-area. An equi-potential bonding must be established between
detector and evaluation unit.
b) Please note the maximum cable lengths between evaluation unit and detec-
tor. See section 7 TECHNICAL DATA.
c) The evaluation unit should not be installed outdoors.
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