Mounting; General Instructions; Mounting Instructions; Mounting 4.1 General Instructions - Siemens SITRANS LG250 Operating Instructions Manual

Screwing in
Moisture
Cable entries - NPT
thread
Suitability for the process
conditions
Installation position
PBD-51041388
4

Mounting

4.1

General instructions

With instruments with threaded process fitting, suitable tools must be
applied for tightening the hexagon.
Warning:
The housing must not be used to screw the instrument in! Applying
tightening force can damage internal parts of the housing.
Use the recommended cables (see chapter "Connecting to power
supply") and tighten the cable gland.
You can give your instrument additional protection against moisture
penetration by leading the connection cable downward in front of the
cable entry. Rain and condensation water can thus drain off. This ap-
plies mainly to outdoor mounting as well as installation in areas where
high humidity is expected (e.g. through cleaning processes) or on
cooled or heated vessels.
In the case of instrument housings with self-sealing NPT threads, it is
not possible to have the cable entries screwed in at the factory. The
openings for the cable glands are therefore covered with red protec-
tive caps as transport protection.
Prior to setup you have to replace these protective caps with ap-
proved cable glands or close the openings with suitable blind plugs.
The suitable cable glands and blind plugs come with the instrument.
Make sure that all parts of the instrument exposed to the process, in
particular the active measuring component, process seal and process
fitting, are suitable for the existing process conditions. These include
above all the process pressure, process temperature as well as the
chemical properties of the medium.
You can find the specifications in chapter "Technical data" resp. on the
nameplate.
4.2

Mounting instructions

Mount SITRANS LG250 in such a way that the distance to vessel
installations or to the vessel wall is at least 300 mm (12 in). In non-
metallic vessels, the distance to the vessel wall should be at least
500 mm (19.7 in).
During operation, the probe must not touch any installations or the
vessel wall. If necessary, fasten the probe end.
In vessels with conical bottom it can be advantageous to mount the
sensor in the center of the vessel, as measurement is then possible
nearly down to the lowest point of the bottom. Keep in mind that
measurement all the way down to the tip of the probe may not be pos-
sible. The exact value of the min. distance (lower dead band) is stated
in chapter "Technical data".
SITRANS LG250 - Operating Instructions
13