Siemens SITRANS LG270 Operating Instructions Manual page 15

Type of vessel
Mounting socket
PBD-51041506
Plastic vessel/Glass vessel
The guided microwave principle requires a metallic surface on the
process fitting. Therefore, in plastic vessels, etc., use an instru-
ment version with flange (from DN 50) or place a metal sheet
(ø > 200 mm/8 in) beneath the process fitting when screwing it in.
Make sure that the plate has direct contact with the process fitting.
When mounting rod or cable probes in vessels without metal walls,
e.g. in plastic vessels, the measured value can be influenced by
strong electromagnetic fields (emitted interference according to
EN 61326: class A). In this case, use a probe with coaxial version.
Fig. 5: Mounting in non-metallic vessel
1 Flange
2 Metal sheet
If possible, avoid sockets. Mount the sensor flush with the vessel top.
If this is not possible, use short sockets with small diameter.
Higher sockets or sockets with a bigger diameter can generally be
used. They can, however, increase the upper dead zone. Check if this
is relevant for your measurement.
In such cases, always carry out a false signal suppression after
mounting. You can find further information under "Setup procedure".
SITRANS LG270 - Operating Instructions
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