Siemens SITRANS LG250 Operating Instructions Manual page 19

PBD-51041053
3
A
2
Fig. 10: Mounting in a standpipe
1 Holes (for mixing)
2 Standpipe - vertically mounted - max. deviation 10 mm (0.4 in)
3 Ventilation opening
A Rod probe with spacer (steel)
B Cable probe with centering weight
h Measuring range
For standpipes, select the probe length such that the upper dead
zone of the probe is above the upper ventilation hole. This allows you
to measure the total level range of the medium in the standpipe. When
designing the standpipe, keep the upper dead zone of the probe in
mind and plan the length above the upper lateral filling opening ac-
cordingly.
Microwaves can penetrate many plastics. This is why plastic tubes are
problematic for measurement applications. If durability is no problem,
we recommend the use of uncoated metal standpipes.
When the SITRANS LG250 is used in standpipes, contact with the
tube wall must be avoided. We recommend for this purpose a cable
probe with centering weight.
Caution:
When mounting, make sure that the cable is straight over its entire
length. A kink in the cable can cause measurement errors and contact
with the tube.
With rod probes, a spacer is generally not required. However, if there
is a risk of the rod probe being pressed against the tube wall by in-
flowing medium, you should mount a spacer at the probe end to avoid
contact with the tube wall. In the case of cable probes, the cable can
be strained.
SITRANS LG250 - Operating Instructions
ø 30 ... 200 mm
(1.18 ... 7.87")
1
ø 30 ... 200 mm
(1.18 ... 7.87")
B
19