Siemens SITRANS LR200 Instruction Manual page 17

WARNING: For vessels with conical or parabolic tops, avoid
mounting the instrument at the centre. (The concavity of the top can
focus echoes into the centre, giving false readings.)
Note:
Under certain circumstances, it may be acceptable to mount SITRANS LR 200 at
the centre of a flat-topped tank: please discuss this with your Siemens Milltronics
Representative.
preferred
undesirable
Keep the emission cone free of interference:
• Make allowance for the emission cone spreading: allow a minimum of 300 mm (1 ft)
for every 3 m (10 ft) of vessel height.
• Locate the antenna away from the side wall, to avoid interference from indirect
echoes.
• Avoid interference (from objects such as ladders or pipes, or from the fill path)
which can cause false reflections
Note:
• Beam angle defined at –3dB
boundary
horn antenna
beam angle:
o
30
4" horn
o
20
6" horn
o
12
8" horn
1.
For more detail on False Echo suppression, see
TVT (Auto False Echo Suppression) setup
7ML19985HP01 SITRANS LR 200 (PROFIBUS PA) – INSTRUCTION MANUAL
Coni
Conical Flat
1
.
Auto False-Echo Suppression
on page 100.
Fl at
Parabolic
minimum of 300 mm (1ft) for
every 3 m (10') of vessel height.
rod antenna
beam
angle
o
20
on page 35, and
Page 11