Varec 7532, Installation And Operation Manual

Page: 14 / 106

Mounting Radar Tank Gauge
14 Installation and Operations Manual
3.3.2 Engineering tips
Measuring conditions
• The measuring range starts at the bottom end of the stilling well.
• In case of media with a low dielectric constant (groups A and B), the pipe end can be
visible through the medium at low levels. In order to guarantee the required accuracy
in these cases, it is recommended to position the zero-point at a distance
C
above the
tank bottom (see Fig.).
• In applications with
planar
or
parabolic
antennas, especially for media with low
dielectric constants (see page 15), the end of the measuring range should not be closer
than 1 m (40”) to the flange.
• For
overspill protection
, it is possible to define a safety distance
(SD)
additionally to
the blocking distance
(BD)
.
• This safety distance
(SD)
is set to 0.5 m (20") by default and generating an alarm in
case the level rises inside the safety distance.
• Distance
B
defined the smallest recommended measurement range.
• Depending on its consistence, foam can either absorb microwaves or reflect them off
the foam surface. Measurement is possible under certain conditions.
Behaviour if measuring range is exceeded
The behaviour in case of the measuring range being exceeded can be freely set: the
default setting is a current of 22 mA and the generation of a digital warning (E681).
reference: flange / BD
(see picture)
reference: antenna tip
(see picture)
recommended additional settings
Blocking
distance
Safety
distance
BD [m / ft] SD [m / ft] A [mm / inch] B [m / ft] C [mm / inch]
7532 RTG (planar) 1 / 3.28 0.5 / 1.6 1000 / 40 0.5 / 1.64
150…300 /
6…12
L0
0-FM
R5
3xxx-17
-00
-0
0-en-00
8
BD
SD
A
100%
0%
B
C
max. level