13
Getting Started
(continued)
Step Two
UNDERSTANDING FILL-HEIGHT (FILL-H)
This is another critical setting for LVU700 series.
FILL-H
(Fill-Height) defines the location of the highest point in
the tank where the sensor will read level changes. When the level rises above
FILL-H
, the sensor will read full
(as long as the level does not enter the dead band). The reference point for definition of
FILL-H
is always from
the bottom location of the Sensor Height. The value must take into account the sensors dead band, any risers,
fittings, structures or extensions associated with the tank or the installation as well as the tanks geometry.
Example #1 – Flat Top Tanks
Tank A
is a vertical tank with a flat top. The highest
value for
FILL-H
can be calculated by subtracting
the
Dead Band
from the
Sensor Height
.
FILL-H
=
Sensor
Height
–
Dead
Band
Tank B
is another vertical tank with a riser that
matches the dead band of the sensor. In this case,
the
FILL-H
will be set to the top of the tank.
Note:
The ratio of height to diameter of the riser
must be no greater than 2:1. Any higher and the
sensor will target the inside wall of the riser.
Example #2 – Dome Top Tanks
Tank C
has a tall enough dome whereas the Dead
Band is above the straight side of the tank. The
FILL-H
can be set to the top of the straight side
(this is advantageous because the top of the
straight side is typically a known volume of liquid).
The sensor is moved to a flat part of
Tank D
. As a
result, the
Dead Band
is now below the straight
side of the tank.
FILL-H
cannot be set to match the
straight side of the tank. Calculate
FILL-H
as
follows:
FILL-H
=
Sensor
Height
–
Dead
Band
Example #3 – Horizontal Tanks
Tank E
is a horizontal tank with a rounded top.
The highest value for
FILL-H
can be calculated by
subtracting the
Dead Band
from the
Sensor
Height
.
FILL-H
=
Sensor
Height
–
Dead
Band
Tank F
is another horizontal tank with a riser that
matches the dead band of the sensor. In this case,
the
FILL-H
will be set to the top of the tank.
Note:
The ratio of height to diameter of the riser
must be no greater than 2:1. Any higher and the
sensor will target the inside wall of the riser.
