12
Getting Started
(continued)
Step Two
UNDERSTANDING FILL-HEIGHT
This is another critical setting for the LVU500 series. 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-Height, the sensor will read full (as long
as the level does not enter the dead band). The reference point for definition of Fill-Height 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-Height can be calculated by
subtracting the Dead Band from the Sensor Height.
Fill-Height
=
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-Height 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-Height 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-Height cannot be set to match
the straight side of the tank. Calculate Fill-Height
as follows:
Fill-Height = Sensor Height – Dead Band
Example #3 – Horizontal Tanks
Tank E
is a horizontal tank with a rounded top.
The highest value for Fill-Height can be calculated
by subtracting the Dead Band from the Sensor
Height.
Fill-Height
=
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-Height 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.
