17
Configuration
(continued)
Step Three
STEP 2 - MEASURE THE TANK
Measuring the tank is one of the most important aspects in
configuring the sensor. When measuring the tank, take
into account the location of the sensor with respect to
fittings, risers, dome tops and bottoms, and identify where
the measurements are taken from the sensor. The Sensor
Height is influenced by the installation location. Sensors
mounted along the sloped portion of the tank will result in a
lower (
HEIGHT
) value. On the other hand, sensors
installed in risers/nozzles will result in a higher (
HEIGHT
)
value.
The basic measurements (
Height
and
Fill-H
) for configuration are described below:
1.
HEIGHT
(Sensor Height) - Distance from the Bottom of
Sensor (sensor’s measurement location) to the bottom of
the tank.
a. The Sensor Height is typically set to the bottom of
the tank.
b. This setting determines the 4mA location.
2.
FILL-H
(Fill-Height) - Distance from the bottom of the
tank to the level of liquid where the tank is full is
FILL-H
.
a. The
FILL-H
is typically set to the liquid full level.
b. This setting determines the 20 mA location.
c. 20mA cannot be set within the sensor’s dead
band [8” (20cm) from bottom of sensor]. Largest
FILL-H
value will be as follows:
Largest
FILL-H
=
HEIGHT
– 8” (20cm)
3.
Relay Set Points –
Distance from the bottom of the tank
to the level of liquid where each relay activates.
a. Pumps/Valves have two set points, one for ON
and the other for OFF.
b. Alarms have one set point which can be used as
a high alarm (energized with level above set
point) or a low alarm (energized with level below
set point).
c. Independent Relays each have two set points,
one for ON and the other for OFF.
