5.18.3 Tank Thresholds
1. As the Density Sensor is installed between the water and
Product Float, the Product Float will not be able to go
further down than the Density Sensor. In order to provide
low-product alarms, the Low and Low-Low product
threshold level should be set above the Density Sensor.
The suggested level is 17 inches (43.2 cm) or higher.
2. Measure the distance between the end of the probe shaft
and top end of the Density Sensor. To this distance, add 2
inches (5.1 cm) to account for the dead zone at the end of
the probe. The resulting value represents the minimum
product Low-Low threshold (see Figure 5-23).
Figure 5-23 Low-Low Threshold
5.18.4 DMS Preliminary Calibration
1. Use a Hydrometer or other density device to measure the
fuel density and temperature. Consult the density-
temperature table to convert measured density into a
value at the reference temperature/temperature corrected
density (59ºF or 68ºF; 15°C or 20° C).
2. Consult the density-temperature table and convert the
temperature-corrected density to the density at the same
temperature as the SiteSentinel® iSite™ controller reads
in the density verification page. The reason for this step is
that the temperature readings from the Hydrometer and
Controller may be different.
3. Click “Verify Density Device Values,” take the difference of
the density results from steps 19 and 20 (Density from
step 19 minus the density from step 20).
4. Go to Tank Setup window (in-tank probe), add the
resulting value from step 3 back to the Factor B and then
click “Apply.” DO NOT JUST ENTER THE RESULT
ALONE. The controller will calculate the new density
readings.
The current density readings from the console will be displayed here
in real time. In the first-time installation, the initial density reading
can be adjusted by changing the B factors ONLY and matching the
density readings between the SiteSentinel® iSite™ and reference
density device. By changing the B factors, the density readings will
be adjusted accordingly. A reference density device with accuracy of
+/- 0.005 kg/m
3
is required for initial calibration.
For a dedicated Density Probe, readings will be displayed from all
three (3) DMS. The calibration process will be the same as above,
just repeated three times.
5.18.5 DMS Final Calibration and Maintenance
Nitrophyl®, the float material, changes change weight and volume
over time when immersed in fuel. As such, it is necessary to calibrate
the Density Sensors again two to three weeks after initial calibration.
1. Repeat the preliminary calibration process.
2. After re-calibrating the Factor B, the Density Sensor is
ready to use.
For daily operations, it is necessary to wait
at least two (2) hour
s
after delivery for valid density readings.
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