Rosemount 2240S, Reference Manual

Page: 51 / 100

Reference Manual
300550EN, Rev AA
December 2010
5-9
Rosemount 2240S
Section 5. Configuration/Operation
Configuration
To convert from the reference system of the water level sensor (WLS) to the
reference system of the tank, the distance
X needs to be calculated by using
the following formula:
X = (R-L1) - (L-L2) .
X =distance between the Tank Zero Level and the Water Zero Level.
L =distance between Water Zero Level and mark on the upper part of the
WLS.
R = Tank Reference Height. This is the distance between the Tank Reference
Point and the Tank Zero Level.
L1 =distance between the Tank Reference Point and the temperature sensor
flange.
L2 =distance between the mark on the top of the WLS and the temperature
sensor flange.
The conversion from the WLS reference system to the tank reference system
is handled by the Rosemount 2240S. In the tank reference system, the Lower
Sensor Limit (0%) and the Upper Sensor Limit (100%) are given by the
following formulas:
Upper Sensor Limit (100%) = L
A
+ X
Lower Sensor Limit (0%) = X
where L
A
is the active length of the Water Level Sensor, and X is the distance
between the Water Zero Level and the Tank Zero Level (Minimum Water
Distance), see examples in Table 5-2 on page 5-10.
Upper and lower Measurement Limit
The Upper Measurement Limit and the Lower Measurement Limit are
obtained using the following formulas:
Upper Measurement Limit (100%) = (L
A
+ X) - UDZ
Lower Measurement Limit (0%) = X + LDZ,
where UDZ is the Upper Dead Zone and LDZ is the Lower Dead Zone.