Emerson Rosemount 5900S Series Reference Manual page 92

Rosemount 5900S Series
Figure 4-3. Definition of Gauge
Reference Distance
4-8
Tank Reference Height (R)
The Tank Reference Height (R) is the distance from the hand dipping nozzle
(Tank Reference Point) to the Zero Level (Dipping Datum Plate) close to, or at
the bottom of the tank. For the Array Antenna with hinged hatch the reference
point is located at the hand dip plate as illustrated in Figure 4-2 on page 4-7.
Gauge Reference Distance (G)
The Gauge Reference Distance (G) is measured from the Gauge Reference
Point to the Tank Reference Point, which is located at the top surface of the
customer's flange or manhole cover on which the level gauge is mounted as
illustrated in Figure 4-1 and Figure 4-3.
For the hinged hatch version of the 5900S with Array Antenna, the Tank
Reference Point and the Gauge Reference Point are located at the same
position i.e. at the hand-dip plate on the Still Pipe Gauge Stand as illustrated
in Figure 4-2 on page 4-7.
Set G=0 for the 5900S with Array Antenna hinged hatch version when using
the hand dip plate as the Tank Reference Point (see Figure 4-2).
G is positive if the Tank Reference Point is located above the Gauge
Reference Point. Otherwise G is negative.
Tank Reference Point
G>0
Minimum Level Offset (C)
The Minimum Level Distance (C) is defined as the distance between the Zero
Level (Dipping Datum Point) and the Minimum Level of the product surface
(tank bottom). By specifying a C-distance, the measuring range can be
extended to the bottom of the tank.
If C>0, negative level values will be displayed when the product surface is
below the Zero Level. Select the Show negative level values as zero check
box in TankMaster WinSetup if you want levels below the Zero Level to be
displayed as Level=0.
Measurements below the Zero Level will not be approved if the C-distance=0,
i.e. the 5900S will report an invalid level.
Hold Off Distance
The Hold Off distance defines how close to the Gauge Reference Point a level
value is accepted. Normally the Hold Off distance does not need to be
changed. However, if there are disturbing echoes in the upper part of the tank,
for example from the tank nozzle, you can increase the Hold Off distance in
order to avoid measurements in the region close to the antenna.
Reference Manual
00809-0100-5900, Rev CA
Gauge Reference Point
G<0
Section 4. Configuration
June 2014