Emerson Process Management ROSEMOUNT 5300 - Manual (Page 252)

Reference Manual
00809-0100-4530, Rev BA
July 2009
Rosemount 5300 Series
C-4
HANDLING OF
DISTURBANCES FROM
NOZZLE
Trim Near Zone Using the Trim Near Zone Function
For transmitters using the Guided Wave Radar technology the performance In
the Near Zone (referred to as the region between 0-3.3 ft. (0-1 m) below the
Upper Reference Point) is normally somewhat limited. However, the
Rosemount 5300 transmitter is equipped with a software functionality that
minimizes the Upper Transition Zone. The factory setting is normally sufficient
and doesn’t need to be repeated after installation.
However, since the setting is optimized depending on actual installation,
further trimming may be necessary in the case of unfavorable conditions. An
example is if there are disturbing obstacles in the Near Zone. Trimming
means that the measurement performance in the Near Zone is maintained
even under these conditions and prevents false echo indication.
NOTE!
Make sure that the product level is below the Near Zone region
(0-3.3 ft. (0-1 m) below the Upper Reference Point) before performing the
Trim Near Zone.
Figure C-2. Echo Curve before
and after Trim Near Zone.
NOTE!
The Trim Near Zone function should only be used for reducing impact from
stationary disturbances. It is not suitable for occasional disturbances.
Trim Near Zone can be done in RRM. The function can be reached from
Device Specific Configuration in the Guided Setup (if the command is
recommended) or from the Advanced Configuration window, Trim Near
Zone tab.
Trim Near Zone