Honeywell SLG 700 User Manual page 101

Dynamic Background:
The feature provides enhanced immunity against measurement conditions by dynamically
adjusting the active Field or Obstacle background profile. (This feature is not available for the
Factory Background Type.) With Dynamic Background enabled, the sensor periodically schedules
automatic updates to the background echo profile. Echoes are only updated if the level is outside
of the transition zones (see section 7.8.3) and the signal is of good quality. Data is collected up to
approximately 30 cm from the level at the time, if this distance is within the requested background
echo length.
The most recently updated background is also stored in permanent memory and is applied after a
sensor reset if dynamic background is enabled. At all times the sensor maintains a copy of the
original user acquired (static) background echo and will revert to this if the dynamic background
feature is once again disabled. Re-enabling dynamic background at that point starts the process
anew. It is recommended that this feature is turned on in all installations where probe build-up or
large ambient temperature swings over 30°C are expected.

Background Capture: This group of controls provide the mechanism for obtaining new
background echoes for the Field and Obstacle background types described above. These
controls are only visible when no other parameters are being edited as the background
echoes are inherently dependent on the current mounting configuration. All edits must be
applied or discarded before a background capture may be started.

Background Type: This control allows the user to select the type of background profile
that should be collected as either Field or Obstacle. (The Factory background profile is
completely static and cannot be captured or dynamically updated.) This type parameter
does not have to be the same as the active Background Type parameter described above
which is located outside this group of controls. In fact, a Field or Obstacle background
profile must be collected first before it can be activated.

Background Length: This control allows the user to enter the desired length of
background profile to collect as measured from the Reference Plane. For the Field
background type the control will be automatically populated with a preset length based on
the current mounting configuration. The length cannot be increased beyond this preset
value and should only be lowered in extreme cases when it is not possible to bring the
surface of the product below this length. For the Obstacle background type the control will
also be automatically populated with this preset length but the value may be increased as
required to cover all obstacles, up to the measureable length of the probe.
Revision 5
SLG 700 Series HART Option User's Manual
Page 93