Honeywell SLG 700 User Manual page 113

Table 22
For each possible medium in the tank there is also a reference point from which the linear
attenuation should be applied. For the Surface and End of Probe reflections this reference point is
the transmitter's Reference Plane. For the Interface reflection this reference point is the location of
the Surface reflection in non-flooded applications and the location of the transmitter's Reference
Plane for flooded applications. The Reflection Model panel has entry fields where the locations
of these reference points can be entered. In many cases, these locations will have been
determined by the transmitter and these entry fields will be pre-populated with the correct values
from the echo curve data.
Dielectric Constants
Under the DCs tab, the user may enter the dielectric constants for the Vapor, Upper Product, and
Lower Product (if applicable). The user can experiment with changing the DCs to see the effect on
the derived gains that are automatically re-calculated. Note that changing the DC values on this
display does not actually send the new values to the transmitter. Once the desired values are
determined, the DC values must be written to the transmitter.
Senor Offsets
There are three offsets used by the algorithm in calculating the distance to surface measurement.
The Process Connector Offset (m) is only used for cases where the optional Remote Mount
cable is installed, as it indicates the observed distance between the Reference and Process
Connector reflections. It is a calculated offset and is therefore a read-only parameter. If the
Remote Mount cable is not installed, this offset will default to zero.
The Reference Plane Offset (m) is a read-only parameter that is determined in the factory for each
transmitter. It corresponds to the distance between the physical reference plane and the internal
datum point, which is the location of either the Reference reflection or the Process Connector
reflection, depending on whether or not the optional remote mount cable has been ordered.
The Calibration Offset (m) is a user-entered offset that may be used to adjust for minor
inaccuracies in the distance measurements caused by differences between the factory and field
conditions. It has a range of ±1.0m and is always treated as a vertical measurement, even if the
probe is mounted on an angle.
Under normal circumstances, the only parameter that may require adjustment in the field is the
Gain parameter under the Model tab.
SLG 700 Series HART Option User's Manual
Revision 5 Page 105